No preview available
HomeMy WebLinkAboutDrainage Reports - 02/16/2016App`roved By PProPed Plans y Final Drainage and Erosion Control Report ' HPE Building 5 Parking Lot Expansion 1 ® Stantec Prepared for: ' Rees Prepared by: Stantec 1 1 ' February 16, 2016 [1 1 Sign -off Sheet This document entitled Final Drainage and Erosion Control Report was prepared by Stantec Consulting Ltd. ("Stantec") for the account of Rees (the "Client"). Any reliance on this document by any third party is strictly prohibited. The material in it reflects Stantec's professional judgment in light of the scope, schedule and other limitations stated in the document and in the contract between Stantec and the Client. The opinions in the document are based on conditions and information existing at the time the document was published and do not take into account any subsequent changes. In preparing the document, Stantec did not verify information supplied to it by others. Any use which a third party makes of this document is the responsibility of such third party. Such third party agrees that Stantec shall not be responsible for costs..or damages of any kind, if any, suffered by it or any other third party as a result of decisions made or _.- ior?s`ta en$based on this document. Prepared by (signature) r�o 3 Mark Oberschmidt, P.E. 35721 iclt,6 ® Stantec FINAL DRAINAGE AND EROSION CONTROL REPORT ' Table of Contents ' EXECUTIVE SUMMARY............................................................................................................... ABBREVIATIONS........................................................................................................................ II ' 1.0 CHAPTER 1 -GENERAL LOCATION AND DESCRIPTION.............................................1.1 1.1 LOCATION.......................................................................................................................1.1 1.2 PROJECT DESCRIPTION.................................................................................................. 1.1 ' 1.3 FLOODPLAIN...................................................................................................................1.1 2.0 CHAPTER 2 - DRAINAGE DESIGN CRITERIA................................................................2.2 ' 2.1 DEVELOPMENT CRITERIA AND CONSTRAINTS.............................................................2.2 2.2 LOW IMPACT DEVELOPMENT........................................................................................2.3 2.3 HYDROLOGICAL CRITERIA............................................................................................2.3 ' 2.4 MODIFICATIONS TO CRITERIA.......................................................................................2.5 3.0 DRAINAGE FACILITY DESIGN......................................................................................3.6 3.1 GENERAL CONCEPT......................................................................................................3.6 3.2 SPECIFIC DETAILS............................................................................................................3.7 3.2.1 Pond A.......................................................................................................... 3.7 3.2.2 Swale.............................................................................................................3.7 ' 3.2.3 Riprap............................................................................................................3.8 3.2.4 Storm Sewer.................................................................................................. 3.8 3.2.5 Low Impact Development......................................................................... 3.9 4.0 EROSION CONTROL..................................................................................................4.11 4.1 LOCATION AND EXISTING & DEVELOPED CONDITIONS..........................................4.1 1 ' 4.2 STORMWATER MANAGEMENT AND BMP'S...............................................................4.13 4.2.1 Temporary Erosion Control/BMP's........................................................... 4.13 4.2.2 Permanent Erosion Control......................................................................4.14 ' 4.2.3 Material Handling and Spill Prevention Control .................................... 4.14 4.2.4 Project close out........................................................................................ 4.16 5.0 CONCLUSIONS..........................................................................................................5.17 ' 5.1 COMPLIANCE WITH STANDARDS...............................................................................5.17 6.0 REFERENCES.................................................................................................................6.1 LIST OF FIGURES ' Figure 1: Existing overflow parking looking SE........................................................................1.2 Figure 2: Looking SE into existing detention pond from service road................................2.3 ' Figure 3: Existing Vegetation August 2015............................................................................4.12 Figure 4: Existing Vegetation August 205..............................................................................4.12 ® Stantec 1 1 FINAL DRAINAGE AND EROSION CONTROL REPORT LIST OF APPENDICES APPENDIX A - RATIONAL CALCULATIONS....................................................................A.1 APPENDIX B - DETENTION CALCULATIONS................................................................... B.2 APPENDIX C - SWALE/INLETS AND PIPE CALCULATIONS..............................................C.3 APPENDIX D - EXCERPTS FROM PREVIOUS DRAINAGE REPORTS ................................. DA APPENDIX E - EROSION CONTROL ESCROW.................................................................E.5 APPENDIX F - FLOODPLAIN MAP...................................................................................F.6 APPENDIXG - USGS SOILS REPORT................................................................................G.7 APPENDIX H - DRAINAGE EXHIBITS...............................................................................H.8 ® Stantec u 1 P FINAL DRAINAGE AND EROSION CONTROL REPORT Executive Summary This report documents the historic and developed hydrologic conditions for the parking lot expansion associated with tenant improvements to Building 5 on the Hewlett Packard Enterprise (HPE) Campus located @ 3420 E Harmony Road in Fort Collins, Colorado. The site is located in south half of Section 33, Township 7 North, Range 68 West of the 6th Principal Meridian in Larimer County. More specifically, site is located at the Northeast corner of East Harmony Road and Ziegler Road. The parking lot expansion is located on the northeast side of the campus and will increase the campus parking capacity by five hundred and nineteen (519) spaces to accommodate expected employees in Building 5. There are two new parking areas provided with the first one being an extension of the existing overflow parking on the north side of the loop road that runs around the campus (Parking Area A). This parking area was already planned for in earlier designs for the campus and is graded consistent with those earlier designs so that the runoff from Parking Area A will be conveyed to the existing detention pond located in the southeast portion of the campus via the existing 4'x10' box culvert that runs under the parking lot. The earlier plans prepared by Sear Brown showed three (3) phases of parking to be constructed. To date only phases 1 and 2 have been constructed. A copy of the earlier proposed parking lot expansion showing three (3) phases of parking is provided for convenience in Appendix D. The second parking area (Parking Area B) is located north and down the hill from Parking Area A and will not drain to the existing detention pond due to topographic limitations. Runoff from Parking Area B will be conveyed to the existing water bridge over the Fossil Creek Reservoir Inlet; Ditch (FCRID) via a pipe. A detention pond is designed to limit the amount of water entering to historic release in accordance with the City of Fort Collins Stormwater requirements. Additional' water quality measures are included through the site including paver blocks in parking stalls; grassed bio swales and landscaped islands. ® Stantec 1 FINAL DRAINAGE AND EROSION CONTROL REPORT Abbreviations FCRID Fossil Creek Reservoir Inlet Ditch UDFCD Urban Drainage and Flood Control District BMP Best Management Practices LID Low Impact Development 5 Stantec I FINAL DRAINAGE AND EROSION CONTROL REPORT iChapter 1 - General Location and Description February lb, 2016 1.0 CHAPTER 1 - GENERAL LOCATION AND DESCRIPTION ' 1.1 LOCATION ' The project is located on the HPE campus at the Southeastern end of Fort Collins in the south half of Section 33, Township 7 North, Range 68 West. More specifically, the campus is located at the northeast comer of Harmony and Ziegler Roads. The site is bounded by the Avago ' property on the west, Hidden Pond Subdivision on the north, FCRID on the north and east and Harmony Road on the south. The HPE campus is legally defined as Lot 1 of the Preston Kelley 2nd Subdivision. ' 1.2 PROJECT DESCRIPTION The parking expansion will take place along the north side of the loop road that connects the ' HPE Campus with the Avago Campus to the west. The loop road also provides access to East Harmony and Ziegler roads. Two parking areas will be developed with this project. t The first area extends the existing overflow parking area on the north side of the loop road to the east and will be accessed via an existing access drive off the loop road and a new drive at the eastern end of the parking area off the existing service rood. A total of 192 spaces are ' provided for in this parking area (Area A). Area A was originally shown on plans prepared by Sear Brown dated 8-26-2000 when Building 5 was originally constructed. This area was designated Phase 3 of the parking lot for Building 5. Phases 1 and 2 were presumably ' constructed with Building 5. The area is now covered with gravel, recycled asphalt and some vegetation and currently used as a staging area for the grounds maintenance crews. A copy of this plan is attached for convenience in Appendix D. ' The second area (Area B) is located north down the slope from the Area A. A single point of access is provided to the lower parking area with the parking extending southeast and northwest from this access. The northwestern limit of the parking area is approximately 50 feet ' from the existing fence /property line. An additional thirty (30) foot tract separates the HPE property line from the Hidden Pond fence line to the northwest. 1.3 FLOODPLAIN ' No portion of the site is in a FEMA or City designated floodplain per FEMA map number 08069CO994F dated 12-19-2006. See FEMA map in Appendix F. 1 ® Stantec ' meov:\2053\active\205305056\rep d\rpl hp Wliding5 droinage.doc 1.1 J I FINAL DRAINAGE AND EROSION CONTROL REPORT Chapter 2 - Drainage Design Criteria February 16, 2016 Figure 1: Existing overflow parking looking SE 2.0 CHAPIFR 2 - DRAINAGE DESYGN CRI'iLRIA 2.1 DEVELOPMENT CRITERIA AND CONSTRAINTS The site is constrained to the north, east, south and west where we must match existing grades either at the property/fence line to the north and east or the existing parking /roadway to the south and east. Historically the undeveloped portion of the site drains north and east into FCRID. The existing parking lot along the north side of the loop road now drains to an existing detention pond at the southeast corner of the HPE campus via a W 0 box culvert that was installed with the original parking lot expansion circa 2000. A larger parking lot consisting of three (3) phases was proposed with the Building 5 construction over the top of the 4x10 box culvert (RCBC). The box culvert replaced an open channel that was approved and constructed circa 1996 followed by modifications circa 2000 using plans prepared by Sear Brown. The existing parking lot was developed as Phases 1 and 2 of parking proposed with the original construction of Building 5 as shown on the drainage exhibit prepared by Sear Brown in August, 2000. Phase 3 of the parking lot expansion was not constructed with the earlier phases but was 2.2 ® Stantec m v.\2=\ac1"\205005056\repprt\rPt_hp WWh0 5_drdR age. 0 i 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 I I 1 1 1 FINAL DRAINAGE AND EROSION CONTROL REPORT Chapter 2 - Drainage .Design Criteria February 16, 2016 overlot graded and is currently used for maintenance storage purposes (see Figure 1). The proposed parking lot extension follows the grading concept shown for the 3,d phase of the parking expansion on the Sear Brown plans directing stormwater flows to the existing box culvert and eventually to the existing detention pond mentioned above. The major difference between this proposed parking lot and the one from 2000 is that a portion of the parking lot will be paved with pervious paving blocks to reduce the overall imperviousness of the project. Figure 2: Looking SE into existing detention pond from service road 2.2 LOW IMPACT DEVELOPMENT The site is designed with low impact development features intended to reduce the runoff from the site and improve the water quality leaving the site. These features included paver blocks in the parking lot, grassed swales to convey concentrated flows and the detention pond. Calculations showing the low impact development areas are provided on the drainage exhibits and in Appendix A. 2.3 HYDROLOGICAL CRITERIA The site is located in the Fox Meadows Drainage Basin (2.4 sq. miles) (Fox Meadows). A master plan was prepared for Fox Meadows in 1981 and again in 1990 with the master drainage plan ® Stantec me v,.\2D53\active\205305056\mpW\pl hp bullding 5 drctnage.d0M 2.3 FINAL DRAINAGE AND EROSION CONTROL REPORT Chapter 2 - Drainage Design Criteria ' February 16,2016 for the Hewlett Packard site. No deviations from the assumptions made in the master drainage ' plan are made with this report. The existing site is divided into two basins for the purposes of detention design even though ' historically both basins contribute flow to the FCRID. Flows from the northwesterly basin (Hl ) contribute flows to FCRID at the northwest corner of the site. The majority of basin HI will not be affected by the development of either parking lot. Basin H 1 includes portions of the new ' parking lot that will not contribute to the lower detention pond (see developed basin discussion that follows). The remainder of the undeveloped site (H2) contributes flow via sheet flow primarily to FCRID along the length of the ditch. ' The design of all stormwater infrastructure is based on the current Fort Collins rainfall curves. The Rational Method was used to determine peak flows from the historic and developed site ' for the 2 and 100-year storm events. Inlets were designed to intercept the 2 and 100 year events in sump conditions. Detention releases for the lower pond are designed to detain the 100-year developed flows to , the lower pond (Pond A) from Basin D2 and restrict them to the combined 2-year historic rates from Basins H1 and H2. It must be noted that portions of the lower developed basin (Basins D1 and D3) do not contribute to the pond and will not be changed substantially as they are , outside of the parking lot limits. All the developed flows from Basin D2 will be detained in the lower pond. The developed contributing area to the lower pond from Basin D2 is 6.04 acres in contrast to the combined basin area of Basins H 1 and H2 of 10.26 acres. The developed flows , from the upper parking lot (Basins D4 and D5) will be detained in the existing pond to the southeast. , The developed site is divided into five (5) main sub -basins designated D1-D5. Basin D1 is at the northwesterly end of the property, contributes stormwater runoff to t the FCRID and the imperviousness of this basin will not change with the development. Basin D2 consists of the lower parking area and is further divided into four minor basins ' (D2a, D2b D2c and D2pond). Basin D2 will contribute stormwater flows to the lower detention pond and these flows will be restricted to the combined 2-year historic rate from Basins H1 & H2. ' These east and west basins in the lower parking lot (D2a and b) will contribute stormwater to a pair of inlets located at the northern edges of the parking lots. The ' flows will then be piped into the detention pond from these inlets. Minor basin D2c defines the limits of contributing area for the swale along the ' north side of the lower parking lot. The overall contributing area to this swale includes minor basins D2c and D2a. Minor basin D21b is not included as it enters the very downstream end of the swale before it enters the detention pond. Stantec 2.4 meo v:\20.53\wtlW \2D5305056\report\rpt--hp building 5 dralnage.doa , 1 I I 1 I L 1 1 1 1 FINAL DRAINAGE AND EROSION CONTROL REPORT Chapter 2 - Drainage Design Criteria February 16, 2016 Minor basin D2pond is the basin within the limits of the pond itself and is only defined to be able to sum up the basins to obtain the overall area of Basin D2 Basin D3 consists of the eastern portion of the project area below the existing parking lot that contributes stormwater runoff to FCRID and the imperviousness of this basin will not change with the development. Basin D4 is the northern portion of the upper parking lot and contributes flow to a proposed inlet on the north side of the parking lot. A pipe from that inlet conveys flows to the existing box culvert and eventually to the existing detention pond. Portions of this parking lot will be paved with paver stones thus reducing the overall imperviousness of the parking lot in comparison to a completely paved parking lot. Basin D4 corresponds to Basin Al in the 2000 report. Basin D4 has a 100-yr composite C factor of 0.60 in contrast to Basin At0, which has a 100-year C factor of 0.92. No additional detention pond work is required for these flows as they were considered in the original design back in 2000. Basin D5 is the southern portion of the upper parking lot and contributes flow to a proposed inlet on the north side of the parking lot. A pipe from that inlet conveys flows to the existing box culvert and eventually to the existing detention pond. Portions of this parking lot will be paved with paver stones thus reducing the overall imperviousness of the parking lot in comparison to the completely paved parking lot. Basin D5 corresponds to Basin A9 in the 2000 report. Basin D4 has a 100-yr composite C factor of 0.60 in contrast to Basin A9, which has a 10D-year C factor of 0.92. No additional detention pond work is required for these flows as they were considered in the original design back in 2000. Upper Basin(s) Comparison 2000 Basin Designation 2000 C100 2015 Basin Designation 2015 C100 A 10 0.92 D4 0.60 A9 0.92 D5 0.60 2.4 MODIFICATIONS TO CRITERIA No modifications to the City criteria were made with the stormwater management design for this project. ® Stantec me v:\2053\pcllve\205305056\repod\mt-hp building. 5_@p1npge.C1= PAN I FINAL DRAINAGE AND EROSION CONTROL REPORT Drainage Facility Design i February 16, 2016 3.0 DRAINAGE FACILITY DESIGN ' 3.1 GENERAL CONCEPT , Stormwater is conveyed to their eventual outfall via a combination of sheet, gutter, Swale or flow. flow from developed areas of the site is detained in a detention pond. ' piped All Two (2) detention ponds will restrict Stormwater releases from the site to historic levels. The existing pond located in the southeastern comer of the campus was designed and ' constructed with the original campus improvements and modified with the construction of Building 5. The upper parking lot (existing and proposed sections) will contribute flows to this existing pond by intercepting the flows in curb inlets and conveying these flows to an existing ' box culvert that sends the flow to the pond. The proposed parking lot is designed with two inlets located on the north and south sides of the parking lot (Basins D4 and D5) that will intercept flows from the parking lot and convey them into the existing RCBC that crosses the , parking lot. The pond was sized to handle the flows from the entire upper parking lot. This was noted in the HPE Building 5 Addendum # 1 Drainage Report prepared by Sear Brown in 2000. Refer to discussions in the hydrological section of this report. The lower pond is sized to restrict the flow to the 2-year historic peak flows from the overall undeveloped site. It must be noted that the development of the parking lots does not impact ' the limits of the entire historic basins) that historically contributed flow to the FCRID. The upper parking lot is graded to convey flows to the existing RCBC that conveys flows southeast to the existing detention pond located in the southeast comer of the property. This follows the ' approved grading and drainage plan prepared for this site circa 2000 by Sear Brown. The upper parking lot is essentially Phase 3 of the parking lot proposed on the drainage exhibit dated B-25-2000 prepared by Sear Brown. The grading intent is the same but the ' imperviousness is significantly reduced by the use of the pervious pavers in place of asphalt in sections of the parking lot. The area of the lower parking lot that contributes to the proposed lower pond (Basin D2) is 6.04 ' acres in contrast to the overall historic area of 10.26 acres (Basins H 1 and H2). The imperviousness of the northwestern and southeastern portions of the historic basins (Dl & D3) are not changed with this development. Along with this, flows from these areas do not and will ' not contribute flows to the lower detention pond location. Therefore, these basins (D1 and D3) are not included in the detention pond sizing. This along with the use of pervious pavers in the parking stalls significantly reduced the detention requirement by reducing the change in ' imperviousness from historic to developed conditions, i.e. a fully paved parking lot would require a lot more detention volume. ' 5 Stantec 3.6 moo v:\2053\ocllve\205305056\mport\rpl_hp Wilding 5_tlralnage.tlocx ' FINAL DRAINAGE AND EROSION CONTROL REPORT Drainage Facility Design February 16, 2016 3.2 SPECIFIC DETAILS Pond A, the lower pond, provides the following o QIDOtopond = 17.73cfs o Qrelease from pond = 0.71 cfs (historic 2-year flow) o Volume required = 34,610 cf (0.79 AF) o Volume provided = 78,802 cf (1.81 AF) o Required 1 00-yr WSEL = 4888.69 feet o Top of Pond Elev = 4890.00 feet o Freeboard (Stage Storage) = 1.31 feet o Freeboard (Outlet Hydraulics)= 1.29 feet Refer to the Detention calculations in Appendix B for additional details The swale along the north side of the lower parking lot is designed