HomeMy WebLinkAboutDrainage Reports - 10/23/2015October 2015 1 Final Drainage Report 1 Metier Law 1 1st Tract of Fairway Estates Subdivision Fort Collins, Colorado ' Prepared for: Metier Law Firm, LLC 1 4828 South College Avenue Fort Collins, Colorado 80525 1 Project No. 0215015.00 City of Fort Collins Approv d Plans Approved by Date: iO/Zs��s 1 01)LLLL 1 LAMP RYNEARSON Leavinga Legacy of & ASSOCIATES g y ENGINEERS I SURVEYORS I PLUNERS 1 Enduring Improvements to; /'�4715InnovationDrive,Suite100 Our Communities Fort Collins, Colorado 80525 [P] 070.226.0342 Lamp Rynearson Purpose Statement . IF] 970.226.0879 w .LRA-Inc.com Copyright Lamp, Rynearson & Associates, Inc., 2013. All rights reserved. 1 FINAL DRAINAGE ANALYSIS ' METIER LAW Fort Collins, Colorado I. Introduction This drainage narrative is intended to serve as an addendum to the approved drainage report titled ' "Drainage Report, Congregation of the Living God Building, 4820 South College Avenue, Project No.: 206.23", prepared by Engineering Professionals Inc., dated August 27, 1987 (87 Report). The purpose of this drainage analysis was to address and improve upon components of the 87 Report due to the changed conditions that have occurred over time which are no longer fully supported by the 87 Report. The design goal was to provide a drainage system that addressed these changes and provide a safe and adequate conveyance given the challenging site constraints that have developed over the years. IL Location The subject property is located at 4820 South College Avenue (Site) in the Northwest Quarter of Section 1, Township 6 North, in Range 69 West of the Sixth Principal Meridian, in the City of Fort Collins, Larimer County, Colorado. The Site lies within the lit Tract of Fairway Estates Subdivision and is located approximately a quarter mile south of the intersection of Harmony Road and South College Avenue. The property is bounded on the north and south by commercial lots, to the west by Southeast Frontage Road and South College Avenue and to the east by a greenbelt public access/utility easement and residential lots. III. Property Description The Site comprises approximately 0.58 acres of the subdivision area and contains an existing building that most recently served as a family center and membership club. The property is in fairly rundown ' condition, which has spurred Metier Properties III, LLC (Owner) to propose improvements to the Site. The proposed Site improvements include a minor addition to the southwest portion of the existing building, interior and exterior improvements throughout and improvements to the overall property including to the existing pavement and drainage, ADA access, and landscaping. Refer to Appendix for proposed Site Plan. Generally, runoff from the west third of the property flows west and south to frontage road and the east two-thirds of the site flows east and south to the existing access and utility easement bordering the Site. A small portion of the property flows to the south adjacent property's east parking lot. Drainage patterns and basins would be generally unchanged from those defined in the 87 Report. All flows ultimately convey south approximately a half mile to Fossil Creek. Copyright Lamp, Rynearson & Associates, Inc., 2013. All rights reserved. October 2015 Metier Law — Drainage Analysis Page 1 Project No. 0215015.00 According to the NRCS website, the site consists mainly of clay and silt loams with a classification of ' Type B & C soils. Refer to Appendix A for soil classification information. ' IV. Existing Conditions As previously mentioned, the existing site drainage is not currently functioning as the 87 Report