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HomeMy WebLinkAboutDrainage Reports - 05/27/2009City of Ft. Collins Awroyed Plans Approved By Wao_ Date -a7 -09 FINAL DRAINAGE AND EROSION CONTROL REPOWE FLATS ,�.T THE OVAL FORT COLLINS, COLORADO Prepzred for: OvAL FLATS, L.L.C. 3003 EAST HARmoNy ROAD, SutTE 300 FORT COLLINS, COLORADO 80528 Submitted on: June 5, 2009 Prepared by: Jim Sell Design, Inc. 153 West Mountain Avenue Fort Collins, Colorado 90524 Phone 970.494.1921 FAX 970.494.2443 FINAL DRAINAGE AND EROSION CONTROL REPORT FLATS AT THE OVAL FORT COLLINS, COLORADO Prepared for: OVAL FLATS, L.L.C. 3003 EAST HARMONY ROAD, SUITE 300 FORT COLLINS, COLORADO 80528 Submitted on: June 5, 2009 Prepared by: Jim Sell Design, Inc. 153 West Mountain Avenue Fort Collins, Colorado 80524 Phone 970.484.1921 FAX 970.484.2443 TABLE OF CONTENTS Table of Contents................................................................ PE Certification and Seal .................................................... Background......................................................................... SiteLocation.................................................................... Existing Site Description ................................................. Development Proposal........................................................ Storm Water Basins and Drainage Patterns ........................ Storm Water Quality........................................................... General............................................................................. Structural Practices....................................................... Non -Structural Practices ............................................... Other Controls.............................................................. Final Stabilization............................................................ WetlandsImpacts................................................................ Hydrology and Hydraulic Criteria ...................................... Development Criteria Reference and Constraints ........... Hydrology Criteria........................................................... Hydraulic Criteria and Calculations ................................ Storm Water Detention....................................................... Developed Storm Water Conditions ................................... Overview.......................................................................... Sub -basin Descriptions.................................................... Storm Drain System Design ............................................ Conclusions......................................................................... Compliance with Standards ............................................. Request for Variance(s)................................................... References........................................................................... APPENDIXA - HYDROLOGIC CALCULATIONS EXISTING CONDITION DEVELOPED CONDITION APPENDIX B - HYDRAULIC CALCULATIONS STORM DRAIN SYSTEM DESIGN INLET DESIGN DETENTION POND DESIGN APPENDIX C- EROSION AND SEDIMENT CONTROL APPENDIX D - BACKGROUND INFORMATION PLAT NRCS SOILS MAP OLD TOWN MASTERPLAN DESIGN GUIDELINES FEMA MAPPING INFORMATION GENERAL INFORMATION Back Pocket: Existing Conditions Drainage Plan Final Drainage and Erosion Control Plan PE CERTIFICATION AND SEAL This report for the final design of The Oval Flats was prepared by me or under my direct supervision in accordance with the provisions of the City of Fort Collins Storm Drainage Design Criteria and Construction Standards. I understand that the City of Fort Collins and its designated city authority do not and will not assume liability for drainage facilities designed by others. M066 Na 6loslwa 'Al btJA F� Registered Professional Engineer State of Colorado I t I BACKGROUND SITE LOCATION The Oval Flats mixed -use redevelopment is located at 306 West Laurel Street, Fort Collins, Colorado 80521 (Refer to Appendix C for a copy of the Plat). The subject site is located in the Northeast Quarter of Section 14, Township 7 North, Range 68 West of the 61h P.M., City of Fort Collins, County of Latimer, State of Colorado. The Oval Flats is bordered to the north by existing residential development, to the south by West Laurel Street; to the east by South Howes Street; and to the west by an existing alley. EXISTING SITE DESCRIPTION The subject site is comprised of t0.83 acre and is currently developed. It contains the former EAE Fraternity house which was abandoned in 2006 after the fraternity was barred from Colorado State University. The existing site improvements include: the EAE fraternity house, several concrete walkways, an asphalt parking lot along the west side of the site and sub -surface utilities. The existing ' vegetation consists of unmaintained grass and many large trees and shrubs. The existing developed runoff flows from the site in three different directions: into South Howes Street, into West Laurel Street or into the existing alley along grades of approximately 1.00% to 3.50%. 1 1 1 C I In general, the on -site soils consist of Fort Collins Loam, l to 3 percent slopes. These soils are NRCS HSG '13' soils (Refer to Appendix C for a copy of the NRCS soils map). A description of the soil type follows: Group 8: Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately course texture. These soils have a moderate rate of water transmission. A soils report (Soilogic #: 07-1088) was completed by Soilogic, Inc. on November 19, 2007. This report contains the results of a complete geotechnical subsurface exploration as well as pertinent geotechnical engineering recommendations. According to the findings presented in the aforementioned report, the on -site soils below the topsoil layer consist of USCS soil group CL. These are inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, and lean clays. This information does not match the soils information from the NRCS web -site. However, it should be considered more reliable/accurate since it is based on site specific soils testing. The sites existing developed runoff ultimately drains into the Poudre River. This condition will not change with the proposed improvements. I DEVELOPMENT PROPOSAL The Oval Flats encompasses 0.83 acre of land are and is anticipated to be a mixed -use development. The subject site is currently zoned C-C (Community Commercial). When complete, the development will consist of approximately 47,040 ft2 of residential space, 4,900 ft2 of commercial space and 3,020 ft2 to be utilized as a common meeting space. The residential space is targeted at undergraduate and graduate CSU students and will have 98 bedrooms in 41 units. The individual units will be a mix of 1, 2, 3 and 4 bedroom units. ' Additional improvements include utility connections to provide the project site with domestic water, sanitary sewer, and storm drain service. This project will be constructed in a single phase. I 1 1 1 1 2 iI I ' STORM WATER BASINS AND DRAINAGE PATTERNS The subject site is located in the Old Town major drainage basin which is located in north -central Fort Collins and has a drainage area of approximately 2,120 acres, including approximately 400 acres of the Colorado State University campus. The entire basin is urbanized, with some development dating back to the late 1800s. Generally, the basin drains from west to east. It receives some runoff water from the Canal Importation Basin directly west of Old Town. Most of the water from Old Town drains to the Poudre River. iStreet flooding is a common occurrence in Old Town. In recent years, several capital projects such as the Howes Street, Locust Street and Oak Street Outfall projects have improved storm ' drainage in Old Town. The existing development was sub -divided into three drainage basins (Refer to the Existing ' Conditions Drainage Plan, Back Pocket). The existing conditions peak runoff in each basin was estiinated for the 2- and 100-year storm events (Refer to Appendix A for calculations). 