to convey flows and provide water quality measures from the western half of the lower parking lot to the lower detention pond. Flows were calculated to a point where the swale enters the pond (DP 2C). The swale has an irregular section and thus the hydraulics for the swale were analyzed using Flowmaster ® software. The section is defined by a vertical wall on the downhill side with 2% cross slopes to a 3-ft valley pan in the center of the swale that has a longitudinal slope of 0.005 ft./ft. On the parking lot side of the swale the cross slope transitions to a 4:1 slope 10-ft uphill from the pan. Refer to Appendix C for additional detail. o Q100 to Swale = 10.53 cfs o Qdesign = 14.00(1.33'Q100) o Flow Depth = 0.46 - 0.52 feet (Q 100 - Qdesign) o Froude # = 0.49-0.51 o Channel depth = 1.0 feet 5 Stantec mB v:\2053\ocllve\205305056\report\rpt_hp bulldIn95 dralna0e.dou 3.7 FINAL DRAINAGE AND EROSION CONTROL REPORT Drainage Facility Design February 16, 2016 Riprap is provided in two (2) separate locations to prevent erosion of the soils due to concentrated flows or high velocities. Riprap is provided at the outfall from Storm Sewer X down to the pan in the detention pond. o D50 = 12 inches o Area = 3 square yards o Thickness = 18 inches Riprap is provided at the outfall from Storm Sewer Y down to the pan in the detention pond. o D50 = 12 inches o Area = 3 square yards o Thickness = 18 inches Five (5) storm sewers are provided with this project, two (2) in upper parking lot, two (2) in the lower parking lot and the detention pond outlet to the water bridge over FCRID located at the southeastern corner of the property. The storm inlet on the north side of the upper parking lot (DP D4) is a 5-ft Type R Inlet. Design details are summarized below. Refer to the spreadsheets in Appendix C for detailed calculations. o Q100 = 4.76cfs o Qintercept = 6.00 cfs o Allowable flow depth = 0.50 N. (top of curb) The storm inlet on the south side of the upper parking lot (DP D5) is a 5-ft Type R inlet. Design details are summarized below. Refer to the spreadsheets in Appendix C for detailed calculations. o Q100 = 1.99 cfs o Qintercept = 6.00 cfs o Allowable flow depth = 0.50 ft. (top of curb) 3.8 Stantec me v:\2053\active\205305056\mWO\V t hp bollding 5 tlralnage.dacx 1 FINAL DRAINAGE AND EROSION CONTROL REPORT Drainage Facility Design February 76, 2016 The storm inlet in the northeast corner of the eastern portion of the lower parking lot (DP D2b) is a 5-ft Type R Inlet. Design details are summarized below. Refer to the spreadsheets in Appendix C for detailed calculations. ' © Q100 = 4.1 cfs o Qintercept = 6.0 cfs o Q100 flow depth = 0.67 ft. The top of wall is 18 inches above the tflowline The storm inlet in the northeast corner of the western portion of the lower parking lot (DP D20) ' is a 5-ft Type R inlet. Design details are summarized below. Refer to the spreadsheets in Appendix C for detailed calculations. o Q100 = 14.6 cfs o Qintercept = 9.7 cfs o Q100 flow depth = curb will be over topped and spill into the proposed swale below the parking lot. Flow depth at the inlet will be approximately 1.0 feet. All storm sewer pipes are 18-inch RCP under pavement and HDPE under grass. The pipes at the respective inlets have the following capacities based on Manning's Equation with a slope as shown and Manning's n value of 0.013 for RCP and 0.012 for HDPE. Storm Sewer Q100 cfs Qcapacity cfs Storm Line X (HDPE) 14.6 (4.9 cfs spills over curb) 14.84 Storm Line C (RCP) 4.76 7.43 Storm Line D (RCP) 1.99 7.43 Storm Line Y (HDPE) 14.6 18.0 Pond Outlet (30" HDPE) 17.73 19.87 3.2.5 Low Impact Development In accordance with City Standards, the site design has implemented the following Low Impact Development construction methods/items ® Stantec m v:\2059\mtive\205MM56\report\rpUp Wilding5&alna®e.dor 3.9 I FINAL DRAINAGE AND EROSION CONTROL REPORT Drainage Facility Design February 16, 2016 Pervious Paver Blocks in parking stalls Grass lined bio swales Flows from all but a small portion of the lower parking lot (areas 5, 50 and 6, 6a) will pass over paver blocks. These 4 areas combined amount to 10,953 sf (4310+6643) or 6% (10,953/180,749) of both parking areas. Based on this we can say that approximately 94% of the parking lot passes over the pavers. The total treated area of the parking lot using the city specified maximum ratio of 3:1 (asphalt /pavers) is 76% treated, which exceeds the required 50%. The Paver blocks account for 25% of the parking areas and provide treatment for more than 50% of the parking area as noted in following table. LID Summary for Parking Lot Parking Lot Overall Area sf Asphalt Area sf Paver Area sf Percentage of Pavers Treated I Area sf % treated Lower West 95271 69721 25550 270/p 60493 87% Lower East 34522 28148 6374 18% 16494 59% Upper North 39140 32102 7038 180A 21114 66% Upper South 11816 5324 6492 55% 5324 100% Totals I 1SD7491 1352951 45454 25% 103425 76% 3.10 ® Stantec meo v:\2053\0live\205375056\report\rpLhp b Ilding 5_dminage.dom 1 1 1 I� 1 FINAL DRAINAGE AND EROSION CONTROL REPORT ' 'Erosion Control February 16, 2016 4.0 EROSION a:u a usd ' 4.1 LOCATION AND EXISTING & DEVELOPED CONDITIONS The site is located on the HPE campus as noted in the introduction to this report. The site is currently covered with a mixture of native grasses in the lower areas and gravel in the upper section that is an extension of the existing parking lot. The site slopes predominantly to the ' north and east towards FCRID with slopes ranging from 1 to 15 percent. The site is bounded by the FCRID on the north and east, an access road on the south, the campus loop road on the south and west and Hidden Pond Estates on the west and north. The total area of the site is ' approximately twelve (12) acres. During construction, approximately eleven acres will be disturbed during construction of the parking lot. The project will include the installation of storm sewer, overlot grading and the installation of ' two paved parking areas and access drives along the north side of the HPE campus. The project is scheduled to be completed in one construction season unless the timing of the start of the project is delayed. Erosion control measures will be the first items constructed at the ' commencement of the project. The owner is planning for this construction to occur in the Spring/Summer of 2016 with estimated construction duration of 2-4 months ' The site is partially vegetated with native grasses and gravel areas outside the existing parking and roadway areas. The gravel area consists of the eastern parking area that was planned for when Building 5 was constructed. This gravel area is approximately one (1.0) acres (9%) and ' the vegetated area is approximately ten (10) acres (91%). Refer to the historic and developed drainage exhibits for additional detail. 1 i 1 The soils consist of clayey looms including Nunn Clay Loam and Lorimer Stoneham Complex which are predominantly hydrologic soils group B. Refer to the USGS soils report in Appendix H for additional detail. The overall runoff coefficient for the site will change from approximately 0.4 under existing conditions to 0.61 under developed conditions. The receiving water for this site is the FCRID, which ultimately conveys irrigation and stormwater to the Fossil Creek Reservoir. The vegetated areas below the existing parking lot are densely vegetated with the native grasses. The density of the vegetation is estimates at 80-90%. See photos on the following pages for examples. ® Stantec mw v:\2053\adlve\205305056\report\Ml_hp buldina 5_dralnage.d= 4.11 FINAL DRAINAGE AND EROSION CONTROL REPORT Erosion Control February 16, 2016 Figure 3: Existing Vegetation August 2015 Figure 4: Existing Vegetation August 205 A dedicated asphalt or concrete batch plant will not be used on this site. All concrete and asphalt will be brought in from outside sources. 4.12 ® Stantec mw v:\2053\active\205305056\re l\fpf_hp building5dralnage.doa I FINAL DRAINAGE AND EROSION CONTROL REPORT ' Erosion Control February 16, 2016 ' PROJECT MANAGER: TBD before construction commences 4.2 STORMWATER MANAGEMENT AND BMP'S ' Installation of permanent (structural) and temporary (non-structural) BMPs will be utilized to deter erosion control and stormwater run-off prior to and during construction activities. The ' permittee is committed to installing the features as listed, maintaining them as needed, and making any necessary modifications and addendums to this plan as construction phasing or site conditions may dictate. Prior to initial site grading activities, pre -construction activities will focus on the development and stabilization of the construction site. This will be conducted with the intention of using silt ' fence, dirt berms, erosion control logs, concrete washout, rock socks and inlet protection and vehicle tracking control where applicable. The following BMP list is not all inclusive and may be modified based on conditions of the job site. The installation of the inlet protection will be ' completed in accordance with to the specifications. Construction access will be limited to the vehicle tracking pad location shown on the grading ' and erosion control plan. Should another access be deemed necessary, a second vehicle tracking pad shall be installed as shown between the upper and lower parking lots. ' Upon completion of the installation of the temporary BMP's, the overlot grading will commence. This operation is most likely to generate a significant amount of airborne particulates (dust). A water truck will be on site to keep the dust down and the wind blow ' erosion to a minimum. SW MP administrators - TBD when the contractor is selected by HPE, the owner 4.2.1 Temporary Erosion Control/BMP's The following temporary erosion control measures are called for on the plans: ' o Silt fence along the downstream property line for the length of the property. Dirt berms may be used in place of silt fence at the discretion of the contractor on ' site o Vehicle Tracking Control Pad at the construction entrance to the site and a secondary pad between the upper and lower parking lots will be installed depending on the sequencing of the construction. o Gravel inlet filters or wattles in front of existing and proposed storm inlets on the site and on the adjacent loop road t 1 o Wattles in the flowline of the proposed swales and other areas of concentrated flow as needed ® Stantec rr. v:\2053\acts a%205305056\report\rpt hp building 5_tlralnage.dom 4.13 FINAL DRAINAGE AND EROSION CONTROL REPORT Erosion Control , February 16, 2016 o Soil roughening during overlot grading , o Water truck on site to water down areas to minimize wind: -blown erosion and provide dust control. ' o Temporary sediment pond on the upstream side of the pond outlet structure ' o Wattles on the downstream side of the concrete lining in FCRID o Concrete washout area to be located in the staging area ' All temporary BMP's will be inspected on a weekly basis and after storm events and repaired or replaced as needed. ' 4.2.2 Permanent Erosion Control The following permanent erosion control measures are called for the plans: ' o Seeding and mulching of all disturbed areas - see landscape plans for seeding mixture ' o Riprop at all storm sewer outfalls - see riprap section for riprop sizing o Pavement and installation of paver blocks in all parking areas ' o Wattle dikes shall remain in place until such time as the soils are sufficiently stabilized with growing vegetation ' 4.2.3 Material Handling and Spill Prevention Control , The storage and handling of any construction material(s) will be managed according to standard procedures and policies and as detailed here. Storage areas and/or materials will be covered and routinely inspected. These policies will be communicated to all contractors, ' subcontractors, and vendors for proper adherence. 4.2.3.1 Identified Potential Pollution Sources Work will take place within the designated site boundary that is identified on the Grading and Erosion Control Plan. The potential pollution sources from the construction equipment include: diesel fuel, engine lubricant, lube oil, sediment, hydraulic fluid and anti -freeze. Any usage of ' portable toilet facilities also presents a potential source of pollution. All portable toilet facilities will be staked down and are monitored at regularly scheduled intervals. A trash receptacle will be on -site also. Receptacles are marked, kept closed, monitored, maintained, and ' emptied at regularly scheduled intervals as needed. Emptying of the receptacles occurs on a weekly regularly scheduled basis to limit the amount of non -hazardous site generated wastes ' Stantec ' 4.14 mw v:\2M\cctive\MS305056\mpon\rpt-hp buiding 5_drdinage.do I FINAL DRAINAGE AND EROSION CONTROL REPORT ' Erosion Control February 16, 2016 ' on site. A concrete washout area (CWA) will be present on -site. A CWA is shown in the staging area on the plans. The location of all portable toilet facilities and trash receptacles are ' specified on the Grading and Erosion Control Plan. Trash receptacles will be placed in the staging area for disposal of all construction debris and workers trash. Routine inspections of the site will be completed to maintain a clean safe ' working area. Loading and unloading of material will be limited to the staging area and the existing ' graveled parking area until grading operations commence in that area requiring the removal of any stored materials. ' 4.2.3.2 Waste management Receptacles for construction and other non -hazardous site generated wastes will be provided ' for material disposal. Receptacles will be; marked kept closed, monitored, maintained, and emptied at regularly scheduled intervals and as needed 4.2.3.3 Concrete waste management In the event that ready -mix concrete is applied or installed on -site for development purpose, all equipment and vehicles that are involved in the making and transporting the concrete mix ' will be cleaned and washed at designated locations. These washout locations will be comprised of excavated depressions that are: well marked, constructed to facilitate the storage of the waste materials with the least impact to the surrounding areas, to maximize ' containment, and to minimize the potential for conveyance away from designated area. Once any individual location is at capacity, that specific facility will be decommissioned until it is remediated, and washout activities will be routed to other designated areas. All cured ' concrete wastes will be excavated and removed off -site for proper disposal. No concrete waste dumping or vehicular/equipment washing will be permitted near or in the storm drainage lines. 4.2.3.4 Spill Prevention, Control and Potential Hazardous Material Handling Materials other than soils that are referred to in Paragraph, Identified, Potential Pollution Sources, will be monitored for safe storage, handling and use. For bulk storage of fuels or other potential pollutants on site, secondary containment will be installed as a leak/spill control ' measure. Portable toilet facilities will be secured and located away from anticipated flow lines. All contractors and subcontractors are required to follow standard procedures when fueling equipment on site to reduce the chance of spills and in the event of a spill to follow SPCC procedures. Equipment maintenance is not expected on site but in the case it is required the maintenance personnel will also follow these same procedures. ® Stantec ' meo W\202\active\2053g M\report\rpl hp Wildng s tlrainage.Com 4.15 I FINAL DRAINAGE AND EROSION CONTROL REPORT Erasion Control ' February 16, 2016 4.2.3.5 Spill Response Procedures ' In the event of fuel storage containment failure or other spills, instructions will be posted on -site for the Owner and/or Owner's representative to be contacted. The Owner and/or Owner's ' representative will be residing locally during the construction activities and will be able to respond immediately. Once on -site, a determination will be made by the Owner and/or Owner's representative whether the nature of the spill warrants the notification of additional ' authorities. Advance preparations will be initiated by the permittee to ensure a prompt and effective response to any spills. These preparations include an action plan to stop/control further leakage, contain the spill with sorbent materials) or an earthen berm, and clean-up ' and remove residual pollutants and contaminated materials. These preparations also include the procurement and on -site storage of sorbent materials for clean-up procedures, preparations for disposal containers for clean-up materials and contaminated soils. , Spill kits will be located in the staging area. 4.2.3.6 Stockpile Management and Controls ' Stockpiles will not be kept or maintained on site. 1 The storage and handling of any construction materials) will be managed according to standard procedures and policies and as detailed here. Storage areas and/or materials will be covered and routinely inspected. These policies will be communicated to all contractors, , subcontractors, and vendors for proper adherence. Vehicle Tracking Controls , A primary vehicle tracking pad is provided at the eastern end of the site near the staging area with a secondary vehicle tracking pad located between the upper and lower parking lots. Any material tracked out onto the loop road within the HPE campus will be removed within 24 , hours. The some is true for any material tracked out onto public streets. 4.2.4 Project close out Disturbed areas outside of the parking lots shall be seeded in accordance with the seeding ' mix shown on the landscape plan and include below for reference. The areas shall also be mulched using a hydro mulch application as noted on the plans. , Temporary BMP's shall be removed once the site is sufficiently stabilized in accordance with the City definition. ' Stantec ' 4.16 me v:\MM\mt[ a\2D53D5056\mporlVpt_hp Wang 5_drano e d FINAL DRAINAGE AND EROSION CONTROL REPORT Conclusions February 16, 2016 5.1 COMPLIANCE WITH STANDARDS The design of the stormwoter management infrastructure associated with the HPE Building 5 Parking Lot expansion complies with the current Fort Collins Stormwater Criteria Manual. (3 Stantec m. v:\2053\.d"\M5305056\.p 0V - hp Wiring 5 tl Inage.=o 5.17 FINAL DRAINAGE AND EROSION CONTROL REPORT References February 16, 2016 6.0 REFERENCES UDFCD Drainage Manuals Volumes 1-3 City of Fort Collins Stormwater Manual Master Drainage Report for HPE Preston Kelly Subdivision Final Drainage Study for HPE Building 5*** Final Drainage and Erosion Control Study for HPE Building 5 Addendum No. 1 for HPE Building 5 Parking Lot Expansion*** Detailed Hydraulic Study Regional Detention Facility for HPE*** Fox Meadows Water Quality Master Plan Alternative Evaluation *** indicates excerpts attached in appendices ® Stantec . v:\20S3\oct"\20530`A56\report\mt hp W116np 5 dminmge.tl 1990 1996 1998 2000 2000 2012 rN I I I 1 I I I I I I APPENDICES I FINAL DRAINAGE AND EROSION CONTROL REPORT ' Appendix A - RATIONAL CALCULATIONS December 23, 2015 ' Appendix A e RATIONAL CALCULATIONS 1 1 1 1 I 1_ ® Stantec 1 A.1 0 v N n o ro C v v v v o m LonA W N F+ m H v v o v v v NJ Qo A W N F+ 0 D go v o G. v V1 a N w � n r a W b• W G 1 rt � O G m R W P. W iq p � a o W r• K In m m r w w o °' LnW Ln W n 0 0 0 0 0 0 N W w V O W O l'1 0 m Cl) 0 ro m 0 M m M r O O O O O O Ln N W N P. rt r m V o O to 0 0 P. V m z G G G0 0 0?? O O O O n In A r I M Ln in l0 F" V 01 O In O o 00 01 cn O l0 V O F. O O O O O O O No Text N N N N ro n m b 0 Q z O n m w 0 0 0 0 0 0 0 0 0 0 0 N 7 N ro N n N m N� 7 m y� W N N m n o 0 r W O 0 N 7 �I pp N V !n tD F+ O A to D Ol Oo W V tDtpo O FO+ W pl lA � Oo W O N M N W A ip V N W ip O C (1 N 1+ 4p lD O 1p a1 W O N Co al m x y GI n H v y a n m 0 M lip F+ lop 000 N V O A O N. A OD 6 w F+ V W A O V G O X r, �R G M M ry b L a W N !n !n W N V O FD+ O Y O 0 0 0 0 0 �pR 0 0 0 0 0 G �, o`e � � � � ue � O' a a W p a O O O O O O O O O O O N N w O G A W a A A O N G T V W V pOD Ol lOi1 V O W O n 0 0 0 0 0 0 0 0 0 0 0 0 W V 1+ A N O p1 W F+ !n !+ V A 1+ O N 1+ O N 1p 1+ O n 0 0 0 0 0 0 0 0 0 0 0 o N A A Cl N O1 N w A A 0 O O N O N O V Y~+ N cm cm Ln 0 ul Ln rn N N z 0 v o O N N N n 0 m a r N � C V P R 0 0 0 0 0 U a 0 0 .• m .� r y W o o A (1 m w 0 to m V Y O 0 0 0 0 0 W o 10 0 0 0 0 0 N N N N N A W T 4 N W W O O In 4p V o 000 O O n E f 1 a A N W J 3 y to VI N A a � 1 I I 1 J tWil p J O .T � W Ol W s I 00 0 0 0 N 0 0 0 0 0 w l 0 0 y 0 < n I F O O 0 D N W o N 0 11 3 W 00 00 2, � 00 ouJ+ao 0 n S 0 0 0 0� o 0 0 0 `P N 00 n F O o O N N C)I6 u 0 0 0 0 0 00 T F 00 o 0 n J N O+ W W 6 0 0' T ? N s + n O n O op 0 0 y W W W 0,W C C C C C A C J J- p N?^ D 0 in in - O+ .