had intended for the following main reasons: ' The 87 Report assumed that an orifice plate would release the 2-year existing flow rate from the eastern portion of the Site into an existing irrigation ditch that traveled adjacent to the eastern property line. Currently, there is no structure in place and the irrigation ditch has since been filled in and relocated to the east side of the access and utility easement and piped underground for ' approximately 130 feet south of the property. As a result, stormwater currently ponds up against the easement and inundate the existing sheds and trash enclosure while excess surcharge weirs over to the south property. • The 87 Report assumed that the 100-year event eastern flows would be entirely contained on site with parking lot detention and all flow would release out of the eastern outfall structure. This is ' currently not the case given the adjacent south property and associated pavement grades limit the grading possibilities and potential storage volume on the Site. Insufficient storage on -site causes surcharge from even the most minor storm event to weir over to the south property. ' • There is now a garage located on the property to the south that experiences water intrusion from ' the excessive flows mentioned above that weir over from the Site to the south property. • Per the drainage report for the south property titled "Final Drainage and Erosion Control Study for Jensen Homes Office Building, Fort Collins, Colorado", prepared by RBD, Inc. Engineering Consultants, dated May 18, 1993 (93 Report), stormwater is also intended to be detained on the adjacent south property (also owned by Metier Properties III, LLC) via parking lot detention and ' was designed to be near its maximum storage capacity during the 100-year event. Excess flows from the subject Site should be limited, to the extent possible, to avoid flooding the south property's parking lot and the existing garage. . ' V. Drainage Criteria A. Regulations/Development Criteria As this analysis serves as an addendum to the approved report, the Rational Method criteria t established by the City of Fort Collins was used, as in the 87 Report. The historic release rate was taken from the 87 Report while the developed 100-year peak flow rate was generated using the most recent Fort Collins rainfall data. Copyright Lamp, Rynearson & Associates, Inc., 2013. All rights reserved. October 2015 Metier Law — Drainage Analysis Page 2 Project No. 0215015.00 Stormwater Quality Stormwater quality will be provided on -site during construction with the use of silt fencing, vehicle tracking devices, inlet protection devices and curb protection. Long-term stormwater ' quality will be improved on -site by retention time in a grass -lined drainage channels, a sand media bio-retention trench at the east end of the east parking lot and a proposed rain garden at the front of the building. B. Variance Request of Low Impact Development (LID) Requirements ' Due to the proposed quantity of removal and replacement of the existing asphalt pavements, the City of Fort Collins criteria requires that pervious pavements shall be used for 25% of the pavement area to be replaced. Because of the presents of bedrock and expansive soils, the ' geotechnical engineer has eliminated the recommendation of a full infiltration system thereby requiring an underdrain system. Due to site constraints, a gravity outfall for an underdrain system is not possible and was verified with City personnel on -site. Therefore, variance was ' requested that a proposed rain garden just to the west of the building and a sand medium bio- retention trench on the east side of the east parking lot be counted toward and in lieu of the pervious pavement requirement. Refer to Appendix for Stormwater Alternative Compliance/Variance Application. VI. Proposed Drainage Design A. General Concept The intent of the proposed re -design was to safely and adequately convey the 100-year design storm given the site constraints previously mentioned. 