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HomeMy WebLinkAboutBRICK STONE APARTMENTS ON HARMONY - PDP - PDP160019 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTPRELIMINARY DRAINAGE REPORT BRICK STONE APARTMENTS Fort Collins, Colorado June 29, 2016 SEEC Enterprises, Prepared LLC for: Park City, PO Box Utah 680513 84068 Prepared by: 301 Fort Collins, North Howes Colorado Street, 80521 Suite 100 Phone: www.northernengineering.970.221.4158 com Fax: 970.221.4159 Project Number: 1229-001  This Drainage Report is consciously provided as a PDF. Please When a consider hard copy the is environment absolutely necessary, before printing we recommend this document double-in its sided entirety. printing. June 29, 2016 City of Fort Collins Stormwater 700 Wood Street Utility Fort Collins, Colorado 80521 RE: Brick Preliminary Stone Apartments Drainage Report for Dear Staff: Northern Engineering is pleased to submit this Preliminary Drainage Report for your review. This report accompanies the Conceptual Review submittal for the proposed Brick Stone Apartments. This Manual report (FCSCM) has been and prepared the Urban in Drainage accordance and with Flood the Control City of District Fort Collins (UDFCD) Stormwater Urban Criteria Storm Drainage proposed Criteria Brick Stone Manual Apartments and serves project. to document We understand the stormwater that review impacts by the associated City of Fort with Collins the is to assure general compliance with standardized criteria. If you should have any questions as you review this report, please feel free to contact us. Sincerely, NORTHERN ENGINEERING SERVICES, INC. Nicholas W. Haws, PE Blaine Mathisen Project Manager Project Engineer Brick Stone Apartments Final Drainage Report TABLE OF CONTENTS I. A. Location GENERAL ......LOCATION ....................AND .........DESCRIPTION ............................................................................................................................................................................ . 1 1 B. Description of Property ..................................................................................................................... 2 C. Floodplain.......................................................................................................................................... 3 II. A. Major DRAINAGE Basin Description BASINS AND .......SUB-.........BASINS .......................................................................................................................................................................... . 4 4 B. Sub-Basin Description ....................................................................................................................... 4 III. A. Regulations.DRAINAGE ..DESIGN ...............CRITERIA ........................................................................................................................................................................................................ . 5 5 B. Four Step Process .............................................................................................................................. 5 C. Development Criteria Reference and Constraints ............................................................................ 6 D. Hydrological Criteria ......................................................................................................................... 7 E. Hydraulic Criteria .............................................................................................................................. 7 F. Floodplain Regulations Compliance .................................................................................................. 7 G. Modifications of Criteria ................................................................................................................... 7 IV. A. General DRAINAGE Concept FACILITY ...........DESIGN ....................................................................................................................................................................................................... . 7 7 B. Specific Details ................................................................................................................................ 10 V. A. Compliance CONCLUSIONS with .Standards ............................................................................................................................................................................................................... .. 11 11 B. Drainage Concept ............................................................................................................................ 12 References ....................................................................................................................... 13 APPENDICES: APPENDIX A – Hydrologic Computations APPENDIX B B.1 – – Hydraulic Storm Sewers Computations (For Future Use) B.B.3 2 – – Detention Inlets Facilities APPENDIX APPENDIX C D – – Water Erosion Quality Control Design Report Computations APPENDIX E – Soils Resource Report Brick Stone Apartments Final Drainage Report LIST Figure OF 1 – TABLES Aerial Photograph AND FIGURES: – Google Earth ........................................................................... 1 Figure Figure 2– 3 - Proposed Existing City Site Floodplain Plan ........................................................................................................................................................................................ . 4 3 MAP POCKET: C5.C5.00 01 - - Historic Drainage Drainage Exhibit Exhibit Brick Stone Apartments Preliminary Drainage Report 1 I. GENERAL LOCATION AND DESCRIPTION A. Location 1. Vicinity Map Figure 1 – Aerial Photograph – Google Earth 2. Brick Township Larimer, Stone State 6 Apartments North, of Colorado. Range project 69 West is located of the in 6th the P.M.Northwest , City of Fort Quarter Collins, of Section County 1, of 3. The College project Avenue. site is Brick located Stone south Apartments of East Harmony will have Road the address and slightly of 201 east W. of Harmony South Road. 4. Currently stormwater the infrastructure existing lot remains associated completely with the undeveloped Brick Stone Apartments however there project is currently on site. There with a is trash a drainage rack that ditch the along city regularly the western maintains property and line cleans (Larimer out. This County ditch Ditch conveys #2) flow southern from property the north line. to south There into is also the an Mail existing Creek irrigation Floodway ditch which along runs the adjacent north to the property ultimate design line that point. is used to convey flow from East Harmony Road east towards its The Mail project Creek Floodway, is currently west bordered by a commercial to the north building, by East Harmony and east Road, by an assisted south by living the complex. Brick Stone Apartments Preliminary Drainage Report 2 B. Description of Property 1. Brick need for Stone a turn Apartments lane onto project the property, is approximately additional 4.area 408 will net be acres. associated However, with due the to the Brick Stone Apartments project. 2. Brick offsite Stone runoff Apartments entering the consists property. of Historically, a portion of an flow existing generated tract between of land. College There will be Avenue the site and via curb a low cut point and along flows the into northern an existing property irrigation line ditch. within Runoff Harmony entering Road the enters existing the site through irrigation the ditch Larimer is conveyed County east. Ditch Additional #2 along concentrated the west property offsite line flow and enters runs down a rip-rap embankment until it also reaches Mail Creek Floodway. 3. According Conservation to the Service United (NRCS) States Soil Department Survey, 56.of 1 Agriculture percent of (the USDA) site Natural consists Resources of Altvan- Satanta the site consists loams, which of Nunn fall clay into loam, Hydrologic which Soil falls Groups into Hydrologic B. The other Soils 43.Group 9 percent C. A more of precise soils investigation was performed by Terracon Consultants Inc. 4. The limits proposed of disturbance development as well will as four include (4) the deciduous clearing trees. of existing The proposed vegetation project within will the include uncovered. a large There multifamily will be a courtyard building with at the associated center of parking the building both underground with an emergency and access sidewalks drive with leading associated up to it. landscaping Along the walls south in side order of the to maintain building, reasonable there will be slopes and underground reduce the via limits Stormtech of disturbance. chambers. Water When quality designing and the detention water quality will be portion provided of the aggregate underground to accommodate chambers for a porosity additional of 0% sediment will be build assumed up. The for the isolator underdrain rows will be wrapped portion, the in a underground geotextile membrane chambers to were avoid modeled sediment with migration. a typical As 40% for porosity the detention for the underdrain aggregate. Brick Stone Apartments Preliminary Drainage Report 3 Figure 2– Proposed Site Plan 5. There major are drainage irrigation ways facilities (Mail Creek (Larimer Floodway) County within Ditch #the 2)property , erosion limits. buffer zones, and 6. The permitted project within site is this within zone the district. Harmony Corridor District (H-C). The proposed use is C. Floodplain 1. The according 2006, subject this to tract property FIRM lies Panel in does an 08069C1000F area not lie of within minimal a for plottable flood Larimer hazard, FEMA County, Zone floodplain. dated X. December However, 19th, 2. A zone portion for Mail of Brick Creek Stone floodway Apartments which is project a City does of Fort however Collins fall floodplain. within an Any erosion buffer development with the safety within regulations the floodway of Chapter must 10 obtain of City a floodplain Municipal use Code. permit A portion and comply of this property structure is is located not allowed within in the an erosion erosion buffer buffer zone zone and for Mail all nonstructural Creek. Construction development of a must vegetation meet within the standards the erosion of Section buffer zone 10-202 must of be City non-Municipal irrigated Code. native Proposed vegetation that enhances the stability of the creek. Brick Stone Apartments Preliminary Drainage Report 4 Figure 3 - Existing City Floodplain II. DRAINAGE BASINS AND SUB-BASINS A. Major Basin Description 1. Brick drains Stone from west Apartments to east is to within the confluence the Mail Creek of Mail Drainage Creek and Basin. Fossil This Creek, basin and generally ultimately to Fossil Creek Reservoir. 