� o m m J �n J s u pro1 - a .. a N J U o 1p J �D J > V F o ryl Z � ^ 1 T O p II II c � II G nQ ^} G1 c W T 3 c m T In £ 3 O 1 3 > = 1Z > m 7 3 C) n A Q n Q � n T �* r ) O 3 R O O (� Q n Ncl R O p w 7 N (] 3 W I N N o n 3 � R N A O � S �o r �HpSi r n � 3 I O R n O O p 3 m Or U1 rn 4i p - O c c 1I II b a R R O o O 3 T 7 T < D < C) - 'I II D j Ln N m U7 N m o V c V J A O 11 'Io $ Q II II "I II N J O O O c m . E � � 19 d Y N y Y � m O � d O Z N - 3 s N y O C U E � r U) . r m C O L m Q N � O O C) y a Y in u U E O . O O U E o � U j U N W ~ m O tyu�L- aO�I-U F �2 Z w O m C N 0C 3 o O o m a N N O Ol P N Z n c n c ry c n c m c m n F °o - m Q ro o m u m o m m + N O _ N U i 0)'1 y p N ` c o 7 N m N 4 '^ v,0 S UE E Q N r > > 3 _p O O o n U O o o 3 N U m O o O O O O O N ac+� u O O 0 0 0 2 o Q o o m ~E O N O m N o > QOQ°o°o z L> Q N N O N O O O O O N o L J$ O m O n N y u m N c ? C N N N � E nm"Ivv p o0 N N 0 u 0 n o N o N L a - 2M12— . v U N o N o N 6 N 6 N 6 N N O m N N O N V Ih V U 0 o o o 0 u u coo m m c m Qa O n a N c N � ❑ ❑ O ❑ O N to J a0 0 0 r m N O Ln w 0 Cn 0 m m 0 0 0 0 O Cn N N N .ly w tr 0 CD r- co r. rr G oc�Kxro 0 t rt 0 0 � n m � o ro r r r r w n r- r- m m m m o m 0 0 0 0 0 m Lo 0 00 00 �o �a x = x n C] o 0 0 ro ro ro ro ro � C+7 C'7 C'1 rt r ro ro 0 0 0 0 0 3 m w cm) 000o C G 7 c"l w r r r r r Fl- w W N N N G o 0 0 0 0 F- cn O O o 0 0 rt r 0 0 0 0 0 \ m 0 CD CD N N CD Cn Cn O Co N rt m 0 0 0 0 0 r r r r 0 o r r n Cn cn w w a 0 0 N r r m rn m b n J J 01 61 lD I w �c �c o o Eo w w o o J b r r M r J co 0 J O iJ J o l0 Q� O J W m ro b7 G r2 H' to cn ro a � to n Cx'7 G En b I I 1 I 1 1 I LID Summary for Parking Lot Parking Lot Overall Area sf Asphalt Area sf Paver Area sf Percentage of Pavers Treated Area sf %treated Lower West 95271 69721 25550 27% 60493 87% Lower East 34522 28148 6374 18% 16494 59% Upper North 39140 32102 7038 18% 21114 66% Upper South 118161 53241 6492 55%1 5324 100% Totals 1807491 1352951 45454 25%1 103425 76% 12/23/2015 Stantec Project # 2053 05056 ' By: MEO HP Building 5 Parking Lot Expansion Area sf Index A P Total Area sf (A+P) A/P A/P max ** A** At sf (A- A**) Location 1 9426 1333 1075914.5 3.0 3999 3999 Lower West 2 2574 2021 4595 3.0 6063 2574 Lower West 3 11403 2534 13937 3.0 7602 7602 Lower West 4 4228 2534 6762 3.0 7602 4228 Lower West 5 4310 0 4310 3.0 0 0 Lower East 6 6643 0 6643 3.0 0 0 Lower East 7 9400 4042 13442 3.0 12126 9400 Lower West 8 14281 5068 19349 3.0 15204 14281 Lower West 91 9749 3016 12765 3.2 3.01 9048 9048 Lower East 101 7446 3358 10804 2.2 3.01 10074 7446 Lower East ill 7318 2674 9992 2.7 3.0 8022 7318 Lower West 12 6566 2674 9240 2.5 3.0 8022 6566 Lower West 13 11433 2400 13833 4.8 3.0 7200 7200 Upper North 14 9768 2239 12007 4.4 3.0 6717 6717 Upper North 15 4696 1003 5699 4.7 3.0 3009 3009 Upper North 16 6205 1396 7601 4.4 3.0 4188 4188 Upper North 17 2170 1915 4085 1.1 3.0 5745 2170 Upper South 18 1617 2401 4018 0.7 3.0 7203 1617 Upper South 19 1537 2176 3713 0.7 3.01 6528 1537 Upper South 20 4525 2670 7195 1.7 3.0 8010 4525 Lower West Total 135295 45454 180749 1136362 103425 At/A 76% Overall Max A/P 7.1 Min A/P 0.0 Avg A/P 2.6 A = Asphalt Area P = Paver Area A,- Treated Asphalt the greater of A & A** 2of4 **A/P max is the maximum recommenoeo A/N ratio Trom me t_ay aTormwaier Uumy anti the A** is based on this max ratio Conclude: The pavers treat more than 50% of the parking lot overall and within each basin and along with detention pond provide sufficient treatment for the asphalt section of the parking lot so that no additional water quality pond is required in the detention pond. 1 1 1 t 1 V:\2053\active\205305056\analysis\anl_asphalt vs pavers.xlsx' Asphalt -Pavers 12/23/2015 Stantec Project # 2053 05056 By: MEO HP Building 5 Parking Lot Expansion 0 I n n I ' 3 of 4 Total Area I A I P V:\2053\active\205305056\analysis\anl_asphalt vs pavers.xlsx Asphalt -Pavers 12/23/2015 Stantec Project# 2053 05056 ' By: MEO HP Building 5 Parking Lot Expansion A/P At At/A Index Lower East Lower West Upper North Upper South Lower East Lower West Upper North Upper South Lower East Lower West Upper North Upper South 11 7.1 3999 42% 21 1 1.3 2574 100% 31 1 4.5 7602 67% 41 1 1.7 4228 100% 51 0.01 0 0% 6 0.0 0 0% 7 2.3 9400 100% 8 2.8 14281 100% 9 3.2 9048 93% 10 2.2 7446 100% 11 2.7 7318 100% 12 2.5 6566 100% 13 4.8 7200 63% 14 4.4 6717 69% 15 4.7 3009 64% 16 4.4 4188 67% 17 1.11 2170 100% 18 0.7 1617 100% 19 0.7 1537 100% 20 1.7 4525 Total 5.4 26.5 18.3 2.5 16494 60493 21114 5324 59% 87% 66% 300% Lower East Lower West Upper North Upper out 3.21 7.11 4.8 1.1 0.01 1.31 4.4 0.7 1.41 2.91 4.6 0.8 4of4 u �J L 1 V:\2053\active\205305056\analysis\anl_asphalt vs pavers.xlsx , Asphalt -Pavers 1 FINAL DRAINAGE AND EROSION CONTROL REPORT Appendix B -DETENTION CALCULATIONS December 23, 2015 ' Appendix B- DETENTION CALCULATIONS i 1 1 1 1 �I E r, ® Stantec ' B.2 A OD CO 0CDOD-40) 00000 00000 A OD O A OD OD A OD OD A OD OD m CD < � CO) m CD A W N — O ,' CO) Er 00.0.0.0. to CD O C 3 O � � N CD OODD O W •* ��CD O in O Cn N O Cn V O < n O c c 3 3 � CD o o o o D z bob aoomtD OD 100 v 101 3 D O 7 a OD CD OD r O O � 0 v, 7 CD o N CO Z D CD c CD O O c Z D rD d 3 c � 3 01 A CD 00 �. ,OOD V CD m �l to S 0) m CD m CD 0 4 co to O m 7 � tC O A CD 0 OD co 3 o O O ~' O Stantec HP Building 5 Parking Lot Expansion Pond 1 Description HP pond for Parking lot Expansion - lower basin (D2 only) Design I Design Basin C I Basin I Tc min I Qd cfs I Or cfs Storm yr Point I factor I Area ac 100-vr 1 21 0.501 6.051 16.281 17.731 0.71 Detention Volume Detention Pond Release Rate is the historic 2 year release from the overall site Required even though the upper portion of the developed site will be detained in the cf AF existing pond to the east. The contributing area to FCRID has been reduced from 10.25 acres to a total of 8.93 acres post development. 6.41 acres contribute to 34610 0.79 the pond directly and the remaining areas outside the limits of the parking lots are not affected by the development and thus not included in the pond sizing calculation. IDF Table LookupColumni 4 Tim min Intensity Inflow I Inflow Release Storage Storage iph Rate cfs Volume cf Volume cf Volume cf Volume AF 5 9.95 29.81 8944 212 8732 0.20 10 7.72 23.13 13878 424 13455 0.31 15 6.52 19.53 17581 635 16946 0.39 20 5.60 16.78 20134 847 19287 0." 25 4.98 14.92 22381 1059 21322 0.49 30 4.52 13.541 24377 12711 23106 0.53 35 4.08 12.22 25671 14831 24188 0.56 40 3.74 11.21 26893 1694 25199 0.58 45 3.46 10.37 27990 1906 26084 0.60 50 3.23 9.68 29033 2118 26915 0.62 55 3.03 9.08 29958 2330 27629 0.63 60 2.86 8.571 30848 2542 28307 0.65 65 2.72 8.151 31783 27531 29030 0.67 70 2.59 7.76 32592 2965 29627 0.68 75 2.48 7.43 33437 3177 30260 0.69 80 2.38 7.13 34228 3389 30839 0.71 85 2.29 6.86 34992 3601 31391 0.72 90 2.21 6.62 35756 3812 31944 0.73 95 2.13 6.381 36376 4024 32352 0.74 100 2.06 6.17 37032 4236 32796 0.75 105 2.00 5.99 37751 4448 33304 0.76 110 1.94 5.81 38363 4660 33703 0.77 115 1.89 5.66 39073 4871 34201 0.79 120 1.841 5.51 396931 50831 34610 0.79 by: MEO 2/16/2016 Page 2 of 2053 050506 Detention Pond.xism 6 CUHP 1 \� M 3 fD rr 0 co A 003 00 O Oi 00 00 00 3 O CL 0000 'm II O O T N fD Q y O 00 d O O M a 00 00 T w .f D. N O W > X_ G) � m 3 A A ? A A 00 00 00 00 00 m �c 00 00 00 00CD o �c 0o -Q rn < o c o 0 0 ;v O O O O O V1 O GQ O O O O mCD O CD CD O m D W y N CD ul '--' O a � O 000 w D 00 v w O W N LA ONW C vA A .0,O m W C/A 00 < 00 y C 0 00 O O V� O N O Litm 3 < O_ � 00 0 0 C 00 �o W O O c ► 00 00 � O m 3 D T o 00 ° < c °' < eD A 00 4 O 0 T O M m 1 < l ^ a 1 T aeb ^ fD O 4 n 3 N w O m � m O o 00 M O V o<i O er p fD tD O 7 -v O '� O O C C ' O .N Ln N oo n c_ x Y 'O W ' N 7 O m w n oo cG = Y El El m U ' n a F. E w ' a E 0 0 a 0 G. E 0 a 2 H E tj W W x 7 N N O O U w O c U O LO n N N O C N to N O i- W tr O d O C O w H 01 C O C tD £ Ln O O O Ln t N N w N O a rn 41 o O a o o Ln c w i o O a o `n W N w o W w �n N N o U O ro lD N „i C] w W O ,i N 3 C co H c cn n w O 4-4 U W O OU ei i N 3 O N N 1l N W [� O cto O m a)U m w w U7 4+ C O U H U U C Ln d O t+ N w tD W }1 W O r O W l4 C 00 H 0x a C a ap 0 01 O o w o a LO w �w 4-4U 00 b 3 y"„ 00 .H o v Q) o >, FC H 0 O w w ti m ro ° w C H U O a) +j N W o 41 U Ln tD 0 W N Ol W N O O O O H fn Ln (71 U O N a aJ w Lr) O N .W1 W lD O H N W 0 W o 1. �n< O > ww O H •-• a0 b) Sd C .,1 w < U 30 H N Do aw HNU tO �- N rn O w O o 4-400 W W N b 0 UD ElU� N o ElV 001 1-4wdFCx � N N Q z \ C O F� rt N m 00 ~ J O\ Ln W N r Ol G cn o v rs < m r tom-' 1 cri 5 n m K - a M a rr M Y a rS r O K O 'O " : r £ o H. cno£ o 'O lO M CD (D £ I (D r C I H- (D K C) K r5 H- n U1 C) M 5 rt tr' rt h £ m w N O A M C (rD tom- h O r t' C W G o M m rr oM o a r o rs m rt n olrtOto p o ro ro n m < P- o m FMI m'o �:l r m m a m v rr v O 7 M rm (D m - o rn rs m r v n rt a r- r O Cl 7 G r a v (* y N. Ln O M N O W O Ln O LM O m C A A A A A A A A A A A A A A A (rD 'j H H C1 00 00 00 00 00 00 00 OD DD 00 00 00 00 00 00 r 00 Oo 00 OD �0 00 tD 00 00 00 OD OD 00 OD 00 H G V �0 OD 00 O 00 O Ln 10 00 OD V V 01 01 M ON a V N V V C 01 O {n O i[� n G ul C in O .� 7�C7 t'� W {n F+ O O U0 O O O O O O O O O rt O£ A G (D O p rt m t" '•�' m 4 E 0 rt F+ W N N W N W W N N F+ F+ O O O M n O O M O 1n Vq 00 {n 00 w 00 w CO w 00 w 0 rt r V W to -Pb A W A -Pb A -Pb A A A A O p H C � H M � rt by G � r 0 O O O O o 0 0 0 0 0 0 0 0 0 0 y£(D {n V 01 C1 00 01 00 V V C1 {n A W N O a W A V V N V N V 1+ A V w OD A O a t �Y �- (D o r -, a 'o p 70 W M (T O O O O O O O O O O O O O O O M crop N (D o 0 0 0 0 0 0 0 0 0 0 0 0 0 o rt n 0 0 0 0 0 0 0 0 0 0 0 CIO 0 0 0 r M N M r ~ r O M o £ o £ 0 0 0 0 0 0 0 0 0 0 00 00 o (D "� 00000000000000 0 M o G 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 co M H M H n- x o nm m a n C N. r,00001-.o"0000000 0 K O {n O O W O W CO W O O G O 0 0 rt a O w F+ O O O O O O O O O O O O rt O N. O O O~1 O O C% O a, N 0% O O O O O O n < C tD O O C1 O C1 V CO O O O C C O Q O W Pb O M O M V A 0 0 0 O O O m rt 7 0 1-3 O m rt O V O O N O N-A fn O V 0 0 0 0 0 O O a m w V V G1 A C1 J.1 in 0 m Ln A W N 0 M r 0 W W I.,V W V MW A A V m (A a z a o n rt K m N r N O r G m ai m ro m �. O N N F+ F+ O O O O O a (D p V N V N V fJ 0 0 0 re p OD to to an in to M O O 0 rt rs N- ^7 N r C) 0 (D N N VN OD W W CO O O N V W V 0 0 0 0 M O£ O w aa% FA+ 1111111111111111 A iD m F+ M ro m ry rt V rr � m ro ro xm K rt N W v� a c IN O Iw io O O O A O O O O I 1 I Q100 cfs Qr cfs 17.73 0.71 Q=CS40.5 S = (Q/C)^2 Slopes (ft/ft) Pipe Diam inches Pipe C Q100 Required Slope ft/ft Qr Required Slope ft/ft 0.002 0.003 0.004 0.005 15 69.954 0.0643 0.00010 3.131 3,831 4.95 18 113.760 0.0243 0.00004 .5.091 6.231 7.19 8.04 21 171.607 0.01071 0.00002 7.67 9.40 10.85 12.13 24 245.019 1 0.00521 0.000011 10.961 13.421 15.50 17.33 30 444.283 1 0.00161 0.000001 19.871 24.331 28.10 31.42 ' Conclude: Select 30-inch pipe since that is the slope we have to get it out ' OUTLET PIPE FROM POND 1 LI r- L 1 FINAL DRAINAGE AND EROSION CONTROL REPORT ' Appendix C - SWALE/INLETS AND PIPE CALCULATIONS December 23, 2015 Appendix C - SWALE/INLETS AND PIPE CALCULATIONS II II II II 1 1 J I C3 1 DESIGN PEAK FLOW FOR ONE-HALF OF STREET OR GRASS -LINED CHANNEL BY THE RATIONAL METHOD Project: His 9L ltdlrq S PlnB Lot Eepensfbn Inlet ID: SoulA sIM Peerkrkln0 Lot (DP 6) 61ww Detail. ROADWAY CENIERUNE Design w. a ernmessal Smash seen aselfisids. M eNI .exp.r.,,aOr . oO C SUMxldmenl Fme= Pram. lm M NRCS Soil TYpe • A. & C. Or D Sh TYR: fbwa OneYgOfO IIrp511eklnpa' pse¢r uses Slam(MI) Lange(n) ow... Own IMs m a Ntbai ovum Flew ChiFlwv - em a Onn n. n ens Y r= l e —W.-IrM Manor S. Design Slam RHum Penn. T, • an Return select On -Hour PmuplWbn. Piinches User-DeBmO Slams Runoff CoeOEbol IIeWe IMa EIeeM to ¢Gspl a wIEUIo1M value). L Unw-DenneO 5ryr. RunO Coetllue d IbevF Ibis Olank to ruepl a eMaleleE verve). Cs' f,ni Kerry4serl Flow 1. u"s SubcetEllmenM. C6 - g.g g.g EM Total Design MY Flow. O= OA ie pM •n�crxsnee! Prole-:. IN 4a ,In', s_ 2053 05058 spuMwn mist DP 5.bsm, ( Peek 2162016. 1 43 �M INLET IN A SUMP OR SAG LOCATION ProJee • HP Building 6 Parking Lot Expansion Inlet ID • Soudr side Parking Lot ( DP 61 L. (0)— H{urb _ H-VM W —" G) urban Inlomlanon Ilnoyll "u, mat Inlet Type • out Deprosswn (wNlnorel to wn4nuou5 gutler Winussm'n'a' fromAllan} e..•• IumWr of Unit InbM (&We or Curb Opening) No V61e1 Ob" InFI.Ime I... of 1.1 Wpfaeslwp 'Mid.,No, . ktlb Inlormtlbn eye o1 a unit Orel. I. Vgln al a Unit Glen W. use Openly Rollo for a Grain (WWI vAues O.1&0.90 AA :bg0ing F.nor for a SIVW Gale ff".1.1W 0.50.010) C (0) sab Weir C W VIWmI (I Velure 215 - n 00) % (G) ;new Cooker cWImarm(I ial nIu.0So-080) Co(G) bN Opndinp Information engtn ore Unit Curb Openuq U (C) INpm of Veri Out Openly In I.W. Hon loth of curb Omw Tlimal In Inner, Hu Ingle of TMaM (see UBDCM Figure ST-5) T WM IMe "In for DoprebeRn Pen bypka.y IN gutler wMln of 2 fWD Wa• .INQN Factor for. 61yb Cub Opening (typkN yelue DA 0) C (c) - :um Opening Weir CoeMklenl (lypkel value 2.13e) C. (C) - Writ Opening Ooflu CWH[o 0nl (lyplu1.1.b 060. 0.70) C. (C) - Intel Inlet Interception Capacity (assumes clogged cdnd@ilan) 0.• 11n Cepti IB GOOD for Minor and Major Storms VO PF ) Ogumy+an• MINOR MINOR CDOTType RCum0,mbp 3Do kMa 1 6D ea n MINOR MNOR WOMrIOe Rptle w ten te n MINOR MAJOR Soo son eon 53.400 f oD 010 010 3.81) 0.67 2053 050%sout0em mlel DP 5 Am, Inlet In Sump N162016, 1.<1 PM DESIGN PEAK FLOW FOR ONE-HALF OF STREET OR GRASS -LINED CHANNEL BY THE RATIONAL METHOD Proleal HP BUlirllrp s Parking Lot Fxpeopo n Intel 0: IIINOM sIM "rearing Lat (DP l) FLOW D I I W s1REu I SOW D I CURER FLOW CUTTER PLUS CMRYOVER FLOW Stw Oeleile — ROADWAY CENTERUNE _ _ _ _ spn roue o anorSbrm Mea Shmn In— PI. eosrla IQ., WM CF aen..."en.)-Ox,.,_'=�,ft II n vnlues In Row N.j IM1em0o11MssMet ana roceeE to them O Allow or ores Inter. FILL IN THIS SECTION R FILL IN THE SECTIONS Meale'nl a OA: nef 61e e1 a YeM ae% SURlaicamee Ale. - A. BELOW. Pomm Impelvin ueness NRCS Sell Type= A. B, C. an rSlle iYCe' FMrs oeteLyM Fv: I Q Ske k UOF rOF. MR. Slope (MI) L. M1 (II Qy2 kNm)IOn I Orm lnktt Ina NNlm OvenenFlax- Channel Flaw = .n. norllle Ian: nenely IIEwino Mlaor Stenrin Major Slam ysem Deslpn Sblm Relutn Peootl, T, •MOSS. Return Penco One Hour PmUpAallon, P� •In... C,• C+= Cr. Uler.OeIMW Slam people Coelflapal (leave IMs prank to accept a Oneulslee value), C - U.er-CemIW Syr. RWOR CoMdele (bM See Elark to appeal a ENalelen Hinea, Cs • Sypene(Celry-0verl Flow pmn a0etre.la SYEC.ICMIem.. q-0. Tenet Rngn Pak Fbw, 0 • 1.a oA cN 2= 1150515 ncrNem INM DP 4.A.M. 0-POW 211=016, 12 52 PM INLET IN A SUMP OR SAG LOCATION Projatt= HP Building 6 Parking Lot Expansion Inlet ID = Nofm aide Parking Lot I DP 4) Lo (C) waum H-ven wo w Wp L.(G) an Mlormerlm Hal l of mml Two = Depresawn (ae]nwneuo..e..us'Mary depmssion'A wm O-Rnow) I W at Unitlnems (Grale m Cum Call No r Depth at FlOwlme (Muse ontl'al depression) P.AA, Deihl Infomratbn a of a that Grate la (G) of a Unit Gate W" ° Dinning Ratio for a Grab meecul value, 0J"US) 11, Fecar far A Same Grate gypwel vime 0.SSo - 0.)0) C (G)= Witr Coetnenl (nocia value 2.15-]60) C. (G)= Oar coelfrlem prolul value 060 0601 Co (GI Openeg Information e We U. Cum CAI 4.IQ° A of Var ltal taro Onemrg in In.. Ha, n of Curb pions Theal In mmuef Ham= of TMasi AN, USDCM Fpure ST-5) Tnele Nqb for EN,AAA Pan mroe' ley the UAW walla of 21ee0 M nrg F.. tar a SA,Ie Cum Coronet, (tyaual .Blue 010) C (C) ` OVenIng Weir Caelklent (fall value 2.136) c� (Q ° Opening 00w Coef stem uMicil value 0(10 0 T0) C. (C) ° I Inlet Interception Capacity (assumes clogged conddlon) 0.' ]spat fly IS GOOD for Millar and Malor Storm. (10 PEAK MINOR MAJOR ODOT Type R Curb Opare, D W imnas 1 8.D 6.0 Immes MINOR MAJOR �O.artlef�6a N/N 18e1 WN feel WP WA WA WA N/A MINOR MAJOR 5.D0 eW 000 5340 IW 010 010 360 06] 2M 05o56 1gMem imel DP 4AWa, Intl In Sump ZfIWO16, 12'.S2 PM wul xsneet wcteaec DESIGN PEAK FLOW FOR ONE-HALF OF STREET I OR GRASS -LINED CHANNEL BY THE RATIONAL METHOD Prolact: HP BUIIEInB 6 ParMny Lot Expenelon InW W: NE comer ERRem elw Lovwr Pe1111M Lol I OP 1.1 I CURER FLOW CUTTER PLUS CARRYOVER FLDW SMw Details — — — — RWDWAY CEHTERUNE — — — — y ofoOMI1604 IIolroer mothocis. �Nma Slono Mautar Sjl�1 -_-. 11.:1 HI Id 12 W.1. Notp•wilmJ CMnmll. 'Ox,...n. do FILL IN THIS SECTION 11 you emer valxsm Ruw 1,101 11 mat u1 m169nao1..J NE IO fh..l O.Il vof A—nM1 CH IeP :1 erOMB In a un I ru FILL IN THE S`_CTIONS SuocfU .l Area= BELOW pen:mJ lmpemallfuss= _ NRCS SdI Type= A.I C. or $Pe TWe: Ftwa Rlttp[J W" IIr Q Sh h LLCn QSUteI Ilieo y QLeanerlAN1 QNalrkn nallearl OveJNFl CeenreA Fl.pv • n e wm ron. n ws Y r Nr. lam Dmgn 91am Rmum PoroJ. T, • years RNum Panop dm-HWf PleoplWlm, P,• ImFea C,• C;• Ci Uxr-Dellnep Sblm RuroD CpMIIUem (Is. mb UWx to evepl a xkuklM...I. ISUxr-DeNIeE Syr Runo6 CJellkimm (Move INe Clank ro alzepl a ulamea value). Cs BI (Cerryuy ) Flew from upeveem Subc9ctlmsntll. r; • CA C.p cM Total Deelpn PeeM Flow, D • N CA pfe 20 06066 mkt OP2D. Wm, O-Pesk 2/16=16, 11:Cl AM INLET IN A SUMP OR SAG LOCATION Project = HP Building 6 ParMng Let Expansion Inlet ID = NE corner EaMem side Lower Panting Lot ( DP Ya) Lo (C) H-cum H Ven We LO(G) ,Iml Iff m ation Medan too M low Intel Type+ .1 tlegeuMrlbllllblwl la wminuoul: gutter nepresslon'afloor lumGer of Unit InMs (Olale Or Curt, Operelin No' Are, Note el FIprINe (WbMe of tonal negozswn) Borrow Del Irtle lnlormtlion sepia of a unit Gale ADD 0. OM Gnle Wa' me Opening Role We Ones (1,B.1 values 015-010) A,.' ImIN Fedor for a Sage Grate inecel yeee 0 W -010) G (0 kale Weir Coolfioenl ( W.1 yWue S 15- 3501 % (G)- rate Grew GaenlcleM mie al value 0.W- 0.60) C. (G)' uN Opeeing elimination all of a unit Cure Opening b (c)' egm oI VmFal Cure Opening In Onee H_. tepid of Cure Cerra Tnrvel In 1.0i Hm - n01e of Mrael (see USOCM Fgure SP5) TIINe= We Width for D.,.n Pan IIYPIWIIY the BMer wieln of t teen Wd Io001n0 Fedor for a Snge Ouro Operng 0,.l value 010) Cr (c) ure opening Wen coefficient nypl l %ewe 2a36) C+, (c) um Ope enO Orifice Ceemnlent gyplui %eee 0 W -0]0) cp (C) 'otal Inlet Interception Capacity (assumes clogged condition) Ce a Om Cepiclly o GOOD for Me,., Mr., 51nnne (1O PFAK) Oq.,w crouwn' MINOR MAJOR LOOL Type R Lum OWnB, on rn 1 80 00 m e MINOR MINOR QO.mMe I3e0m1 WA Kel WA feel WA WA WA WA WA 5.00 6.00 8.00 6140 2 DO 0 to 010 3.60 061 MAJOR eel Ilcnas IlUlas legmes eel 2053 05056 inlet 01"2gxlsm. Inlet In Sump 21162016, 1143 AM DESIGN PEAK FLOW FOR ONE-HALF OF STREET OR GRASS -LINED CHANNEL BY THE RATIONAL METHOD Prolowt HP Ba11011q 6 ParMrq Lot Eallanalon InIM ID: NE comer WMm a1W ak L.ovyar Mpa`p La (DP L) '� Sine, DMYIa _ - RMDWAY CENTERLINE _ _ Damon e y "Rennuned enoughother reattooks M. Iloul war now la la d.—I OR t.Nkkl '0.,.„ -r-2.4 ( 14.6 (cls 'll ovI ms-14, ,. 1 anll ,--a to eMel QHAII orArea Ink,. e iwiFMM np Ic insaneness: ner m u $ch rnelll AW Avee Palum unpanNRICIS ioasnesa- NRCS ball Type= A. S. L,mD A. r TryeDismissal c'. See k IMBn QSeM Lllea Sb (Nnl I.e n (fll oseekNmnekn QhulNNna Metln O Iakj Flmr CM1ennal Flaw = a onne n. n ena r me ,. roffincaSnoin, Mera slmm Design Mason Rental PI T, =�L�-1—I yeare RMum PenaC On>Hwr PmUpllallon, P� =I I IInaIMre Wm-DeMOtl UfeM1DeOneE lain Runoff OX Lu1XAC0bNM saw (leaveINIsblankklam Becccepl0 a uulwlhfladlulelep vae By".. (Cikny-0sia) Flaw Inm uptnam 9ub.%hma0lmulu0el,l. ,DLC.5 ^= s TaMl Design Paid, FbWA• 2l 168 00 Taaesnnel Pmrecn- ILL IN TMl _`.ECTII]I. IR IlL Iry I HE S'ECTICNE 203 0505E Inlet OPI dam, 0-Peak 21161 18. 1Y13 AM INLET IN A SUMP OR SAG LOCATION Protect • HP Building 6 ParMng Lot Explanation Inlet ID • HE comer Western alka of Loacr Parking Let (DP gel L. (C) N-Van We Np A' "Ran Inlomlallon Road, ype n one Inlet Type nut Depteeean Patio eael to coninuoVe Buller ufpreeelon'e'Imm CAnne) w• lumner of Unit Inns (Crete of Cut Conant) Ne YMr Dentin M Fawl nit ("Me of Real numanmmil pard, Depth • 'enalnfomtnkn faun of a Unit Grno L. (G) .,a 01 a One Goal. We, me Open., Ratio for a Greek (lygWl Me. 01 SJac A a • brunt F., ar a Seale Case peo al vaue 0.50 -0 Tp) Q (G) an, Weir Cehciem 0ypiral value 2 15.3.e0) c. (G) Isle Cale eoeRlnleat (Niplall value 0 W- 0 e0) Ce (G) '.et opening Irrfofmnan each of It Unit out Oman I e (c) • roanof vetui cum Cllan la lianas tin' kcn M cut orlo. Tltmal In Inches Nmr' rele of Tnron (sae UBDCM Fdgne ST-5) Tnea • Me Wkh for Oepmeakn Pan offooally lM gutln inch of 2 fan) Wi' kaxem Fuel 1.. Slack Cum Opening (tooled Make 0.10) ca (0) '.um Opening Weir Coamtlml topical .1. 2.3 311) C. (c) • lure Opening Oflnne Coenkkn (typical enue 0.60- 0]0) C. (e) • 'ofal Inlet Interception Capacity (assumes clogged condition) Q. a YARNING: Inlet Capacity offs than O Peak In MAJOR Stein D,.e..,ne,a - MINOR MNIXV COOT Typo R LUN Openlry 3.00 In•Jree 1 8g 00 MINOR MAJOR �] O"amea peace WA ael WA halt WA WA WA WA WA 5,00 6,00 6,00 6340 2,00 0m 010 360 0,67 Some overflow is expected at this location - the overflow (4.9 cfs) will spill down the slope into the Swale and be conveyed to the pond Determine Required Length of Weir for given Flow and Head Formula : Q = CLHA312 L = Q/CHa3J2 Qcfs Hft C Lft 4.9 0.5 2.6 5.33 For a flow depth of 0.5 feet over the top of the curb (1-ft deep @ flowline) the required weir length, i.e. overtopped length, would be approximately 5 feet. 2053 05056 Inlet DP2A,dAam, Inlet In Sump 2/162016, 11 13 AM Project Description Friction Method Manning Formula Solve For Normal Depth Input Data Channel Slope 0.00500 f 4t 14 00 g'/s Discharge � Qdesign = Section Definitions 1.33-Q 100 Station (it) Elevation (ft) 1+00 4890.00 1+00 4889.00 1+10 4888.80 1+12 4888.72 1+13 4888.80 1+23 4889.00 1+27 4890.00 Roughness Segment Definitions Start Station (1+00, 4890,00) (1+00, 4889,00) (1+10, 4888.80) (1+13, 4888,80) Options Ending Station (1+00, 4889.00) (1+10. 4888.80) (1+13, 4888,80) (1+27, 4890.00) current rtougnness weighted Pavlovskirs Method Method Open Channel Weighting Method Pavlovsko's Method Closed Channel Weighting Method PaVIOV5ku'S Method Results Normal Depth 0.52 ft Elevation Range 4888.72 to 4890.00 ft Flow Area 9.27 Roughness Coel6cient 0.016 0.032 0.016 0.032 Bentley Systems, Inc. Bentley FlowMaster VBI (SELECTsenes 1) [08.11.01.031 2/16/2016 12:13:43 PM 27 siemons Company Drfva Suite 200 W Watertown, CT 06796 USA +1403-76&1668 Page 1 of 2 I 1 1 n I 1 t 1 I I Worksheet for Pond channel Qdesign Results Wetted Perimeter 24.22 It Hydraulic Radius 0.34 ft Top Width 23.95 ft Normal Depth 0.52 It Critical Depth 0.39 ft Critical Slope 0.02230 ftM Velocity 1.69 tvs Velocity Head 0.D4 It Specific Energy 0.56 ft Froude Number 0.51 Flow Type Sulecritical GVF Input Data Downstream Depth 0.00 It Length O.DO ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Downstream Velocity Infinity ft/s Upstream Velocity Infinity Ns Normal Depth 0.52 ft Critical Depth 0.39 It Channel Slope 0.00500 ft/ft Critical Slope 0.02230 fUft Bentley Systems, Inc. Bentley FlowMaster VSI (SELECTseries 1) [08.11.01.03] 21161201612:13:43 PM 27 Slemons Company Drive Suite 200 W Watertown, CT 06796 USA +1-203-756-1666 Page 2 of 2 1 Cross Section for Pond channel Qdesign Project Description Friction Method Manning Formula Solve For Normal Depth Input Data Channel Slope 0.00500 ftft Normal Depth 0.52 t Discharge 14.00 ftYs pond wall Cross Section Image 489�.20 4890.10 4890.00 4869.90 - 4:1 slope t, 4889.80 4889.70 parking lot 4889.60 4889.50, 488940 4889.30 W 4889.20 4889.10 4888.90889. (10 10 ft @ 2%bc 4888.80 side of pan 4888.73 4888.64i 4888,50 1+05 1+10 1+15 1+20 1+25 1+00 13-ft vallev Dan I Bentley Systems, Inc. Bentley FlowMester V8i (SELECTserles 1) [06.11.01.031 2I612016 12:14:04 PM 27 Sleri Company Drive State 200 W Watertown, CT 06796 USA +1.203-755.1666 Page 1 of 1 Worksheet for Pond channel Project Description Friction Method Manning Formula Solve For Normal Depth Input Data Channel Slope 0 00500 tuft Discharge 10.53 Wfs Section Definitions Station (ft) Elevation (ft) 1+00 4890.00 1+00 4889,00 1+10 4888.80 1+12 4888,72 1+13 48B8.80 1+23 4889,00 1+27 4890.00 Roughness Segment Definitions Start Station Ending Station (1+00, 4890.00) (1+00, 4889.00) (1+00, 4889.00) (1+10, 4888.80) (1+10, 4888.80) (1.13, 4886 80) (1+13, 4688,80) (1+27, 4890 00) Options current tlougnness welgmeo PavlovskiPs Method Method Open Channel Weighting Method PavlovskiPs Method Closed Channel Weighting Method PavlovskiPs Method Results Normal Depth 0.46 ft Elevation Range 4888.72 to 4890.00 ft Flow Area 6.95 ft Roughness Coefficient 0.016 0 032 0,016 0.032 Bentley Systems, Inc. Bentley FI"IW et V81 (SELEC.Tserles 1) 108.11,01.031 2/16/2016 12:10:45 PM 27 Siemens Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 2 Worksheet for Pond channel Results Wetted Perimeter 23.93 ft Hydraulic Radius 0.29 ft Top Width 23.72 ft Normal Depth 0.46 ft Critical Depth 0.35 ft Critical Slope 0.02368 ft/ft Velocity 1.52 ft/s Velocity Head 0.04 ft Specific Energy 0.50 It Froude Number 0.49 Flow Type Subcritical GVF Input Data Downstream Depth 0.00 it Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 If Profile Description Profile Headloss 0.00 If Downstream Velocity Infinity fUs Upstream Velocity Infinity f /s Normal Depth 0.46 ft Critical Depth 0.35 ft Channel Slope 0,00500 tuft Critical Slope 0.02368 ft/ft Bentley systems, Inc. Bentley FlowMaster Vei (SELECTseries 1) [08.11.01.031 21161201612:10:45 PM 27 Siemens Company Drive Suite 200 W Watertown, CT 06795 USA +1-203455-1666 Page 2 of 2 Cross Section for Pond channel Project Description Friction Method Manning Formula Solve For Normal Depth Input Data Channel Slope 0.00500 tuft Normal Depth 0.46 ft Discharge pond wall 10.53 ft-/s Cross Section Image 4890.20 4890.10 4890.00 _ 4889.90 4889.80 4889.70 4889.60 _ 4889.60 4889.40 4:1 slope to 4889.30 1parking lot W 4889.20 4889.10 4869.00 4888.90 4888,80 4888.70 -. 