1 LJ 1 t EX 1: This basin is located along the west side of the subject site. It is comprised of roof area, concrete walks/patios and an asphalt parking lot. The existing runoff in this basin flows overland and into the existing alley that neighbors the subject site along its west property line. The runoff in the alley drains north to Myrtle Street. In Myrtle Street, the runoff flows east and into an existing combination inlet at the southwest corner of South Howes Street and Myrtle Street (Refer to Appendix C for an exhibit from the City of Fort Collins GIS Utility Mapping). - EX2: This basin is located along the east side of the project site. It is comprised of some roof areas, concrete walks, and grassy areas. The existing runoff in this basin flows overland and into South Howes Street. From there the runoff drains south to Myrtle Street and then to same inlet as the runoff from basin EX 1. EX3: This basin is located along the south side of the existing project site. The excess surface runoff in it flows overland and into West Laurel Street. In the street, the runoff flows east along existing curb and gutter and then into an existing combination inlet at the northwest corner of West Laurel Street and South Howes Street. The existing inlet connects to an existing 12" clay storm drain pipe in South Howes Street via an existing 12" PVC pipe. The subject site is not affected by off -site runoff. We are not aware of existing drainage studies for the subject site or surrounding properties that include information which affects our current work. The project site is not located within a FEMA designated 100-year floodplain per Map Number 08069CO979G (Effective date: June 17, 2008). 1 I I 1 1 1 1 1 1 1 STORM WATER QUALITY GENERAL The Colorado Department of Public Health and Environment (CDPHE) states in the Rationale Stormwater Discharges Associated with Construction Activity General Permit in Colorado that, under the framework of the NPDES and CDPS stormwater regulations, a discharge permit is required for construction activities. Projects with I acre or more of earth disturbance (Phase 11) require a CDPS permit, which involves the completion and submittal of a "General Permit for Stormwater Discharges Associated with Construction Activity". Projects that include earth disturbance require a Stormwater Management Plan (SWMP). The SWMP is required as a permit condition, must reflect current site conditions, must be available for review by state inspectors and be available as a public document. The goal of the SWMP is to describe appropriate controls and measures to improve water quality by reducing pollutants in stormwater discharges and ensure compliance with the requirements of the stormwater permit. The SWMP must be completed and implemented at the time the project breaks ground and revised if necessary as construction proceeds to accurately reflect the current conditions and practices at the site. TEMPORARY STRUCTURAL AND NON-STRUCTURAL PRACTICES Structural controls reduce the amounts of pollutants that migrate off the urban landscape by reducing runoff and providing facilities that remove pollutants from stormwater. This type of Best Management Practice (BMP) includes physical processes ranging from diversion structures to silt fences to retention ponds. Physical BMPs are generally simple, low cost and effective if they are correctly installed and properly maintained. Nonstructural BMPs prevent or limit the entry of pollutants into stormwater at their source through operational or managerial techniques. STRUCTURAL PRACTICES The following are examples of temporary BMPs that may need to be installed and maintained in order to control on -site erosion and prevent sediment from migrating within the project site and off -site during construction. Mulching (MU): plant residues applied to the soil surface to prevent erosion by protecting the soil surface from raindrop impact and to foster the growth of vegetation (e.g., temporary seeding) by increasing the available moisture. This BMP should be applied in conjunction with the temporary seeding after the interim or final design grade has been reached and permanent stabilization is still a ways off. Mulching and temporary seeding are BMPs that help prevent erosion from occurring. When properly installed and maintained, they can improve the performance and decrease the maintenance and/or replacement interval of other BMPs such as gravel inlet protection or straw wattles. 1 • Silt Fence (SF): a woven synthetic fabric that filters runoff. The silt fence is a temporary ' barrier placed at the base of a disturbed area. This BMP should be installed prior to the start of any earth disturbing activity and remain in place and in an operational and maintained condition until final stabilization of the tributary area is achieved. NON-STRUCTURAL PRACTICES The following information about non-structural practices was excerpted from Volume 3 — Best ' Management Practices, Urban Drainage and Flood Control District (UDFCD). Nonstructural BMPs are intended to prevent or reduce the contamination of stormwater runoff. ' They are applicable to a variety of different sources or activities. By reducing pollutant generation, adverse water quality impacts are reduced from potential pollutant sources. Preventing and controlling the sources of these pollutants requires a change in behavior. ' Because non-structural BMPs are so closely tied to people's activities and behavior, their effectiveness depends on people's attitude, their willingness to accept information and their ' willingness to put BMPs into practice. ' The two main objectives of non-structural BMPs are: 1. Reduce or eliminate the pollutants that impact water quality at their source, thus reducing the need for structural control requirements. 2. Address water quality concerns that are not cost effectively handled by structural controls. ' Options: 1. Illicit Discharge Controls (UDFCD, Page NS-16) 2. Good Housekeeping (UDFCD, Page NS-20) 3. Preventative Maintenance (UDFCD, Page NS-22) 4. Spill Prevention and Response (UDFCD, Page NS-27) ' OTHER CONTROLS Many other potential pollutant sources will exist during construction. Some of these include: exposed and stored soils, tracking of mud and debris from construction equipment to adjacent roadways, outdoor material storage, vehicle maintenance and fueling, on -site waste disposal, equipment washing and concrete washout. ' Some of the items listed above can be managed by designating an area of the site where the activity takes place. For example, materials storage, waste disposal and vehicle maintenance and fueling can occur within an enclosed and secure area. The area can be enclosed with temporary cyclone fencing and accessed through a gate with a lock. Soil stockpiles should be kept below the locally mandated maximum height and surrounded with 1 silt fencing. If the storage of these soils is going to be for an extended period of time, then consider temporarily seeding the soil to minimize soil loss to wind and water erosion. ' The off -site tracking of mud and debris is easily controlled by installing Vehicle Tracking Control (VTC). This is a stabilized stone pad located at points of ingress and egress on a construction site. It is designed to reduce the amount of mud transported onto the public roads by ' construction traffic. If the site is extraordinarily muddy, then consider designating an area to I wash construction vehicles before they leave the site and enter the public right-of-way. A BMP ' such as this is a good way to avoid the costs associated with street cleaning or accidentally discharging large amounts of sediment into other storm drain systems. ' When in doubt, choose methods that prevent pollution rather than ones that force clean-up at the downstream end just before the stormwater enters the receiving waters. In other words, the most efficient construction site BMPs are those that prevent erosion from occurring. ' FINAL STABILIZATION Final stabilization is reached when all soil disturbing activities at the site have been completed, and uniform vegetative cover has been established with a density of at least 70 percent of pre - disturbance levels or equivalent permanent physical erosion reduction methods have been ' employed. 1 L' i 1 1 1 1 i 1 1 1 i 1 1 1 1 1 1 1 1 WETLANDS IMPACTS There are no existing wetlands which the proposed redevelopment will disturb. 