2. There Apartments are no project previous site. drainage studies for the area associated with Brick Stone B. Sub-Basin Description 1. Brick Stone Apartments historically sheet flows north to south towards Mail Creek. Basin H1 Basin runoff H1 is discharged is associated directly with into the entire Mail Creek. project Within area (4.Basin 408 H1 acres) there because is an existing all the drainage embankment ditch towards along the Mail west Creek. property This line offsite that flow directs will not offsite be flow disturbed via a or rip-altered rap during erosion or buffer after zone the construction which is associated of Brick with Stone the Apartments. Mail Creek Basin Floodway. H1 lies No within structures an will be placed within the erosion buffer zone. Brick Stone Apartments Preliminary Drainage Report 5 Basin OS1 Basin from College OS1 is Avenue associated to the with new the drive south entrance side of the located East at Harmony the northeast Road corner right of of way the project curb cut site. at a Historically, low point along the flow the north associated property with line this and area then has entered entered an the existing site via a irrigation However, ditch the Brick that Stone runs west Apartments to east along project the will south extend side the of Harmony limits of the Road. right of way to ditch. ultimate Instead design of the at historic the proposed flow from shared Harmony access, Road which entering will remove the irrigation a portion ditch of the at the eventually project enter site it the will existing remain irrigation in a concentrated ditch just flow west within of S. Boardwalk the curb and Drive. gutter There and will be Apartments no detention project or water site. quality provided for this off site basin on the Brick Stone 2. A Section more detailed IV.A.4., description below. of the projects proposed drainage patterns follows in 3. There is offsite flow associated with Brick Stone Apartments as previously discussed. A Map full-Pocket size copy at the of the end Historic of this report. and Proposed Drainage Exhibit can be found in the III. DRAINAGE DESIGN CRITERIA A. Regulations There Apartments are no project. optional provisions outside of the FCSCM proposed with the Brick Stone B. Four Step Process The project overall utilizes stormwater the “Four management Step Process” strategy to minimize employed adverse with impacts the Brick of Stone urbanization Apartments on receiving incorporated waters. each The step. following is a description of how the proposed development has Step 1 – Employ Runoff Reduction Practices Several reduction techniques of runoff peaks, have been volumes, utilized and with pollutant the proposed loads as development the site is developed to facilitate from the the current use by implementing multiple Low-Impact Development (LID) strategies including: Providing south portion as much of the vegetated site to reduce open the areas overall as possible impervious along area the and north, to minimize east, west directly and connected impervious areas (MDCIA). Routing water quality flows, purposes. to the extent Stormwater feasible, will through be routed underground through Stormtech drain rock to Isolator increase Rows for infiltration Providing reduce loads regional on downstream detention to storm increase infrastructure. time of concentration, promote infiltration and Routing runoff from the roofs directly into isolator rows Brick order Stone to maintain Apartments existing will drainage minimize patterns, the limits specifically of disturbance along the to the west fullest property extent line in where there is already an existing drainage ditch. Brick Stone Apartments Preliminary Drainage Report 6 Step Slow 2 Release – Implement BMPs That Provide a Water Quality Capture Volume (WQCV) with The BMPs efforts required taken for in water Step quality. 1 will facilitate Stormwater the reduction generated of on runoff the western and provide portion the of necessary the project grade constraints site will remain and the unaltered lack of space and will along be free the released south side directly of the into limits Mail of disturbance Creek. Due to all runoff be free generated released into from Mail the Creek. landscape The and remaining sidewalks portion on the of the south site side will of be the captured building in will inlets and will be roof released leaders at and the routed historic to 2-underground year event with detention a reduction and water because quality of the facilities. non-catchable Runoff flow leaving the site untreated. Step As stated 3 – Stabilize in Section Drainageways I.B.5, above, there are major drainageways in the subject site. The erosion undeveloped buffer and zone no per construction city of Fort will Collins be required City Flood within Risk this Map zone. will The remain Mail completely Creek floodway the Brick will Stone also Apartments remain completely project will unaltered. be reduced The as limits much of as disturbance possible. Flow associated associated with with not be Larimer disturbed County during Ditch construction. #2 will also By remain under-utilizing unaltered the and site the and infrastructure keeping a large with area it will undisturbed, Furthermore, combined this project with will LID, pay the one-likelihood time stormwater of bed and development bank erosion fees, is as greatly well as reduced. ongoing stability. monthly stormwater utility fees, both of which help achieve Citywide drainageway Step 4 – Implement Site Specific and Other Source Control BMPs. The parking, Brick landscaping Stone Apartments walls, and project a sidewalk includes path two all buildings of which with will a require courtyard, the need associated for site specific source controls including: A localized trash enclosure placed in the underground parking lot C. Development Criteria Reference and Constraints 1. There are no known drainage studies for the existing property. 2. There for discusses Fort is Collins a the drainage historic Supportive study use for of Housing” the the existing adjacent by S. irrigation lot A. Miro, to the ditch Inc. east dated that titled runs May “Final west 25th, Drainage to 2007 east along Report which East Harmony Road. 3. The surrounded subject by property currently is essentially developed an properties. "in-fill" development As such, several project constraints as the property have been is identified system including: during the course of this analysis that will impact the proposed drainage Existing maintained. elevations along the north, south, east, and west property lines will be Overall drainage patterns of the existing site will be maintained. Release rates can not adversely impact existing infrastructure. Brick Stone Apartments Preliminary Drainage Report 7 D. Hydrological Criteria 1. The Figure City RA-of 16 Fort of Collins the FCSCM, Rainfall serve Intensity-as the Duration-source for Frequency all hydrologic Curves, computations as depicted in associated utilized for with Rational this Method development. runoff calculations. Tabulated data contained in Table RA-7 has been 2. The coefficients Rational contained Method has in Tables been employed RO-11 and to RO-compute 12 of stormwater the FCSCM. runoff utilizing 3. The procedure Rational has Formula-been utilized based for Modified detention Federal storage Aviation calculations. Administration (FAA) 4. Two The first separate event design analyzed storms is the have “Minor,been ” utilized or “Initial” to address Storm, which distinct has drainage a 2-year scenarios. recurrence 100-year recurrence interval. The interval. second event considered is the “Major Storm,” which has a 5. No that other are not assumptions referenced or by calculation current City methods of Fort Collins have been criteria. used with this development E. Hydraulic Criteria 1. As Creek. previously The majority noted, of the runoff subject historically property related historically to the drains site sheet north flows to south with into the Mail exception flow. of Larimer County Ditch #2, which conveys offsite flows in a concentrated 2. All in accordance drainage facilities with criteria proposed outlined with in the the Brick FCSCM Stone and/Apartments or the Urban project Drainage are designed and Flood Control District’s (UDFCD) Urban Storm Drainage Criteria Manual. 