4888.60 4888.50 1.05 1 .1J 1.16 1.20 1,25 1.00 10ft@2%both sides of pan 13-ft valley Dan I Baetley SyaMne, Ine. Bantlty PtorrtIWW Vll(EP.LECTWIN 1) [18.1'1.01.0]j 2M61201612:10:28 PM 27 Blamona Company 0" SUND 200 W Wtlwtown, CT 16711 USA .1. 03.7WIM Papa 1 of 1 u FINAL DRAINAGE AND EROSION CONTROL REPORT Appendix D - EXCERPTS FROM PREVIOUS DRAINAGE REPORTS December 23, 2015 ' Appendix D - EXCERPTS FROM PREVIOUS DRAINAGE ' REPORTS [1 r [l 1 1 1 11 1 1 ' DA ® Stantec FINAL DRAINAGE STUDY FOR HEWLETT-PACKARD COMPANY BUILDING 5 FORT COLLINS, COLORADO October 4, 1996 Prepared for: H + L Architecture 1621 18th Street, Suite 100 Denver, Colorado 80202 Prepared by: RBD, Inc. Engineering Consultants A Division of Sear Brown 209 South Meldrlun Fort Collins, Colorado 80521 (970) 482-5922 RBD Job No. 282-015 REV. 3 's unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com or additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA RMINC. Engineering Consultants A divisimi ofThe.Ya Brnwn Group 209 S. Meldrum Fort Collins, Colorado 80521 970/482-5922 October 4, 1996 Mr. Basil Hamdan. City of Fort Collins Utility Services - Stormwater 235 Mathews Street Fort Collins, Colorado 80522 RE: Final Drainage Study for Hewlett-Packard Company Building 5 Dear Basil: We are pleased to resubmit to you, for your review and approval, this Final Drainage Study for the revised Hewlett-Packard expansion. All computations within this report have been completed in compliance with the City of Fort Collins Storm Drainage Design Criteria. We have addressed the minor comments noted from your review dated 9-23-96. We appreciate your time and consideration in reviewing this resubmittal. Please call if you have any questions. Respectfully, RBD Inc. Engineering Consultants AmA by: �4`�� R��°�g'�. Reviewed by: n-MorleyP. � <° Kevin W. Gingery, PE Engineer ��' Project Manager, Water Resources t� tuat_� cc: Maryanne Dinkey - Hewlett-Packard Mark Williams - H + L Denver 3031458-5526 1rhis unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com or additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA DESC IMON PAGE GENERAL LOCATION AND DESCRIPTION 1 I. A. Location I B. Description of Property I II. DRAINAGE BASINS I A. Major Basin Description I B. Sub -Basin Description 2 C. SWMM Revisions 2 III. DRAINAGE DESIGN CRITERIA 3 A. Regulations 3 B. Development Criteria Reference and Constraints 3 C. Hydrologic Criteria 3 D. Hydraulic Criteria 3 E. Variances from Criteria 3 IV. DRAINAGE FACILITY DESIGN 3 A. General Concept 3 B. Specific Details 4 V. STORM WATER QUALITY 5 A. General Concept 5 VI. EROSION CONTROL 5 A. General Concept 5 B. Specific Details 5 VII. CONCLUSIONS 6 A. Compliance with Standards 6 B. Drainage Concept 6 C. Storm Water Quality Concept 7 D. Erosion Control Concepts 7 REFERENCES 7 APPENDIX VICINITY MAP 2 HYDROLOGY 3 DESIGN OF INLETS, STORM DRAIN, AND SWALES 14 100-YEAR SWMM MODEL 68 [lbis unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com nr additional information or an official coov. please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA 1 1 1 1 1 1 1 1 1 i 1 1 1 1 TABLE OF CONTENTS (continued) REGIONAL STORM DRAINAGE CHANNEL 81 RIP RAP DESIGN 98 EROSION CONTROL 101 Total pages 110 is unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com or additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA FINAL DRAINAGE STUDY FOR HEWLETT-PACKARD COMPANY BUILDING 5 FORT COLLINS, COLORADO GENERAL LOCATION AND DESCRIPTION A. Location The Hewlett-Packard site is located in southeast Fort Collins (see vicinity map in Appendix), north of Harmony Road and east of County Road 9 within the Southwest 1/4 of Section 33, Township 7 North, Range 68 West of the 6th P.M., City of Fort Collins, Latimer County, Colorado. B. Description of Property The Hewlett-Packard Building 5 site is north of the existing Fort Collins Hewlett- Packard office and industrial development and encompasses approximately 24.5 acres. The existing topography generally slopes from west to east at approximately 0.7 percent. Native grasses overlaying lean clay with sand or sandy lean clay cover the majority of the site except for existing parking areas located in the southeast corner. The proposed site consists of one large office buildings and surrounding parking areas which will be developed in a similar style to the previous development. DRAINAGE BASINS A. Major Basin Description The Hewlett-Packard site lies entirely within the Fox Meadows Drainage Basin which is approximately bounded by Horsetooth Road on the north, Harmony Road on the south, the Cache La Poudre River and I-25 on the east and Lemay Avenue on the west (refer to the general location Map in Appendix). A Master Plan for the Fox Meadows Drainage Basin (Basin H) was prepared by Resource Consultants, Inc., in 1981. This area was studied again by Nolte and Associates in 1990 when a master drainage plan was prepared for the Hewlett-Packard site. Nolte's master drainage report did not alter any of the assumptions or conclusions which were made in the Fox Meadows Master Drainage Plan. As recommended in Nolte's Report a regional drainage channel is designed to accept 100-year storm event flows from the developed site and the upstream 1 is unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com or additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA ' basins from the west. The channel is located along the north side of the Hewlett- Packard site and discharges to the existing north detention pond. ' The north detention pond discharges to a series of detention ponds to the south ' through a 30 inch diameter pipe. Nolte's report recommended that the 30-inch diameter outlet pipe of this north pond be enlarged to 48-inch diameter at the development of the entire Hewlett Packard Site. This increased diameter is required ' to avoid surcharging the north detention pond which would result in uncontrolled overland flow. It is not clear at which point in the development the outlet pipe should be enlarged. The upgrading of this outlet pipe is outside the scope of this ' project and is not being constructed at this time. B. Sub -Basin Description Historically the site receives flows from the west at two discharge points along County Road 9. Flows discharge from the former NCR site, now Symbios, through two 30-inch concrete pipes under County Road 9 at the top of the proposed regional drainage channel. Flow from the second discharge point at the northwest corner of the Hewlett-Packard property presently comes from an existing 18-inch ' CMP culvert in poor condition and a newly constructed 18 inch diameter RCP pipe. Future flows are expected from the Symbios site and the English Ranch Subdivision. These offsite flows and the onsite flows then flow east overland across the site to the Fossil Creek Reservoir Inlet Ditch. (refer to Figure 2 Fox Meadows Drainage Master Plan in the appendix). A small portion of the site which is currently landscaped discharges flows into the existing stormwater system ' to the south. C. SWMM Revisions ' Infiltration parameters in the SWMM model were updated to match current City of Fort Collins Stormwater Utility criteria. The proposed upstream detention ponds were previously modeled as pipes allowed to surcharge; these were remodeled using three-point rating curves to limit discharge to the 24 cfs each recommended by the Fox Meadows Master Drainage Plan. As described in the ' Appendix, the two on -site basins (30 and 34) were updated to match current grading, particularly that associated with this project. The conveyance elements (35,36 and 38) which comprise the regional drainage channel were updated. from ' the site master plan to match current design. Additional changes in the basin have occured since the above mentioned SWMM ' model changes were completed. Specifically the addition of the Symbios site to the west. The Symbios site is required to detain and release at a 100 year rate of 24 cfs which is accounted for in this SWMM model. - The Symbios report is not 1 1 2 J 1 I i I 1 unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com Vis or additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA ' for the final site condition and has not yet been approved, therefore we have not updated this SWMM model to reflect the new Symbios site. ' ' III. DRAINAGE DESIGN CRITERIA ' A. Regulations , The City of Fort Collins Storm Drainage Design Criteria is being used for the ' subject site. Criteria as established by the Fox Meadows Basin Drainage Master Plan will also be used. ' B. Development Criteria Reference and Constraints , The Hewlett-Packard Building 5 site drainage and proposed drainage channel are designed in conformance with the Fox Meadows Drainage Basin Master Plan (Basin H) and the Hewlett-Packard Master Drainage Plan. ! C. Hydrologic Criteria ' The runoff for the regional drainage channel and site detention requirements are , calculated using a SWMM model, updated from Nolte's Master Drainage Plan ' These will be designed for the 100-year storm event. The most recent 100-year storm event hyetograph and infiltration parameters determined by the City of Fort ' Collins are used in calculating runoff values. The rational method is used to determine the peak flow from the developed runoff ' for design of the hydraulic structures and interior roadway drainage facilities. These are designed using the 10 and 100 year rainfall criteria from the City of Fort Collins. , ' D. Hydraulic Criteria All hydraulic calculations within this report are prepared in accordance with the ! City of Fort Collins Drainage Criteria and included in the Appendix. E. Variances from Criteria ! No variances are being sought for the proposed project site. i 3 ' 's unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com or additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA , IV. DRAINAGE FACILITY DESIGN ' ' A. General Concept , All developed runoff except for sub -basin 15 is routed northeasterly to the regional drainage channel along the north perimeter of the Hewlett-Packard property. Sub - basin 15 discharges to the existing system to the south. ' The western portion of the site will remain undeveloped except for a temporary ' circulation road. This area will generally flow overland to the regional drainage channel. ' The roof drainage is collected from two points and discharged by pipe to the regional drainage channel. , All other runoff, which is produced by the parking lots, will surface flow to the north and east discharging through Type R curb inlets into the regional drainage t channel. The flows in the regional drainage channel pass through a culvert underneath the east access road and into the existing north detention pond. ' B. Specific Details ' Storm water from sub -basin 5, flows north towards the regional channel and is intercepted by curb and gutter and taken to the east towards design point 6. The , flow from sub -basin 5,6 and 7 then discharges to the regional channel through a 15 foot wide Type R curb inlet. Storm water from sub -basin 8 is in 10 collected a ' foot Type R curb inlet with the by-pass flow continuing to design point 11. No storm flow is intercepted until design point 13 where a 15 foot wide type R inlet intercepts the flow. The by-pass flow ' a portion of continues to the south east in ' the curb a gutter until design point 16/17 where flows are intercepted by a 15 foot wide Type R inlet. Design point 16/17 is inundated during the 100 year storm to a level of 4910.13 with flows passing around the curb return and across the access e ' drive into the north detention pond. During the 10 year storm all flows pass to the regional channel through 10 foot wide Type R Inlet. No flows will pass off site , during either the 10 year or 100 year storm event. Please refer to the Appendix ' for water surface elevations and calculations. ' The Storm water from the building roof area discharges from the north side of the building and flow to a single point northeast of the buildings and is taken to the regional drainage channel by a single pipe. Storm water from 15 flows sub -basins to existing area inlets to the south. ' 4 rhis unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA i Basin 1, the eastern half of County Road 9 Avenue flows in the street to inlets which discharge to the regional channel. This is considered in the SWMM model. Basin 3 is unimproved except for the western portion of a temporary circulation road. Storm water from this sub -basin sheet flows from west to east then southeast j� to the regional channel. No positive grading to control flows is anticipated. 1 Basin 4 is unimproved except for the eastern portion of the temporary circulation l� road. Storm water from this sub -basin sheet flows east to the edge of the proposed parking circulation road where a shallow ditch takes flow north to a culvert which discharges to the regional channel. V. STORM WATER QUALITY A. General Concept I Hewlett-Packard is anticipating construction beginning in Fall 1996. We have sought to find various Best Management Practices for the treatment of storm water runoff. The Hewlett-Packard project will be providing a grassed regional drainage f�channel and existing grassed detention ponds. These grass -lined features will f provide a mechanism for pollutants to settle out of the storm water runoff before entering the Fossil Creek Reservoir Inlet Ditch or downstream storm drainage facilities. VI. EROSION CONTROL A. General Concept This development lies within the Moderate Rainfall Erodibility Zone and the Moderate Wind Erodibility Zone per the City of Fort Collins zone maps. The l potential exists for erosion problems after completion of the improvements, due J to some existing and proposed site slopes of greater than 2 percent. It is also anticipated that the project site improvements will be subject to both wind and 1 rainfall erosion before new vegetation can take hold or before the project is J completed. i(} The Erosion Control Performance Standard (PS) during construction for this project was computed to be 75.9 percent per the criteria in the City of Fort Collins Erosion Control Reference Manual for Construction sites. The Effectiveness (EFF) of the proposed erosion control plan during construction was calculated to be 79.8 percent. Therefore, the erosion control plan below meets the City of Fort ' Collins' requirements. The Effectiveness of the proposed erosion control plan after construction is 98.4% which exceeds the required 89.2%. A copy of the I l S fJ [rhis unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: httpa/citydocs.fcgov.com or additional information or an official copy, please contact Ciry of Fart Gllins Utilities 700 Wood Street Fort Collins, CO 80524 USA I ' calculations has been included in the Appendix. An erosion control escrow cost ' estimate of $18,826.00 is also included in the Erosion Control section of the Appendix. B. Specific Details Prior to over lot grading gravel inlet filters must be placed over the two existing inlets at the west portion (basin 9) of the site. After the over lot grading has been completed, the regional drainage channel shall have temporary vegetation seed applied and sedimentation berm installed. After seeding, a hay or straw mulch shall be applied over the seed at a rate of 2 tons/acre minimum, and the mulch shall be adequately anchored, tacked, or crimped into the soil. All other areas which will not be covered by asphalt or building will have a roughened surface. ' Those roads and parking lots that are to be paved as part of the Building 5 project must have a 1-inch layer of gravel mulch ('A" to 11h" gravel) applied at a rate of at least 135 tons/acre immediately after over lot grading is completed. The ' pavement structure shall be applied as soon as possible after the utilities have been installed. After installation of the concrete sidewalk culvert and curb inlets, the inlets shall be filtered with a combination of concrete blocks, 1h" wire screen, and ' 3/4"coarse gravel. After installation of the storm drains, riprap protection and gravel inlet filters shall be installed at the outlets. If the disturbed areas will not be built on within one growing season, a permanent seed shall be applied. After seeding, a hay or straw mulch shall be applied over the seed at a minimum rate of 2 tons/acre, and the mulch shall be adequately anchored, tacked or crimped into the soil. In the event a portion of the roadway pavement surface and utilities will not be constructed for an extended period of time after over lot grading, a temporary vegetation seed and mulch shall also be applied to the roadway areas as discussed above All construction activities must also comply with the State of Colorado permitting ' process for Storm water Discharges Associated with Construction Activity. A Colorado Department of Health NPDES permit will be required before any construction grading can begin within this development. L� I 1 6 is unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.wm ' or additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA 1 1 17 u I i I �I I I r I r ' ' VII. CONCLUSIONS ' A. Compliance with Standards All computations that have been completed within this report are in compliance with the City of Fort Collins Erosion Control Reference Manual for Construction , Sites and the Stone Drainage Design Criteria Manual. ' B. Drainage Concept , The proposed drainage concepts adequately provide for the transmission of developed onsite nmoff to the existing drainage facilities at the eastern edge of the subject site. The 100-year runoff generated by development of this site will be carried to the proposed regional drainage channel then to existing onsite detention ponds. The detention ponds will then discharge to the Fossil Creek Reservoir Inlet Ditch in accordance with the Fox meadows Basin (Basin H) Drainage Master Plan. ' If for some unforeseen reason groundwater is encountered at the time of construction, a Colorado Department of Health Construction Dewatering Permit ' would be required. C. Storm Water Quality Concept Because storm water quality has become a requirement, the site has addressed this storm water aspect. The grass lined regional drainage channel and the existing detention ponds will provide a mechanism for water pollutants to filter out of the storm water runoff before entering the Fossil Creek Reservoir Inlet Ditch or downstream storm drainage facilities. D. Erosion Control Concepts . The proposed erosion control concepts adequately provide for the control of wind and rainfall erosion from the Hewlett-Packard Building 5 expansion. Through the construction of the proposed erosion control concepts, the City of Fort Collins performance standards will be met. The proposed erosion control concepts presented in this report and shown on the erosion control plan are in compliance with the City of Fort Collins erosion control criteria. REFERENCES 1. Storm Drainage Design Criteria and Construction Standards by the City of Fort Collins, 1 Colorado, May 1984. 7 ' is unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydocs.fegov.com or additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA FA 3 4 1 1 1 1 1 1 1 Erosion Control Reference Manual for Construction Sites by the City of Fort Collins, Colorado, January 1991. Fox Meadows Basin (Basin H) Drainage Master Plan, Fort Collins, Colorado, by Resource Consultants Inc., February 25, 1981. Master Drainage Report, Hewlett Packard Site, Preston Kelly Subdivision, Fort Collins, Colorado by Nolte and Associates, revised October 1990. Overall Drainage Study for the NCR Site and Preliminary Drainage Study, First Phase NCR Site, Fort Collins, Colorado, by RBD, Inc., Engineering Consultants, May 2, 1994. 8 1rhi-s unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydms.fcgov.com or additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA • x 'A PROF EROff WORT'+: -.,' r�p.}{� _ .rT - ,•-• .. .. , :.. :.,:: •fir^^' ((n.J�{{ ^^�.:: .;:. _. i �• 1. • Ir '•r �. 1 J'It• r• r '� ' 1. is •4n' - :(Y1 •i -. _ ,'t- it Study ,Detailed.Hydraulic ( J` Regonal:'Detention Facilities: `( : •1 I Y '1• X. �•• _ _ ., ,+. .. :11 ' :j' •ram •', •-.J,.,:+ :, '�•:1 _ •rf -I, T 5 R• - 'I 1 n.'\� �,�',n i �• G 1 � .. Jai: _tom' / / 1� •+l . ,i• Packard:: _ C•o -. Y .�wl�ett �•• .O ,•, •-ti � hn � �C.olorad ..1 ••1 1, I • -,. t• l/ 1 .R.: 'ice ?{' .;' f\- .'' .I• •; ''• 'f r:: 'L .� ryt r( 1• I :I t! 1 IJ• •1 A �. 1• . .1 �J u y� ,r• a' .I . t r' .y . , i. :fir i •i .t rt 'T 'tr •): r. .l. 2 /Its\�� .,• J..•1• •f v .",' f. ... Y' • M1' 1 'G '-f .li . . I' I: 1 1 i , i. V, Yi- : Ir wr R•'BROWN• ;•: . "',�'+', is unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com r: • • ' ,- or additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA:- a a SEAR• BROWN July 3; 2000 Mr. Basil Hamdan City of Fort Collins Stormwater Utility Services . 700 Wood Street Fort Collins, Colorado 80522 ARCHITECTURE 209 South Meldrum ENGINEERING Fort ColiinsX080521-2603 PLANNING 970.482.5922 phone CONSTRUCTION 970.482.6368 fax www.searbrown.com RE: Detailed Hydraulic Analysis of HP Site Regional Detention Facilities Dear Basil: We are pleased to submit to you, for your review, this revised Detailed Hydraulic Analysis for the Regional Detention Facilities at the Hewlett-Packard Site on Harmony Road in Fort Collins. All computations within this report have been completed in compliance with the City of Fort Collins Storm Drainage Design Criteria. We appreciate your time and consideration in reviewing this submittal. Please contact us if you have any questions. Respectfully, Sear -Brown Prepared By: /JYereyFranz, E.I.T. Water Resource Engineer File: 564-014 (B) Reviewed By: c�Lj David K. ThE Senior Engineer - I unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydoes.fcgov.com additional information or an official coov. please contact Citv of Fort Collins Utilities 700 Wood Street Fort Collins. CO 80524 USA 11 PAGE 1 EXECUTIVE SUMMARY ...................................................... iv I. GENERAL LOCATION AND DESCRIPTION A. Location....theSit...............................................1 B. Description of the Site • 1 II. REGIONAL DRAINAGE HISTORY A. Major Basin Description............................................I B. Sub -basin Description..............................................I C. Previous Drainage Studies...........................................2 III. PROJECT SCOPE A. SWMM Model Update.............................................3 1. EXTRAN SWMM Model ....... • 4 2. Physically Based SWMM Model ................................ 