1 iJ HYDROLOGY AND HYDRAULIC CRITERIA DEVELOPMENT CRITERIA REFERENCE AND CONSTRAINTS ' The calculation methods presented in this report conform to the standards set forth in the City of Fort Collins Storm Drainage Design Criteria and Construction Standards (SDDC) and, in ' certain cases, Volumes 1 through 3 of the UDFCDs Urban Storm Drainage Criteria Manual (Manual). ' HYDROLOGY CRITERIA The Rational Method was used to estimate the existing condition and proposed developed ' conditions runoff. For this final design submittal, the existing and developed composite runoff coefficients were calculated using Table 3-3, Rational Method Runoff Coefficients for Composite Analysis. The rainfall intensity data for the enclosed hydrologic calculations were read from the City of ' Fort Collins Rainfall Intensity -Duration -Frequency Table, Figure 3-la and Figure 3-Ib. HYDRAULIC CRITERIA AND CALCULATIONS With this submittal we provided inlet sizing calculations for the proposed Type 13 inlets (Refer to Appendix B), emergency spillway sizing calculations, orifice plate sizing calculations and hydraulic grade line calculations. I i I STORM WATER DETENTION According to the Old Town Master Drainage Plan, Section R3. Redevelopment Criteria (Refer to Appendix C for the excerpt) and with respect to the required storage volume, the proposed redevelopment can take credit for the existing on -site impervious area. The required storage volume was estimated with the FAA Method using the following procedure. We took credit for the existing impervious surface area, t0.45 acre. The remainder of the existing site, t0.38 acre of pervious surfaces was used to size the on -site detention pond. More specifically, the on -site detention pond was sized to detain the percentage of the existing pervious area that we expect to be converted into impervious surface area. With respect to the detention pond sizing calculation presented in Appendix B, we conservatively assumed all the existing pervious surface areas would be converted to impervious area. This assumption is reflected in the 2-year and 100-year runoff coefficients (C): 0.93 and 1.00, respectively. The total release rate, 0.27cfs, is based on the 2-year release rate from the pervious surface area in each of the existing condition basins (i.e., EX-1, EX-2 and EX-3). ' Fonnula: Basin2_yea,: CiA EX-12-y=: (0.25)(2.86)(0.01)=0.007cfs EX-22_y,ar : (0.25)(2.86)(0.26)=0.19cfs EX-32_y,, : (0.25)(2.86)(0.1 1)=0.078efs Notes: 1. Runoff coefficient (C) of 0.25 to describe the compacted existing soils 2. Assumed T 5.00min for each basins pervious surface area; therefore, i=2.86 in/hr ' The 100-year release rate from the on -site detention pond is f 1.75cfs. This is less than the combined 100-year peak runoff from existing basins EX-2 and EX-3, 1.72cfs and 0.88cfs, respectively. The difference is that existing runoff drains to the surface whereas the release from the pond will drain directly to the existing 12" storm drain system in South Howes Street. The proposed detention pond is located in the parking area. During a 100-year storm event, like the 100-year design storm used herein, the detained runoff is designed to pond to a depth of 1.00' (i.e., Elev.=4998.40) in the proposed on -site parking area. The lowest adjacent proposed building ' finished floor elevation is set at 4999.50. By conforming to Section 9.4 of the SDDC, the proposed building is reasonably protected from inundation by ponded water during the 100-year design storm event. ' The emergency spillway elevation is set at 4998.50. Stormwater that passes through the spillway will drain east and into South Howes Street. The street section that we outfall into is at the ' upstream end of the basin; therefore, sufficient street capacity should be available to pass these flows. The on -site detention pond will drain through (2)-CDOT Concrete Inlets, Type 13. The inlets will drain through the proposed 12" storm drain pipe (upsized to 15" within the South Howes Street R.O.W.). The release rate from the outlet structure will be controlled by a 5'/d' vertical ' orifice plate. to I ' Water quality treatment for this site is provided for in the Udall Natural Area in a regional water quality facility. t i i 1 1 I I 1 1 1 I 1 1 LJ E 1 r, DEVELOPED STORM WATER CONDITIONS OVERVIEW In general, the majority of the developed storrnwater runoff from the subject site drains to an on - site detention pond that will outfall into an existing storm drain system in South Howes Street. SUB -BASIN DESCRIPTIONS The project site is divided into eight on -site developed stormwater basins (Refer to the Final Drainage and Erosion Control Plan, Back Pocket). A 1 and A2: These basins encompass most of the proposed developed area which is comprised of mostly hardscape. They drain to the proposed on -site detention pond. 81 thru 84: These four basins are situated around the perimeter of the project site and drain offsite without being detained. The undetained off -site runoff was accounted for in the design of our on -site detention pond. RF1: This basin consists of roof area for the proposed building. The roof drainage will be connected directly to the proposed storm drain infrastructure using 10" and 12" A2000 PVC pipe. We provided inverts for this system. STORM DRAIN SYSTEM DESIGN We designed a single on -site storm drain system. This system will connect to an existing 12" clay storm drain pipe in South Howes Street. Appendix B presents capacity calculations for the 12" A2000 PVC and 15" RCP storm drain pipes that we propose to construct. With this submittal we provided additional design information for the storm drain infrastructure, including: hydraulic grade line calculations and plan and profiles. 12 I CONCLUSIONS COMPLIANCE WITH STANDARDS This Final Drainage and Erosion Control Report for The Oval Flats is in general compliance with the City of Fort Collins Storm Drainage Design Criteria and construction Standards. REQUEST FOR VARIANCE(S) None at this time. 13 I 1 REFERENCES Storm Drainage Design Criteria and Construction Standards, City of Fort Collins, Colorado, 1 April 1997. Urban Storm Drainage Criteria Manual, Vol. 1, 2 and 3, Denver Regional Council of 1 Governments, Denver, Colorado. Volume 3 Revision, October 2005. 1 1 1 1 1 1 1 1 1 1 CI 1 1 1 14 1 ' APPENDIX A HYDROLOGIC CALCULATIONS d 1 1 1 1 EXISTING CONDITION 1 1 1 1 1 I LII 1 ri Existing Condition Runoff Coefficient Calculations Rational Method Procedure Basin(s) Area n2 Area ac Type of Development Composite C2 & Cio Composite Cfoo EX1 14366.44 0.33 Business 0.93 1.00 EX2 14919.52 0.34 Business 0.41 0.51 EX3 6780.46 0.16 Business 0.46 0.57 Site 36066.42 0.83 Business 0.62 I 0.78 ' Notes: 1. The runoff coefficients for composite analysis were read from Table 3-3, Rational Method Runoff Coefficients for Composite Analysis. For Asphalt, Concrete, and Roofs: C=0.95 and Lawns (Heavy Soil, Average 2 to 7%) C=0.25. ' 2. Table 3-4, Rational Method Frequency Adjustment Factors, was used to calculate CIO and C,00. 3. Lawns (Heavy Soil, Average 2% to 7%): suggested based on findings (i.e., USCS Type CL soils) discussed in Geotechnical Exploration Report 306 West Laurel Street Apartments, SOILOGIC #07-1088, Dated: November 19, 2007. 1 1 ' Project Number: 2549 Designer: Herman H. Feissner, P.E. Project Name: Flats at the Oval Date: 6/4/2009 m m r m m m m m m m m m r m m m m m m 2-year t r Calculations for Existing Conditions Rabonal Me1Mla Ra' . DATA OVER DTIMEOF CHANNELIZED TIME OF. CF h[E!-U`E TIMEOF FINAL' FLOW(k) FLOVV(tj FLOMW t. Cammanb :,. .Design Nunolf: .. CallOutetl Basin(s). Point aea. Coefficient Length Sbpe t LanBln Sltye VebcRy F Length S100e Vewly to E auets) Ca it % Ran it - % Msea nin ft % ftlsec 'dvn .Nn - EXt EX1 033 093 66 1.20 2A.. 0 000 D_W 0.W 0 0T ow SO�Surface rumnacrossexisting asphalt parking area to alley 0.34 041 W 340 fi10 0 000 000 0.00 0 OW OW o00 6.f0 Sudaze mm0 across existing grass no longer malnlaine6) EX3 r E%3 0?6 048 5Y 300 604 0 0.00 0.00 0.00 0 0.00 000 -O.W 6.01 Surface rump across exlrting grass lm longer maintaineu Projttl NYm�w: 2548 [Wyre: Nw—H Fa—,. PE. Rgacl Name FYt. AIM OrY V ab: NM . I ' 2-year Runoff for Existing Conditions Rational Method Procedure 0 0 I 1 E 1 I J I Basm(s) 61RECT RUNOFF - Comments Design Point Area Cz acr a min .. Rainfall C'A Intensity U) Runoff(0) cres inlhr cis 0 releaserate hom, EX2 X 0 6604 0.14 71 3 2-year existing release rate item EX-2 EX3 EX3 04 4.70 046 07 1 2.72 0.79 2-year existing release rle from EX-3 Project Number: 2549 Project Name: Flats at the Oval Designer: Herman H. Feissner P.E Date: lV412009 m m m m m m = = m o o e d® m m m m m 100-year t, Calculations for Existing Conditions Fafional M." P aaas. DATA OVERLAND TIME OF. CWSNNELREn TIME OF CNANNELIZED TIME OF FINAL FLOW( FLOW(In) FLOW(fo) I. Commend _ .Oesign Runoff - ConpuleE Basin(s) Point Area CaeZ.t Leap Sbpe t Lergln Slope Veloci(y 4, Lenglfl Slope Vebcily 'W� I. acres) Cam fl % nvn fl % .fl/sec mn ft % fUsec min min EX1 E%1 033 It O6 1.2I1 1.p 0 000 0.00 000 0 0.00 0.00 O.LV S00 Surfxerurwff Ting aspLalt parking cream alloy _I EX2 El 03a O51 50 3C0 SYl 0 0.00 OW 000 0 0.00 0.00 - 000 520 Surface runoff '[ins grass (no longer mantaird) EX3 EX3 0.10 0.57 1 52 3001 197 f 0 1 ON I 0.00 0.00 0 O.rq 0.00 O.Op Sao Surface rurnff across'ling grass lm longer maintafrj Proiecr NumE r'. 