1. Proposed Site Drainage Existing and proposed basin maps were prepared that included east, west and south basins. South Basin: Approximately 920 square -feet of paved area currently flows to the south property's east parking lot detention area, as off -site flow, that was not accounted for in Basin 1 of the 93 Report. There is also approximately 1,520 square -feet of area that should not have been included in Basin 1 of the 93 Report as it flows to the west and frontage road. The net result is that there is approximately 600 square -feet of area that should not have been included in Basin 1 of the 93 Report and, therefore, is area that results in excess capacity within Basin 1 and the south detention area. Proposed conditions result in approximately 540 square -feet of additional net area, beyond that of existing conditions, contributing to the south property's parking lot detention area in Basin 1 of the 93 Report as off -site flow. This area is less than the 600 Copyright Lamp, Rynearson & Associates, Inc., 2013. All rights reserved. October 2015 Metier Law — Drainage Analysis Page 3 Project No. 0215015.00 square -foot area described above and results in approximately 60 square -feet of net area and resulting volume available within Basin 1 and the associated detention area to the south. Because of this; further evaluation of the South Basin was not performed. West Basin: For the western basin, an insignificant decrease in impervious area from existing to developed condition was observed which resulted in essentially no change to the 100-year peak flow rate. A slight decrease to the basin area resulted in a slight increase to the 2-year composite C value of 0.01 and no change to the 100-year composite C value (Refer to Appendix for west basin impervious and composite C value calculations). A rain garden is also proposed for the west side of the building but will not have a significant impact to imperviousness, flow patterns or basin area. The western drainage basin is proposed to flow historically and un-detained. Most of the changes are proposed for the east basin and are described below. East Basin: For the eastern basin, a net increase in impervious area (±700 sf) from existing to developed condition was observed with a reduction in roof area and an increase to sidewalk areas. This resulted in a slight increase to the 2-year composite C value of 0.03 and an increase to the 100-year composite C value of 0.02 (Refer to Appendix for east basin impervious and composite C value calculations). The following is a summary of the imperviousness, C-values, and flow rates observed for the existing and proposed conditions (Refer to Appendix for Drainage Basin Maps and associated calculations): Basin Existing C2 Existing C1oo Developed C2 Developed C100 El 0.34 0.55 0.37 0.57 Wl 0.34 0.55 0.35 0.55 Basin Existing Q2 Existing Q100 Developed Q2 Developed Q100 El 0.31 2.19 0.34 2.27 Wl 0.28 1.98 0.29 1.98 Existing Developed Basin Imp% Imp% El 56.1 61.0 Wl 56.6 56.5 See Appendix for existing and proposed Basin Maps and basin map of 93 Report. Copyright Lamp, Rynearson & Associates, Inc., 2013. All rights reserved. October 2015 Metier Law — Drainage Analysis Page 4 Project No. 0215015.00 East Detention: In order to obtain the maximum available storage in the east parking