3. As regulatory stated in floodplain Section I.(Mail C.1, Creek above, Floodway)the subject . property is located within a City 4. The drainageways. Brick Stone Apartments project does not propose to modify any natural F. Floodplain Regulations Compliance 1. As Creek previously Floodway)mentioned, . However, the all project structures site falls are located within a outside City regulatory of the City floodplain floodplain (Mail and erosion buffer zone. G. Modifications of Criteria 1. The this time. proposed Brick Stone Apartments development is not requesting modification at IV. DRAINAGE FACILITY DESIGN A. General Concept 1. The existing main drainage objectives patterns of the and Brick ensure Stone no Apartments adverse impacts drainage to any design adjacent are to properties maintain or existing infrastructure. Brick Stone Apartments Preliminary Drainage Report 8 2. As However, previously these mentioned, flows are there going are to get off-constrained site flows draining in curb onto and gutter the existing in order property. to keep the flow in the East Harmony Road right of way. 3. A Contents list of tables at the and front figures of the used document. within this The report tables can and be figures found are in the located Table within of the sections to which the content best applies. 4. The designated Brick Stone as Basins Apartments W.1, E.project 1, E.2, is OS.associated 1, OS.2, with OS.3, seven and OS.major 4. However, drainage basins, there are only other five two basins basins within (OS.1 the and project OS.2) boundaries are associated (W.1, with E.1, East E.2, Harmony OS.3, and Road. OS.4), the Basin W.1 Basin multifamily W.1 is building located it along has an the associated western portion emergency of the drive building access. and The the majority west half of of the runoff buildings generated roof. Runoff in this from basin the is roof garnered will enter on the roof western leaders portion which will of the convey multifamily the flow to emergency an isolator access row within drive isle. the underground The remaining Stormtech portion of chambers runoff is generated underneath within the the paved area will and enter landscaping the underground areas directly Stormtech west chambers of the building. via 5’ Runoff Type R generated inlet located in this at the south within end MC-of 4500 the emergency Stormtech chambers access drive. that Water are wrapped quality and in a detention geotextile will membrane both occur to avoid release sediment rate via a migration. flow control Basin manhole W.1 will directly release into at the a portion Mail Creek of the Floodway. historic 2-year Basin E.1 Basin E.1 is located along the eastern property line and contains the eastern portion of the majority multifamily of runoff building, is produced southeast via the parking roof which lot, and is routed a small via portion roof leaders of landscaping. into a A proposed The remaining storm portion system of which the runoff runs north is generated to south within underneath the parking the shared lot and access landscaping drive. islands. two 5’ Type Runoff R Inlets from located the parking at the lot south and landscaping and west sides islands of the will southern sheet flow parking into one lot. of Once conveyed all the to MC-runoff 4500 has Stormtech been gathered chambers into the located proposed underground storm system in the it southern will be section 4500 Stormtech of the parking chambers. lot. Water Basin quality E.1 will and release detention at a will portion both of occur the historic within MC- 2-year release rate via a flow control manhole directly into the Mail Creek Floodway. Basin E.2 Basin generated E.2 contains in the landscaping all the landscaping area will sheet north flow of the north multifamily into Harmony building. Road. Runoff Once into Harmony proposed double Road it Combination will flow west Inlet to east within via the curb new and turn gutter lane. and Once eventually in the inlet enter the a runoff with. Runoff will be will conveyed be routed via the to MC-same 4500 storm Stormtech system that chambers Basin located E.1 is being underground conveyed in the within southern the MC-section 4500 of Stormtech the parking chambers. lot. Water Basin quality E.2 and will detention release at will a portion both occur of the Brick Stone Apartments Preliminary Drainage Report 9 historic Floodway. 2-year release rate via a flow control manhole directly into the Mail Creek Basin OS.1 Basin OS.1 is 100% asphalt and is associated exclusively with the new turn lane being though constructed this area is near not within the northeast the projects corner boundaries, of the Brick the Stone Brick Apartments Stone Apartments site. Even project new turn will lane. provide The turn detention lane is and a part water of quality the cities for master the runoff plan generated to eventually within increase this East same Harmony double Combination Road to ultimate Inlet that design. Basin Runoff E.2 is generated utilizing. in Once Basin in OS.the 1 inlet will the enter runoff the will conveyed be conveyed in. Runoff via will the be same routed storm to system MC-4500 that Stormtech Basins E.1 chambers and E.2 located are being underground detention will in both the occur southern within section the MC-of the 4500 southeast Stormtech. parking Basin lot. OS.Water 1 will quality release and at a portion Mail Creek of the Floodway. historic 2-year release rate via a flow control manhole directly into the Basin OS.2 Basin OS.2 is the same basin as the previously discussed Basin OS1 from the historic analysis. from College Basin Ave. OS.to 2 roughly consists the of the middle southern of the portion Brick Stone of East Apartments Harmony Road project stretching site. Runoff located generated just west of within S. Boardwalk the right of Drive, way into will still the existing reach its irrigation ultimate ditch. design The point runoff generated Basins OS.within 1 and Basin E.2 because OS.2 will the bypass double the Combination double Combination Inlet is designed Inlet associated specifically with to only capture the runoff generated in those two basins. Basin OS.3 Basin multifamily OS.3 building is within and the parking limits of lot disturbance which consists and occupies of landscaping the area and just pedestrian south of the sidewalks. untreated but Historically because this the Brick basin Stone sheet Apartments flows south project to Mail is Creek increasing undetained the and imperviousness from the max allowable of this area historic the runoff 2-year generated release rate. from Basin this basin OS.3 will will continue be subtracted to sheet flow south directly into Mail Creek. Basin OS.4 Basin untouched OS.4 and contains undisturbed the Larimer natural County landscaping Ditch #areas 2 and outside the remaining of the limits portion of of the disturbance. allowable historic Runoff 2-generated year release from rate this because basin it will is not not being be subtracted altered from from its the historic max condition. Creek. Runoff generated in Basin OS.4 will continue to sheet flow south into Mail Brick Stone Apartments Preliminary Drainage Report 10 B. Specific Details 1. The existing main stormwater drainage problems infrastructure associated present, with steep this existing project grades, site is the city deficiency floodplains, of existing entering drainage the site. ditches, Currently and the an majority influx of of runoff the site generated drains south from via East sheet Harmony flow directly Road into following Mail Creek. water quality The proposed devices: site will mitigate these issues by instituting the Basins underground W.1, E.systems. 1, E.2, and OS.1 will be routed into isolator rows within the The sediment Stormtech migration. chambers will be wrapped with a geotextile membrane to avoid Water impacts quality of runoff plates leaving will be the placed site and at entering each of the Mail two Creek. outfalls to further reduce the When aggregate sizing (typically the water assumed quality to chambers be 40%) a was porosity used of to 0% reduce for the any underdrain possibility of overloading the system with sediment buildup. 2. The calculating release the rate 2-for year the peak undeveloped runoff rate land for (the pre-entire development) project area was and established excluding by basin OS.patterns 3 100-and year quantitites. event (0.98 The cfs) overall because historic it remains 2-year unaltered peak runoff from rate historic was calculated drainage at 2.(W.27 1, cfs, E.1, resulting E.2, and in OS.a maximum 1). This release release rate rate was of 1.utilized 29 cfs in for the the FAA remaining procedure basins detention storage computations (Refer to Appendix B for these calculations). 