2549 Damp— H—nanH F,, PE. Prgxl None: F4rx ar Ne Oval pale: Ne/[Wi I ' 100-year Runoff for Existing Conditions Rational Method Procedure t 1 1 1 1 t 1 F 1 Basin(s) DIRECT RUNOFF - Comments Design '. Rainfall Point Area Cz I C-A Intensity {I) Runoff(0) acr s min acres inlhr CIS EX1 EX1 0.33 1.00 6 00 0.33 9.90 3.18 100-year existng release rate from EX-1 ear release rate from EX-2 EX3 EX3 0.16 0.67 5 00 0.09 9.95 0.88 100--year existing release ate from E%-3 Project Number: 25,t9 Project Name: Flats at the Oval Designer: Herman H Feissner,, P.E. Dale: N420o9 1 I DEVELOPED CONDITION 1 1 1 1 1 I tProposed Condition Runoff Coefficient Calculations Rational Method Procedure 1 Basin(s) Area _ �e _ Area' ac Type of Development Composite CZ& CIO Composite - CtDO Al 15234.30 0.35 Business 0.88 1.00 A2 1615.47 0.04 Business 0.95 1.00 B1 730.04 0.02 Business 0.42 0.52 B2 563.12 0.01 Business 0.63 0.79 B3 353.61 0.01 Business 0.95 1.00 B4 661.97 0.02 Business 0.44 0.55 RF1 16997.79 0.39 Business 0.95 1.00 Site 1 36156.30 1 0.83 1 Business 0.89 1.00 Notes: 1. The runoff coefficients for composite analysis were read from Table 3-3, Rational Method Runoff Coefficients for Composite Analysis. For Asphalt, Concrete, and Roofs: C=0.95 and Lawns (Heavy Soil, Average 2 to 7%) C=0.25. ' 2. Table 3-4, Rational Method Frequency Adjustment Factors, was used to calculate C1e and CIm. 3. Lawns (Heavy Soil, Average 2% to 7%): suggested based on findings (i.e., USCS Type CL soils) discussed in Geotechnical Exploration Report 306 West Laurel Street Apartments, SOILOGIC #07-1088, Dated: November 19, 2007. 4. Added area (i.e., 88.08 ft2) from roof overhang areas outside the property line to developed runoff calculations L 1 1 1 11 Project Number: 2549 Project Name: Flats at the Oval Designer: Herman H. Feissner, P.E. Date: 6/4/2009 10-year t , Calculations for Developed Conditions Rat Jnel Melhotl Rocedlre DATA OVERLAND TWE OF FLOW(tj CHANNELIZED TIME OF - FLOW(ta) CHANNELIZED TWE OF '. FLOW(te) .FINAL I. Basin(s) 9esign Point Area - acre($) Runoff CoeRcient C1a Length It<.. Slope t in . Length ft Slope % Vekaty ry/sec � min Length ry Slope % Vebcgy . fl/sec '. 1a .. min. Oompulatl t. min Commer - Al Al 0.35 0.88 1 0 1 10.00 0.00 1 0 1 0.00 aao 0.00 0 0.00 0.00 1 0.00 5.00 A2 A2 0.04 0.95 0 10.00 0.00 0 0.00 0.00 000 0 0.00 0.00 000 5.W 81 81 o.oz o.az o 19.00 0.01 0 000 0.00 0.00 o 000 0,00 0.00 s.ao Bz Bz o.ot o.s3 9 10.0o D0o 0 0.00 9.00 0.00 o a.00 0.09 00o s.op B3 83 0.01 0.95 0 10.00 0.00 0 000 1 0.00 1 0.00 0 1 0.00 0.00 1 0.00 5.00 Ba Ba 1 0.0z 1 o.aa o 10.00 o.D1 a o 0o I am aw 0 0.00 0.0o a oo s.op 1 RF1 RP0.39 0.95 0 10.00 0.00 0 0.00 0.00 0.00 0 000 0.00 000 5.00 Site Site 0.83 0.89 0 10.00 0.W 0 0.00 000 000 0 0.00 0.00 000 1 S00 I PtPi Number: 2S p Daa,g-H -H Fei... PE. Pro:: Name: Flats at the Oval Oatm W42 M ' 10-year Runoff for Developed Conditions Rational Method Procedure 1 1 1 1 1 1 1 Basin(s) DIRECT RUNOFF. " Comments - 'Design - Point - ` Area acre s - C,a k min C•A acres F2amfa11 Intensity (i) in/hr Runoff (0) cfs Al Al 0.35 0.88 1 5.00 0.31 1 4.87 1.50 A2 I A2 0.04 0,95 1 5.00 0,04 4.87 0.17 Bl 1 B7 002 0.42 5. 00 0.07 4.87 0.03 B2 B2 0,01 0.63 5.00 0.01 487 0.04 B3 B3 0,01 0.95 5.00 0.01 4.87 0.04 B4 B4 0,02 0.44 1 5.00 0.01 1 4.87 0.03 RF7 RFl 0,39 0.95 5.00 0.37 4.87 1.81 Site I Site 1 0.83 1 0.89 5.00 0.74 4.87 3.62 Pqg t Numaec 2549 Prgect Name: Flats of the Oval Designer: Heenan H. Feissner, P.E. Date: 6142009 1 M i M M M M M M � M M M M M M M M M M 100-year t, Calculations for Developed Conditions Rafprel Ma1Mtl Ff ocgtlive DATA OVERLAND TIME OF FLOW(tJ. - CHANNELIZED TIME OF FLOW(W CHANNELIZED TIME OF FLOW(6) FINAL Basin(s)'Point Design - _ Area "acre(s) :RunoR Coeffkient CIO Length fi Slope % t min Length ft Slope % Velocity fVsec I. in length tl Slope % Velocity' .(Uses - to min Computed I. min Oommems Al I Al 0.35 100 0 low 0.00 0 om I 0.00 I 000 1 0 1 om I 000 0.0) 1 5.00 1 A2 A2 0.04 _ 1.00 0 10.00 0,00 0 0.00 0.00 0.00 0 000 0.00 000 5.00 el 91 o.oz asz o 10.00 0.01 0 0,000.00 0,000 o00 0.00 -o.00 s.00 B2 Bz o.01 o.�s o 1o.eo o.o0 0 0.00 om o00 0 000 0.0o 0.00 5.00 B3 B3 0.01 1.00 0 10.00 000 0 000 0.00 000 0 0.00 0.00 0,00 5.00 B4 M 0.02 0.55 0 1000 O.W 0 0,00 0.00 000 1 0 1 0.W 0.00 0,00 5.W RFt RFt 0.39 100 0 10.00 O.GO 0 0W om 000 0 am 0.00 0.00 5.00 Site Site 0.83 1.00 0 I IO.GO 0.00 1 0 000 1 0.00 1 000 1 0 1 000 0.00 I o.00 1 5.00 Pmje Number'. 2UQ D.,r.n H--H Feis , PE 400l Name: FNrsY IM Ov Oat.: &N " I 1 1 I 1 i 1 1 E H 1 1 1 1 1 1 1 100-year Runoff for Developed Conditions Rational Metho t Procedure Basins) DIRECT RUNOFF. Comments Design Point - Area acre(s) C,w 6 _ min C' A - acre(s) Katintall mtensay V l irvhr. Runoff (Q)- Gifts Al A2 Al A2 5 0.04 0 100 5.0 5.00 5.00__0.01 5.00 5A0 . 5— 004995 0.01 0.01 — 9 5 995 9 95 I — 9.95 8 0.37 81 _ B2 B3 B4 B1 B2 B3 B4 OW 0.01 r-0.01 0.02 052 0.79 1.00 0.5515.00 0.09- 0.10 0.08 0.01 9.95 0.08 RF1 RF1T0.39 1.00 1.00 5.00 5.00 0.39 0.83 — 9.95 J.Ba B.ZB Site I Site 1 0.83 9.95 Project Number: 2549 Designer: Herman H. Feissner, PE Project Name: Flats at the Oval Dale: 6/4/2009 1 APPENDIX B HYDRAULIC CALCULATIONS Proposed 12" A2000 PVC ON -SITE Storm Drain Project Description Friction Method Manning Formula Solve For Full Flow Capacity Input Data Roughness Coefficient 0.013 Channel Slope 0.50 % Normal Depth 1.00 ft Diameter 12 in Discharge 2.52 ft'/s 'Results Discharge 2.52 ft-/s Normal Depth 1.00 ft Flow Area 0.79 ft2 Wetted Perimeter 3.14 ft Top Width 0.00 ft Critical Depth 0.68 ft Percent Full 100.0 Critical Slope 0.00770 Poft Velocity 3.21 ft/s Velocity Head - 0.16 ft - Specific Energy 1.16 ft Froude Number 0.00 Maximum Discharge 2.71 ft'/s Discharge Full 2.52 ft'/s Slope Full 0.00500 ft/ft Flow Type SubCritical GVF Input Data Downstream Depth 0.00 ft Length 0.00 fit Number Of Steps 0 GVF Output Data Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % Normal Depth Over Rise 100.00 % Bentley Systems, Inc. Haestad Methods Solution Center Bentley FlowMaster [08.01.071.001 6/2/2009 4:46:51 PM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 2 II I Proposed 12" A2000 PVC ON -SITE Storm Drain GVF Output Data ' Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 1.00 ft Critical Depth 0.68 ft Channel Slope 0.50 % 1 Critical Slope 0.00770 ft/ft I I O 1 1 1 ' 6/2/2009 4:46:51 PM Bentley Systems, Inc. Haestad Methods Solution Center Bentley FlowMaster [08.01.071.00] 27 Siemens Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 2 of 2 I Proposed IS" RCP OFF -SITE Storm Drain Project Description Friction Method Manning Formula Solve For Full Flow Capacity Input Data Roughness Coefficient 0.013 Channel Slope 0.50 % Normal Depth 1.25 ft Diameter 15 in Discharge 4.57 ft3/s Results Discharge 4.57 ft-/s Normal Depth 1.25 ft Flow Area 1.23 ft' Wetted Perimeter 3.93 ft Top Width 0.00 ft Critical Depth 0.87 ft Percent Full 100.0 % Critical Slope 0.00732 ft/ft Velocity 3.72 ft/s Velocity Head - 0.22 ft Specific Energy 1.47 ft Froude Number 0.00 Maximum Discharge 4.91 ft'/s Discharge Full 4.57 ft-/s Slope Full 0.00500 ft/ft Flow Type SubCritical GVF Input Data Downstream Depth 0.00 ft Length 0.00 it Number Of Steps 0 GVF Output Data Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % Normal Depth Over Rise 100.00 % Bentley Systems, Inc. Haestad Methods Solution Center Bentley FlowMaster 108.01.071.00] 6/2/2009 4:47:46 PM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 2 Proposed 15" RCP OFF -SITE Storm Drain GVF Output Data Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 1.25 ft Critical Depth 0.87 ft Channel Slope 0.50 % Critical Slope 0.00732 ft/ft 1 11212101 4:47:46 PM Bentley Systems, Inc. Haestad Methods Solution Center Bentley FlowMaster [08.01.071.001 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 2 of 2 Existing 12" Clay Storm Drain Pipe ProjectDescription j Friction Method Manning Formula Solve For Full Flow Capacity Input Data Roughness Coefficient 0,015 Channel Slope 0.83 % Normal Depth 1.00 ft Diameter 12 in Discharge 2.81 ft3/s Results Discharge 2.81 ft-/s Normal Depth 1.00 ft Flow Area 0.79 ft' Wetted Perimeter 3.14 ft Top