lot, the pavement is proposed to be re -graded to the extent possible while maintaining reasonable slopes. An orifice plate and structure is proposed to detain and convey flows to the existing pipe that carries small irrigation flows on the east side of the existing access and utility easement. Hydraflow Hydrographs Extension for AutoCAD Civil 3D 2014, Version 10.3 by Autodesk, Inc. was used to route the updated hydrology through the proposed stage -storage and set deliberate weir elevations to effectively control the flows that leave the storage area to the existing irrigation pipe while not exceeding the 2-year historic release rate (defined in the 87 Report). A calculated developed flow rate of 2.27 cfs was used for the 100-year peak in -flow rate within the model. The first weir, denoted as Weir A in the model, represents the stage at which flow begins to flow to the south property and in front of the garage at an elevation of approximately 5006.80. The volume provided in the on -site parking lot and bio-retention facility at this elevation is approximately 350 cubic feet. The model suggests that flow to the south would occur from minute 4.0 to minute 10, for 6 total minutes. During this time, an average flow rate of around 0.10 cfs would flow south and through the proposed concrete gutter pan in front of the garage. The resulting volume due to this flow was calculated to be approximately 36 cubic -feet. When figuring in the equivalent available storage as a result of the 60 square -feet of area described above and the extra 9 cubic - feet of storage provided beyond the volume required in the 93 report, the net additional volume added to Basin 1 and detention area of the 93 Report is 22 cubic -feet. Proposed flows to the south detention facility is anticipated to occur within the first 10 minutes of the event and, when reviewed against the available storage volume (2,124 cubic feet) versus time outlined in the 93 Report, this volume appears to be available. Run-off routed to the south property's east parking lot was designed to be detained and release at a rate of 0.09 cfs. (Refer to the Appendix for the south property detention details in the 93 Report excerpts). The second weir, denoted as Weir B, was set at 5006.94 at the proposed outfall structure itself and would function as an emergency spillway during larger events. The model suggest that no flow would exit over this weir during the 100-year event. Routing the flows through the model resulted in a required orifice size of 3.8 inches. The emergency spillway was modeled at 8 feet wide. The 100-year water surface elevation was determined to be 5006.88. Given the on -site and surrounding constraints, a required detention storage volume could not truly be determined as the maximum parking lot storage that can be achieved is Copyright Lamp, Rynearson & Associates, Inc., 2013. All rights reserved. October 2015 Metier Law — Drainage Analysis Page 5 Project No. 0215015.00 severely limited. A total hydraulic volume of 359 cubic -feet was routed through the proposed stage -storage and through the on -site outfall structure as well as to the south detention area. Approximately 324 cubic feet of the parking lot storage was used within the model. The modeling showed that there was no inundation of structures and that the release rate did not exceed the historical rate. Therefore, it was determined that the stormwater was effectively managed and the storage provided was acceptable (Refer to Appendix for Hydraflow detention calculations). The drain time for the detention basin was determined by the new State Stormwater Detention and Infiltration Design Data Sheet. Based on this sheet the time to drain 97% of the inflow volume of the 5-year storm is 1-hour and the time to drain 99% of the inflow volume for the 100-year storm is 2-hours. This meets the State drain time requirement. Refer to Appendix for the Stormwater Detention and Infiltration Design Data Sheet. 