3. Detention Pond Calculations The and they Brick have Stone a Apartments combined max project release has rate two of separate 1.29 cfs. underground The release detention rate for each facilities pond associated was determined only with Basin as a portion W.1 which of the occupies max release 32% rate. of the The area West associated Pond is with Basins 32% of W.the 1, max E.1, release E.2, and rate, OS.allowing 1. Therefore, for a release the West rate Pond of 0.will 41 release cfs. The at remaining a rate of 68% release of rate the max of 0.release 88 cfs. rate Adding of 1.those 29 will two be release allocated rates to together East Pond, (0.41 allowing cfs + 0.for 88 a cfs) brings the max release rate from the site to 1.29 cfs. Detention 4500 chambers will be from provided Stormtech. onsite in the form of underground detention using MC- West Pond The for West FAA Pond, method based was used on characteristics to size the underground of Basin W.pond 1 with for an detention. adjusted Calculations release rate of 0.ft a 44 total cfs, of formulate 48 MC-4500 a detention chambers volume will of be 8,used. 796 cu. West ft. Pond In order will to discharge detain 8,south 796 cu. towards Mail Creek through a flow control manhole. East Pond The for East FAA Pond, method based was on used characteristics to size the underground of Basins E.1, pond E.2, for and detention. OS.1 with Calculations an adjusted order to detain release 18,rate 878 of cu. 0.88 ft. cfs, a total formulate of 110 a MC-detention 4500 chambers volume of will 18,878 be used. cu. ft. East In Pond will discharge south towards Mail Creek through a flow control manhole. Brick Stone Apartments Preliminary Drainage Report 11 4. Water Quality Results Basin W.1 Basin an assumed W.1’s porosity water quality of 0% will to allow be provided for the via entire underground water quality Stormtech volume chambers to be with achieved through either exclusively roof leaders within or the a chambers. 5’ Type R Inlet. Runoff Following will enter UDFCD the underground standards, system a required aggregate WQCV porosity of 871.of 0% 2 means cu. ft. must 5 MC-be 4500 provided chambers for Basin must W.be 1, used and to assuming capture an this runoff. further The reduce 5 water sediment quality migration. chambers However, will be wrapped Brick Stone with Apartments a geotextile project membrane will to wrap conservative 18 of the and MC-enhance 4500 chambers the downstream associated stability. with City West of Pond Fort Collins in order has to be agreed that the Stormtech chambers are an acceptable LID treatment. Basin E.1, E.2, and OS.1 Basin’s Stormtech E.1, chambers E.2, and with OS.1 an will assumed also have porosity water of quality 0% (same provided as above)via underground . Runoff will enter double the Combination underground Inlet. system Following through UDFCD either standards, roof leaders, a required a 5’ Type WQCV R Inlet, of or 1742.a 4 cu. porosity ft. must of 0% be yields provided 13 for MC-Basins 4500 E.Stormtech 1, E.2, and chambers. OS.1, and The assuming 13 water an quality aggregate chambers migration. will However, be wrapped Brick Stone with a Apartments geotextile membrane project will to wrap further 26 reduce of the MC-sediment 4500 chambers downstream associated stability. with City East of Fort Pond Collins in order has agreed to be conservative that the StormTech and enhance chambers the are an acceptable LID. 5. West WQCV, pond 48 will attributed have a to total detention, of 53 MC-and 4500 18 of chambers, the chambers 5 of will them be attributed wrapped to with a geotextile membrane. 6. East to WQCV, Pond 110 will have attributed a total to of detention, 123 MC-4500 and 26 chambers, of the chambers 13 of them will be attributed wrapped with a geotextile membrane. 7. In clogged the case runoff that will any overtop of the 5’ the Type curb R and inlets gutter within and Basin flow south W.1 and towards E.1 get Mail Creek as it has historically. 8. In runoff the will case pond that the about double 4.9” Combination before overtopping Inlet within the highpoint the turn within lane gets the clogged turn lane existing and irrigation then flow ditch, east towards where it S. has Boardwalk historically Drive gone. where it will enter the V. CONCLUSIONS A. Compliance with Standards 1. The the City drainage of Fort design Collins’ proposed Stormwater with Criteria the Brick Manual. Stone Apartments project complies with 2. The the City drainage of Fort design Collins’ proposed Master with Drainage the Brick Plan Stone for the Apartments Mail Creek project Basin. complies with Brick Stone Apartments Preliminary Drainage Report 12 3. There Brick Stone are city Apartments regulatory project. floodplains Nonstructural and erosion development buffer zones will associated meet the with standards the of Section erosion buffer 10-202 zone of the will City be included Municipal on Code. all the The plans boundaries so that it of is the readily floodplain evident and that the Brick Stone Apartments project is not disturbing or altering it. 4. The Stone drainage Apartments plan development and stormwater are management compliant with measures all applicable proposed State with and the Federal Brick regulations governing stormwater discharge. B. Drainage Concept 1. The associated drainage with design its stormwater proposed with runoff. this Brick project Stone will Apartments effectively limit will detain potential for damage a portion of a reduced the previous 2-year and historic proposed rate offsite during runoff. the developed Brick Stone 100-Apartments year storm. will be releasing at 2. Brick anticipated Stone to Apartments be treated will on site. provide water quality for runoff that was not originally 3. The Drainage proposed Plan Brick recommendations Stone Apartments for the development Mail Creek major will not drainage impact basin. the Master Brick Stone Apartments Preliminary Drainage Report 13 References 1. Final Drainage Report For Fort Collins Supportive Housing, May 25, 2007, S. A. Miro, Inc. 2. City November of Fort 5, Collins 2009, Landscape BHA Design, Design Inc. Guidelines with City of for Fort Stormwater Collins Utility and Detention Services. Facilities, 3. Fort 174, Collins 2011, Stormwater and referenced Criteria in Section Manual, 26-City 500 of (Fort c) of Collins, the City Colorado, of Fort Collins as adopted Municipal by Ordinance Code. No. 4. Larimer Reenacted, County Effective Urban October Area Street 1, 2002, Standards, Repealed Adopted and Reenacted, January 2, Effective 2001, Repealed April 1, 2007. and 5. Soils Service, Resource United Report States for Department Larimer County of Agriculture. Area, Colorado, Natural Resources Conservation 6. Urban District, Storm Wright-Drainage McLaughlin Criteria Engineers, Manual, Denver, Volumes Colorado, 1-3, Urban Revised Drainage April and 2008. Flood Control APPENDIX A HYDROLOGIC COMPUTATIONS Brick Stone Apartments CHARACTER OF SURFACE: Runoff Coefficient Percentage Impervious Project: Brick Stone Apartments Streets, Parking Lots, Roofs, Alleys, and Drives: Calculations By: B. Mathisen Asphalt ……....……………...……….....…...……………….………………………………….0.. 95 100% Date: Concrete …….......……………….….……….………………..….………………………………… 0.95 90% Gravel ……….…………………….….…………………………..……………………………….0.. 50 40% Roofs …….…….………………..……………….…………………………………………….. 0.95 90% Pavers…………………………...………………..……………………………………………..0.40 22% Lawns and Landscaping Sandy Soil ……..……………..……………….…………………………………………….. 0.15 0% Clayey Soil ….….………….…….…………..………………………………………………. 0.25 0% 2-year Cf = 1.00 100-year Cf = 1.25 Basin ID Basin Area (s.f.) Basin Area (ac) Area of Asphalt (ac) Area of Concrete (ac) Area of Roofs (ac) Area of Gravel (ac) Area of Pavers (ac) Area of Lawns and Landscaping (ac) 2-year Composite Runoff Coefficient 10-year Composite Runoff Coefficient 100-year Composite Runoff Coefficient Composite % Imperv. H1 191991 4.41 0.000 0.002 0.000 0.103 0.000 4.30 0.26 0.26 0.32 1% OS1 42674 0.98 0.980 0.000 0.000 0.000 0.000 0.00 0.95 0.95 1.00 100% TOTAL 234665 5.39 0.980 0.002 0.000 0.103 0.000 4.30 0.30 0.30 0.38 19% DEVELOPED COMPOSITE % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS Runoff Coefficients are taken from the City of Fort Collins Storm Drainage Design Criteria and Construction Standards, Table 3-3. % Impervious taken from UDFCD USDCM, Volume I. 10-year Cf = 1.00 June 29nd, 2016 **Soil Classification of site is Clay Loam** Page 1 of 23 Historic D:\Projects\1229-001\Drainage\Hydrology\1229-001_Rational-Calcs (Historic).xlsx\C-Values Brick Stone Apartments Overland Flow, Time of Concentration: Project: Brick Stone Apartments Calculations By: Date: Gutter/Swale Flow, Time of Concentration: Tt = L / 60V Tc = Ti + Tt (Equation RO-2) Velocity (Gutter Flow), V = 20·S½ Velocity (Swale Flow), V = 15·S½ NOTE: C-value for overland flows over grassy surfaces; C = 0.25 Is Length >500' ? (C*2-Cf yr Cf=1.00) (10-C*Cf yr Cf=1.00) (100-C*Cf yr Cf=1.25) Length, L (ft) Slope, S (%) 2-Ti yr (min) 10-Ti yr (min) 100-Ti yr (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) (min) Tt Length, L (ft) Slope, S (%) Velocity, V (ft/s) (min) Tt 2-yr (min) Tc 10-yr (min) Tc 100-yr (min) Tc h1 H1 No 0.26 0.26 0.32 294 9.44% 12.8 12.8 11.8 N/A N/A N/A N/A N/A 13 13 12 os1 OS1 No 0.95 0.95 1.00 31 3.30% 1.0 1.0 0.7 665 0.60% 1.55 7.2 N/A N/A N/A 8 8 8 DEVELOPED TIME OF CONCENTRATION COMPUTATIONS Brick Stone Apartments Rational Method Equation: Project: Brick Stone Apartments Calculations By: Date: From Section 3.2.1 of the CFCSDDC Rainfall Intensity: h1 H1 4.41 13 13 12 0.26 0.26 0.32 2.02 3.45 7.29 2.27 3.89 10.29 os1 OS1 0.98 8 8 8 0.95 0.95 1.00 2.40 4.10 8.59 2.23 3.82 8.42 Area, A (acres) Intensity, i2 (in/hr) 100-yr Tc (min) DEVELOPED RUNOFF COMPUTATIONS C100 Design Point Flow, Q100 (cfs) Flow, Q2 (cfs) 10-yr Tc (min) 2-yr Tc (min) C2 Flow, Q10 (cfs) Intensity, i100 (in/hr) Basin(s) B. Mathisen June 29nd, 2016 Intensity, i10 (in/hr) Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1 C10 Q  C f  C  i  A  Page 3 of 23 Historic D:\Projects\1229-001\Drainage\Hydrology\1229-001_Rational-Calcs (Historic).xlsx\Direct-Runoff Brick Stone Apartments CHARACTER OF SURFACE: Runoff Coefficient Percentage Impervious Project: Brick Stone Apartments Streets, Parking Lots, Roofs, Alleys, and Drives: Calculations By: B. Mathisen Asphalt ……....