Width 0.00 ft Critical Depth 0.72 ft Percent Full 100.0 % Critical Slope 0.01104 ft/ft Velocity 3.58 ft/s Velocity Head 0.20 ft Specific Energy 1.20 ft Froude Number 0.00 Maximum Discharge 3.03 ft'/s Discharge Full 2.81 ft-/s Slope Full 0,00830 ft/ft Flow Type SubCritical GVF Input Data Downstream Depth 0.00 ft Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % Normal Depth Over Rise 100.00 % Bentley Systems, Inc. Haestad Methods Solution Center Bentley FlowMaster [08.01.071.00] 6/4/2009 4:16:24 PM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 2 ' Existing 12" Clay Storm Drain Pipe GVF Output Data ' Downstream Velocity Infinity f /s Upstream Velocity Infinity ft/s Normal Depth 1.00 ft ' Critical Depth 0.72 ft Channel Slope 0.83 % ' Critical Slope 0.01104 ft/ft 1 1 1 Bentley Systems, Inc. Haestao Methods Solution Center Bentley FlowMaster [08.01.071.00] 11412001 4:16:24 PM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1.203-755-1666 Page 2 of 2 ' 1 I STORM DRAIN SYSTEM DESIGN l _J i i 1 1 1 1 1 1 i 1 1 1 i 1 1 i 1 Scenario: Base Pipe Report Upstream Downstream Total Length Constructed Section Mannings Full Upstream Upstream Downstream Downstream Hydraulic Hydraulic Node Node System (ft) Slope Size n Capacity Ground Invert Ground Invert Grade Grade Flow (tuft) (cfs) Elevation Elevation Elevation Elevation Line In Line Out (cfs) (ft) (ft) (ft) (ft) (ft) (ft) STM MH#3 STM MH#2 1.75 5Z58 0.005 12 inch 0.013 2.48 4,998.24 4,994.40 4,998.16 4,994.12 4,995.02 4,994.68 STM MH#2 STM MH#1 1.75 67.17 0.005 15 inch 0.013 4.60 4,998.16 4,993.87 4,997.00 4,993.53 4,994.40 4,994.06 STM INLET STM MH#3 1.75 58.84 0.005 12 inch 0.013 2.50 4,997.30 4,994.79 4,998.24 4,994.50 4,995.41 4,995.19 Title: The Oval Flats Project Engineer: Herman Feissner, P.E. cA..Astormcad\2549_stonncad.stm Jim Sell Design IncFort Collin StormCAD v5.6 [05.06.014.001 O6/04/09 04:22:04 PM 0 Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 1 Label: STM MH#3 Rim: 4,998.24 ft Sump: 4,994.40 ft Label: STM INLET Rim: 4,997.30 ft Sump: 4,994.79 ft Label: P-3 Up. Invert: 4,994.79 ft Dn. Invert: 4,994.50 ft L: 58.84 ft Size: 12 inch S: 0.005 ft/ft 0+00 M M M M Profile Scenario: Base Label: P-2 Up. Invert: 4,994.40 ft Dn. Invert: 4,994.12 ft L: 57.58 ft Size: 12 inch S: 0.005 ft/ft 1+00 Station (ft) 5,000.00 Label: STM MH#2 Rim: 4,998.16 ft Sump: 4,993.87 ft Label: STM MH#1 Rim: 4,997.00 ft Sump: 4,992.34 ft Label: P-1 Up. Invert: 4,993.87 ft Dn. Invert: 4,993.53 ft L: 67.17 ft 4,990.00 Size: 15 inch S: 0.005 ft/ft 2+00 Elevation (ft) Title: The Oval Flats Project Engineer: Herman Feissner, P.E. c:\..Astorrncatl\2549_stormcao.stm Jim Sell Design IncFort Collin StormCAD v5.6 [05.06.014.001 06/04/09 04:24:40 PM 0 Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 1 I 1 1 1 1 1 1 1 1 J 1 INLET DESIGN Area Inlet Capacity Calculations - D.P. Al Grate: CDOT Concrete Inlet - Type 13 (DOUBLE) Weir Perimeter, L = 71.50 in 5.96 ft Open Area, A = 666.96 in` 4.63 fe "Open area for single inlet grate: 333.48 in` Clogging Factor, c = 50% Stage Interval, oh = 0.10 ft Weir Calculation: Orifice Calculation: Qw = CLH" Q. = CA(2gH)" C= 3.00 C= 0.61 cL = 2.98 ft Ac = 2.32 ft' Water Depth ft Elevation ft Qw:wL cfs Q INLET cfs ; Rules-- cfs 0.00 4997.30 0.00 0.00 0.00 0.10 4997.40 0.28 3.58 0.28 0.20 4997.50 0.80 5.07 0.80 0.30 4997.60 1.47 6.21 1.47 0.40 4997.70 2.26 7.17 2.26 0.50 4997.80 3.16 8.02 3.16 0.60 4997.90 4.15 8.78 4.15 0.70 4998.00 5.23 9.48 5.23 0.80 4998.10 6.40 10.14 6.40 0.90 4998.20 7.63 10.75 7.63 1.00 4998.30 8.94 11.34 8.94 `"Proposed top of grate elevation ,Qu,-3.48 cfs ti Water will pond to ±4997.83 -Qioo=7.73 cfs \, Water will pond to ±4998.21 Notes: 1. 010 and Q1w are a summation of developed flows from basins Al, A2 and RF1 Project Name: Flats at the Oval Project Number: 2549 Designer: Herman Feissner, P.E. Date: 6/4/2009 f 1 7 1 jC r N.l A F4d HH3 onOBM2Ate: HF-6et C R TWE 1 1U4In"inOIOep.Dasnska35 ]BM (ApproaM knurl) L-. B PLAN VIEW TYPE 13 INLET FUR GUTTER TYPE 2 u I 11 (t)s00n sitlea0.50 in. (Open mee only) I\�A R C�— (t) 9nan aiae: tB.DD in. (Aiapnadl Img111) NO. 13 GRATE A MEN HNA u OUX IS TO 2" C C EXIFIM 10 ,M EDGE 6 3i• 1 "I"PI"PI"PP HI" TIE MPNC FRAK c C cur WRE U.M DmRasM. A r r A ye I SECTION C-C �" SECTION 0-0 IMF NO. 13 GRATING & FRAMES SECTION B-B TV --y D uAl . la M.IW I1L x ie/r^ N• 1 39K I � 1 r 01 rII r1 I dot I r f03 I I I I r f'/i 2i/i r��1 ll�t LU 4v., M F 1M .1 + 1 31'A --M 'I SECTION E{ SECTION F-F BENDING DIAGRAM S NL 6 SM. DIN MN6 .NE Ulf-TOWITT g9RpxMME T1E1EM - SN Les. SECTIUN A -A 0NM-W IN. He H14 R. GENERAL NOTES L mNEI[ SIINL K a S. Ne£1 ufr BE GIST-MR.LLT ON MCMT. 2. CMT-NN arKAETE n#LS AIN1 EE FGRMD MI e0M IONS. 1 FlIP35N GOIEAEfE LYMiR6 SMNl EE aWEf1ED K M f. RFMiLWCIM19 BNIS AIKL BE GRfPMD IV N01 SHItt NAVE A 2 M. MNO6M LIFIRMCE ILL RaNFMCMG BNM SNKL BE WONT MATED, 5, STEPS 9W1 BE PIWBOEO MEN MIST O N&SIal "11" IS EW TO M QEA1M PON 3 FTA MNM S CaFMN TO MSHTO u I". 6, N.L MALES NM MINES WNL BE WAY OR GUCTIE OAST IRON IN ACCAWM NTM SL95ECTION SII.W. GRAIES NW FNANES SNNL BE DECION D TO MTNSTNM HS N 100M. 2. STATIW POINT 15 AT PIE mnrn OF TIE MEL N.l A F4d HH3 onOBM2Ate: HF-6et C R TWE 1 1U4In"inOIOep.Dasnska35 ]BM (ApproaM knurl) L-. B PLAN VIEW TYPE 13 INLET FUR GUTTER TYPE 2 u I 11 (t)s00n sitlea0.50 in. (Open mee only) I\�A R C�— (t) 9nan aiae: tB.DD in. (Aiapnadl Img111) NO. 13 GRATE A MEN HNA u OUX IS TO 2" C C EXIFIM 10 ,M EDGE 6 3i• 1 "I"PI"PI"PP HI" TIE MPNC FRAK c C cur WRE U.M DmRasM. A r r A ye I SECTION C-C �" SECTION 0-0 IMF NO. 13 GRATING & FRAMES SECTION B-B TV --y D uAl . la M.IW I1L x ie/r^ N• 1 39K I � 1 r 01 rII r1 I dot I r f03 I I I I r f'/i 2i/i r��1 ll�t LU 4v., M F 1M .1 + 1 31'A --M 'I SECTION E{ SECTION F-F BENDING DIAGRAM S NL 6 SM. DIN MN6 .NE Ulf-TOWITT g9RpxMME T1E1EM - SN Les. SECTIUN A -A 0NM-W IN. He H14 R. GENERAL NOTES L mNEI[ SIINL K a S. Ne£1 ufr BE GIST-MR.LLT ON MCMT. 2. CMT-NN arKAETE n#LS AIN1 EE FGRMD MI e0M IONS. 1 FlIP35N GOIEAEfE LYMiR6 SMNl EE aWEf1ED K M f. RFMiLWCIM19 BNIS AIKL BE GRfPMD IV N01 SHItt NAVE A 2 M. MNO6M LIFIRMCE ILL RaNFMCMG BNM SNKL BE WONT MATED, 5, STEPS 9W1 BE PIWBOEO MEN MIST O N&SIal "11" IS EW TO M QEA1M PON 3 FTA MNM S CaFMN TO MSHTO u I". 6, N.L MALES NM MINES WNL BE WAY OR GUCTIE OAST IRON IN ACCAWM NTM SL95ECTION SII.W. GRAIES NW FNANES SNNL BE DECION D TO MTNSTNM HS N 100M. 2. STATIW POINT 15 AT PIE mnrn OF TIE MEL REINWCRW IW.OF YAiIN"1 PME In. N CONJE2 STEEL albAS SEC. A -A SEC B9 W. YDS. 9 IS. M00. I IN. I M. P-0• Iz 12 V 1 to .TB Yd' 1.5 70 f 1 2/ IB 4'-0• L6 SO 6 1 N Ia V'i• 1.0 IS, v 30 IB yq- IA 1" 6 30 Is 54' 21 In y 30 IN 6'V 24 I30 0 ]0 10 6'i" 2e 141 a So a NP 25 ISl 9 SO 16 T-6• v 16e 10 30 Is C-rv' 1.. 1➢ 10 30 IS 3.0 137 H 30 IB sP 31 100 a AI 10 9'-0• 3J z65 tl 30 IB 10'-0• 3.4 119 13 30 IB 03HWEIESU YT OVEMMI. MIfL WRRIE Wp11111E3 ➢gIAE VRUE OG0.PIM BY P6f. QUANTITIES FOR ONE INLET NMOt N0. ulNExslWs PE00. x LENOM fM a rs r-r In+• foz z rfYi z�a' " E-sYi fur = 6 MW THIS DDA6104 Fm WH 6 MINUO'/.4 W "OVER 3 R.-0 M BAR LIST FOR H - 3 FT.-D IN. Com uter F11e Information I Dote: Sheet Revisions Colorado Department of Transportation a201 East Mkm s AvaWe <7 Danreq Gabmde 50222 FNOne: L30J) y51-9063 Project Development Branch SRJ/LTA elo me t Branch CONCRETE INLET TYPE 13 STANDARD PLAN NO. Creatbn Dats: 07/0a/06 UNUas SRV [envnmta M-60413 Laat Meallleanon Dale: W/0a/06 1nItIWa: LTA F0RGa0: ve .d0l.alete.a0.m/Des s Part/ Or ' Fb Nam.: 50a0130101.d Laavm ey: arahaL perenemeat e.wcn 3ar va. zoos Sheet No. 1 of 1 1� cM vem I .staxaa Ve ma. a sae un� DiAd' I DETENTION POND DESIGN 1 1 1 1 1 1 J 1 1 1 1 1 I i 1 I 11 1 ' Developed Condition Required Detention Volume, 100-year On -Site Detention Pond t This spreadsheet calculates the required storage volume (i.e., detention) for Mere development of a currently developed site by converting the existing pervious area to Impervious area using 'C'. - The Release Rate (See Below) is based oar the calculated 2-year release rate from the existing pervious area. ' Input Data: Runoff Coefficient, Cl 0.93 2-year Ste" Events 1.00 100-year Storm Event xisting Pervious Area: 0.38 acres Release Rate: 0.27 cis "See calculations in report narrative RESULTS Re ufred Detention ac-R 3179.24 1 0.073 Time minutes Cummulative Time seconds 100-year Intensity inlhr aim CIS Runoff Volume Its Cummulalive Release It, Required Detention ft I ac-ft 0 0 0.00 0.00 0.00 0.00 0.00 0.000 5 300 9.95 3.82 1146.24 79.50 1066.74 0.024 10 600 7.72 2.96 1778.69 