2. Proposed Rain Garden A rain garden is proposed for the west side of the existing building to provide filtering ' and groundwater recharge elements to the western drainage basin. Approximately 4,443 square feet of contributory area would flow to the garden and would include a portion of ' the roof through a roof leader (±955 sf) and up -gradient grassed areas (±3500 sf). The imperviousness of this sub -basin was calculated to be approximately 21%. The Urban Drainage rain garden spreadsheet was used to calculate the required bottom area and ' ponding volume for the garden at 24 square feet and 35 cubic feet, respectively. The actual bottom area and ponding volume provided are 361 square feet and 559 cubic feet, respectively. The pond is designed to weir to the southwest corner of the property, over ' the existing sidewalk, and to the drainage pan on the east side of the frontage road. Also, the landscape plans specify in detail the design section, media, and plantings to be used. Due to topographic site constraints, an underdrain was not used within this design as a ' gravity outlet cannot be achieved. The footprint of the raingarden was therefore oversized to achieve the drain time based on the Geotechnical Engineer supported ' infiltration rate of 1.41 micro m/sec. Refer to the Appendix for Rain Garden and contributory basin calculations). Drain time for the rain garden was determined by the new State Stormwater Detention and Infiltration Design Data Sheet. Based on this sheet the.time to drain 97% of the inflow volume of the 5-year storm is 30-hours and the time to drain 99% of the inflow volume for the 100-year storm is a little more than 116-hours. This meets the State drain time requirement. Refer to Appendix for the Stormwater Detention and Infiltration Design Data Sheet. Copyright Lamp, Rynearson & Associates, Inc., 2013. All rights reserved. October 2015 Metier Law — Drainage Analysis Page 6 Project No. 0215015.00 3. Proposed Sand Medium Bio-Retention ' A sand media, bio-retention trench is to be located at the east end of the east parking lot to capture a portion of the site's run-off and provide long term water quality measures through infiltration. Approximately 8,520 square feet of contributory area would flow to the garden and would include a portion of the roof through a roof leader (±955 sf), asphalt pavement (±1,910 sf), concrete walks (±685) and up -gradient grassed areas (±4,970 sf). The imperviousness of this sub -basin was calculated to be approximately 41%. Due to topographic site constraints, an underdrain was not used within this design as a gravity outlet cannot be achieved. The trench is designed to overflow on -site and just ' to the north of the proposed outfall structure so that all flow that does not infiltrate will be subject to detention and the required historic release rate. (See the Construction Drawings for design details and sand media specifications). ' VII. Conclusions The drainage design considerations contained herein is intended as an addendum to the 87 Report to better accommodate the current conditions and constraints that have occurred over time. All flow patterns and basins have generally remained unchanged from those specified in the 87 Report. ' An effort was made to increase the available on -site parking lot storage, limit the flow to the south property while not exceeding the 