……………...……….....…...……………….………………………………….0.. 95 100% Date: Concrete …….......……………….….……….………………..….………………………………… 0.95 90% Gravel ……….…………………….….…………………………..……………………………….0.. 50 40% Roofs …….…….………………..……………….…………………………………………….. 0.95 90% Pavers…………………………...………………..……………………………………………..0.40 22% Lawns and Landscaping Sandy Soil ……..……………..……………….…………………………………………….. 0.15 0% Clayey Soil ….….………….…….…………..………………………………………………. 0.25 0% 2-year Cf = 1.00 100-year Cf = 1.25 Basin ID Basin Area (s.f.) Basin Area (ac) Area of Asphalt (ac) Area of Concrete (ac) Area of Roofs (ac) Area of Gravel (ac) Area of Pavers (ac) Area of Lawns and Landscaping (ac) 2-year Composite Runoff Coefficient 10-year Composite Runoff Coefficient 100-year Composite Runoff Coefficient Composite % Imperv. W.1 33858.2 0.777 0.093 0.141 0.495 0.000 0.000 0.05 0.91 0.91 1.00 86% E.1 50902.3 1.169 0.316 0.295 0.495 0.000 0.000 0.06 0.91 0.91 1.00 88% E.2 17035.5 0.391 0.000 0.104 0.000 0.000 0.000 0.29 0.44 0.44 0.55 24% OS.1 5643.7 0.130 0.130 0.000 0.000 0.000 0.000 0.00 0.95 0.95 1.00 100% OS.2 40416.7 0.928 0.928 0.000 0.000 0.000 0.000 0.00 0.95 0.95 1.00 100% OS.3 7397.3 0.170 0.000 0.075 0.000 0.000 0.000 0.09 0.56 0.56 0.70 40% OS.4 82798.7 1.901 0.000 0.021 0.000 0.102 0.000 1.78 0.27 0.27 0.34 3% TOTAL 238053 5.465 1.466 0.636 0.990 0.102 0.000 2.27 0.61 0.61 0.76 54% DEVELOPED COMPOSITE % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS Brick Stone Apartments Overland Flow, Time of Concentration: Project: Brick Stone Apartments Calculations By: Date: Gutter/Swale Flow, Time of Concentration: Tt = L / 60V Tc = Ti + Tt (Equation RO-2) Velocity (Gutter Flow), V = 20·S½ Velocity (Swale Flow), V = 15·S½ NOTE: C-value for overland flows over grassy surfaces; C = 0.25 Is Length >500' ? (C*2-Cf yr Cf=1.00) (10-C*Cf yr Cf=1.00) (100-C*Cf yr Cf=1.25) Length, L (ft) Slope, S (%) 2-Ti yr (min) 10-Ti yr (min) 100-Ti yr (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) (min) Tt Length, L (ft) Slope, S (%) Velocity, V (ft/s) (min) Tt 2-yr (min) Tc 10-yr (min) Tc 100-yr (min) Tc w W.1 No 0.91 0.91 1.00 203 0.50% 6.5 6.5 3.4 25 100.00% 20.00 0.0 N/A N/A N/A 7 7 5 e E.1 No 0.91 0.91 1.00 166 1.10% 4.4 4.4 2.3 147 3.20% 3.58 0.7 N/A N/A N/A 5 5 5 e E.2 No 0.44 0.44 0.55 64 2.10% 7.7 7.7 6.5 N/A N/A N/A N/A N/A 8 8 6 Brick Stone Apartments Rational Method Equation: Project: Brick Stone Apartments Calculations By: Date: From Section 3.2.1 of the CFCSDDC Rainfall Intensity: w W.1 0.78 7 7 5 0.91 0.91 1.00 2.60 4.44 9.95 1.83 3.12 7.73 e E.1 1.17 5 5 5 0.91 0.91 1.00 2.85 4.87 9.95 3.04 5.19 11.63 e E.2 0.39 8 8 6 0.44 0.44 0.55 2.46 4.21 9.31 0.42 0.72 1.99 e OS.1 0.13 5 5 5 0.95 0.95 1.00 2.85 4.87 9.95 0.35 0.60 1.29 OS.2 0.93 5 5 5 0.95 0.95 1.00 2.85 4.87 9.95 2.51 4.29 9.23 OS.3 0.17 12 12 9 0.56 0.56 0.70 2.09 3.57 8.21 0.20 0.34 0.98 OS.4 1.90 18 18 17 0.27 0.27 0.34 1.70 2.90 6.20 0.88 1.49 3.99 DEVELOPED RUNOFF COMPUTATIONS C100 Design Point Flow, Q100 (cfs) Flow, Q2 (cfs) 10-yr Tc (min) 2-yr Tc (min) C2 Flow, Q10 (cfs) Intensity, i100 (in/hr) Basin(s) B. Mathisen June 29th, 2016 Intensity, i10 (in/hr) Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1 C10 Area, A (acres) Intensity, i2 (in/hr) 100-yr Tc (min) Q  C f  C  i  A  Page 3 of 23 Proposed D:\Projects\1229-001\Drainage\Hydrology\1229-001_Rational-Calcs(Proposed_final).xlsx\Direct-Runoff Brick Stone Apartments CHARACTER OF SURFACE: Runoff Coefficient Percentage Impervious Project: Brick Stone Apartments Streets, Parking Lots, Roofs, Alleys, and Drives: Calculations By: B. Mathisen Asphalt ……....……………...……….....…...……………….………………………………….. 0.95 100% Date: June 29th, 2016 Concrete …….......……………….….……….………………..….………………………………… 0.95 90% Gravel ……….…………………….….…………………………..……………………………….. 0.50 40% Roofs …….…….………………..……………….…………………………………………….. 0.95 90% Pavers…………………………...………………..…………………………………………….. 0.40 22% Lawns and Landscaping Sandy Soil ……..……………..……………….…………………………………………….. 0.15 0% Clayey Soil ….….………….…….…………..………………………………………………. 0.25 0% 2-year Cf = 1.00 100-year Cf = 1.25 Design Point Basin IDs Basin Area (s.f.) Basin Area (ac) Area of Asphalt (ac) Area of Concrete (ac) Area of Roofs (ac) Area of Gravel (ac) Area of Pavers (ac) Area of Lawns and Landscaping (ac) 2-year Composite Runoff Coefficient 10-year Composite Runoff Coefficient 100-year Composite Runoff Coefficient Composite % Imperv. i1 E.2 & OS.1 22679 0.52 0.13 0.10 0.00 0.00 0.29 0.56 0.56 0.71 43% e E.1, E.2, & OS.1 73582 1.69 0.45 0.40 0.50 0.35 0.81 0.81 1.00 74% COMBINED DEVELOPED COMPOSITE % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS **Soil Classification of site is Sandy Loam** 10-year Cf = 1.00 Runoff Coefficients are taken from the City of Fort Collins Storm Drainage Design Criteria and Construction Standards, Table 3-3. % Impervious taken from UDFCD USDCM, Volume I. Page 4 of 23 Proposed D:\Projects\1229-001\Drainage\Hydrology\1229-001_Rational-Calcs(Proposed_final).xlsx\Comb-C-Values Brick Stone Apartments Overland Flow, Time of Concentration: Project: Brick Stone Apartments Calculations By: Date: Gutter/Swale Flow, Time of Concentration: Tt = L / 60V Tc = Ti + Tt (Equation RO-2) Velocity (Gutter Flow), V = 20·S½ Velocity (Swale Flow), V = 15·S½ NOTE: C-value for overland flows over grassy surfaces; C = 0.25 Is Length >500' ? (C*2-Cf yr Cf=1.00) (10-C*Cf yr Cf=1.00) (100-C*Cf yr Cf=1.25) Length, L (ft) Slope, S (%) 2-Ti yr (min) 10-Ti yr (min) 100-Ti yr (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) (min) Tt Length, L (ft) Slope, S (%) Velocity, V (ft/s) (min) Tt 2-yr (min) Tc 10-yr (min) Tc 100-yr (min) Tc i1 e E.2 & OS.1 No 0.56 0.56 0.71 15 2.10% 3.0 3.0 2.2 N/A N/A N/A N/A 5 8 10 E.1, E.2, & OS.1 No 0.81 0.81 1.00 64 2.15% 3.4 3.4 1.2 452 0.60% 1.55 4.9 N/A N/A 8 12 13 COMBINED DEVELOPED TIME OF CONCENTRATION COMPUTATIONS Brick Stone Apartments Rational Method Equation: Project: Brick Stone Apartments Calculations By: Date: From Section 3.2.1 of the CFCSDDC Rainfall Intensity: i1 e E.2 & OS.1 0.52 5 8 10 0.56 0.56 0.71 2.85 4.10 7.72 0.8 1.2 2.8 E.1, E.2, & OS.1 1.69 8 12 13 0.81 0.81 1.00 2.40 3.57 7.04 3.3 4.9 11.9 COMBINED DEVELOPED RUNOFF COMPUTATIONS B. Mathisen June 29th, 2016 Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1 Design Point Basin(s) Area, A (acres) 2-yr (min) Tc 10-yr (min) Tc 100-yr (min) Tc Flow, (cfs) Q2 Flow, (Q10 cfs) Flow, Q100 (cfs) C2 C10 C100 Intensity, (in/i2 hr) Intensity, (in/i10 hr) Intensity, (in/i100 hr) Q  C f  C  i  A  Page 6 of 23 Proposed D:\Projects\1229-001\Drainage\Hydrology\1229-001_Rational-Calcs(Proposed_final).xlsx\Comb-Direct-Runoff Brick Stone Apartments DESIGN POINT BASIN ID TOTAL AREA (acres) C2 C100 2-yr (min) Tc 100-yr (min) Tc (cfs) Q2 (Q100 cfs) w W.1 0.78 0.91 1.00 6.5 5.0 1.83 7.73 e E.1 1.17 0.91 1.00 5.1 5.0 3.04 11.63 e E.2 0.39 0.44 0.55 7.7 6.5 0.42 1.99 e OS.1 0.13 0.95 1.00 5.0 5.0 0.35 1.29 OS.2 0.93 0.95 1.00 5.0 5.0 2.51 9.23 OS.3 0.17 0.56 0.70 11.7 8.7 0.20 0.98 OS.4 1.90 0.27 0.34 18.4 16.9 0.88 3.99 DESIGN POINT BASIN ID TOTAL AREA (acres) C2 C100 2-yr (min) Tc 100-yr (min) Tc (cfs) Q2 (Q100 cfs) i1 E.2 & OS.1 0.52 0.56 0.71 5.0 10.3 0.84 2.84 e E.1, E.2, & OS.1 1.69 0.81 1.00 8.3 12.8 3.27 11.89 Page 7 of 23 D:\Projects\Proposed 1229-001\Drainage\Hydrology\1229-001_Rational-Calcs(Proposed_final).xlsx\SUMMARY-TABLE APPENDIX B HYDRAULIC COMPUTATIONS B.1 – Storm Sewers B.2 – Detention Facilities APPENDIX B.1 STORM SEWERS APPENDIX B.2 INLETS (FOR FUTURE USE) Project = Inlet ID = Design Information (Input) MINOR MAJOR Type of Inlet Inlet Type = Local Depression (additional to continuous gutter depression 'a' from 'Q-Allow') alocal = 2.00 2.00 inches Number of Unit Inlets (Grate or Curb Opening) No = 2 2 Water Depth at Flowline (outside of local depression) Flow Depth = 2.5 4.3 inches Grate Information MINOR MAJOR Length of a Unit Grate Lo (G) = 3.00 3.00 feet Width of a Unit Grate Wo = 1.73 1.73 feet Area Opening Ratio for a Grate (typical values 0.15-0.90) Aratio = 0.43 0.43 Clogging Factor for a Single Grate (typical value 0.50 - 0.70) Cf (G) = 0.50 0.50 Grate Weir Coefficient (typical value 2.15 - 3.60) Cw (G) = 3.30 3.30 Grate Orifice Coefficient (typical value 0.60 - 0.80) Co (G) = 0.60 0.60 Curb Opening Information MINOR MAJOR Length of a Unit Curb Opening Lo (C) = 3.00 3.00 feet Height of Vertical Curb Opening in Inches Hvert = 6.50 6.50 inches Height of Curb Orifice Throat in Inches Hthroat = 5.25 5.25 inches Angle of Throat (see USDCM Figure ST-5) Theta = 0.00 0.00 degrees Side Width for Depression Pan (typically the gutter width of 2 feet) Wp = 2.00 2.00 feet Clogging Factor for a Single Curb Opening (typical value 0.10) Cf (C) = 0.10 0.10 Curb Opening Weir Coefficient (typical value 2.3-3.6) Cw (C) = 3.70 3.70 Curb Opening Orifice Coefficient (typical value 0.60 - 0.70) Co (C) = 0.66 0.66 MINOR MAJOR Total Inlet Interception Capacity (assumes clogged condition) Qa = 0.4 2.1 cfs Inlet Capacity IS GOOD for Minor and Major Storms (>Q PEAK) Q PEAK REQUIRED = 0.4 2.0 cfs INLET IN A SUMP OR SAG LOCATION Brick Stone Apartments East Harmony Road Design Point i1 CDOT/Denver 13 Combination H-VertCurb H- W Lo (C) Lo (G) Wo WP Combo_Inlet.xlsm, Inlet In Sump 6/28/2016, 11:56 AM APPENDIX B.3 DETENTION FACILITIES Pond No : 1 100-yr 1.00 13.00 min 18878 ft3 1.69 acres 0.433 ac-ft Max Release Rate = 0.88 cfs Time (min) Ft Collins 100-yr Intensity (in/hr) Inflow Volume (ft3) Outflow