4 ' 2. Interim & Final SWMM Models ................................ 6 B. SWMM - EXTRAN Model of Regional Detention Facility ................. 6 1. EXTRAN Description ........................................ 6 2. Extent of EXTRAN Model • • 7 3. Modeling Approach..........................................7 IV. HYDRAULIC ANALYSIS A. Regional Drainage Channel and Culvert ................................ 8 1. Analysis...................................................8 2. Recommendations........................................9 B. North Pond.......................................................9 1. Analysis .................................................9 2. Recommendationss.. • • 9 C. Volleyball and Basketball Court Area .................................. 9 ' 1. Analysis ................................................10 2. Recommendationss .10 D. Closed Storm Drain System ......................................... 10 1. Analysis .................................................. 2. Recommendationss 10 .II E. South Ponds.....................................................11 1. Analysis..................................................II 2. Recommendations..........................................II F. Dam Pond.......................................................12 1. Analysis..................................................12 i_ VIM unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com or additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA M 11 V CONCLUSION A. Regional Channel .................................................13 B. Volleyball and Basketball Court Area ................................. 13 VI. REFERENCES........................................................17 �1 ii copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydoes.fcgov.com runofficial or additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood street Fort Collins, CO 80524 U: PROJECTLOCATION.........................................................1 OVERALL SWMM BASIN SCHEMATIC FROM NOLTE AND ASSOCIATES .......... 3 SWMM BASIN REVISIONS FOR HEWLETT-PACKARD BUILDING 5 ................ 5 SWMM BASIN REVISIONS FOR SYMBIOS LOGIC ............................... 11 SWMM BASIN REVISIONS FOR HP BUILDING 4 EXTRAN SWMM MODEL ......... 26 ' 100-YEAR FULLY DEVELOPED CONDITION SWMM MODEL USED TO GENERATE EXTRAN HYDROGRAPHS ............................... 41 61 EXTRAN MODEL DEVELOPMENT CALCULATIONS ............................ EXTRAN MODEL INPUT AND OUTPUT FILES ................................. 105 EXTRAN OUTPUT SUMMARY ............................................... 164 SWMM BASIN REVISIONS FOR HP BUILDING 4 FINAL SWMM MODEL .......... 177 100-YEAR FULLY DEVELOPED CONDITION SWMM MODEL WITH PHYSICALLY BASED POND RATING CURVES ............................................. 184 EXTRAN OUTPUT SYNTHETIC POND RATING CURVE DEVELOPMENT ......... 213 100-YEAR FULLY DEVELOPED CONDITION SWMM MODEL WITH SYNTHETIC ,. POND RATING CURVE ..................................................... 233 is unofficial copy was downloaded on ]ul-23-2015 from the City of Fort Collins Public Records Website: http://citydocs.fegov.com or additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA EXECUTIVE SUMMARY Purpose ' • The City of Fort Collins, as part of the Drainage Design requirements for Hewlett- Packard Building 4 construction, has required an analysis of potential flooding conditions at the eastern end of the Hewlett-Packard (HP) site in Fort Collins, Colorado. • Potential for flooding to the Fossil Creek Reservoir Inlet Ditch (Fossil Creek Ditch) was ' identified in the Master Drainage Report for the Hewlett-Packard Site, Preston Kelly Subdivision, by Nolte and Associates in 1990. • This report has been prepared as part of the Building 4 Drainage Design to address the 1 issues brought up in the Nolte report. Confirm Flooding to Fossil Creek Ditch • Detailed hydraulic analysis has been performed using the EXTRAN block of SWMM ' 4.40. EXTRAN allows analysis of hydraulic systems with time -dependent flow and tailwater conditions by solving the full set of Saint-Venant Equations. • Analysis of the HP site, with runoff from a 100-Year storm, confirms limited flooding 1 conditions, restricted to the eastern access road and the southeastern entrance, and depths ' of water less than 10-inches. • Recommendations presented in this report are intended to prevent uncontrolled flow of stormwater runoff into the Fossil Creek Ditch. Recommended Improvements Regional Channel • Based on a survey performed for this report, the north bank of the regional channel was not constructed according to the design plans. • Construct bank of the regional channel to elevation 4911.0. Regrade service road ' to elevation 4911.0. iv J is unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA North Ball Field i Pond and ' 0 100-Year flows are contained within the existing pond, with approximately 1 R of in , freeboard. No improvements are recommended this area. ' • A small berm (approximately 1.0 fl) has been graded in along the eastern side of flow inches deep, the volleyball and basketball courts, to prevent overland (6 maximum) from heading east toward Fossil Creek Ditch. The construction of this berm was completed based on the recommendation of a previous version of this improvements in this report. Therefore, no additional are recommended area. ' Conclusion , ' • The grading improvements recommended in this report are sufficient to prevent the flow of water from the HP site into the Fossil Creek Ditch. uncontrolled ' • One area of grading improvements is necessary along the regional channel and overflow parking access road. The construction of these improvements will positively convey runoff through the fence between the ball fields and to the Dam Pond for further , detention and controlled release. These improvements should be designed and built with the HP Parking currently in the design phase. project , i r i i 1 1- i v 1rhis unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydms.fcgov.com or additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA , DETAILED HYDRAULIC ANALYSIS REGIONAL DETENTION FACILITIES HEWLETT-PACKARD COMPANY FORT COLLINS, COLORADO I. GENERAL LOCATION AND DESCRIPTION A. Location The Hewlett-Packard Site discussed in this report is located in Fort Collins, Colorado, north of Harmony Road and east of County Road 9 (see the Vicinity Map in the Appendix, page 2). The site lies within the southwest 1/4 section of Section 33, Township 7 North, Range 68 West of the 6ih Principal Meridian, City of Fort Collins, Larimer County, Colorado. B. Description of the Site The project site encompasses the Hewlett-Packard (HP) facility on Harmony Road in Fort Collins. It is bounded by Harmony Road on the south, County Road 9 on the west and a regional drainage swale on the north and east sides. The entire site totals approximately 152 acres. Historic vegetation and topography have been developed into buildings and parking lots to the extent that the current level of development approaches the Fully Developed Condition envisioned by early master planning efforts performed by Nolte and Associates in 1990. rH. REGIONAL DRAINAGE HISTORY A. Major Basin Description The Hewlett-Packard site lies entirely within the Fox Meadows Drainage Basin. The Fox Meadows basin is approximately bounded by Horsetooth Road on the north, Harmony Road on the south, the Cache La Poudre River and 1-25 on the east, and Lemay Avenue on the west. Storm runoff travels from west to east, and ' discharges to the Cache La Poudre River, B. Sub -basin Description The HP site sub -basins drain from west to east over the site, traveling as overland ' flow, channel flow and pipe flow to reach one of the four detention ponds on the site. Closed pipe systems connect the ponds, allowing them to drain to the Dam Pond on the southeast corner of the site. See page 14 in the text for a map of the site with the ponds and athletic facilities labeled. The three southern ponds are also used for irrigation and are designed to retain the irrigation water and allow _ excess stormwater to flow downstream. The final collection pond on the HP site, `'.. 1 's unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com ' or additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA ' the Dam Pond, releases minor flows through aN 18-inch/24-inch pipe combination to the Fossil Creek Reservoir Inlet Ditch, and diverts major flows over the ditch via an overflow spillway on the east embankment of the pond. C. Previous Drainage Studies Drainage studies for this drainage basin began in 1976 with a "Drainage ' Study for Hewlett- Packard," performed by ' Anderson and Hastings Consulting Engineers, Inc. A further study was ' performed in 1979 by James H. Stewart & Associates entitled "Report ' of Drainage Study, North Portion of Preston - Kelly Subdivision." Master I I I planning was initiated by the City of Fort Collins in 1981 with the "Fox Meadows Basin (Basin H) Drainage Master Plan," developed by Resource Consultants, Inc. This original master plan forms the basis for all later development studies. A "Master Drainage Report, Drainage Study Anderson and Hastings, 1976 Drainage Study Stewart & Associates, 1979 Drainage Master Plan of Entire Basin Resource Consultants, 1981 Updated Hydrology for the Fox Meadows Basin Resource Consultants, 1987 Master Drainage Report Nolte and Associates, 1990 HP Building 5 Drainage Report The Sear -Brown Group, 1996 Symbios Logic Site Development The Sear -Brown Group, 1997 . HP Building 4 The Sear -Brown Group, 1998 Figure: History of Drainage Studies Prepared for Hewlett- Packard Site, Preston Kelly Subdivision, Fort Collins, Colorado," was prepared by Nolte and Associates. This Master Plan established the SWMM model for the drainage basin. The report by Nolte did not change any assumptions or conclusions from the Master Plan prepared by Resource Consultants. Later development projects have revised the original SWMM model by Nolte. More recent development in this basin has included the HP Building 5 construction, Symbios Logic site development just west of County Road 9, and HP Building 4 construction, for which this report is required. The SWMM updates for these three projects were performed by RBD, Inc. / The Sear -Brown Group. The Nolte SWMM model was updated during the design for HP Building 5 to reflect the additional impervious surface area from the building and parking is unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com or additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA a M lots. The 100-Year regional drainage Swale proposed by the Nolte report was designed and constructed with the Hewlett-Packard Building 5 project. The SWMM Model was further updated for the Symbios Logic development to account for changes in basin imperviousness and on -site detention upstream of the HP site. The discharge from the Symbios Logic site flows in the regional channel to the on -site detention ponds on the HP site. The Final Drainage and Erosion Control Study for Hewlett-Packard Building 4 did not make any changes to the SWMM model from the Building 5 update. It was determined that the basin parameters used for the Building 5 update of the model were sufficient to represent the additional impervious area associated with Building 4. Therefore, the Symbios Logic SWMM model was used as the starting point for updates associated with this project. The Final Drainage and Erosion Control Study for Hewlett-Packard Building 4 (The Sear -Brown Group, April 1998) did not update the SWMM model. This detailed hydraulic analysis, however, does make some minor adjustments to the SWMM basin lines within the HP site to reflect actual site grading and closed drainage systems. These changes were used to develop hydrographs for the EXTRAN model required for this project and also incorporated into the final SWMM model included in the appendix. This final SWMM model, in the appendix section labeled "100-Year Fully Developed Condition SWMM Model," contains the most up-to-date information for the entire basin, including revisions for HP buildings 4 and 5, and the Symbios Logic site west of County Road 9. This model should be used for any further updates to this watershed. III. PROJECT SCOPE A. SWMM Model Update This report has been prepared to address the potential of uncontrolled flooding caused by the overtopping of the north detention pond, as mentioned in the Master Drainage Report by Nolte and Associates, 1990. In order to assess the potential flooding conditions resulting from build -out at the end of Building 4 construction, the Fox Meadows Basin (Basin H) SWMM model basin boundaries were updated in two ways. The basin boundaries were updated both 1) inside the HP site and 2) along the perimeter. The internal basin boundaries were adjusted to reflect actual drainage patterns from the buildings and closed drainage systems between the buildings, including changes made to storm sewers associated with Building 4. Perimeter basin limits along the northern and eastern basin boundaries of the SWMM model were adjusted to include the regional detention channel in its constructed location. Previous studies appeared to approximate its location. The basin adjustments along the perimeter caused an overall increase in the watershed area for the HP site of about seven percent (70/o), to a new value of 151.8 acres. This area was not is unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Websitc: http://citydocs.fcgov.com or additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA subtracted from the adjacent drainage basin to the north. The drainage basin to the north is a separate part of the Fox Meadows Basin, and as such, has a separate ' SWMM model. See page 28 in the Appendix for an accounting of the area in the previous model and the updated model. Four SWMM models have been created as part of this project. The first, called the EXTRAN SWMM Model, was created to generate runoff hydrographs for the EXTRAN model. The second attempted to mimic the EXTRAN results with physically based detention pond rating curves for each of the four ponds on the HP site. The third was a tnmcated model used only to quantify the total flow into the pond system. The fourth, called the Final SWMM Model, transferred the ' basin updates from the EXTRAN SWMM Model to the overall Fox Meadows Basin H SWMM Model for use in subsequent modeling updates. ' 1. EXTRAN SWMM Model [564014A2.DAT] This SWMM model was created to generate runoff hydrographs for the 1 EXTRAN model. As necessary for the EXTRAN model, some of the HP site SWMM basins were divided into smaller sub -basins to reflect runoff tributary to key points in the model. These key points were typically ' entrances to closed storm drain systems, pond inflows or incoming channel flows. See page 14 for the location and peak value of these discharges. The SWMM model requires certain parameters for each basin in order to generate runoff information. For the basins that existed in previous models, tributary width and slope were calculated consistent with those previous models. Tributary width was determined by deriving the it flow path length used in the previous model, and using with the new basin area to compute the new tributary width. If the new derived value of tributary width was not possible within the revised basin delineation, then the tributary width was calculated as described for new basins, below. Slope was assumed to remain the same. For basins that were unique to the EXTRAN hydrograph generating SWMM model, tributary width was ' calculated by dividing the basin area by the average of several flow path lengths tributary to the basin outlet. At the request of the City of Fort ' Collins, tributary width was also calculated by assuming a maximum flow length 300 ft for developed basins or 500 ft for undeveloped basins. of The minimum flow path length derived by these two methods was used to calculate tributary width. For the new basins, slope was calculated based on contour plans provided by Hewlett-Packard. Percent impervious values were calculated for the smaller sub -basins by measuring the impervious area and total area directly and calculating a percent impervious. At the request of the City of Fort Collins, the percent of imperviousness area with no detention depth was set to I percent. 1� ' s unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com oiadditional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA SWMM uses the S-hydrograph concept to evaluate a basins response to a given perturbation or rainfall. The S-hydrograph is basically a step response function, or the response of a basin to a constant rainfall intensity of infinite duration. The S-hydrograph used by SWMM is a discrete hydrograph that is generated by summing the discharges of many discrete At unit hydrographs offset by a time At thereby producing the infinite duration constant intensity storm. The method is denoted with the "S" because of the summing operation. If the S-hydrograph were truly a step response function, then it would be smooth continuous function asymptotically approaching the theoretical maximum discharge of the basin. By contrast, a discrete S-hydrograph only calculates discharge at specific temporal intervals. This results in an S-hydrograph that approaches the theoretical maximum discharge and then oscillates about that maximum due to the limitations of the discrete summation. When the discrete S-hydrograph is offset temporally by the storm duration and subtracted from the discrete S-hydrograph beginning at time 0 (which is the S-hydrograph procedure), these oscillations are pronounced, particularly when the difference between the two gets small (this corresponds to the receding limb of the hydrograph). Correcting this oscillation is required to maintain stability in the EXTRAN model in which the hydrographs are to be input. This correction was made conservatively by ignoring the "valley" portion of the oscillations. 2. Physically Based SWMM Model [564014F3.DAT] At the request of the city, Sear -Brown attempted to generate a physically based rating curve for each of the four ponds on the HP site. The rating curves were generated from the time -series pond water surface elevations and discharges from EXTRAN. Due to the dynamic interaction of the ponds, some of the rating curves were.not true functions, but had a hysteretic quality. This means that for any given pond water surface elevation (or storage), there are two different discharges possible. One discharge occurs when the pond is filling and the other occurs when the pond is draining. Mod-SWMM requires a one-to-one monotonically increasing function as input for a detention pond rating curve. In order to ' obtain the pond rating curves, best -fit functions were substituted for the hysteretic loops. Documentation for the rating curve development and model output can be found in the appendix. The results of this model showed discrepancies in pond outflow of up to 60 percent compared to the EXTRAN model and an error of approximately 25 percent at the basin C; "t outlet. Due to the magnitude of these errors, Sear -Brown was directed by d'ri-k'S city staff to prepare a single pond rating curve that would model all of the ponds together. SS - �� vgs y a" dw�or 5 is unofficial copy was downloaded on JW-23-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com or additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA ' 3. Interim & Final SWMM Models [564014F2.DAT & 564014F4.DAT] The final SWMM model developed for this project is the overall basin ' model, to be used for future changes in the drainage basin. Tributary width and slope were determined in the same manner as for the EXTRAN Hydrograph SWMM model. Percent impervious values were determined by ' aggregating the percent impervious values for the smaller sub -basins used in the EXTRAN SWMM model. In this way, the overall SWMM model reflects the same detail of analysis for the HP site that was used in the ' EXTRAN model. At the request of the City of Fort Collins, the percent of impervious area with no detention depth was set to 1 percent. This final SWMM model includes a storage -discharge rating curve that represents the ' complex behavior of the interconnected pond and conduit system. In order to obtain this synthetic rating curve, an interim SWMM model was prepared to integrate all of the inflows to the detention pond system. The storage portion of this rating curve was prepared by performing a mass balance on the inflow to the pond system from SWMM compared to the outflow of the Dam Pond from EXTRAN. This storage was reduced by approximately 22 percent (decrease from 32 percent in previous version due to change in EXTRAN pond volume modeling approach) to account for additional routing attenuation that couldn't be modeled with a single pond. The discharge portion of the rating curve was obtained from the outflow of the Dam Pond in the EXTRAN model. This discharge was temporally adjusted ' so that the peak discharge and the peak storage coincided. The results of this analysis and the final SWMM model can be found in the appendix. B. SWMM - EXTRAN Model of Regional Detention Facility [564014X2.DAT] 1. EXTRAN Description ' The Sear -Brown Group first attempted to model this site with the EXTRAN block of SWMM 4.30. This version was unable to produce stable results, so it was converted to version 4.40 to utilize the better error handling and more ' stable solution algorithm of the new version. The EXTRAN block of SWMM 4.40 was used to complete the detailed hydraulic analysis required for this report. "EXTRAN is a dynamic flow routing model used to compute backwater profiles in open channel and/or closed conduit systems experiencing unsteady flow. It represents the drainage system as links and nodes, allowing simulation of parallel or looped pipe networks; weirs, orifices and pumps; and system surcharges. EXTRAN is used most efficiently if it is only applied to those parts of the drainage system that cannot be simulated accurately by simpler, less costly models." (EPA, 1992) (No pumps exist in the EXTRAN model presented ' in this report.) '[rhis unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydoes.fcgov.com or additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA r r r 2. Extent of EXTRAN Model In order to accurately assess the potential flooding conditions and hydraulic performance of the existing linked detention ponds, the regional drainage system at the east end of the HP Site was modeled in EXTRAN. See pages 106 and 107 in the Appendix for a schematic of the location of the links and nodes used in this model. As can be seen from the schematics in the Appendix, the entire storm sewer network between the buildings was not modeled, only the segment of pipe immediately upstream from the north detention pond outlet (Conduits 541 & 542). The detention ponds were modeled using rating curves developed from the contour plans provided by HP. Surface area for pond surcharging above the defined pond boundaries was also estimated from the contour plans. Pipe inverts and ground elevations were taken from survey performed for this project. Distances were scaled from the contour plans. Weir parameters were based on surveyed measurements and standard tables of weir coefficients. Details specific to each portion of the model will be discussed in the Hydraulic Analysis section below. EXTRAN Modeling Process 1. Model existing condition for point of interest. 