2-year historic release rate to the existing irrigation pipe. A variance was requested to allow a rain garden and sand media bio-retention trench in lieu of the pervious ' pavement requirement. We believe that the proposed drainage design will provide a substantial improvement, both on -site and for the properties to the south. Copyright Lamp, Rynearson & Associates, Inc., 2013. All rights reserved. October 2015 Metier Law — Drainage Analysis Page 7 Project No. 0215015.00 VIII. References 1. Engineering Professionals, Inc., August 27, 1997, Drainage Report, Congregation of the Living God Building, 4820 South College Avenue. 2. RBD, Inc., Engineering Consultants, May 18, 1993, Final Drainage and Erosion Control Study for Jensen Homes Office Building, Fort Collins, Colorado. 3. United States Department of Agriculture Natural Resources Conservation Service; Web Soil Survey; accessed July, 2015. 4. Urban Drainage & Flood Control District (UDFCD), 2001 (Revised 2008), Urban Storm Drainage Criteria Manual, Volume 3, Denver, Colorado. 5. City of Fort Collins, December 2011, Fort Collins Amendments to the Urban Drainage and Flood Control District Criteria Manual Volume 1, Chapter 5 - Runoff. Copyright Lamp, Rynearson & Associates, Inc., 2013. All rights reserved. Metier Law — Drainage Analysis Project No. 0215015.00 October 2015 Page 8 1 IX. Appendix 1. NRCS Soils Data 2. Proposed Site Plan 3. Drainage Basin Maps 4. Rational Method Calculations 5. Hydraflow Detention Modeling Calculations 6. Detention - Stormwater Detention and Infiltration Design Data Sheet 7. Low Impact Development Facilities Basin Map 8. Rain Garden Calculations 9. Rain Garden - Stormwater Detention and Infiltration Design Data Sheet 10. Bio-Retention Trench Weir Calculations 11. 87 Report 12. Drainage Plan from 93 Report Copyright Lamp, Rynearson & Associates, Inc., 2013. All rights reserved. October 2015 Metier Law — Drainage Analysis Page 9 Project No. 0215015.00 Appendix 4 31' 14' N 4 31'TN Custom Soil Resource Report Soil Map 3 tr tr 45:Fa:. 493500 493520 493540 493560 4a.7P� .. 3 f` Map Scale: 1:839 R pnnted on A pp4-dt (8.5" X 11'� sheet. Mete N rs 0 10 20 40 60 A 0 40 80 160 2400 Map piojemm: Web Merotor Cnrner mordlnates: WGS84 Edge bm: UIM Zom 13N WGS84 8 g 40°31'l4'N 3 Li d g� 2 4!' 11 5 CL En ) k J °' {\// /)) ` �/CD § r - ` $-5 ` 0M z \d§k �- )(E © m2 $ § o .- |»m ! �© 0« 2 * !2 �i2 f\)3 r|$ ;/|±) / \A ƒ 0=- ! �§ 0 7 k=; 2 -k©( ff ■ w - 2E\� �® - j {ƒ § ®kf !f| §\) \ \ \ k\/§ \k \ \ m\ \ \�{\\\ �\ a § & § ; k »| `D - ! /{{> 00) �- // k / )§r 2§f)\ i E E « «�■§« ( _ / : ` {7i] ƒ// q ! ƒf f/§ \ §) 0 ®: f / _ \ !-c M$EE = 2§ -= 0E \§ 2\ �• {)\ _ « & _ mod) /f /f 7 ; ( / ) Lu ƒ/ en ƒ{)k§ A' )o C3 (,a 16 f 0 k k \ E k 0 z \ > \ / § §i ) § \ j �« �m� § m w ® co u IL ( - ® r D \ § \ 2 ! ! r _\k)\\ \ * - ! f - § ! ! !!*a ) 7- !! ! &| En_ \) S■ v» e 0 k 4$■ 0>+ 0 \ ■ ' Custom Soil Resource Report Larimer County Area, Colorado 35—Fort Collins loam, 0 to 3 percent slopes ' Map Unit Setting National map unit symbol. 2tlnc Elevation: 4,020 to 6,730 feet ' Mean annual precipitation: 14 to 16 inches Mean annual air temperature: 46 to 48 degrees F Frost -free period. 