Adjustment Factor (Qav cfs) Outflow Volume (ft3) Storage Volume (ft3) 5 9.950 5045 1.00 0.88 264 4781 10 7.720 7828 1.00 0.88 528 7300 15 6.520 9917 0.93 0.82 739 9178 20 5.600 11357 0.83 0.73 871 10486 25 4.980 12624 0.76 0.67 1003 11621 30 4.520 13750 0.72 0.63 1135 12615 35 4.080 14480 0.69 0.60 1267 13213 40 3.740 15169 0.66 0.58 1399 13770 45 3.460 15788 0.64 0.57 1531 14257 50 3.230 16376 0.63 0.55 1663 14713 55 3.030 16898 0.62 0.54 1795 15103 60 2.860 17400 0.61 0.54 1927 15473 65 2.720 17928 0.60 0.53 2059 15868 70 2.590 18384 0.59 0.52 2191 16193 75 2.480 18860 0.59 0.52 2323 16537 80 2.380 19307 0.58 0.51 2455 16851 85 2.290 19738 0.58 0.51 2587 17150 90 2.210 20168 0.57 0.50 2719 17449 95 2.130 20518 0.57 0.50 2851 17667 100 2.060 20888 0.57 0.50 2983 17905 105 2.000 21294 0.56 0.49 3115 18179 110 1.940 21639 0.56 0.49 3247 18392 115 1.890 22039 0.56 0.49 3379 18660 120 1.840 22389 0.55 0.49 3511 18878 *Note: Using the method described in Urban Storm Drainage Criteria Manual Volume 2. A = Tc = Project Location : Design Point C = Design Storm DETENTION POND CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF Input Variables Results Required Detention Volume Fort Collins, Colorado 1229-001 6/22/2016 ADS StormTech Design Tool http://stormtechcalc.azurewebsites.net/ 1/1 User Inputs Chamber Model MC­4500 Outlet Control Structure Yes (Outlet) Project Name Harmony Multi­Family Project Location Fort Collins, CO ­ East Pond (Detention) Project Date 06/29/2016 Engineer B. Mathisen Measurement Type Imperial Required Storage Volume 18878 cubic ft. Stone Porosity 40% Stone Above Chamber 12 in. Stone Foundation Depth 9 in. Average Cover Over Chambers 24 in. Design Constraint WIDTH Design Constraint Dimension 50 ft. Results System Volume and Bed Size Installed Storage Volume 18972 cubic ft. Storage Volume Per Chamber 162.6 cubic ft. Storage Volume Per End Cap 108.6 cubic ft. Number Of Chambers Required 110 each Number Of End Caps Required 10 each Rows/Chambers 5 row(s) of 22 chamber(s) Maximum Length 103.71 ft. Maximum Width 47.27 ft. Approx. Bed Size Required 4902 square ft. System Components Amount Of Stone Required 778 cubic yards Volume Of Excavation (Not Including Fill) 1225 cubic yards Non­woven Filter Fabric Required 1303 square yards Length Of Isolator Row 95.7 ft. Woven Isolator Row Fabric 219 square yards © ADS StormTech 2015 Pond No : 1 100-yr 1.00 5.00 min 8796 ft3 0.78 acres 0.202 ac-ft Max Release Rate = 0.41 cfs Time (min) Ft Collins 100-yr Intensity (in/hr) Inflow Volume (ft3) Outflow Adjustment Factor (Qav cfs) Outflow Volume (ft3) Storage Volume (ft3) 5 9.950 2328 1.00 0.41 123 2205 10 7.720 3613 0.75 0.31 185 3428 15 6.520 4577 0.67 0.27 246 4331 20 5.600 5242 0.63 0.26 308 4934 25 4.980 5827 0.60 0.25 369 5458 30 4.520 6346 0.58 0.24 431 5916 35 4.080 6683 0.57 0.23 492 6191 40 3.740 7001 0.56 0.23 554 6448 45 3.460 7287 0.56 0.23 615 6672 50 3.230 7558 0.55 0.23 677 6882 55 3.030 7799 0.55 0.22 738 7061 60 2.860 8031 0.54 0.22 800 7231 65 2.720 8274 0.54 0.22 861 7413 70 2.590 8485 0.54 0.22 923 7562 75 2.480 8705 0.53 0.22 984 7721 80 2.380 8911 0.53 0.22 1046 7865 85 2.290 9110 0.53 0.22 1107 8003 90 2.210 9309 0.53 0.22 1169 8140 95 2.130 9470 0.53 0.22 1230 8240 100 2.060 9641 0.53 0.22 1292 8349 105 2.000 9828 0.52 0.21 1353 8475 110 1.940 9987 0.52 0.21 1415 8573 115 1.890 10172 0.52 0.21 1476 8696 120 1.840 10333 0.52 0.21 1538 8796 *Note: Using the method described in Urban Storm Drainage Criteria Manual Volume 2. A = Tc = Project Location : Design Point C = Design Storm DETENTION POND CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF Input Variables Results Required Detention Volume Fort Collins, Colorado 1229-001 6/22/2016 ADS StormTech Design Tool http://stormtechcalc.azurewebsites.net/ 1/1 User Inputs Chamber Model MC­4500 Outlet Control Structure Yes (Outlet) Project Name Harmony Multi­Family Project Location Fort Collins, CO ­ West Pond (Detention) Project Date 06/29/2016 Engineer B. Mathisen Measurement Type Imperial Required Storage Volume 8796 cubic ft. Stone Porosity 40% Stone Above Chamber 12 in. Stone Foundation Depth 9 in. Average Cover Over Chambers 24 in. Design Constraint WIDTH Design Constraint Dimension 50 ft. Results System Volume and Bed Size Installed Storage Volume 8891 cubic ft. Storage Volume Per Chamber 162.6 cubic ft. Storage Volume Per End Cap 108.6 cubic ft. Number Of Chambers Required 48 each Number Of End Caps Required 10 each Rows/Chambers 3 row(s) of 10 chamber(s) Leftover Rows/Chambers 2 row(s) of 9 chamber(s) Maximum Length 50.97 ft. Maximum Width 47.27 ft. Approx. Bed Size Required 2406 square ft. System Components Amount Of Stone Required 399 cubic yards Volume Of Excavation (Not Including Fill) 602 cubic yards Non­woven Filter Fabric Required 676 square yards Length Of Isolator Row 47.4 ft. Woven Isolator Row Fabric 108 square yards © ADS StormTech 2015 APPENDIX C WATER QUALITY DESIGN COMPUTATIONS Project Tittle Date: Project Number Calcs By: Client Pond Designation 0.8 WQCV = Watershed inches of Runoff (inches) 74.00% a = Runoff Volume Reduction (constant) i = Total imperviouness Ratio (i = Iwq/100) 0.235 in A = 1.69 ac V = 0.04 ac-ft V = Water Quality Design Volume (ac-ft) WQCV = Water Quality Capture Volume (inches) A = Watershed Area (acres) 1.2 = 20% Additional Volume (Sediment Accumulation) Drain Time a = i = WQCV = Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event Brick Stone Apartments June 29,2016 1229-001 B. Mathisen East Pond 0.235 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 WQCV (watershed inches) Total Imperviousness Ratio (i = Iwq/100) Water Quality Capture Volume 6 hr 12 hr 24 hr 40 hr WQCV  a  0.91 i 3  1 . 19 i 2  0 . 78 i  WQCV  a  0.91 i 3  1 . 19 i 2  0 . 78 i  12 * * 1 . 2 V WQCV  A       6/22/2016 ADS StormTech Design Tool http://stormtechcalc.azurewebsites.net/ 1/1 User Inputs Chamber Model MC­4500 Outlet Control Structure Yes (Outlet) Project Name Harmony Multi­Family Project Location Fort Collins, CO ­ East Pond (Water Quality) Project Date 06/29/2016 Engineer B. Mathisen Measurement Type Imperial Required Storage Volume 1742.4 cubic ft. Stone Porosity 0% Stone Above Chamber 12 in. Stone Foundation Depth 9 in. Average Cover Over Chambers 24 in. Design Constraint WIDTH Design Constraint Dimension 50 ft. Results System Volume and Bed Size Installed Storage Volume 1742 cubic ft. Storage Volume Per Chamber 106.5 cubic ft. Storage Volume Per End Cap 35.7 cubic ft. Number Of Chambers Required 13 each Number Of End Caps Required 10 each Rows/Chambers 3 row(s) of 3 chamber(s) Leftover Rows/Chambers 2 row(s) of 2 chamber(s) Maximum Length 22.79 ft. Maximum Width 47.27 ft. Approx. Bed Size Required 1075 square ft. System Components Amount Of Stone Required 204 cubic yards Volume Of Excavation (Not Including Fill) 269 cubic yards Non­woven Filter Fabric Required 338 square yards Length Of Isolator Row 19.2 ft. Woven Isolator Row Fabric 44 square yards © ADS StormTech 2015 Project Tittle Date: Project Number Calcs By: Client Pond Designation 0.8 WQCV = Watershed inches of Runoff (inches) 86.00% a = Runoff Volume Reduction (constant) i = Total imperviouness Ratio (i = Iwq/100) 0.296 in A = 0.78 ac V = 0.02 ac-ft V = Water Quality Design Volume (ac-ft) WQCV = Water Quality Capture Volume (inches) A = Watershed Area (acres) 1.2 = 20% Additional Volume (Sediment Accumulation) Drain Time a = i = WQCV = Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event Brick Stone Apartments June 29, 2016 1229-001 B. Mathisen West Pond 0.296 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 WQCV (watershed inches) Total Imperviousness Ratio (i = Iwq/100) Water Quality Capture Volume 6 hr 12 hr 24 hr 40 hr WQCV  a  0.91 i 3  1 . 19 i 2  0 . 78 i  WQCV  a  0.91 i 3  1 . 19 i 2  0 . 78 i  12 * * 1 . 2 V WQCV  A       6/22/2016 ADS StormTech Design Tool http://stormtechcalc.azurewebsites.net/ 1/1 User Inputs Chamber Model MC­4500 Outlet Control Structure Yes (Outlet) Project Name Harmony Multi­Family Project Location Fort Collins, CO ­ West Pond (Water Quality) Project Date 06/29/2016 Engineer B. Mathisen Measurement Type Imperial Required Storage Volume 871.2 cubic ft. Stone Porosity 0% Stone Above Chamber 12 in. Stone Foundation Depth 9 in. Average Cover Over Chambers 24 in. Design Constraint WIDTH Design Constraint Dimension 50 ft. Results System Volume and Bed Size Installed Storage Volume 890 cubic ft. Storage Volume Per Chamber 106.5 cubic ft. Storage Volume Per End Cap 35.7 cubic ft. Number Of Chambers Required 5 each Number Of End Caps Required 10 each Rows/Chambers 5 row(s) of 1 chamber(s) Maximum Length 18.63 ft. Maximum Width 47.27 ft. Approx. Bed Size Required 869 square ft. System Components Amount Of Stone Required 184 cubic yards Volume Of Excavation (Not Including Fill) 217 cubic yards Non­woven Filter Fabric Required 280 square yards Length Of Isolator Row 11.1 ft. Woven Isolator Row Fabric 26 square yards © ADS StormTech 2015 APPENDIX D EROSION CONTROL REPORT Brick Stone Apartments Final Erosion Control Report A with comprehensive the final construction Erosion and drawings. Sediment It should Control be Plan noted, (along however, with associated that any such details) Erosion will be and included Sediment the BMPs Control depicted, Plan and serves additional only as or a different general BMPs guide from to the those Contractor. included Staging may be and/necessary or phasing during of construction, or as required by the authorities having jurisdiction. It maintained shall be the and responsibility followed. The