2. Document extent of uncontrolled flow and surcharging. 3. Refine model to control surcharging using proposed solutions. 4. Proceed downstream. 5. Document final improved conditions after all surcharging is addressed to account for backwater effects. Figure: EXTRAN Modeling Process 3. Modeling Approach The EXTRAN model for this project was developed from upstream to downstream. All of the pieces were assembled based on existing conditions, then the model was executed. A typical pattern emerged as each piece of the model was analyzed. This process is illustrated in the above figure. First, the problem(s) with the existing condition for the segment under examination were documented. Then a proposed solution was iterated upon until the previously documented problem was alleviated. 117his unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA ' At that point, the analysis could proceed downstream to the next problem area. This procedure was necessary because of the nature of the hydraulic model. If an existing condition like uncontrolled flooding in an upstream portion of the model was left uncorrected, then the entire model downstream from that point would be unreliable, because of the ' uncertainty of the flow path and quantity of runoff traveling downstream. The end result was two -fold: ' • An EXTRAN model was produced reflecting the recommended improvements to the regional detention facility. • A written log of the existing condition problems was generated ' during the modeling process. IV. HYDRAULIC ANALYSIS ' Uncontrolled flow to Fossil Creek Ditch occurred in two locations: • Regional Drainage Channel and Culvert ' • Volleyball and Basketball Court Area (potential uncontrolled flow) No uncontrolled flow to Fossil Creek Ditch occurred in the remaining locations: • North Pond 0 Closed Storm Drain System ' 0 South Ponds • Dam Pond A. Regional Drainage Channel and Culvert 1. Analysis ' The major source of inflow to the regional detention facility is the regional channel that forms the northern border of the HP site watershed area. ' Design plans for HP Building 5 show the trapezoidal channel having a bottom width of 5.0 feet and side slopes of 4:1, see pages 64 and 65 in the Appendix. The northern channel bank is shown with a top of bank elevation of 4910.50 from the 75 x 48 inch HERCP culvert entrance on the downstream end, to approximately 500 feet upstream, where the bank rises above 4910.50. Survey performed for this project reveals that the north bank of the regional channel does not reach elevation 4910.50. In contrast to the ' design plans, the north bank has been constructed at an elevation of approximately 4909.5, from the culvert entrance to 380 feet +/- upstream (the limit of survey). The design plans also call for the bank to extend at elevation 4910.50 to the south edge of the access road over the culvert. . - The extension of the north bank would channel the flow over the access 8 is unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydoes.fcgov.com or additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA r r r road and into the North Pond when it overtops the road, instead of flowing uncontrolled to the Fossil Creek Ditch. This extension of the north bank has not been constructed at this time. The maximum water surface elevation in the regional channel at the entrance to the culvert is 4909.77, see the maximum elevation of junction 2 on page 168 of the Appendix. Under currently constructed conditions, water will spill over the east bank of the regional channel just upstream of the installed culvert. The 75 x 48 inch HERCP culvert is designed to pass most of the 100-Year discharge in the channel, the culvert (as discussed This culvert, as construcl not need modification. 3. Recommendation with the rest overtopping the service road over above) and entering the north detention pond. ed, will function in its designed capacity and does The north bank of the regional channel needs to conform to the design plans for the channel from the HP Building 5 Project. The north bank should have a minimum elevation of 4911.0 and extend south past the service road to the North Pond. The service road will need regrading in the immediate vicinity of the culvert to reach the 4911.0 elevation. The design of this overtopping protection which provides approximately 1.23 feet of freeboard is expected to occur with the proposed overflow parking lot currently in the review process. B. North Pond 1. Analysis The north pond was modeled using the existing contour information provided by HP. When storm flows are routed to the pond, assuming the regional channel is modified as described above, the pond water surface rises to elevation 4908.27. The east bank of the pond is currently at elevations between 4909 and 4910. See the As -Built Condition Flooding Limits Diagram, page 15, for the extent of flooding. 2. Recommendation The existing pond is adequate to prevent flow into Fossil Creek Inlet Ditch. At the maximum water surface elevation, the north pond will have approximately one foot of freeboard, based on one -foot contour mapping. No improvements are necessary in this area. I vs unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Websitc: http://citydocs.fcgov.com or additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA 0 ' .._ C. Volleyball and Basketball Court Area 1. Analysis After it leaves the North Pond, stonnwater will flow past the volleyball and basketball courts through the fenceline that separates the softball fields. This flow is conveyed to the Dam Pond as it sheet -flows down the slope and may spread to the east and enter the Fossil Creek Inlet Ditch. Contour plans from before the construction of the volleyball and ' basketball courts indicate that part of the overland runoff could flow into Fossil Creek Inlet Ditch. Regrading of this area has been performed since the previous submittal of this report. HP has constructed a small berm to ' the north and east of the ball courts. The Sear -Brown Group has performed a field survey of this area to verify that it will effectively ' convey the sheet flow to the dam pond. 2. Recommendation ' Because the flow through the baseball fence line occurs at a depth less than 6 inches, and the flow depth of this sheet flow is not expected to ' increase as it makes its way to the Dam Pond, the recently constructed berm should be adequate to convey flows to the Dam Pond and prevent uncontrolled spilling into the Fossil Creek Ditch. An exhibit of the ' surveyed berm is provided in the appendix on page 96. No further improvements are necessary in this area. ' D. Closed Storm Drain System ' 1. Analysis The existing closed storm drain system has been constructed to convey parking lot and building runoff to appropriate detention ponds. The portion of the closed storm drainage system modeled in EXTRAN includes the outlet pipe from the North Pond, the first pipe segment west from the junction of the North Pond outlet pipe, and the trunk line from ' that junction down to the southeast pond. Runoff is added to the pipe network at locations corresponding to the parking lot inlets. See the Peak Inflow schematic on page 14 of the text, and the EXTRAN Model ' schematic on page 60 of the Appendix. ' A 36-inch concrete pipe has been installed as the outlet from the North Pond. The lateral joining this pipe from the south side of the Building 6 Annex is 36-inch concrete pipe as well. The pipe downstream from this junction of two 36-inch pipes is a single 30-inch pipe. This system intercepts additional flow from parking lot inlets, and discharges to the 10 ' 's unofficial copy was downloaded on !ul-23-2015 from the City of Fort Collins Public Records Website: http://citydoes.fcgov.com or additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA • Southeast Pond (labeled Pond "7" on the EXTRAN Schematic, page 60 in the Appendix). The capacity of the closed storm drain system is supplemented by overland flow along the roadway and overflow toward the Dam pond when flow depths exceed the curb height. As such, these conduits were modeled with overflow channels in order to ensure that no flow was lost from the system due to flooding at the adjacent nodes. 2. Recommendation Although the closed storm drain system does not have sufficient capacity to convey the 100-Year runoff from the North Pond (Pond "3" in the EXTRAN Schematic) to the Southeast Pond (Pond "7"), the overflow is safely carried by the roadway section with flooding confined to about 450 ft of the the outer perimeter of the parking area (based on existing 1-foot contours obtained from HP), as shown in both the As -Built Condition Flooding Limits figure and the Improved Condition Flooding Limits figure, pages 15 and 16 respectively. Therefore, no improvements are recommended for this section of the model. 1, E. South Ponds. 1. Analysis The two southern ponds, as constructed, convey 100-year runoff from the Southwest Pond to the Southeast Pond through a 48-inch concrete pipe culvert. An outlet weir has been constructed to detain irrigation water in the Southwest Pond. When the water surface exceeds the height of the weir (crest elevation 4902.12 - see page 90 in the appendix), flow passes over the outlet weir in the western pond and through the 48-inch pipe to the eastern pond. The EXTRAN analysis indicates that water surface in the southwest pond will rise to 4910.27. This is slightly above the minimum entrance road elevation of 4910 between the Southwestern Pond and the Southeastern Pond. Therefore, slight overtopping of the entrance road is anticipated during the 100-Year storm (86.3 cfs sheet flow). The water surface in the southeast pond will rise to 4906.44, leaving approximately one foot of freeboard (based on one -foot contour mapping). r2. Recommendation No improvements are recommended in this area as the entrance road overtopping is contained within the site. 11 • 1' Inkis unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: hup://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA ` / c F. Dam Pond 1. Analysis This pond appropriately handles the 100-Year flows without overtopping the embankment. 100-Year conditions will inundate the pedestrian bridge crossing the center of the pond to a depth of 2.0 feet (based on an approximate deck elevation of 4890.25). Due to the depth of ponding over the bridge and a flow width of approximately 430 ft (based on a water surface elevation of 4892.21 and the one -foot contour mapping provided by HP), the 'bridge and channel between the east and west portion of the Dam Pond were not modeled as a constriction in the flow through the pond. The pond rating curve does reflect the surface area at each contour. elevation, and so accounts InvE/. =171 ' Sluice G07b� 0.0 18"'Pmc 00H/e 7.37' 12.1' 4.75' Figure: Dam Pond Outlet Works Configuration for the unique geometry of the pond. At peak stage, the pond will discharge through two outlets. Minor flows (up to a maximum of 21.7 cfs) will pass through the low flow outlet, an 18-inch pipe that connects to the 24-inch maintenance drain pipe that discharges to the Fossil Creek Inlet Ditch. This discharge is considered `controlled" flow and is not part of the "uncontrolled" flooding that this report is intended to address. The remaining water that is detained by the Dam Pond will ultimately rise to a water surface elevation of 4892.21. At water surface elevations above the " invert of the, overflow weir (4891.48), runoff will leave the detention pond through the overflow weir and bypass the Fossil Creek Ditch. No uncontrolled flooding in this location was predicted by the model. Peak 12 1rhis unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins public Records Website: http://citydocs.fcgov.com or additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA r discharge over the spillway is 100.7 cfs. Pond detention beyond the defined pond boundaries was contained within the grading of the surrounding area and did not demonstrate any adverse impacts. As a side note, the Dam Pond has a lower outlet, a 24-inch pipe controlled by a manually operated sluice gate. See the figure on page 12 for reference. This appears to be for maintenance use in draining the pond. It was not included in the model as an outlet to the pond. The minor outlet, an 18-inch RCP, has a free opening. The 18-inch pipe discharges into the lower 24-inch .pipe. Manning's equation shows that the 24-inch pipe has a lower capacity than the 18-inch pipe based on their respective slopes. The 18-inch pipe was included in the model as an orifice due to its steep slope and short length. Therefore, the minor outlet from the pond was modeled as a 24-inch pipe at 1.62 percent slope (based on the Anderson and Hastings design plans, 1979), but using the invert of the 18-inch outlet. This approach accurately reflects the capacity and elevation of the minor outlet. Moreover, the downstream controlling water surface elevation on this pipe was assumed to be constant at an elevation of 4878.53, which is consistent with the water surface elevation in the Fossil Creek Ditch when it is flowing at capacity. 2. Recommendation No improvements are recommended in this area. V. CONCLUSION A. Regional Channel The regional channel and adjacent roadway grading needs to be constructed to the specifications designed as part of the Building 5 project. The regional channel design for HP Building 5 is sufficient to control the anticipated runoff for the 100- Year storm. No additional improvements in this area are recommended. B. Volleyball and Basketball Court Area As discussed above, a 1-foot high berm has been constructed to channel overland sheet flow toward the Dam Pond. This berm should be adequate, therefore no further improvements are necessary in this area. 100-Year flows will be adequately conveyed through the HP site if the improvements recommended in this report are implemented. Flooding will be contained within the limits shown in the Proposed Improvement Conditions Flooding Limits figure on page 16. 13 is unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydms.fcgov.com or additional information or an official conv. olease contact Citv of Fort Collins Utilities 700 Wood Street Fort Collins. CO 80524 USA 1 • ' VI. REFERENCES rStorm Drainage Design Criteria and Construction Standards by the City of Fort Collins, Colorado, May 1984, Revised January 1997. Fox Meadows Basin (Basin H) Drainage Master Plan, Fort Collins, Colorado, by Resource Consultants, Inc., February 25, 1981. rMaster Drainage Report, Hewlett-Packard Site, Preston Kelly Subdivision, Fort Collins, Colorado, by Nolte and Associates, revised October 1990. ' Storm Water Management Model User's Manual Version 4, EXTRAN Addendum, Athens, Georgia, by the Environmental Research Laboratory Office of Research and Development, U.S. EPA, 1992 Final Drainage Study for Hewlett-Packard Company, Building 5, Fort Collins, Colorado, by RBD, Inc. Engineering Consultants, A Division of Sear -Brown, October 4, 1996. ' Overall Drainage Study and Phase 1 Final Drainage Study for the Symbios Logic Site, The Sear Group, July 23, 1997. Fort Collins, Colorado, by -Brown 1 r r P r r r 17 r unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Websitc: http://citydocs.fegov.com Additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA Prl (• coums VTnMMq rIRT Addendum No. l to the Drainage and Erosion Control Report for the Hewlett-Packard Company Building 5, Northeast Parking Lot Expansion Fort Collins, Colorado August 25, 2000 ff000�SEAR- BROWN is unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydoes.fcgov.com or additional information or an official coon, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA 1 1 1 1 1 1 ARCHITECTURE 209 South Meldmm ENGINEERING Fort Collim.CO 80521-2603 ne ff�SE�AR-B�ROW�N CONSPUNNING 97082.5922 TRVCTION 970.4.482b3(iB fu fax wwwsearbrown.com August 25, 2000 Mr. Donnie Dustin City of Fort Collins Water Utilities --Storm Water 700 Wood Street Fort Collins, Colorado 80521 RE: Addendum No. 1 to the Drainage and Erosion Control Report for the Hewlett-Packard Company, Building 5 Mr. Dustin: We are pleased to submit to you, for your review and approval, this addendum to the Drainage and Erosion Control Report for the Hewlett-Packard Company, Building 5. All computations within this report have been completed in compliance with the City of Fort Collins Storm Drainage Design Criteria. We appreciate your time and consideration in reviewing this submittal. Please call if you have any questions. Respectfully, The Sear -Brown Group Prepared by: Reviewed by: John Gooch, EIT Jim Allen -Morley, P.E. Drainage Engineer Project Manager cc: File 564-014 VO RL�c._ unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com additional information or an official wov, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA y a a ', '' TABLE OF CONTENTS PAGE I. GENERAL LOCATION AND DESCRIPTION 4 A. Location 4 B. Description of Property 4 II. DRAINAGE BASINS 4 A. Major Basin Description 4 B. Sub -Basin Description 5 III. DRAINAGE DESIGN CRITERIA 5 A. Regulations 5 B. Development Criteria Reference and Constraints 5 C. Hydrologic Criteria 5 D. Hydraulic Criteria 6 E. Variances from Criteria 6 TV. DRAINAGE FACILITY DESIGN 6 A. General Concept 6 B. Specific Details 7 V. STORM WATER QUALITY 7 A. General Concept 7 VI. EROSION CONTROL 8 A. General Concept 8 VII. CONCLUSIONS 8 A. Compliance with Standards 8 B. Drainage Concepts 8 C. Storm Water Quality Concept 9 D. Erosion Control Concept 9 REFERENCE 10 APPENDIX 11 A: VICINITY MAP 12 B: RATIONAL METHOD HYDROLOGY 13 C: FLOWMASTER ANALYSIS 14 D: UD SEWER 15 E: LTD INLET 16 F: MASTER PLAN UPDATE 17 G: BOX CULVERT DETAILS 18 H: UTILITY PLANS 19 1 is unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com or additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA I I I 1 ADDENDUM NO.1 TO THE DRAINAGE AND EROSION CONTROL REPORT FOR THE HEWLETT PACKARD COMPANY BUILDING 5, NORTHEAST PARKING LOT EXPANSION FORT COLLINS, COLORADO I. GENERAL LOCATION AND DESCRIPTION A. Location The Hewlett Packard site is a commercial development located in Southeast Fort Collins (see vicinity map in Appendix), North of Harmony Road and East of County Road 9 within the Southwest'/4 of Section 33, Township 7 North, Range 68 West of the 6i° P.M., City of Fort Collins, Larimer County, Colorado. B. Description of Property The Hewlett-Packard Building 5, Northeast Parking Lot Expansion is North and East of the existing Fort Collins Hewlett-Packard office and industrial development and encompasses approximately 3.47 acres. The existing topography generally slopes from South to North at approximately 2 percent. Native grasses overlaying lean clay with sand or sandy lean clay cover the majority of the site, except for the existing gravel overflow parking lot located in the North and Northeast corner of the site. II. DRAINAGE BASINS A. Major Basin Description The Hewlett-Packard site lies entirely within the Fox Meadows Drainage Basin which is approximately bounded by Horsetooth Road on the North, Harmony Road on the South, the Cache La Poudre River and I-25 on the East, and Lemay Avenue on the West. A Master Plan for the Fox Meadows Drainage Basin (Basin H) was prepared by Resource Consultants, Inc., in 1981. This area was studied again by Nolte and Associates in 1990 when a Master Drainage Plan was prepared for the Hewlett-Packard site. Nolte's Master Drainage Report did not alter any of the assumptions or conclusions, which were made in the Fox Meadows Master Drainage Plan. As recommended in Nolte's Report, a regional drainage channel is designed to accept 100-year storm event flows from the developed site and the upstream basins from the West. The channel is located along the North side of the Hewlett-Packard site and discharges to the existing North detention pond. H runofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydoes.fcgov.com mr additional information or an official corn. please contact Citv of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA rThe North detention pond discharges to a series of detention ponds to the South through a 30-inch diameter pipe. Nolte's report recommended that the 30-inch diameter outlet pipe for the North pond be enlarged to 48-inch diameter at the development of the entire Hewlett-Packard Site. This increased diameter is required to avoid surcharging the North detention pond, which would result in uncontrolled overland flow. It is not clear at which point in the development the outlet pipe should be enlarged. The upgrading of this outlet pipe is outside the scope of this project and is not being constructed at this time. B. Sub -Basin Description Please refer to the Detailed Hydraulic Study Regional Detention Facilities report (July 3, 2000), by Sear Brown. III. DRAINAGE DESIGN CRITERIA A. Regulations The City of Fort Collins Storm Drainage Design Criteria is being used for the subject site. Criteria established by the Fox Meadows Basin Drainage Master Plan will also — be used. B. Development Criteria Reference and Constraints The addendum to the Drainage and Erosion Control Report for the Hewlett-Packard Building 5 site is in conformance with the Fox Meadows Drainage Basin Master Plan and the Hewlett-Packard Master Drainage Plan. C. Hydrological Criteria Previous SWMM modeling for the regional drainage channel and site detention requirements were updated to determine flow through the channel due to the addition of approximately 3.47 acres of hard area. It is important to note that the Northeast parking lot was designed under new rainfall criteria, whereas the original site was designed using old rainfall