143 to 154 days Farmland classification: Prime farmland if irrigated ' Map Unit Composition Fort collins and similar soils: 85 percent ' Estimates are based on observations, descriptions, and transects of the mapunit. Description of Fort Collins ' Setting Landform: Interfluves Down -slope shape: Linear Across -slope shape: Linear ' Parent material: Pleistocene or older alluvium derived from igneous, metamorphic and sedimentary rock and/or eolian deposits Typical profile Ap - 0 to 4 inches: loam Bt1- 4 to 9 inches: clay loam Bt2 - 9 to 16 inches: clay loam Bk1 - 16 to 29 inches: loam Bk2 - 29 to 80 inches: loam Properties and qualities Slope: 0 to 3 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.20 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: 12 percent Salinity, maximum in profile: Nonsaline (0.1 to 1.0 mmhos/cm) Sodium adsorption ratio, maximum in profile: 0.5 Available water storage in profile: High (about 9.1 inches) Interpretive groups Land capability classification (irrigated): 2e Land capability classification (nonirrigated): 4c Hydrologic Soil Group: C Ecological site: Loamy Plains (R067BY002CO) 12 ' Custom Soil Resource Report ' 36—Fort Collins loam, 3 to 5 percent slopes Map Unit Setting ' National map unit symbol: jpw9 Elevation: 4,800 to 5,500 feet Mean annual precipitation: 13 to 15 inches ' Mean annual air temperature: 48 to 50 degrees F Frost -free period. 135 to 150 days Farmland classification: Prime farmland if irrigated ' Map Unit Composition Fort collins and similar soils: 90 percent Estimates are based on observations, descriptions, and transects of the mapunit. ' Description of Fort Collins Setting Landform: Terraces, fans ' Landform position (three-dimensional): Base slope, riser Down -slope shape: Linear Across -slope shape: Linear ' Parent material: Alluvium Typical profile H1 - 0 to 9 inches: loam ' H2 - 9 to 20 inches: loam, clay loam H2 - 9 to 20 inches: loam, silt loam, fine sandy loam H3 - 20 to 60 inches: H3 - 20 to 60 inches: H3 - 20 to 60 inches: Properties and qualities Slope: 3 to 5 percent ' Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Low ' Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.60 to 2.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding. None i ' 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 25.5 inches) Interpretive groups Land capability classification (irrigated): 3e ' Land capability classification (nonirrigated): 3e Hydrologic Soil Group: B Ecological site: Loamy Plains (R067XY002CO) 13 LRW R NGB [mm R Noe RR1�R GS R�r Liu- scNE: T•. RD• RRi1R LEGEND __ _. ANdI'J91F PARKING PAVNG PRUP=Rtt lYY a.. 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Is Is' J B.es' r _ n aono L�.�R _ _ cc W 8 -- eac I w.ra I I I TRAw � J I g - SEELOSIIRE J I 3-z• scN w PVC SEE ARcw>TTECIIAYL PLANS O L - y EA fINC ONNT PIP S AT A - II 2 0" —� trot t((}}7 � _ _ --N w P r�NEnT) rwu,In Nc1 wn {,rI EK G N6iY 1� W P/JI pRSEE CEfAIL III J � 0 O - _ t. _ E s000m O F A N I• _ - �j�_ __ ---_ - DUSTING INNYGf I / BLAL➢FD / � 3 ema�� sR,TcE SEANCE PAWS LABES PARK, Lam MID SOLI CORI 6' CONCRETE PAN I J ➢PLOpI DY:101 GBH ➢� AK. EXWTNG BUILDING ME DETAL . ^ O I � I L.__/__ /_ OHEMmIIe-an Bo(eY O CONCRETE C CONCRETE �' W WT U PA NG 1 R A _ _ OM1 F NT ILIl6 - TWBmIR BYElR6 F.® RRL— CONTRUClim TO EPND FORA CONCRETE R DRNIPLE PAN SO THAT PRONSED fLpn LIIE ._ TrFwRFNNA-RasR/rsl�v. O AII(OR1TE5 RIM fXWAAG wan; AND OIRTER I MN_ fLON l. STOR RINkMR IMLV SI POSIN: IRSB.RB F PROMOIC IROII aBATH, CURB NO WARN. E: IMi.w O SuSCRADE WAL— St18fAACE OIL R TR 01b - R RIRR,1Fn = RRAL— MI NNR NLR ®I R1RFp F M . RA1Ll I I TR 0.Rf1 PIT. M F'B RI W' l9pBRlry F M IRRrP R'ROr, M IY'IL iKIIM1 ORD7L P M 10l 4RNa TR NIYRY RF ftl6Tf4 V M dWAlP6 MKWFE M .� M�f015 TA9(B CU ID8 RI Mf RY 4rrRP3 V Ip6 R 1[ r1P6 R M HR BRRm �� W11.FYi 1EI q TR MFR4F BMI6 F IO4 90w1 llll W I SEE 5'ACM iY DATE IN P REPORT REPAIR TI MD ai NICA GEMEM i0 Rf PWfg. W PER 1NE Q ADDITIONS. RE 2D SOUTH COJ IS g1NJEO 10/6/20 5 IN TriE REPoRI i TOR •GE02CHNIGL ENGINEERING REMFI. YFIrER UAW rIRY MOTTOS. 