159.00 1619.69 0.037 15 900 6.52 2.50 2253.31 238.50 2014.81 0.046 20 1200 5.60 2.15 2580.48 318.00 2262.48 0.052 25 1500 4.98 1.91 2868.48 397.50 2470.98 0.057 30 1800 4.52 1.74 3124.22 477.00 2647.22 0,061 35 21 no 4.08 1.57 3290.11 556.50 1 2733.61 0.063 40 2400 3.74 1.44 3446.78 1 636.00 1 2810.78 0.065 45 2700 3.46 1.33 3587.33 715.50 2871.83 0.066 50 3000 3.23 1.24 3720.96 795.00 2925.96 0.067 55 3300 3.03 1.16 3839.62 874.50 2965.12 0.068 60 3600 2.86 1.10 3953.66 954.00 2999.66 0.069 65 3900 2.72 004 4073.47 1033.50 3039.97 0.070 70 4200 2.59 0.99 4177.15 1113.00 3064.15 0.070 75 4500 1 2.48 0.95 4285.44 1192.50 3092.94 0.071 80 4800 1 2.38 0.91 4386.82 1272.00 3114.82 0.072 85 5100 2.29 0.88 4484.74 1351.50 3133.24 0.072 90 5400 2.21 0.85 4582.66 1431.00 3151.66 0.072 95 5700 2.13 0.82 4662.14 1510.50 3151.64 0.072 100 6000 2.06 0.79 4746.24 1590.00 3156.24 0.072 105 6300 2.00 0.77 4838.40 1669.50 3168.90 0.073 110 6600 1.94 1 0.74 1 4916.74 1 1749.00 1 3167.74 0.073 115 120 6900 7200 1.89 1.84 0.73 0.71 500R74 5087.23 1828t50 1908.00 3170124 1 3179.23 0073 1 0.073 125 1 7500 1.79 0.69 5155.201 1987.50 3167.70 0.073 130 7800 1.75 0.67 5241.60 2067.00 3174.60 0.073 135 8100 1.71 0.66 5318.7ti 2146.50 3172.28 0.073 140 8400 1.67 0.64 5386.75 2226.00 3160.75 0.073 145 8700 1.63 0.63 5445.50 2305.50 3140.00 0.072 150 9000 1.60 0.61 5529.60 1 2385.00 1 3144.60 0.072 155 9300 1.67 0.60 5606.781 2464.50 3142.28 0.072 160 9600 1.54 0.59 5677.06 2544.00 3133.06 0.072 165 9900 1.51 0.58 5740.42 2623.50 3116.92 0.072 170 10200 1.48 0.57 5796.86 2703.00 3093.86 0.071 175 10500 1.45 0.56 5846.40 2782.50 3063.90 0.070 180 10800 1.42 0.55 5889. 22 2862.00 3027.02 0.069 185 11100 1.40 0.54 5967.36 2941.50 3025.86 0,069 190 11400 1.38 0.53 6041.09 3021.00 3020.09 0.069 195 11700 1 1.36 0.52 6110.21 3100.50 3009.71 0.069 200 1 12000 1 1.34 0.51 6174.72 3180.00 1 2994.72 0,069 205 1 12300 1.32 0.51 6234.62 3259.50 2975.12 0,068 210 1 12600 1.30 1.50 6289.92 3339.00 2950.92 0.068 215 1 12900 1 1.28 0.49 6340.61 3418.50 2922.11 0.067 220 1 13200 1.26 0.48 6366.69 3498.00 2888.69 0.066 225 13500 1.24 0.48 6428.16 3577.50 2850.66 0.065 230 1 13800 1 1.22 0.47 6465.02 3657.00 2808.02 0.064 235 114100 1.21 0.46 6551.42 1 3736.50 2814.92 0.065 240 1 14400 1 1.20 0.46 6635.52 3816.00 2819.52 0.065 Notes: 1. Sp-eadsheel Created: 05195 By: M. rater; Modified: 11197 By: D. Judish; Meddled: 1 t198 By C. Li 2. Assumed that all existing pervious area Is converted to imparvl0es area I ' Developed Condition Required Detention Volume, 100-year On -Site Detention Pond 1 I 1 1 1 1 t Input Data: Runoff Coefficient, C: C'C,: lrea Draining to Pond Release Rate: 0.93 2-year Storm Evenl? 1.00 100-year Storm Event 0.78 acres 1.75 cfs RESULTS Required Detention ft ac-ft 3261.60. 0:073 Time Tsecon minutesds mmulative Time .100-year Intensity in/hr Q100 cis Runoff Volume fta CummulaUve Release° ft3 Required Detention ft ao-ft 0 0 0.00 0.00 0.00 1 0.00 0.00 0.000 5 300 9.95 7.76 2328.301 525.00 1803.30 0.041 10 600 7.72 6.02 3612.96 1050.00 2562.96 0.059 15 900 6.52 5.09 4577.04 11575.00 3002.04 0.069 20 1200 5.60 4.37 5241.60 1 2100.00 3141.60 1 0.072 25 30 1500 1 1800 4:98 4.52 3.88 M 1 3.53 5826.60 6346.08 2625.00 3150.00 3201.60 3196.08 0,073 0.073 35 2100 4.08 1 3.18 6683.04 3675.00 3008.04 0.069 40 2400 1 3.74 2.92 7001.28 4200.00 2801.28 0.064 45 2700 3.46 2.70 7286.76 4725.00 2561.76 0.059 50 3000 3.23 2.52 7558.20 5250.00 2308.20 0.053 55 3300 3.03 2.36 7799.22 5775.00 2024.22 0.046 60 3600 2.86 2.23 8030.88 6300.00 1730.88 0.040 65 3900 2.72 2.12 8274.24 6825.00 1449.24 0.033 70 4200 2.59 2.02 8484.84 7350.00 1134.84 0.026 75 4500 2.48 1.93 1 8704.80 7875.00 829.80 0.019 80 4800 2.38 1.86 8910.72 8400.00 510.72 0.012 85 5100 2.29 1.79 9109.62 8925.00 184.62 0.004 90 5400 2.21 1.72 9308.52 9450.00 -141.48 -0.003 95 5700 2.13 1.66 9469.98 9975.00 -505.02 -0.012 100 6000 2.06 1.61 9640.80 10500.00 -859.20 -0.020 105 6300 2.00 1.56 9828.00 11025.00 -1197.00 -0.027 110 6600 1.94 1.51 9987.12 11550.00 -1562.88 -0.036 115 6900 1.89 1.47 10171.98 12075.00 -1903.02 -0.044 120 7200 1.84 1.44 10333.44 12600.00 -2266.56 -0.052 125 7500 1.79 1.40 10471.50 13125.00 -2653.50 -0.061 130 7800 1.75 1 1.37 10647.00 13650.00 -3003.00 -0.069 135 8100 1.71 1.33 10803.78 14175.00 -3371.22 -0.077 140 8400 1.67 1.30 10941.84 14700.00 -3758.16 -0.086 145 8700 1 1.63 1.27 11061.18 15225.00 -4163.82 -0.096 150 9000 1.60 1.25 11232.00 15750.00 -4518.00 -0.104 155 9300 1.57 1.22 11388.78 16275.00 A886.22 -0.112 160 9600 1.54 1 1.20 11531.521 16800.00 -5268.48 -0.121 165 9900 1.51 1 1.18 11660.22 17325.00 -5664.78 -0.130 170 10200 1.48 1.15 11774.88 17850.00 -6075.12 -0.139 175 10500 1.45 1.13 11875.50 18375.00 -6499.50 -0.149 130 o 10800 1.42 1.11 11962.08 18900.00 -6937.92 -0.159 185 11100 1.40 1.09 12121.20 19425.00 -7303.80 -0.168 190 11400 1.38 1.08 12270.96 19950.00 -7679.04 -0.176 195 11700 1.36 1.06 12411.36 20475.00 -8063.64 -0.185 200 12000 1.34 1.05 12542.40 21000.00 -8457.60 -0.194 205 12300 1.32 1.03 12664.08 21525.00 -8860 992 -0.203 210 12600 1.30 1.01 12776.40 22050.00 -9273.60 -0.213 215 12900 1.28 1.00 12879.36 22575.00 -9695.64 -0.223 220 13200 1.26 0.98 12972.96 23100.00 -10127.04 -0.232 225 13500 1.24 0.97 13057.20 23625.00 -10567.80 -0.243 230 13800 1.22 0.95 13132.08 24150.00 17.92 -110 -0.253 235 14100 1.21 0.94 13307.58 24675.00 -11367, 2 1 -0.261 240 14400 1.20 1 0.94 1 13478.401 25200.00 -11721.60 -0.269 Notes: 1. Spreadsheet Created: 05195 By: M. Fater; Modified: 11197 By: D. Judish; Modified: 11198 By: C. Li 2. Assumed that all existing per, bus area is converted 0 impervious area I Developed Condition Available Detention Volume On -Site Detention Pond ) Available Detention Volume: I' _ 4d(A+6+ AB 3 Where: V= Volume between contours, ft' Ad= Change in depth between A and B, ft A= Surface area of contour line (i.e., lower), ft' B= Surface area of contour line at a depth relevant to ad (i.e., upper), fe _ Volume Elevators feet .. . A ft A fl B f? - Volume ft, : Cummulabve .Volume to - Cummulaeve Volume ac-ft Vn 4997.30 0.00 0 0 0 0 0.00 V, 4998.00 0.70 0 3,717 867 867 0.020 Vmo-we' 4998.40 0.40 3,717 8,131 2,313 3,180 0.073 VE—Moncy 8,11 ar 4998.50 0.10 8,131 9,567 884 4,064 0.093 Vz 4999.00 0.50 9,567 13,299 5,691 9,755 0.224 Notes: 1. Proposed Finished Floor Elevations: F.F.E.=4999.5 and F.F.E =5000.3. 2. Maximum ponding depth allowed in the parking area: 1.00 ft (per Section 9.4 of the SDDCCS) 3. Elevation 4997.30 (See Above) is the Top of Grate elevation for the area inlet box. The lowest elevation in the parking lot (i.e., curb cut FL elevation at the island) is 4997.40; therefore, the maximum popping depth in the parking lot is 1.00 ft. Project Name: Flats at the Oval Designer: Herman Feissner, P.E. Project Number: 2549 Date: 6/4/2009 II 1 Developed Condition Orifice Plate Sizing Calculations 1 -year developed condition attenuate to -year historic rate Design Point= Al Onfice Calculation: 1 Qo = CA(2gH)as 100-year WSEL= 4998.40 Invert Out= 4994.79 1 Allowable Release Rate= 1.75 cfs H= 3.46 ft C= 0.65 g = 32.2 fills 1 Qo= 1.75 cfs Dia.= 0.29 ft A= 0.18 ft2 1 A= 25.95 in Diameter of Orifice: 5.75 in 1 1 i i 1 1 Project Number: 2549 Project Name: Flats at the Oval Designer: Herman Feissner, P.E. Date: 61412009 1 Emergency Spillway - Basin Al Project Description Solve For Discharge Input Data Headwater Elevation 4999.00 ft Crest Elevation 4998.50 ft Tailwater Elevation 4998.50 ft Weir Coefficient 2.82 US Crest Length 8.00 ft Number Of Contractions 2 Results Discharge 7.88 ft'/s Headwater Height Above Crest 0.50 ft Tailwater Height Above Crest 0.00 ft Flow Area 4.00 ft' Velocity 1.97 ft/s Wetted Perimeter 9.00 ft Top Width 8.00 ft Bentley Systems, Inc. Haestad Methods Solution Center Bentley FlowMaster (08.01.071.00) 6/4/2009 4:59:03 PM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 1 Emergency Spillway - Section 1 (U.S. of SW Chase) GVF Input Data Downstream Depth 0.00 ft Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 0.90 ft Critical Depth 0.60 ft Channel Slope 0.00600 ft/ft Critical Slope 0.05536 ft/ft Bentley Systems, Inc. Haestad Methods Solution Center Bentley FlowMaster [08.01.071.00] 6/4/2009 5:04:30 PM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 2 of 2 Emergency Spillway, Sidewalk Chase Project Description Solve For Discharge Input Data Headwater Elevation 4999A5 ft Crest Elevation 4998.33 ft Tailwater Elevation 4998.30 ft Weir Coefficient 2.82 US Crest