criteria. SWMM modeling for Basin 32 (Agilent site) was also run under the new rainfall criteria, as seen in Appendix F. As before, the new SWMM model was run using the 100-year storm event. The new model produced a flow of 302.9 cfs versus the previous 258.4 cfs. Details on how this flow was calculated as well as the release rate for the detention pond can be found in Appendix F. It is important to note that the 302.9 cfs flow accounts for flows from the existing on -site basins, newly proposed on -site basins, and also any off -site basins. The Rational Method was used to determine peak flows from the newly proposed basins using the 10-year and 100-year storm event intensities, 5 rhis unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http;//citydoes.fcgov.com or additional information or an official cony, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA 1 eprovided by the City of Fort Collins. Once obtained, these flows were then used to design the hydraulic structures and interior roadway drainage facilities of the parking lot, these being proposed inlets (inlets 1-6, 10). Inputting the results from the SWMM model and rational method into UD Sewer, the 302.9 cis flow was used to size the box culvert, while the 100-year design flows at ' inlets 1-10 (1-6, 10 are proposed, 7-9 are existing), were used to determine the required pipe sizes to convey developed runoff to the box culvert. These calculations and criteria are included in Appendices B and D. D. Hydraulic Criteria ' All hydraulic calculations within this report have been prepared in accordance with the City of Fort Collins Drainage Criteria and are included in the Appendix. ' E. Variances from Criteria ' No variances are being sought for the proposed project site. ' IV. DRAINAGE FACILITY DESIGN ' A. rl 1 F I General Concept The existing drainage pattern for the site has changed. Runoff from the proposed site, which previously flowed to the Northeast and off -site, will now be delivered to a 4' x 10' concrete box culvert and conveyed Southeast to on -site detention in the North detention pond. The 4' x 10' culvert will replace the regional drainage channel for the span of the proposed parking lot (approximately 1254') to accommodate increased run-off flow. As before, all flows from the existing basins, excluding sub - basin 15, will be routed Northeasterly to the regional drainage channel (at the West end) and the 4' x 10' box culvert (from the West to the East end) along the North perimeter of the Hewlett-Packard property (see sheet C3.2a). Sub -basin 15 will again discharge to the existing system to the South. Run-off produced by the existing parking lots around the building will surface flow to the North and East discharging through the existing Type R curb inlets into the 4' x 10' box culvert. The flows will then be conveyed to the Southeast, pass under the East access road and into the existing North detention pond. Run-off from the proposed parking lot will surface flow to the curb and gutter on the North and South sides of the proposed parking lot and discharge through Type R curb inlets into the 4' x 10' box culvert. These flows will also be conveyed to the Southeast and into the North detention pond. rs unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com or additional information or an official coov. please contact Citv of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA '' 11 11 11 11 Run-off from the roof of Building 5, will be conveyed to the 4' x 10' box culvert via the existing 24" RCP (see sheet C3.2). The 24" RCP will be tied into the box culvert. The Western portion of the site will remain undeveloped except for a temporary circulation road. This area will generally flow overland to the regional drainage channel. B. Specific Details As noted above, the existing drainage pattern has been changed. The installation of 1,254 feet of 4'x 10' box culvert, with wing wall entrance and exit, will replace the natural drainage channel and convey run-off Southeasterly under the proposed parking lot and into the North detention pond. The existing Type R inlets, which formerly discharged run-off from the existing parking lots on the North side of the Building into the regional drainage channel, will tie-in to the 4' x 10' culvert (see detail in Appendix G). It is important to note that based on LTD Sewer results, the existing 15" storm pipe at Inlet 8, should be tom out and replaced with 18" RCP to provide necessary conveyance of storm water to the 4' x 10' culvert. The proposed parking lot will be crowned to minimize fill and convey water to the curb and gutter on the North and South sides of the parking lot. Curb chases will allow water to flow to the Southeast and into the 3 sump inlets (Wets 1,3,5) on the North side and 3 sump inlets (Inlets 2,4,6) on the South side of the parking lot. These inlets will tie-in to the 4' x 10' culvert. The flows from these inlets will combine with flows from the existing inlets (Inlets 7,8,9) and flow Southeasterly to the North detention pond via the 4' x 10' box culvert. Due to undetained run-off eroding the embankment (adjacent to the existing 72" HERCP) on the South side of the entrance into the existing overflow gravel parking lot, a 6' concrete cross -pan will be installed to convey water across the entrance (Southeasterly) and into proposed inlet 10. Likewise, any run-off flowing North in the curb and gutter, just South of the entrance, will enter the cross -pan at the entrance and fall into inlet 10 (see Drainage and Erosion Control Plan). Inlet 10 will discharge these flows into the North detention pond. V. STORM WATER QUALITY A. General Concept The grass -lined regional detention channel and grass -lined detention ponds will provide storm water quality. These grass -lined features will provide a mechanism 7 rw s unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com or additional information or an official cony. Please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA 1 ' for pollutants to settle out of the storm water runoff before entering the Fossil Creek Reservoir Inlet Ditch or downstream storm drainage facilities. VI. EROSION CONTROL ' A. General Concept This development lies within the Moderate Rainfall Erodibility Zone and the Moderate Wind Erodibility Zone per the City of Fort Collins zone maps. The potential exists for erosion problems after completion of the improvements, due to ' some existing and proposed site slopes of greater than 2 percent. It is also anticipated that the project site improvements will be subject to both wind and rainfall erosion before new vegetation can take hold or before the project is completed. B. Specific Details With this project being installed in 3 separate phases, it will be necessary that any disturbed areas not built on within one growing season be seeded. After seeding, a hay or straw mulch shall be applied over the seed at a minimum rate of 2 tons/acre, and the mulch shall be adequately anchored, tacked, or crimped into the soil. In the event a portion of the roadway pavement surface and utilities will not be constructed for an extended period of time, a temporary vegetation seed and mulch shall also be applied to the roadway areas as discussed above. A silt fence will also be installed around the site, as shown on the Drainage and Erosion Control sheet. ' All construction activities must also comply with the State of Colorado permitting process for Storm Water Discharges Associated with Construction Activity. A ' Colorado Department of Health NPDES permit will be required before any construction grading can begin with this development. VH. CONCLUSIONS ' A. Compliance with Standards All computations completed within this report are in compliance with the City of Fort Collins Erosion Control Reference Manual for Construction Sites and the Storm Drainage Design Criteria Manual. ' B. Drainage Concept The proposed drainage concepts adequately provide for transmission of developed onsite run-off to the existing and proposed drainage facilities at the Eastern edge of the subject site. The 100-yr run-off generated by development of the parking lot will 8 unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com or additional information or an official coov. Please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 U! be carried to the proposed storm drainage culvert and then to existing on -site detention ponds. The detention ponds will then discharge to the Fossil Creek Reservoir Inlet Ditch in accordance with the Fox Meadows Basin Drainage Master Plan. If for some unforeseen reason groundwater is encountered at the time of construction, a Colorado Department of Health Construction Dewatering Permit will be required. C. Storm Water Quality Concept Because storm water quality has become a requirement, the site has addressed this storm water aspect. The grass -lined regional drainage channel and existing detention ponds will provide a mechanism for water pollutants to filter out of the storm water runoff before entering the Fossil Creek Reservoir Inlet Ditch or downstream storm drainage facilities. D. Erosion Control Concept -The proposed erosion control concepts adequately provide for the control of wind and rainfall erosion for the Hewlett-Packard Building 5, Northeast Parking Lot ' Expansion. Through the implementation of the proposed erosion control concepts, the City of Fort Collins performance standards will be met. The proposed erosion control concepts presented in this report and shown on the erosion control plan are ' in compliance with the City of Fort Collins erosion control criteria. 1 ' 1 9 is unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydoes.fegov.com tor additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA REFERENCES - 1. Storm Drainage Design Criteria and Construction Standards, by the City of Fort Collins, Colorado, May 1984, interim revision January 1997. 2. Erosion Control Reference Manual for Construction Sites by the City of Fort Collins, Colorado, January 1991. 3. Fox Meadows Basin (Basin H) Drainage Master Plan, Fort Collins, Colorado, by Resource Consultants, Inc., February 25, 1981. 4. Master Drainage Report, Hewlett-Packard Site, Preston Kelly Subdivision, Fort Collins, Colorado, by Nolte and Associates, revised October 1990. 5. Overall Drainage Study for the NCR Site and Preliminary Drainage Study, First Phase NCR Site, Fort Collins, Colorado, by RBD, Inc., Engineering Consultants, May 2, 1994. 6. Detailed Hydraulic Study Regional Detention Facilities, Hewlett-Packard Company, Fort Collins, Colorado, by the Sear -Brown Group, April 24, 2000. 10 IINs unofficial copy was downloaded on Jul-23-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com or additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA FINAL DRAINAGE AND EROSION CONTROL REPORT Appendix E - EROSION CONTROL ESCROW February 16, 2016 Appendix E - EROSION CONTRA, 6. <, I 1 1 1 1 LJ 1 11 1 1 Erosion and Sediment Control Escrow/Security Calculation for The City of Fort Collins Project: HP Building 5 Lower Parking Lot Expansion EROSION CONTROL BMPS Silt Fence (SF) Inlet Protection (IP) Concrete Washout Area (CWA) Vehicle Tracking Control (VTC) Temporary Sediment Basin (TSB) Wattles in Swales (add all other BMPs for the site in this list) BMP Amount Units Estimated Quantity L. F. 600 EA 2 EA 1 EA 2 EA 0 EA 0 Disturbed Acres: 6.05 Unit Price $2.50 $125.00 $200.00 $300.00 $400.00 $125.00 1 Total ' Price $1,500.00 $250.00 $200.00 $600.00 ' $0.00 Sub -Total: $2,550.00 1.5 x Sub -Total: $3,825.00 Amount of security: $3,825.00 Reseeding Amount Total Acres x Price/acre: Unit Price of Seeding per acre: $1,000,00 Sub -Total: 1.5 x Sub -Total: Amount to Re -seed: Miniumum Escrow Amount Minimum escrow amount. $3,000.00 Erosion Control Escrow. Fields in yellow should be amended for this project. "The amount of the security must be based on one and one-half times the estimate of the cost to install the approved measures, or one and one-half times the cost to re -vegetate the disturbed land to dry land grasses based upon unit cost determined by the City's Annual Revegetation and Stabilization Rid, whichever is greater. In no instance, will the amount of security be less than one thousand five hundred dollars (SI,500) for residential development or three thousand dollars (53,000) for commercial development" tdnfac The overall site is approximately 10.2 acres. The upper parking lot will be completed when the lower parking lot gets started 2/17/2016 1:13 PM I 1 1 V Q0531x wQ053050561 Jyan12053 05056 MP EC Eav As FINAL DRAINAGE AND EROSION CONTROL REPORT ' Appendix F - Floodplain map February 16, 2016 ' Appendix F - FLOODPLAIN MAP I �I J 11 I 1 I 1 I I I I I I I I I I I I I / I I I \ I I + K g � / 0 7/ 2 i x k]B ( £ Rio ^CD a§f | >4 z 7 ,IISSOA | ^^ �!APO o % ■ § |!q| 0 § /\\ | /k \ m 8 m !» - k 2[■ m q p!b §� § CEO � \!/ 20 | \ 2§ 7 2 M \ § Al M Ilo `( § m � § § |i \!! Z ;; !■K ; / _! 2 4 mo § § :! !, k§}| \11 \!jf( ! m m ; , !, §!! I I FINAL DRAINAGE AND EROSION CONTROL REPORT ' Appendix G - USGS soils Report February 16. 2016 ' Appendix G - USGS SOILS REPORT 11 1 1 1 I 1 I 1 I 1 G.7 1 USDA United States Department of Agriculture FRCS Natural Resources Conservation Service A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants Custom Soil Resource Report for Larimer County Area, Colorado HP Building 5 Parking Expansion September 29, 2015 I Contents Preface....................................................................................................................2 How Soil Surveys Are Made..................................................................................5 SoilMap..................................................................................................................7 SoilMap................................................................................................................8 Legend..................................................................................................................9 MapUnit Legend................................................................................................10 Map Unit Descriptions........................................................................................10 ' Larimer County Area, Colorado......................................................................12 5—Aquepts, loamy......................................................................................12 62—Larimer-Stoneham complex, 3 to 10 percent slopes ...........................12 73—Nunn clay loam, 0 to 1 percent slopes.................................................14 74—Nunn clay loam, 1 to 3 percent slopes.................................................15 Soil Information for All Uses...............................................................................17 Soil Properties and Qualities..............................................................................17 Soil Qualities and Features.............................................................................17 HydrologicSoil Group.................................................................................17 References............................................................................................................22 1 1 1 1 4 How Soil Surveys Are Made Soil surveys are made to provide information about the soils and miscellaneous areas in a specific area. They include a description of the soils and miscellaneous areas and their location on the landscape and tables that show soil properties and limitations affecting various uses. Soil scientists observed the steepness, length, and shape of the slopes; the general pattern of drainage; the kinds of crops and native plants; and the kinds of bedrock. They observed and described many soil profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The profile extends from the surface down into the unconsolidated material in which the soil formed or from the surface down to bedrock. The unconsolidated material is devoid of roots and other living organisms and has not been changed by other biological activity. Currently, soils are mapped according to the boundaries of major land resource areas (MLRAs). MLRAs are geographically associated land resource units that share common characteristics related to physiography, geology, climate, water resources, soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically consist of parts of one or more MLRA. The soils and miscellaneous areas in a survey area occur in an orderly pattern that is related to the geology, landforms, relief, climate, and natural vegetation of the area. Each kind of soil and miscellaneous area is associated with a particular kind of landform or with a segment of the landform. By observing the soils and miscellaneous areas in the survey area and relating their position to specific segments of the landform, a soil scientist develops a concept, or model, of how they were formed. Thus, during mapping, this model enables the soil scientist to predict with a considerable degree of accuracy the kind of soil or miscellaneous area at a specific location on the landscape. Commonly, individual soils on the landscape merge into one another as their characteristics gradually change. To construct an accurate soil map, however, soil scientists must determine the boundaries between the soils. They can observe only a limited number of soil profiles. Nevertheless, these observations, supplemented by an understanding of the soil -vegetation -landscape relationship, are sufficient to verify predictions of the kinds of soil in an area and to determine the boundaries. Soil scientists recorded the characteristics of the soil profiles that they studied. They noted soil color, texture, size and shape of soil aggregates, kind and amount of rock fragments, distribution of plant roots, reaction, and other features that enable them to identify soils. After describing the soils in the survey area and determining their properties, the soil scientists assigned the soils to taxonomic classes (units). Taxonomic classes are concepts. Each taxonomic class has a set of soil characteristics with precisely defined limits. The classes are used as a basis for comparison to classify soils systematically. Soil taxonomy, the system of taxonomic classification used in the United States, is based mainly on the kind and character of soil properties and the arrangement of horizons within the profile. After the soil scientists classified and named the soils in the survey area, they compared the I t F L Custom Soil Resource Report individual soils with similar soils in the same taxonomic class in other areas so that they could confirm data and assemble additional data based on experience and research. The objective of soil mapping is not to delineate pure map unit components; the objective is to separate the landscape into landforms or landform segments that have similar use and management requirements. Each map unit is defined by a unique combination of soil components and/or miscellaneous areas in predictable proportions. Some components may be highly contrasting to the other components of the map unit. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The delineation of such landforms and landform segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, onsite investigation is needed to define and locate the soils and miscellaneous areas. Soil scientists make many field observations in the process of producing a soil map. The frequency of observation is dependent upon several factors, including scale of mapping, intensity of mapping, design of map units, complexity of the landscape, and experience of the soil scientist. Observations are made to test and refine the soil - landscape model and predictions and to verify the classification of the soils at specific locations. Once the soil -landscape model is refined, a significantly smaller number of measurements of individual soil properties are made and recorded. These measurements may include field measurements, such as those for color, depth to bedrock, and texture, and laboratory measurements, such as those for content of sand, silt, clay, salt, and other components. Properties of each soil typically vary from one point to another across the landscape. Observations for map unit components are aggregated to develop ranges of ' characteristics for the components. The aggregated values are presented. Direct measurements do not exist for every property presented for every map unit component. Values for some properties are estimated from combinations of other properties. 1 1 I L While a soil survey is in progress, samples of some of the soils in the area generally are collected for laboratory analyses and for engineering tests. Soil scientists interpret the data from these analyses and tests as well as the field -observed characteristics and the soil properties to determine the expected behavior of the soils under different uses. Interpretations for all of the soils are field tested through observation of the soils in different uses and under different levels of management. Some interpretations are modified to fit local conditions, and some new interpretations are developed to meet local needs. Data are assembled from other sources, such as research information, production records, and field experience of specialists. For example, data on crop yields under defined levels of management are assembled from farm records and from field or plot experiments on the same kinds of soil. Predictions about soil behavior are based not only on soil properties but also on such variables as climate and biological activity. Soil conditions -are predictable over long periods of time, but they are not predictable from year to year. For example, soil scientists can predict with a fairly high degree of accuracy that a given soil will have a high water table within certain depths in most years, but they cannot predict that a high water table will always be at a specific level in the soil on a specific date. After soil scientists located and identified the significant natural bodies of soil in the survey area, they drew the boundaries of these bodies on aerial photographs and identified each as a specific map unit. Aerial photographs show trees, buildings, fields, roads, and rivers, all of which help in locating boundaries accurately. Soil Map The soil map section includes the soil map for the defined area of interest, a list of soil map units on the map and extent of each map unit, and cartographic symbols displayed on the map. Also presented are various metadata about data used to produce the map, and a description of each soil map unit. 7 1� ay' E 'JIT �' LK}/-J$b' (J(1pJ8p6 L=E%LT �f�N pSCGdCD ay' E 'JIT �' LK}/-J$b' (J(1pJ8p6 L=E%LT �f�N pSCGdCD M.9ZQ e50[ M N 2 Q� fS B �0 3 N Z a�4k I 1 1 1 1 1 I� J 1 I w o_ D - s 7 m V N N N D i o a o m = a F c• m m o D 0 � m o o O � °• O F m - o - m c c � g m •_ r m f G� a v O w a y o n s o a a a F • y m m - o '� 33 co �? S'Q%3oi a �o mm �.m33 m �N �m my aNm cm g s v m�3 �c 2 �wmH 0' a� 5 d o mfn3 mK .N da �. m o^�� mao m O my sl m m wmo a ag 3 m o -'° 0, 00> 3Au a my my 3 m 3 .0mo m o'er n N3 n oamm(n mom°-' �' 0S0m v d �n m� o n� 3Qm �Z3 o w oo < <D .am IR mZ mwmom m , m _nm 0. C (n mD rZ3D% vo "aff on c'mmmm vc s o 32 �0=�3 w -i �3� a a p �mm w 0 y m 3 o N y A m= m 6 'm m vv m 3 3 N a n �-m 5m5 mw 0'2 o�io m m- m a n t3 .