of the Erosion Contractor and Sediment to ensure Control erosion Plan control is intended measures to be are a properly living document, location of BMPs constantly as they adapting are installed, to site conditions removed or and modified needs. in The conjunction Contractor with shall construction update the activities. It is imperative to appropriately reflect the current site conditions at all times. The during Erosion construction, and Sediment as well Control as permanent Plan shall erosion address control both protection. temporary measures Best Management to be implemented Practices from not limited the Volume to, silt 3, fencing Chapter along 7 – the Construction disturbed perimeter, BMPs will gutter be utilized. protection Measures in the may adjacent include, roadways but are and clean-inlet up procedures, protection at designated proposed storm concrete inlets. washout Vehicle areas, tracking dumpsters, control and pads, job spill site containment restrooms shall and also be provided by the Contractor. Grading Plans at and final Erosion design will Control also Notes contain can a be full-found size Erosion on Sheet Control CS2 of Plan the as Utility well Plans. as a separate The Utility sheet dedicated Contractor to shall Erosion be aware Control of, Details. and adhere In addition to, the applicable to this report requirements and the referenced outlined in plan any sheets, existing the Development to issuance of Agreement(the Development s) of record, Construction as well Permit. as the Development Also, the Site Agreement, Contractor to for be this recorded project prior will be Public required Health to and secure Environment a Stormwater (CDPHE)Construction , Water General Quality Control Permit Division from the – Colorado Stormwater Department Program, of before shall develop commencing a comprehensive any earth disturbing StormWater activities. Management Prior to Plan securing (SWMP) said pursuant permit, to the CDPHE Site Contractor requirements inspections, and and maintenance guidelines. The of construction SWMP will BMPs. further describe and document the ongoing activities, APPENDIX E Soils Resource Report United States Department of Agriculture 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 Natural Area, Colorado Resources Conservation Service June 15, 2016 Preface Soil surveys contain information that affects land use planning in survey areas. They highlight soil limitations that affect various land uses and provide information about the properties of the soils in the survey areas. Soil surveys are designed for many different users, including farmers, ranchers, foresters, agronomists, urban planners, community officials, engineers, developers, builders, and home buyers. Also, conservationists, teachers, students, and specialists in recreation, waste disposal, and pollution control can use the surveys to help them understand, protect, or enhance the environment. Various land use regulations of Federal, State, and local governments may impose special restrictions on land use or land treatment. Soil surveys identify soil properties that are used in making various land use or land treatment decisions. The information is intended to help the land users identify and reduce the effects of soil limitations on various land uses. The landowner or user is responsible for identifying and complying with existing laws and regulations. Although soil survey information can be used for general farm, local, and wider area planning, onsite investigation is needed to supplement this information in some cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/portal/ nrcs/main/soils/health/) and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center (http:// offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/? cid=nrcs142p2_053951). Great differences in soil properties can occur within short distances. Some soils are seasonally wet or subject to flooding. Some are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic tank absorption fields. A high water table makes a soil poorly suited to basements or underground installations. The National Cooperative Soil Survey is a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (NRCS) has leadership for the Federal part of the National Cooperative Soil Survey. Information about soils is updated periodically. Updated information is available through the NRCS Web Soil Survey, the site for official soil survey information. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means 2 for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer. 3 Contents Preface....................................................................................................................2 How Soil Surveys Are Made..................................................................................5 Soil Map..................................................................................................................7 Soil Map................................................................................................................8 Legend..................................................................................................................9 Map Unit Legend................................................................................................10 Map Unit Descriptions........................................................................................10 Larimer County Area, Colorado......................................................................12 4—Altvan-Satanta loams, 3 to 9 percent slopes.........................................12 74—Nunn clay loam, 1 to 3 percent slopes.................................................13 References............................................................................................................15 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 5 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. 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. Custom Soil Resource Report 6 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 8 Custom Soil Resource Report Soil Map 4485740 4485760 4485780 4485800 4485820 4485840 4485860 4485880 4485740 4485760 4485780 4485800 4485820 4485840 4485860 4485880 493570 493590 493610 493630 493650 493670 493690 493710 493730 493750 493770 493790 493570 493590 493610 493630 493650 493670 493690 493710 493730 493750 493770 493790 40° 31' 25'' N 105° 4' 33'' W 40° 31' 25'' N 105° 4' 23'' W 40° 31' 20'' N 105° 4' 33'' W 40° 31' 20'' N 105° 4' 23'' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 50 100 200 300 Feet 0 15 30 60 90 Meters Map Scale: 1:1,110 if printed on A landscape (11" x 8.5") sheet. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of Map Unit Legend Larimer County Area, Colorado (CO644) Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 4 Altvan-Satanta loams, 3 to 9 percent slopes 2.2 56.1% 74 Nunn clay loam, 1 to 3 percent slopes 1.7 43.9% Totals for Area of Interest 3.9 100.0% 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 of the 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 it was 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 have similar use and management requirements. The delineation of such segments on the map provides sufficient information for the development of resource plans. If Custom Soil Resource Report 10 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. Custom Soil Resource Report 11 Larimer County Area, Colorado 4—Altvan-Satanta loams, 3 to 9 percent slopes Map Unit Setting National map unit symbol: jpwf Elevation: 5,200 to 6,200 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: Farmland of statewide importance Map Unit Composition Altvan and similar soils: 55 percent Satanta and similar soils: 35 percent Minor components: 10 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Altvan Setting Landform: Fans, benches, terraces Landform position (three-dimensional): Base slope, side slope, tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Mixed alluvium Typical profile H1 - 0 to 9 inches: loam H2 - 9 to 16 inches: clay loam, loam, sandy clay loam H2 - 9 to 16 inches: loam, fine sandy loam, silt loam H2 - 9 to 16 inches: gravelly sand, gravelly coarse sand, coarse sand H3 - 16 to 31 inches: H3 - 16 to 31 inches: H3 - 16 to 31 inches: H4 - 31 to 60 inches: H4 - 31 to 60 inches: H4 - 31 to 60 inches: Properties and qualities Slope: 6 to 9 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 Available water storage in profile: Very high (about 13.7 inches) Interpretive groups Land capability classification (irrigated): 4e Land capability classification (nonirrigated): 4e Custom Soil Resource Report 12 Hydrologic Soil Group: B Description of Satanta Setting Landform: Structural benches, terraces Landform position (three-dimensional): Side slope, tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Mixed alluvium and/or eolian deposits Typical profile H1 - 0 to 9 inches: loam H2 - 9 to 14 inches: loam, clay loam, sandy clay loam H2 - 9 to 14 inches: loam, clay loam, fine sandy loam H2 - 9 to 14 inches: H3 - 14 to 60 inches: H3 - 14 to 60 inches: H3 - 14 to 60 inches: Properties and qualities Slope: 3 to 6 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 Available water storage in profile: Very high (about 27.4 inches) Interpretive groups Land capability classification (irrigated): 2e Land capability classification (nonirrigated): 3e Hydrologic Soil Group: B Minor Components Nunn Percent of map unit: 6 percent Larimer Percent of map unit: 4 percent 74—Nunn clay loam, 1 to 3 percent slopes Map Unit Setting National map unit symbol: jpxn Elevation: 4,800 to 5,600 feet Custom Soil Resource Report 13 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 Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Nunn Setting Landform: Terraces, fans 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 Minor Components Ulm Percent of map unit: 10 percent Satanta Percent of map unit: 5 percent Custom Soil Resource Report 14 References American Association of State Highway and Transportation Officials (AASHTO). 