Length 4.00 ft Number Of Contractions 2 Results Discharge 8.03 Wis Headwater Height Above Crest 0.82 ft Tailwater Height Above Crest -0.03 ft Flow Area 3.28 ft2 Velocity 2.45 fits Wetted Perimeter 5.64 ft Top Width 4.00 ft Bentley Systems, Inc. Haestad Methods Solution Center Bentley FlowMaster [08.01.071.001 6/4/2009 5:10:34 PM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA *1-203-755-1666 Page 1 of i Emergency Spillway - Section 2 (D.S, of SW Chase) Results Flow Type Subcritical GVF Input Data Downstream Depth 0.00 ft Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 0.80 ft Critical Depth 0.50 ft Channel Slope 0.00600 ft/ft Critical Slope 0.05645 ft/ft Bentley Systems, Inc. Haestad Methods Solution Center Bentley FlowMaster [08.01.071.001 61412009 5:05:33 PM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 2 of 2 I ' APPENDIX C EROSION AND SEDIMENT CONTROL 1 d 1 I 'I 1 I 1 '-1 1 iI 1 1 II 1 I ' RAINFALL PERFORMANCE STANDARD EVALUATION STANDARD FORM A 1 t 1 1 1 1 II 1 B 1 j 1 Area Sub -Basin Lemth Sub Basin Slboe Sub -Basin Developed Sub -Basin Erodibility Zone Asb ac Lsb ft Ss1) % Lb ft Sb PS Al Moderate/Moderate' 0.35 94 2.50 A2 Moderate/Moderate' 0.04 89 1.00 Bt Moderate/Moderate' 0.02 61 1.73 B2 Moderate/Moderate' 0.01 8 2.00 83 Moderate/Moderate' 0.01 10 2.00 B4 Moderate/Moderate' 0.02 16 2.00 RF1 Moderate/Moderate' 0.39 52 2.00 0.83 Lb ' £(' Sb-Lsb)/(E(Asb) — 70 - MODERATE WIND ERODIBILITY ZONE & MODERATE RAINFALL ERODIBILITY ZONE Sb = E(Asb•Ssb)/(E(Asb) _ = 2.16 PS (during construction) = 79% PS (after construction) = 0.7910.85 = 93% (from Table 8-A) EFFECTIVENESS CALCULATIONS DURING CONSTRUCTION STANDARD FORM B 1 Erosion Control Method C-Factor Value P-Factor Value Comments BARE SOIL 1 1.00 0.90 GRAVEL MULCH 2 O.05 1.00 STRAW -HAY MULCH 3 0.06 1.00 HYDRAULIC MULCH 4 0.10 1.00 ESTABLISHED GRASS COVER 5 0.35 1.00 PAVEMENT 6 0.01 1.00 STRAW BALE, GRAVEL FILTER 7 1.00 0.80 SILT FENCE BARRIER 8 1.00 0.50 1 $u0�Bd51� Sub -Basin $u0�Bd51� Sub -Basin �5 PS AREA AREA ac Prowl Site Pre'ect Site 79% i5% Oa83 0.83 Net C-Factor = 0.01 ' Net P-Factor = 1.00 EFF = (1-C`P)100 = (1-0.01'1)100 ' = 99% > 79% (PS) EFFECTIVENESS CALCULATIONS AFTER CONSTRUCTION STANDARD FORM B EROSION CONTROL METHOD C-FACTOR VALUE P-FACTOR VALUE COMMENTS BARE SOIL 1 1.00 0.90 GRAVEL MULCH 2 O.05 1.00 STRAW -HAY MULCH 3 0.06 1.00 1 % to 5% Slopes and 6% to 10% Slopes HYDRAULIC MULCH 4 0.10 1.00 @ 2 tons/acre ESTABLISHED GRASS COVER 5 0.07 1.00 Sod Grass 6 0.01 1.00 Asphalt/Concrete Pavement 7 0.01 1.00 STRAW BALE, GRAVEL FILTER 8 1.00 0.80 SILT FENCE BARRIER 9 1.00 0.50 Sub -Basin PS AREA ac j Proect Site 1 93% 1 0.83 Sub -Basin SUB -BASIN AREA AREA 112 PRACTICE C'A P"A REMARKS Al Al Pervious 1566 13668 6 7 16 137 1566 136 i8 Sod Grass AsphalUConcrete Pavement Impervious A2 A2 Pervious 0 1615 6 7 0 16 0 1615 Sod Grass AsphalUConcrete Pavement Impervious B1 B1 Pervious 556 174 6 7 6 2 556 174 Sod Grass Asphalt/Concrete Pavement Impervious B2 B2 Pervious 258 306 6 7 3 3 258 306 Sod Grass Asphalt/Concrete Pavement Impervious B3 B3 Pervious 0 354 0 7 0 4 0 354 n/a Asphalt/Concrete Pavement Impervious B4 B4 Pervious - 482 180 6 7 5 2 482 180 Sod Grass Asphalt/Concrete Pavement Impervious RF1 Pervious RF1 Impervious 0 16998 0 7 0 170 0 16998 n/a AsphalUConcrete Pavement Net C-Factor = 0.01 Net P-Factor = 1.00 EFF = (1-C-P)100 = (1-0.01 `1)100 = 99% > 93% M M M= M = = M M= M M M= M s® M EROSION CONTROL CONSTRUCTION SEQUENCE ST475777= Sequence for 2009thm 2010 Indicate by use of a bar line or symbols when erosion control measures will be installed. Major modifications to an approved schedule may require submitting a new schedule for approval by the City Engineer. Year 2009 2010 Month J J A S O N D J F M A M J J A 5 O N D Overlot Grading Wind Erosion Control Soil Roughening Perimeter Barrier Additional Barriers Vegetative Methods Soil Sealant Other Rainfall Erosion Control Structural: Sediment Trap/Basin Inlet Filters _ Straw Barriers Silt Fence Barriers — --^------.----' Sand Bags Bare Soil Preparation Contour Furrows Terracing Asphalt/Concrete Paving 7-7 _ T -- 6— — _—. — �' — --- Other Vegetative: Permanent Seed Planting Mulching/Sealant Temporary Seed Planting Sod Installation Nettings/Mats/Blankets Other STRUCTURES: INSTALLED BY: TBD MAINTAINED BY: TBD VEGETATIONIMULCHING CONTRACTOR: TBD DATE SUBMITTED: TBD APPROVED BY CITY OF FORT COLLINS: TBD I 1 1 1 1 1 1 1 1 1 Surety Calculations NOTE: The quantities listed are based on the BMPs shown on the Drainage and Erosion Control Plan (Sheet 6) for Flats at the Oval Method 1: BMP Costs' Description Quantity Unit Unit Price Total Silt Fence (SF) 200 If $1.40 $280 20'x50'x8" Vehicle Tracking Control Pad (VTC) 1 ea $595.00 $595 Inlet Protection (IP) 3 ea $60.00 $180 1. Includes material and installation costs Sub -Total: $1,055 50% Multiplier: $528 Total: $1,583 Method 2: Cost to Reseed Disturbed Acreage Description Quantity Unit Unit Price Total Disturbed Acreage 0.83 ac $750.00 $623 ' Project Number: 2549 Project Name: Flats at the Oval Method 1 is GREATER, therefore: Sub -Total: $623 50% Multiplier: $311 Total: $934 Select Method 1: $1,583 Designer: Herman Feissner, P.E. Date: 6/4/2009 LJ APPENDIX D BACKGROUND INFORMA 1 1 1 1 1 1 I 1 1 PLAT 1 1 1 1 1 1 1 1 LJ 1 FLATS AT THE OVAL BEING A REPLAT OF LOTS 1, 7, AND THE SOUTH HALF OF LOT 2, BLOCK 96, HARRISON'S ADDITION TO THE CITY OF FORT COLLINS, LOCATED IN THE NORTHEAST 1/4 OF SECTION 14, TOWNSHIP 7 NORTH, RANGE 69 WEST OF THE 6TH P.M., CITY OF FORT COLLINS, COUNTY OF LARIMER, STATE OF COLORADO St ll ym..e®. Ill.., pl me,,......_,.,.,..� m sr.r,n m .a.meb�.. a..a«e=.wm.mw m,ied.w ml:Wr®w.e.,.w �• wti •� e. e...u. w..a p.m a.0 �mm r.goauv> r w.Pe Ill ,—e,,.,.,�....U...J_e wmwvm..,.v.,k,J. •wm,W �mmuu, ea.S.ro!= ��'e�N�pgm,. y]vea ul m.um..,+mauuev R+=a�w�n (aN �^.eY Mrv•• eOaY m.uv.um.e.mm�m m�.•ux u.'vm.w-.,:+wr"w'ww c.uer' W > em,.m u • y.r w � mn �. e. •.mnmua e. nv e,. et LY hMmm�n� a,.4.�p.mHr.mrmepnvm �w vnr All om.'�.. ws w mW.emnm.mWaxaru..wrs.+•m o-.wrm na•m> x r u.•n arr. r�..� a � i.a ... w..m ..... m.r •..mw.m�.... u.am.. _ v avvwnw®o Swe..11wvenus—I, PY.I..,_pr c. w m,s.r�aW. w..umr��nn M.a®.a.wwme.mmn.v P n, n nvM, (M W�P'r umvyn..wue,.w =w o= =w 0 3�m fro Zo �a Hui pZ �J v0 U ZO LL i m i = m m m m MI = m m m m � m = m FLATS AT THE OVAL BEING A REPLAT OF LOTS 1, 7, AND THE SOUTH HALF OF LOT 2, BLOCK 96, HARRISON'S ADDITION TO THE CITY OF FORT COLLINS, LOCATED IN THE NORTHEAST 1/4 OF SECTION 14, TOWNSHIP 7 NORTH, RANGE 69 WEST OF THE 6TH P.M., CITY OF FORT COLLINS, COUNTY OF LARIMER, STATE OF COLORADO �p a� oa 02 ti EST L1V Rf1 YTi[R IRD w, U1W�nCv1 I � O J ZO �U Oz H NJ J VO �U wF z0 O LL I NRCS SOILS MAP 1 1 1 1 1 1 1 C 1 H I 1 1 1 i 1 1 1 Hydrologic Soil Group—Larimer County Area, Colorado (SAE Redevelopment Project - 2549) N 0 5 10 20 Meters 30 Feet A0 25 50 100 150 USDA Natural Resources Web Soil Survey 2.0 7/28/2008 Conservation Service National Cooperative Soil Survey Pagel of 4 M M i ® ® M _ M ® M ® _ ® ® M M M i M Hydrologic Soil Group—Larimer County Area, Colorado (SAE Redevelopment Project - 2549) MAP LEGEND Area of Interest (AOI) ,�,� Local Roads O Area of Interest (AD]) Other Roads soils Soil Map Units Soil Ratings O A Q AID o B Q BID oD Q CID O D Not rated or not available Political Features Municipalities O Cities 0 Urban Areas Water Features [] Oceans Streams and Canals Transportation .I Rails Roads Interstate Highways N US Routes State Highways MAP INFORMATION Original soil survey map sheets were prepared at publication scale. Viewing scale and printing scale, however, may vary from the original. Please rely on the bar scale on each map sheet for proper map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: http://websoilsuwey.nres.usda.gov Coordinate System: UTM Zone 13N This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Larimer County Area, Colorado Survey Area Data: Version 6, Jan 15, 2008 Date(s) aerial images were photographed: 1999 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. USDA Natural Resources Web Soil Survey 2.0 7/28/2008 Conservation Service National Cooperative Soil Survey Page 2 of 4 Hydrologic Soil Group-Larimer County Area, Colorado t Hydrologic Soil Group 1 H 1 1 1 e 1 SAE Redevelopment Project - 2549 Hydrologic Soil Group— Summary by Map Unit— Larimer County Area, Colorado Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 35 Fort Collins loam, 1 to 3 percent slopes 8 0.8 100.0 % Totals for Area of Interest (AOI) I 0.8 I 100.0% Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long -duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and CID). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. ' Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink -swell potential, soils that have a high water table, soils that have a claypan or clay layer ' at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or CID), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. ' Rating Options Aggregation Method., Dominant Condition ' Component Percent Cutoff.' None Specified ' U.Natural Resources Web Soil Survey 2.0 7/28/2008 Conservation Service National Cooperative Soil Survey Page 3 of 4 LJ OLD TOWN MASTERPLAN DESIGN GUIDELINES 1 1 1 1 1 1 1 1 I 0 1 1 11 1 I I 1 1 U 1 1 1 1 R3. DEVELOPMENT CRITERIA R3.1 On -Site Detention Due to the mostly developed nature of the Old Town Basin, future development drainage criteria will likely not be a significant factor in the reduction of flood hazards within the basin. However, limiting the impact of future development on storm runoff will serve to minimize local flooding problems, and may be slightly beneficial with regard to reducing flood flows along major flow paths. rAoo ardingiV..iL:is recommended•that.all :new :.developmeat ._-GL4--,T-OW F33asinthat=will, rease,impervious stuttaee,arca:by 3, 00.-square feet -•or greater•be required to prorade nn ite,deten ion4n>order;to: mduee.-the-developed :coadition 1flOryear}reak rana#f from rthe additionaissimpcmous rsurface :to=r2-year >iaistorical: Aow;, vates':=Sroni0he:'same .;area: , , New rdeve4cplraent that,_inereases.the impervious area_by>less >than, 5 0,Owsquare feet will be exempt �,fm- m the,on-site detention &,equirement. R3.2 Water Quality Detention ,It s,.reseanmended-3hat all stew development. within the .Old-drown-aasin.beTequired to provide extended detention for water quahtyipurposes;_unless it is shown -that>runoff'froni the site sis conveyed., into either one..of the three ekisting°or the -one proposed regional -water quality cdetentien=ponds_ Three -existing water quality ponds are located at ;thedownstream:end of:the Howes Street, Oak Street sandl Locust Street=Outfallsa .An,additional ':.regional •waterquality cdetention:pond is.:proposed°to serve the -Magnolia Street Outf lil. ' R3.3 Adherence to City Drainage Criteria 1 All future development is referred to the City of Fort Collins Storm Drainage Design Criteria and Construction Standards for design and implementation of all storm water detention, 1 conveyance, and water quality facilities. In general, it is anticipated that future development and re -development in the Old Town Basin will be required to meet the City's drainage criteria and storm drainage design standards. 1 With regard to the components of the Selected Plan of Improvements, these components were generally designed in accordance with existing storm drainage criteria adopted by the City of Fort Collins. Detailed investigation of the with -project condition hydraulic modeling results could possibly reveal that street drainage criteria are not met at every location within the basin 1 COFC 14.6 selected plan,pFAPP RAOC R_ 16 ANdERsoN CONSUITINq tNgINEERS, INC. P http://mail.google.com/maiU?ui=1&attid=0.1&disp=inhne&view=aft&th=l lb56lb7ac8fdeee 7/24/2008 I FEMA MAPPING INFORMATION E 1 1 1 1 I I 1 1 M S M M ® ® i ® ® ® ® = = _ Mon Ia t is Prod ct SS�e LL0485x 00 ZONE X ITHIS PANEL IS LOCATED ST, RANGE 7 NORTH. THE FROM THE LL0516x un sn MAP SCALE 1" = 500' rnnet_ mrfaU FLOOD INSURANCE RATE MAP LARMR COUNTY, COLORADO AND INCORPORATED AREAS PANEL 979 OF 984 (SEE MAP INMX FOR F RM PANEL IAYOLM SAEylurIDY NLIMBER PANEL SSffi1X IwuNm,wmm aaotm ll,l o mmrrnunll.rnror on"x oom , Nalco b Ilv: lM MF M - a. E . WLLt b urd Mlw iNalV sate Pba: M GnmuM1/ N"nbt Nam !n"dpld b urE M Yaemtn applbetlen b M Mfec{ ,perrE MAP NUMBER y M 08089C09790 ° MAP REVISED flap la' JUNE 17, 2006 FederIFmerge-ey Management Agency :m-U,e This map does not reflect changes haw Men made subsequent to the date on the ,duct Information spout National Flood Insurance the FEMA Flood Map Store at v'xm.mse.Mma.gw I GENERAL INFORMATION L. 1 1 1 1 i 1 1 C 1 1 1 0 1 1 1 1 1 I I 1 1 I 1 r I Time Minutes Storm Event 2-year 10- ear_ 1 1 00-ear 5 2.85 4.87 9.95 10 2.21 3.78 7.72 15 1.87 3.19 6.52 20 1.61 2.74 5.60 25 1.43 2.44 4.98 30 1.3 2.21 4.52 35 1.17 2.00 4.08 40 1.07 1.83 3.74 45 0.99 1.69 3.46 50 0.92 1.58 3.23 55 0.87 1.48 3.03 60 0.82 1.40 2.86 Table ' Project Number: 2549 Designer: Herman H. Feissner, P.E. Project Name: Flats at the Oval Date: 6/4/2009 Existing Condition Percent Imperviousness The Oval Flats - EXISTING CONDITION % Impervious:11 55.8% Total Site Area, It: 36066.41 0.83 acres Total Pervious Area: 16777.29 ft' Adjusted Pervious Area: 8388.65 ft' Notes: 1. The balance of the existing site is assumed to be 100% impervious 2. Existing soils are compacted: therefore, infiltration rates are lower Developed Condition Percent Imperviousness The Oval Flats - PROPOSED CONDITION % Impervious:11 92.4% Total Site Area, ft': 36066.41 0.83 acres Pervious Area, ft' Area # Description: Lawns-NRCS Type'B' per 11DFCD Table RO-3: 0% Imp. Al-1 1 16.87 Al-2 641.22 Al-3 172.10 Al-4 420.76 A1-5 244.50 Al-6 44.24 Bl-1 206.09 Bl-2 350.22 B2-1 81.18 132-2 129.45 B2-3 46.96 B4-1 403.18 Total Pervious Area: 2756.77 ft' Notes: 1. The balance of the existing site is assumed to be 100% impervious 2. Proposed pervious areas are assumed to be 100% pervious Project Number: 2549 Designer: Herman H. Feissner, P.E. Project Name: Flats at the Oval Date: 6/4/2009 -1 I E%.CARACE � R I I, RIN:4B96.95 TOP 4'a PIPE TH D MANHOLE 15 NE ST/EAST:4993.001 FL (1.00'v1.25') CHANNEL TXRU LOT 10 10 MANHOE NCt11179OU1H:4992.25 BLOCK 106 0 CSU O I LOT 11 BLOCK 106 I LOT12 I BLOCK 105 LOT 13 BLOCK 106 CSU LEGEND O PROPOSED STORM ORMN MANHOLE ® PROPOSED STORM DRAN PIPE DIRECTION OF Poll SURFACE ROW DRANAGE BASIN ID 100 0.23 0.35 10— or RUNOF 0.7 Color CENT 1Do-yeo RUNOFF CDEFFICIENT BA9N AREA (ACRES) DESIGN POINT BASIN DELINEATION Si SILT PENCE SEE DETAIL D23. DTL SHT 14 IP GRAVEL INLET PROTECTION - AREA INLET SEE DETAIL D24, DR SAT 14 IP GRAVEL INLET PROTECTION - CURB NLET SEE SHEET on, DTL SHT 14 VEHICLE TRACKING CONTROL SEE DETAIL. DTL SHT t4 SUMNARYCF D OIPED RUNCIFF GIWNAGE AREA DESIGN POOL RUNCiF 1"W'ols 100ryrtr4 At Al 1.110 &JIS N A2 M17 JIM In 01 0.113 0.0 p1 B2 SW 0.10 B0 S] O.W 0.00 BO B• 0.04 0.10 "I RFl 1.51 ]ae u wim Nonnul CENTER OF caOMW 7-800-922-1987 or 8-1-1 Mail wt 2 J 0 J NOTES; u Q (2)-CDOT CONCRETE INLET, TYPE 13 -1/C THICK(mll STEEL ORIFICE PLATE -ORIFICE PLATE OPENING DIAMETER: 5.75' O O GONG INFALL CURB, SEE DTL SHT 10 J O 12' A2000 PVC STORM DRAIN (PRIVATE) W a OLu CRRESTELLWAY LEVATON: 4998.50 C L CREST MOTH: 8' r OS GONG OUTFACE CURB, SEE On. SHT 10 Z © EASTNG 12' CLAY STORM DRAIN < 02' WDE CURB CUT .Q N OB PROPOSED MANAGE EASEMENT 0 O9 15' RCP STORM MAN (PUBLIC) u. W 4' DIA. SHALLOW MANHOLE W/FLAT TOP LL J 11 APPROXIMATE LOCAL HIGH PONT THAT SPLITS RUNOFF Q BETNEEN THE OUST. ALLEY AND HEST LAUREL STREET O 12 PROPOSED ON-9TE DETENTION POND = STORAGE VOLUME: 0.073 ac-fl AT OUSEL: 4995A0 IJ PROPOSED SYSTEM FOR CCNNEClINO ROOF DRAINS TO r r THE ON -SITE STORM DRAIN SYSTEM (PRIVATE) Q MATERIALADS N-12, 512E RMIMS' to 12' FOR INVERTS, SEE DTL SHT 7 f g 14 EMSTNG STORM DRAIN INLET 15 EXISTING STORM ORAN MANHOLE R.• +<IceoM�m�lwair.n tfi 4' SIDEWALK CHASE SEE DTL SHT 11 1' CONCRETE PAN AT 1% WITH 4' CURBS FOR 17 ROUTING DOWNSPOUT DRAINAGE TO ALLEY. SEE GRADING PLAN FOR DETAIL City of Fort Collins, Colorado UTILITY PLAN APPROVAL AWROVID. Co Ill ps DreWT By HHF CHECKED BY: Checked By HIT wrwaNYbwr wy uw CHECKED In' DI MAY.30N swllln•rlNq DM ReNsion CHECKEDBV'. T,.IN.LmH.• R+r 15D Project# 29E9 CHECKED BY. 0 1Y NY 4i P.r.m Re••r au CHECKED BY'. E,mvnnlsl Pl••r PW BMIE-1'•fP LHECKID eY: SHEET 06 OF 14 y LaM•ta➢e Itetilutto°. 6npmr•rvlp. f ➢la mm 1 CO ]° ON M• 1121li dA' On W ]W C --� ) EK1 �� LEGEND ( A I ( Chi u%TY NOmcAIMM 6 . �► �� DIRECTIONLO POB111VE CUTER noO q % \I i F i 1 SA]FACE FLOW O 634ti]OO 87• Q' ' / / 1 R \ �/ 1 oo DRAINAGE BASIN ID m•• ° / 1 \g r ` ii ffee ~ �.23075 GOEFfiGENT�F i EXL I t I 100-ryeoo RUNOFF / I ®� \ 00 FFI.ENT J N R / 1 ' 034 D'N1 i BASN AREA (ACRES) 0 C I f EX _� ' rc ® OESGN PUNT 0 ° 0.33 .93 Ia 1' ! —T I ] '^? M M IIIIIIIII BASN DELINEATION N/! 0 � � ° � � I ♦, „r it i s i �� ¢ �I wuwar a IXI8lINO RIx+oFF DRAINAGE DESIGN RIMOFmbdi F AREA POINTIPOINT x-YN1].N 1O9y®r, dm IXt 9.t] 33