��^M m 3 w �` m m 3 to a w n am -m m m Omw N m O Custom Soil Resource Report LI ' Map Unit Legend I� 1 Larimer County Area, Colorado (CO644) Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 5 Aquepts, loamy 2.4 17.4% 62 Larimer-Stoneham complex, 3 to 10 percent slopes 8.7 62.8% 73 Nunn day loam, 0 to 1 percent slopes 0.2 1.2% 74 Nunn clay loam, 1 to 3 percent slopes 2.6 18.6% Totals for Area of Interest 13.8 100.0% Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more ' major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties ofthe soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend ' beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic ' classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. ' Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different ' management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially ' where the pattern was so complex that itwas impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape. The presence of minor components in a map unit in no way diminishes the usefulness ' or accuracy of the data. The objective of mapping is not to delineate pure taxonomic classes but rather to separate the landscape into landforms or landform segments that 10 Custom Soil Resource Report have similar use and management requirements. The delineation of such segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, however, onsite investigation is needed to define and locate the soils and miscellaneous areas. An identifying symbol precedes the map unit name in the map unit descriptions. Each description includes general facts about the unit and gives important soil properties and qualities. Soils that have profiles that are almost alike make up a soil series. Except for differences in texture of the surface layer, all the soils of a series have major horizons that are similar in composition, thickness, and arrangement. Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity, degree of erosion, and other characteristics that affect their use. On the basis of such differences, a soil series is divided into soil phases. Most of the areas shown on the detailed soil maps are phases of soil series. The name of a soil phase commonly indicates a feature that affects use or management. For example, Alpha silt loam, 0 to 2 percent slopes, is a phase of the Alpha series. Some map units are made up of two or more major soils or miscellaneous areas. These map units are complexes, associations, or undifferentiated groups. A complex consists of two or more soils or miscellaneous areas in such an intricate pattern or in such small areas that they cannot be shown separately on the maps. The pattern and proportion of the soils or miscellaneous areas are somewhat similar in all areas. Alpha -Beta complex, 0 to 6 percent slopes, is an example. An association is made up of two or more geographically associated soils or miscellaneous areas that are shown as one unit on the maps. Because of present or anticipated uses of the map units in the survey area, it was not considered practical or necessary to map the soils or miscellaneous areas separately. The pattern and relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha - Beta association, 0 to 2 percent slopes, is an example. An undifferentiated group is made up of two or more soils or miscellaneous areas that could be mapped individually but are mapped as one unit because similar interpretations can be made for use and management. The pattern and proportion of the soils or miscellaneous areas in a mapped area are not uniform. An area can be made up of only one of the major soils or miscellaneous areas, or it can be made up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example. Some surveys include miscellaneous areas. Such areas have little or no soil material and support little or no vegetation. Rock outcrop is an example. 11 Custom Soil Resource Report ' Larimer County Area, Colorado ' 6—Aquepts, loamy Map Unit Setting ' National map unit symbol. jpws Elevation: 4,500 to 6,700 feet Mean annual precipitation: 12 to 18 inches ' Mean annual air temperature: 39 to 50 degrees F Frost -free period: 80 to 140 days Farmland classification: Not prime farmland Map Unit Composition Aquepts and similar soils: 80 percent Estimates are based on observations, descriptions, and transects of the mapunit. ' Description of Aquepts Setting Landform: Stream terraces, draws, depressions Landform position (three-dimensional): Base slope, tread, dip Down -slope shape: Linear Across -slope shape: Linear ' Parent material: Loamy alluvium Typical profile H1 - 0 to 60 inches: variable ' Properties and qualities Slope: 0 to 3 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Very poorly drained ' Runoff class: Negligible Capacity of the most limiting layer to transmit water (Ksat): Moderately high to very high (0.60 to 99.90 in/hr) Depth to water table: About 6 to 18 inches Frequency of flooding: Rare Frequency of ponding: None ' Interpretive groups Land capability classification (irrigated): 5w Land capability classification (noninigated): 3w ' Hydrologic Soil Group: A/D 62—Larimer-Stoneham complex, 3 to 10 percent slopes ' Map Unit Setting National map unit symbol. jpx7 Elevation: 4,800 to 5,800 feet ' Mean annual precipitation: 13 to 15 inches Mean annual air temperature: 48 to 50 degrees F 1 12 , Custom Soil Resource Report Frost -free period: 135 to 150 days Farmland classification: Farmland of local importance Map Unit Composition t Larimer and similar soils: 35 percent Stoneham and similar soils: 25 percent Estimates are based on observations, descriptions, and transects of the mapunit. ' Description of Larimer Setting ' Landform: Terraces, fans, benches Landform position (three-dimensional): Base slope, tread Down -slope shape: Linear Across -slope shape: Linear ' Parent material: Alluvium Typical profile HI - 0 to 7 inches: fine sandy loam ' H2 - 7 to 22 inches: loam H3 - 22 to 30 inches: gravelly sandy clay loam, gravelly loam, sandy clay loam H3 - 22 to 30 inches: very gravelly sand, very cobbly sand, very gravelly loamy sand ' H3 - 22 to 30 inches: H4 - 30 to 60 inches: H4 - 30 to 60 inches: ' H4 - 30 to 60 inches: Properties and qualities Slope: 5 to 10 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.60 to 2.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 10 percent Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water storage in profile: High (about 9.7 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 4e Hydrologic Soil Group: B Ecological site: Loamy Plains (R067XY002CO) Description of Stoneham Setting Landform: Terraces Landform position (three-dimensional): Tread Down -slope shape: Linear Across -slope shape: Linear Parent material. Mixed alluvium and/or eolian deposits 13 Custom Soil Resource Report Typical profile H1 - 0 to 4 inches: loam ' H2 - 4 to 10 inches: clay loam, sandy clay loam, loam H2 - 4 to 10 inches: loam, clay loam, sandy clay loam H2 - 4 to 10 inches: sandy loam, gravelly sandy loam H3 - 10 to 14 inches: ' H3 - 10 to 14 inches: H3 - 10 to 14 inches: H4 - 14 to 60 inches: ' H4 - 14 to 60 inches: Properties and qualities Slope: 3 to 5 percent ' Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high ' (0.60 to 2.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding. None ' Frequency of ponding: None Calcium carbonate, maximum in profile: 15 percent Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water storage in profile: Very high (about 14.7 inches) ' Interpretive groups Land capability classification (irrigated): 4e ' Land capability classification (nonirrigated): 4e Hydrologic Soil Group: B Ecological site: Loamy Plains (R067XY002CO) ' 73—Nunn clay loam, 0 to 1 percent slopes Map Unit Setting ' National map unit symbol: 2ting Elevation: 4,100 to 5,700 feet Mean annual precipitation: 14 to 15 inches Mean annual air temperature: 48 to 52 degrees F Frost -free period: 135 to 152 days Farmland classification: Prime farmland if irrigated ' Map Unit Composition Nunn and similar soils: 85 percent ' Estimates are based on observations, descriptions, and transects of the mapunit. Description of Nunn ' Setting Landform: Terraces Landform position (three-dimensional): Tread 1 14 Custom Soil Resource Report Down -slope shape: Linear Across -slope shape: Linear Parent material: Pleistocene aged alluvium derived from igneous, metamorphic and sedimentary rock and/or eolian deposits Typical profile Ap - 0 to 6 inches: clay loam Bt1 - 6 to 10 inches: clay loam Bt2 - 10 to 26 inches: clay loam Btk - 26 to 31 inches: clay loam Bk1 - 31 to 47 inches: loam Bk2 - 47 to 80 inches: loam Properties and qualities Slope: 0 to 1 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately low to moderately high (0.06 to 0.20 in/hr) Depth to water table: More than 80 inches Frequency of flooding. None Frequency of ponding: None Calcium carbonate, maximum in profile: 7 percent Salinity, maximum in profile: Nonsaline (0.1 to 1.0 mmhos/cm) Sodium adsorption ratio, maximum in profile: 0.5 Available water storage in profile: High (about 9.1 inches) Interpretive groups Land capability classification (irrigated): 3e Land capability classification (nonirrigated): 4e Hydrologic Soil Group: C Ecological site: Clayey Plains (R067BY042CO) 74—Nunn clay loam, 1 to 3 percent slopes Map Unit Setting National map unit symbol. jpxn Elevation: 4,800 to 5,600 feet Mean annual precipitation: 13 to 15 inches Mean annual air temperature: 48 to 50 degrees F Frost -free period. 135 to 150 days Farmland classification: Prime farmland if irrigated Map Unit Composition Nunn and similar soils: 85 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Nunn Setting Landform: Fans, terraces 15 Custom Soil Resource Report ' Landform position (three-dimensional): Base slope, tread Down -slope shape: Linear ' Across -slope shape: Linear Parent material: Alluvium Typical profile ' H1 - 0 to 10 inches: clay loam H2 - 10 to 60 inches: clay loam, clay H2 - 10 to 60 inches: ' Properties and qualities Slope: 1 to 3 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained ' Runoff class: High Capacity of the most limiting layer to transmit water (Ksat): Moderately low to moderately high (0.06 to 0.20 in/hr) ' Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 15 percent ' Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water storage in profile: Very high (about 18.9 inches) Interpretive groups ' Land capability classification (irrigated): 2e Land capability classification (nonirrigated): 3e Hydrologic Soil Group: C 16 Soil Information for All Uses Soil Properties and Qualities The Soil Properties and Qualities section includes various soil properties and qualities displayed as thematic maps with a summary table for the soil map units in the selected area of interest. A single value or rating for each map unit is generated by aggregating the interpretive ratings of individual map unit components. This aggregation process is defined for each property or quality. Soil Qualities and Features Soil qualities are behavior and performance attributes that are not directly measured, but are inferred from observations of dynamic conditions and from soil properties. Example soil qualities include natural drainage, and frost action. Soil features are attributes that are not directly part of the soil. Example soil features include slope and depth to restrictive layer. These features can greatly impact the use and management of the soil. Hydrologic Soil Group Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long - duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. 17 Custom Soil Resource Report ' Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. ' Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink -swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for ' drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. 1 11 18 L I 105D 0' 2E W 4486200 ti z z 4486250 4486300 4486350 4486400 4485450 44tbx 105° 0'49'VI n N s _3 d 0 U/ C 0-0 CD 105^ 0' 26' W rrm�� z v O n d Of d U 7 O (n N O U) E O N 7 U C m N p ao N rn C N 'O N U O a m t 3 V U > m O V N m m O j C d OI O L m y y C V m M U N m m N m �'+ E U N c o' E E Om z d a U CO E N O m vrn'° m N o E a ai ��vDdEo d d C E m O NO_ m Q m O D Nm o" N E3: n p N 0 g m � am O r 0 m LwO O m m O Nmv� N m NN t oLL ETwa`m o �u ao o a m mZ IL oai m > oa E�E am� N •- N m jp J (n N C C N "' J m V co . a �° o m> n Z E Q a coi m o N m E cEL >.� �L ami rnm id d m `o rnm y O O CF'00 m Z(n amia m 0 'n a� N O'er O C yL D -m0 F a N m m6 O m ON :�E -p tL m y O c m O i-n m � m a w > Z amm EE F w E a N a E O o to � U O � n� ¢ t� m F- L... O O (n U) O (n o m O N m F- 0 E r w N 1 r 10 C m o c a T i a T t n r w o c r 2 N n a v m o 0 t a o E �L° v m o o ¢ `p 2 U U ❑ m z m o m V a: _❑ d' 29 An 9< W 0 ® 0 w C �. (D 3 i \ .. m W J u a d a r a r a R m n U a c o c _ U O — c a aDi r v 79 Q o r c o a° ❑ ❑ ❑ o ] ❑ ❑ ❑ S a° ❑ ❑ t< c< a m m U ci ❑ z m< a m m U L)) ❑`) Z a m m 0< t Q W Vl U) a y O N Custom Soil Resource Report Table —Hydrologic Soil Group Hydrologic Soil Group— Summary by Map Unit— Larimer County Area, Colorado (CO644) Map unit symbol Map unit name Rating Acres In AOI Percent of AOI 5 Aquepts, loarny AID 2.4 17.4% 62 Larimer-Stoneham complex, 3 to 10 percent slopes B 8.7 62.8% 73 Nunn day loam, 0 to 1 percent slopes C 0.2 1.2% 74 Nunn day loam, 1 to 3 percent slopes C 2.6 18.6% Totals for Area of Interest 13.8 100.0% Rating Options —Hydrologic Soil Group Aggregation Method: Dominant Condition Component Percent Cutoff.. None Specified Tie -break Rule: Higher 21 I FINAL DRAINAGE AND EROSION CONTROL REPORT 1 Appendix H - DRAINAGE EXHIBITS February 16, 2016 1 Appendix H - DRAINAGE EXHIBITS II II II II i 1 1 1 1 1 1 H.8 1 m- ?rl a Z 0 O m 4�Z3 z Nr 2Nwzw zwox Q K Q -W xF Viw3% N LL U- O4 LLpWd V) 3 p Op w Z o 0 Y z n LL Q = W a :� sz z oa z 4 ¢ �a Q W�y v �O < X YVl W x QJQ W ZLL+7 W LL �=J q6 P O¢ z Nm w ¢�¢ZCZ Za Q ❑ N o ¢ y K 0 na m zz o v E wm n G Pvnm.mwwe.n.n-m�sm�a LO ^y a0 O rn o rn o o ^o % O O 4 n z a 3o z_ 0 p o� O O ✓ E O O O J U O W W 3 o 0 m O O N p W Q CL Z W CD W w J 2 n O 0 Q Q a 19 z a \ 4 < \ a a m Q ?OQ 7 Q y D :s Q �E i Rm i .ew:e.rae,v nca�«w.r SEAR�BROWN� N vwwas Y5 i 1 I < �I r 3333 4 o o o - 0 00 U 4' z €0 _ QJ E tt O > m rcrc W O o O m ZZ O � 0 d o 0 O O F r _E pop Via: W N 0 a CD aW� o z a � J P ❑ O Z � O � 0 x � a O� 0 0 ,6 2 P as �~ 0 Zx O = o 0 0 a ® W �04<w 2 � � a i .c G C E 0 G I u ) @ # ■ i a + • ) + 2 � �§ �• © � � ±)\��! ! •� � r;, � @| - �+» ! | /§� agHg\Qnun! � IN g9Aonnawe`ax 55 oah/ a�aawaeeaQ� e )\\\§§§§§ ill | |�|�(�(§/�cn § i| �1� ° / + l 6 0 ! / |� 9 % : i 1 I 1 1 1 1 1 1 11 1 i u IJ LJ 1 1 j� r I SEE DRAINAGE AND EROSION CONTROL PLAN FROM HEVAETT PACKAGE BUILDING 5 - BY SEAR BROWN DATED DB-2D00 FOR DRAINAGE PATTERNS IN REST OF PARKING ' LOT EXISTING DETENTION POND M V a Hieterie Flew 0w. Qeei0n Corfeibetin0 ieil C2 Q100 To," Qiph HOB 02efe C"00 Helee Point eaairfs Ana eo h eb H1 H1 1.17 0. Od1 856 2.35 821 0.07 4G5 NWCemeraM Oren mb FCR0 H2 Htd H2 1026 003 0.41 10.SD 2-17 7.67 0.71 5201 FCRO aI SE erW of"e. 02=DaIwtion Ports I 1 1 1 I RNwta Rate br Pond A See De.ebpe0 D ExhbN �1 0 I10' 160' DRAINA r FlsN0 HISTORIC BASIN/AREA (ac)/C HI I. A HISTORIC DESIGN POINT DEVELOPED BASIN/AREA (oc)/CIOO 4 DEVELOPED DESIGN POINT OVERLAND FLOW CONCENTRATED FLOW MAJOR BASIN BOUNDARY MINOR BASIN BOUNDARY Te TRAVEL PATH .�f (3 Stantec Stantec Consulting Services Inc 2950 East Ho yRood. Sute 290 rat co0m co la. 97o,182 22 9wnv.eontmxm Copyright Reserved M cvf,aca m sMvv oa a erReberr b a a9+erelvv IA W t bN M eW y-ef Y/T O mwbn 04 m �M+�f b SpMc WnWI Wey. M Ceppbll a aapb eeemma ve M poCeh of Sbdbc. RbpOYFPO,Ia YeW MI C+Wy a?n Ilm Rm w11aaE Uy f bnlec b Ie[tl1bn. Consultants Legend Notes I. Aeu:e see Sedim sf.i dlne lots Ure COEe la dbwmb uei xNlm � NWtl Hobla &Aer Ime Revision •ntlND® qiq er btt Me,' Aow nBD fY9 IfIII_If ,,lip I5.1].D Issued n "ppO n'MAOO geNmv 6taSyCffiJe.M rRa U(LFer_o 1112M Perrmt-Seal a... am DT. "A M Client/Project HEWLETT-PACKARD HP BUILDING 5 PARKING LOT EXPANSION Fort Collins, CO Title HISTORIC DRAINAGE EXHIBIT Project No. Scale 2053D5056 AS SHOWN Droving No. Sheet Revision C500 I of 3 0 1L FOSSIL CREEK RESERVOIR INLET DITCH STORM LINE Y SEE DRAINAGE AND EROSION CONTROL PLAN FROM HEWLETT PACKAGE BUILDING 5 BY SEAR BROWN DATED O 000 FOR DRAINAGE PATTERNS IN REST OF PARKING LOT SWALE SECTION A -A STORM LINE X rC D DETENTION POND A DETENTION POND OUTLET � EXISTING DEtENTION POND er Develooea Flnw Summary Design Point Contributing Basins Total Area oc C2 C100 Te min 12 ism 1100 1ph 02 ofa 0100 afa Note, D1 Dt 1.88 10.02 12.83 2.02 7 04 0.08 5.43 ne mange - undetained 02 D2 6.05 1g 1.70 5.92 2.40 17.73 detain III in new pond released to Water Bridge D3 D3 1.00 t0.60 12.09 7.29 0.04 2.99 re change - "restored D4 D4 0.93 HD.42 2.46 8.59 0.95 C76 detained in existing pond to SE D5 D4kD5 1.29 2.52 8.80 1.51 7.11 detainetl in existing pond to SE Stapp Stooge ElevR StagaR CtamWative valuing, d 4885bl) 0,00 0 488700 1.00 3.157 4888.00 200 18005 488900 3.00 42,850 489000 4,00 78,802 Pon ? Summ TOo-TEAR STORM Pond Req'd WSELR Req'd Ralwe ds I seq'd 8mrage cr R*q'd Sbragei AF AQMaI WSELR A d888 GA 1 71 10 O ]a 71 HP Parking tot Expansion Ana Smakdown Areas by surface mwrage and pen e Aephah sf 121 Pewrs sf Ill Gravels? 121 laedaapa bletda d U Conpg,se rf (2) Open Spew of (1) Totals? 11.56914 9 15200 239M 494982 26.0116 13.3% 1.3% 2.2% 34% 53.896 10D% I=LID improvement 2-lnoeryArea Percentages are based on the oveL l site area sF sI Total LID Im mvement area= 308432 rfl.3% Taailmpervlous Arta= 136S50 30.7% NOTES I SEE SITE PLAN AND SHEET DR3 FOR LIMITS OFF ASPHALT, PAVERS AND GRAVEL - LEFT OFF THIS PLAN FOR CLARITY \ EXISTING SPILLWAY/WATER \ BRIDGE OVER FCRID ION POND OUTLET TO SPILLWAY Par raltwtan,as and Paver Siod, De Iw AN. Location Overall Paver pawr Eaten Paver Asphalt Asphalt/ Parking Block Block paver Percentage Area sf Paver Areasf Area Area Area Ratio Required Provided provided s 25% If If Lower East D2A) 35626 $907 9393 487 26% ]6720 2.8 Laver West D2b 909M 22228 22827 ISO 25% 682M 3.0 Upper D4 & DS 51350 12788 135B 7Q 26% 3930 2.8 Taal 177685 4SM 26% 133265 2.9 DRAINAGE IFGEND HISTORIC BASIN/AREA (oc)/C Nt Ht HISTORIC DESIGN POINT DEVELOPED BASIN/AREA (cc)/Cl00 t Dt DEVELOPED DESIGN POINT DVERLAND FLOW CONCENTRATED FLOW MAJOR BASIN BOUNDARY MINOR BASIN BOUNDARY Te TRAVEL PATH ...... ^�^� (3 Stantec Starlet Consulting Services Inc. N50 East tlam101 Y Road. Will Z90 Pon COON CO let. 9M.4823922 vwwslontec.com Copyright Reserved n,. cPnllav uar .ear Im m gsoenwa Im d d�evbq. o0 'rot err ve dq.nv � qn .,q, q e..ea'+vNa N mmAn.n m Sl�Nec IN carnoNr to a tltto Aa aewm qa dow,gl ae N xaPOIY q 1MIOC.PgOYclbngaplgaM WP'PP OIM IAT xa� wIhMUGY ShnM Olgrl4PT. Consultants Legend k 0 150' 300' Notes n sea vcHm 3.1.1 of IN L. IN Code la dbwabO ws MN, IN NWd N O'd BMIIe lane Revision n +m7 v4am a�urota nvw Nm Ia91Ir ?INN Mea wo I312D Issued By ydr YYMMW nb Ngro; 0.VS1,CID6aPNNAG[ MEO DI9 MW Is. -in awn. cN, DI n. tY,MMDp Permit -Seal CSent/Project HEWLETT-PACKARD HP BUILDING 5 PARKING LOT EXPANSION Fart Collins, CO Title DEVELOPED DRAINAGE EXHIBIT Project No. Scale 205305056 AS SHOWN Drawing No. Sheet Reylsion C501 2 of 3 0 I J Area IF Index A P Total Area sf (AIP) A/P A/P max •• A•• At at (A -A••) Location 1 9426 1333 10759 7.1 1.3 3.0 3999 3.0 6063 3999 2574 Lower West Lover West 2 2574 2021 4595 11403 2534 13937 4228 2534 6762 4310 0 4310 6643 0 6643 9400 4042 13442 14281 S068 19349 9749 3016 12765 7446 3358 10804 7328 2674 9992 6566 _2674 9240 111433 2400 13833 9768 2239 112007 46% 1003 15699 3 4.5 3.0 7602 7602 Lower West 4 1.7 3.0 7602 3.0 0 422E Lower West 5 0.0 0 Lower East 6 0.0 3.0 00 Lower East 7 2.3 3.0 12126 9400 Lower Wen 8 2J1 3.0 15204 14281 Lower West 9 3.2 3.0 9048 904E Lower East 10 11.2 13.0 1D074 7444 Lower East 11 2.7 3.0 6022 7318 Lower West 12 2.5 3.0 8022 6566 Lower West 1 4.9 3.0 72DO 7200 Upper North 14 4.4 3.0 16717 6717 Upper North 15 4.7 3.0 3009 3009 Upper North 16 17 6205 1396 2170 _ 1915 1617 _ 2401 1537 _ 2176 4525 2670 135295 '45454 7601 4.4 3.0 4188 4198 Upper North 4085 1.1 3.0 '5745 2170 Upper South 18 19 4018 0.7 3.0 7203 1617 Upper South 0.7 3.0 6529 1537 1525 103425 Upper South 20 _ �7M L7 3.0 , 801D 1136362 Lower WestTotal 49 1 overall At/A 76% Max A/P 7.1 Min A/P 0.0 Avg A/P 2.6 A=Asphalt Area P= Paver Area At- Treated Asphalt the greater of A$ A•• ••A/P max is the maximum rewmmended A/P ratio from the City Stomnvater Utility and the A•• is based on this max ratio Conclude: The pavers treat more than 50%of the parking lot overall and within each basin and along with detention pond provide sufficient treatment for the asphalt section of the Parking lot so that. additional water quality pond is required in the detention pond. UDSurnmoryfor Parton Lot Parking lot Overall Arsasf Asphalt Ani Paver Areasf Percentage of Pavers Treated Area sf I % treated Lower Wes[ 95271 69721 25550 27% 6W93 a haler East 345 2814E 274 m 11 59% U rliorth 391 RID2 103E M 2111! 6W6 U rSouth 11816 Slri 6W2 SS% 5324 3 Torah 1M17 ]35293 QS481 238s ]18423 SITE LEGEND ® - ASPHALT HATCHING - PERVIOUS PAVER HATCHING - GRAVEL AREA HATCHING - CONCRETE HATCHING DRAINAGE I FCEND M1 HISTORIC BASIN/AREA (pc)/C [.0 HISTORIC DESIGN POINT A DEVELOPED BASIN/AROtEA (oc)/CI00 t, DEVELOPED DESIGN POINT OVERLAND FLOW CONCENTRATED FLOW z MAJOR BASIN BOUNDARY MINOR BASIN BOUNDARY - - - - - Ti, TRAVEL PATH ......... -- (3 Stantec Stantec Consulting Services Inc. 295D Eost Hortrony, Rood Suite 290 Fort Coca CO lei 9M.4823922 wwwslontec.com Copyright Reserved tre caaxvvwvaey ore x�naomac la r4 arv!reiom y.; snrr�lroamwe-ms arse y..�..++wa mmu+n..l •.. slm�.xl.rna.trr. ne caonwn ro aae>oes mo avow oe me moan m slmwc. vroremcle� a �a is om anoow oma mm mo wnAv..e or ilom.c slaooun. consultants Legend �k 0 W 100, i. Haase see xr�a, sal ar lrre taa uw coos la aio«me ases..anm me rvalad nmaa ana tare Revision N Alasa navAoo AMBIL81 ac AI® Isazle Ito\ wai ,.HI ISI]9 Issued °r A'ad wAeAop Rio Nmne: OSL55 Csx-DRAMAGE MED on NLe 1511 w+. rnm. op. Rr MAsno Permit -Seal Cient/Project HEWLETT-PACKARD HP BUILDING 5 PARKING LOT EXPANSION s.w r.se.s. rn LOW IMPACT DEVELOPMENT DRAINAGE EXHIBIT Project No. Scale 20530M AS SHOWN Drowing No. Sheet Revision C502 3 of 3 0 .A asa-.no