2004. Standard specifications for transportation materials and methods of sampling and testing. 24th edition. American Society for Testing and Materials (ASTM). 2005. Standard classification of soils for engineering purposes. ASTM Standard D2487-00. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife Service FWS/OBS-79/31. Federal Register. July 13, 1994. Changes in hydric soils of the United States. Federal Register. September 18, 2002. Hydric soils of the United States. Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils in the United States. National Research Council. 1995. Wetlands: Characteristics and boundaries. Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S. Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/nrcs/ detail/national/soils/?cid=nrcs142p2_054262 Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service, U.S. Department of Agriculture Handbook 436. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/national/soils/?cid=nrcs142p2_053577 Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of Agriculture, Natural Resources Conservation Service. http://www.nrcs.usda.gov/wps/ portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580 Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and Delaware Department of Natural Resources and Environmental Control, Wetlands Section. United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of Engineers wetlands delineation manual. Waterways Experiment Station Technical Report Y-87-1. United States Department of Agriculture, Natural Resources Conservation Service. National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/ home/?cid=nrcs142p2_053374 United States Department of Agriculture, Natural Resources Conservation Service. National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/ detail/national/landuse/rangepasture/?cid=stelprdb1043084 15 United States Department of Agriculture, Natural Resources Conservation Service. National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/soils/scientists/?cid=nrcs142p2_054242 United States Department of Agriculture, Natural Resources Conservation Service. 2006. Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/? cid=nrcs142p2_053624 United States Department of Agriculture, Soil Conservation Service. 1961. Land capability classification. U.S. Department of Agriculture Handbook 210. http:// www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf Custom Soil Resource Report 16 MAP POCKET HISTORIC DRAINAGE EXHIBIT PROPOSED DRAINAGE EXHIBIT S CONTROL IRR CONTROL IRR CONTROL IRR VAULT ELEC VAULT ELEC TELE TELE S VAULT F.O. VAULT ELEC H Y D T T T E T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T W W W W W W W W W W W W W W W T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T FO FO FO FO FO FO FO FO FO FO FO FO FO FO FO G X / / S CONTROL IRR CONTROL IRR CONTROL IRR TELE TELE S VAULT F.O. VAULT ELEC H Y D T T E T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T W W W W W W W W W W W W W W W T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T FO FO FO FO FO FO FO FO FO FO FO FO FO FO FO G SS / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / w e i1 EXISTING DRAINAGE CULVERT EROSION BUFFER ZONE PER CITY OF FORT COLLINS CITY FLOOD RISK MAP MAIL CREEK FLOODWAY FORT COLLINS SUPPORTIVE HOUSING SUBDIVISION LOT 26 FAIRWAY ESTATES FAIRWAY ESTATES LOT 26 FAIRWAY ESTATES 3RD EAST HARMONY ROAD (PUBLIC R.O.W. VARIES) FAIRWAY ESTATES EV E E E G G G G G G G G G G G G G G G G E E E E E E E E E E E E E G S W F UD UD UD UD 50' DRAINAGE EASEMENT LARIMER COUNTY DITCH #2 53 MC-4500 CHAMBERS 123 MC-4500 CHAMBERS ISOLATOR ROW FLOW CONTROL MANHOLE\ FLOW CONTROL MANHOLE 3:1 3:1 5:1 3:1 3:1 (3.0:1) (2.7:1) (2.8:1) (3.8:1) (2.1:1) (1.6:1) (10.2:1) ISOLATOR ROW os.2 os.1 CTIY FLOODPLAIN INLET INLET INLET E.1 OS.4 W.1 OS.1 E.2 OS.2 OS.3 INLET PEDESTRIAN BRIDGE Sheet Of 9 Sheets BRICK STONE APARTMENTS DRAWING FILENAME: D:\Projects\1229-001\Dwg\Drng\1229-001_DRNG.dwg LAYOUT NAME: C5.01 DATE: Jun 28, 2016 - 10:54am CAD OPERATOR: blaine LIST OF XREFS: [1229-001_xSITE] [1229-001_xEXST] [1229-001_xGRAD] [1229-001_xTOPO] [NES-xborder] [1229-001_xPutil] These drawings are instruments of service provided by Northern Engineering Services, Inc. and are not to be used for any type of construction unless signed and sealed by a Professional Engineer in the employ of Northern Engineering Services, Inc. NOT FOR CONSTRUCTION REVIEW SET ENGINEER ING N O R T H E RN 6.29.16 301 North Howes Street, Suite 100 Fort Collins, Colorado 80521 www.northernengineering.com Phone: 970.221.4158 CALL UTILITY NOTIFICATION CENTER OF COLORADO Know what'sbelow. Call before you dig. R GRAPHIC SCALE: LEGEND: ST A2 a3 4950 4:1 79.45  HP RUNOFF SUMMARY TABLE: FOR DRAINAGE REVIEW ONLY NOT FOR CONSTRUCTION NOTES: ( IN FEET ) 0 1 INCH = 40 FEET 40 40 80 120 NORTH C5.01 DRAINAGE EXHIBIT DESIGN POINT BASIN ID TOTAL AREA (acres) C2 C100 2-yr Tc (min) 100-yr Tc (min) Q2 (cfs) Q100 (cfs) w W.1 0.78 0.91 1.00 6.5 5.0 1.83 7.73 e E.1 1.17 0.91 1.00 5.1 5.0 3.04 11.63 e E.2 0.39 0.44 0.55 7.7 6.5 0.42 1.99 e OS.1 0.13 0.95 1.00 5.0 5.0 0.35 1.29 OS.2 0.93 0.95 1.00 5.0 5.0 2.51 9.23 OS.3 0.17 0.56 0.70 11.7 8.7 0.20 0.98 OS.4 1.90 0.27 0.34 18.4 16.9 0.88 3.99 9 / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / H1 OS1 MAIL CREEK FLOODWAY EROSION BUFFER ZONE PER CITY OF FORT COLLINS CITY FLOOD RISK MAP LOT 26 FAIRWAY ESTATES LOT 25 FAIRWAY ESTATES FAIRWAY ESTATES LOT 26 FAIRWAY ESTATES 3RD EAST HARMONY ROAD (PUBLIC R.O.W. VARIES) FAIRWAY ESTATES LARIMER COUNTY DITCH #2 EXISTING PIPES APPEAR TO BE ABANDONED EXISTING ROADSIDE DITCH EXISTING RIPRAP RUNDOWN EXISTING IRRIGATION CONCRETE STRUCTURE EXISTING CONCRETE BOX CULVERTS EXISTING 24" RCP CITY FLOODPLAIN Sheet Of 9 Sheets BRICK STONE APARTMENTS DRAWING FILENAME: D:\Projects\1229-001\Dwg\Drng\1229-001_EX_DRNG.dwg LAYOUT NAME: C5.00 DATE: Jun 28, 2016 - 10:51am CAD OPERATOR: blaine LIST OF XREFS: [1229-001_xEXST] [1229-001_xTOPO] [NES-xborder] These drawings are instruments of service provided by Northern Engineering Services, Inc. and are not to be used for any type of construction unless signed and sealed by a Professional Engineer in the employ of Northern Engineering Services, Inc. NOT FOR CONSTRUCTION REVIEW SET ENGINEER ING N O R T H E RN 6.29.16 301 North Howes Street, Suite 100 Fort Collins, Colorado 80521 www.northernengineering.com Phone: 970.221.4158 CALL UTILITY NOTIFICATION CENTER OF COLORADO Know what'sbelow. Call before you dig. R GRAPHIC SCALE: LEGEND: ST A2 a3 4950 4:1 79.45  HP RUNOFF SUMMARY TABLE: FOR DRAINAGE REVIEW ONLY NOT FOR CONSTRUCTION NOTES: ( IN FEET ) 0 1 INCH = 40 FEET 40 40 80 120 NORTH C5.00 HISTORIC DRAINAGE EXHIBIT DESIGN POINT BASIN ID TOTAL AREA (acres) C2 C100 2-yr Tc (min) 100-yr Tc (min) Q2 (cfs) Q100 (cfs) h1 H1 4.41 0.26 0.32 12.8 11.8 2.27 10.29 os1 OS1 0.98 0.95 1.00 8.2 7.9 2.23 8.42 8 the version date(s) listed below. Soil Survey Area: Larimer County Area, Colorado Survey Area Data: Version 10, Sep 22, 2015 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Apr 22, 2011—Apr 28, 2011 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Custom Soil Resource Report 9 12 hr 12 hr Brick Stone Apartments Project Number : Project Name : West Pond Page 1 of 1 1229-001_West Pond_DetentionVolume_FAAModified Method.xls Brick Stone Apartments Project Number : Project Name : East Pond Page 1 of 1 1229-001_East Pond_DetentionVolume_FAAModified Method.xls B. Mathisen June 29th, 2016 Design Point Basin IDs Overland Flow Gutter/Pipe Flow Swale Flow Time of Concentration (Equation RO-4)   1 3 1 . 87 1 . 1 * S Ti   C Cf L Page 5 of 23 Proposed D:\Projects\1229-001\Drainage\Hydrology\1229-001_Rational-Calcs(Proposed_final).xlsx\Comb-Tc-10-yr_&_100-yr e OS.1 No 0.95 0.95 1.00 10 0.80% 1.0 1.0 0.6 61 0.50% 1.41 0.7 N/A N/A N/A 5 5 5 OS.2 No 0.95 0.95 1.00 85 2.00% 2.1 2.1 1.4 149 4.00% 4.00 0.6 N/A N/A N/A 5 5 5 OS.3 No 0.56 0.56 0.70 85 0.50% 11.7 11.7 8.7 N/A N/A N/A N/A N/A 12 12 9 OS.4 No 0.27 0.27 0.34 311 3.30% 18.4 18.4 16.9 N/A N/A N/A N/A N/A 18 18 17 DEVELOPED TIME OF CONCENTRATION COMPUTATIONS Gutter/Pipe Flow Swale Flow Design Point Basin Overland Flow B. Mathisen June 29th, 2016 Time of Concentration (Equation RO-4)   1 3 1 . 87 1 . 1 * S Ti   C Cf L Page 2 of 23 Proposed D:\Projects\1229-001\Drainage\Hydrology\1229-001_Rational-Calcs(Proposed_final).xlsx\Tc-10-yr_&_100-yr Runoff Coefficients are taken from the City of Fort Collins Storm Drainage Design Criteria and Construction Standards, Table 3-3. % Impervious taken from UDFCD USDCM, Volume I. 10-year Cf = 1.00 June 29th, 2016 **Soil Classification of site is Clay Loam** Page 1 of 23 Proposed D:\Projects\1229-001\Drainage\Hydrology\1229-001_Rational-Calcs(Proposed_final).xlsx\C-Values Gutter/Pipe Flow Swale Flow Design Point Basin Overland Flow B. Mathisen June 29nd, 2016 Time of Concentration (Equation RO-4)   1 3 1 . 87 1 . 1 * S Ti   C Cf L Page 2 of 23 Historic D:\Projects\1229-001\Drainage\Hydrology\1229-001_Rational-Calcs (Historic).xlsx\Tc-10-yr_&_100-yr