1e3O $WTM C01EGf AVENUE FORT CIXLrED. CIXgUC9. TERRALM PROUCCT Na m15SOW'. PREPARED R TEARI'ON. OITTD NLY t. 2015. ALL ��R PROPGSEO PETNODS Df REPAIR ANO(a1 RER.KfMENT TO BE APPROIED R ONNER PRIOR TO CONSTRICTION. EEY�ii 6 M 12 ♦N♦MENEM 1 ♦ f .. .f • I QW • • • I I Iay Owe .me �urx oouccc we aeon awn 0..1. mow a� N m � m O O ,p (D N N N N O O f` n m m 7 m m O m E LO p O G O U u OJ oEQ O c' o� Q 0 �' O a ° 3 J O U ,n Z J O U C) m Cn O Q LLI — LLI Q z J J Cl-C O G l o Li liJ p z Q o z p In z o Q m U O W Z Q Z Q x 0 w p JOB N�i��TAifB 02150,5.00 BOOK rAOE !�TIEO/5/2015 sr�r E3 _____________� (b 10 D �e m > - 1'. r0' PWWYD M'IDW OtYNIZ H191 DFSOI rroxr DRVNL( a�w rWE __ DRYNCC BlW .Ru 1 z-rtw wr�rr wrrrnorr '_ _ lao-rcw mxnrr cncr*nun urvalnuEn nw rwon � I � I I K 0 1me r.r�a mow u0e wwwow 2 u. N m a n \7 W 0 0 N N N N O O n n mm m m E cO 00 m - c o Q O U N 3 0 r 3 Q a LLL 3 J Q U vi z J O U Z � U3 O I= _ LU > W Q z - w r w J Cl- O ` V Q 10 wo W N U) a z a O o z z Q a U m O W V Q 0- Z O C c 0- JOB M�®FTAq 0215 15.00 BOOK ►AOF CAT 0/6/i015 EEX� 3 I 1 '' (11) Section 4.0 is amended to read as follows: 4.0 Intensity -Duration -Frequency Curves for Rational Method: The one -hour rainfall Intensity -Duration -Frequency tables for use the Rational Method of runoff analysis are provided in Table RA-7 and in Table RA-8. Table RA-7 -- City of Fort Collins Rainfall Intensity -Duration -Frequency Table for Use with the Rational Method (5 minutes to 30 minutes) Duration (min) 5 2-Year Intensity (in/hr) 2.85 10-Year Intensity (in/hr) 4.87 100-Year Intensity (in/hr) 9.95 6 2.67 4.56 9.31 7 2.52 4.31 8.8 8 2.4 4.1 8.38 9 2.3 3.93 8.03 10 2.21 3.78 7.72 11 2.13 3.63 7.42 12 2.05 3.5 7.16 13 1.98 3.39 6.92 14 1.92 3.29 6.71 15 1.87 3.19 6.52 16 1.81 3.08 6.3 17 1.75 2.99 6.1 18 1.7 2.9 5.92 19 1.65 2.82 5.75 20 1.61 2.74 5.6 21 1.56 2.67 5.46 22 1.53 2.61 5.32 23 1.49 2.55 5.2 24 1.46 2.49 5.09 25 1.43 2.44 4.98 26 1.4 2.39 4.87 27 1.37 2.34 4.79 28 1.34 2.29 4.69 29 1.32 2.25 4.6 30 1.3 2.21 4.52 N m 5 O O n U m m m =m Na O1 N O O O O E i 0 a 0 U m n m 00 N o N Y O N N m J a c J m O w 0 v Q V y 0 O 0 a N O N a ° mm a c o p 0 0 0 v o N O o � m m N H N m Q O N O N N O �Q a o0a Q v o0 n�o Q m m a N A O H (2 N m Z Z ? o nw< n mQ m m x y N C 0 c O — m mvw3w o m a y � c n X W m E c Z d O F a `o K C � W W ❑ J Z a � m L J d d P N O O O U N � ai o o N N o N p > U LL M M N O m o m J O N O 7 m O O J L N N N m O O N O N N O U ry e h O O N m Cl O J Z O m a O N N C ❑ O IA Vl (O C U 6 N o 0 O 0 b n n d U ^ U z .00 0 c r�inm K U 0 0 0 n o 0 0 o N Z Z 2 n m m m N Z d N N H ❑ � w ❑ �o v w m co o a` o 0 o c N W 'c_ Da E c I 7, ZN ❑ k E Zy?R Ow z LA iy QQ_ J W V 12 0 wag Q 3 JdW J F U m 1'l Yi pE 0~ C r M V O 0 n m c i 0 v o m 11ff11 r m n r II � c m m m F E'�viNo rn IU co 1- �000 00 m ¢ r o 0 0 o00 j C O o o N C O O O O O O O o Q r O r W J COO O J Q p yC r COO O O O O i > O O O 000 ar � Z J COO O 0 mceoo N J r e- l7 O J C m O O N 2 m w o r E000 N r �CmC10 �r C m m 0 O LL ❑ram moo 000 �_ oom 0 2 N� t N m J Q Z Z J Y m 0 F C ?a° 0 E 9 :z 1 O W z V1r� Q a J Zud >O � N Qa� .J M d ❑ 6 FV —m mmm Ul Q f�l m m Q O m t�1 O O O O N E v > e .00 f0a L7 o00 d o0 � ap D N 006 �n Y N m J a J m 0 0 m N O a „3m m m 0 0 n � �M w `o v E 0 n n a > ? m n n m N t7 a 00 o o 00 ¢ m n N Q d d � Q 0 0 0 0 F Q m Q VI ocdr m N N q O F z z O m N Q Q m m m ❑ Q 0 W N a u 0 c a N aiW3`9 m mm d d U m E c Z < a `o C � W O 2 m` N m m L m F O O N ° J 1� O m m m O a N N N � to N O O O Q U P � F = N N n n o coo N N N pU n y `n in ui o U'e NNo O O J F yNj N N f'l m O N N O N N O U N — N No P I70 J.L ON O O N a vnN N 0 o io c N N m m U o a o anrn m ° 'D U o 0 0 D C U N n 000 m E 2 00 N N O a Z Z Z O mQ n m m m D ��5 v mm Qw w 0pm N v N O ym Q N O O O 'c m a d Z y QN W N< Col. Wu0 OG w ��dll CL. Ny� u�1 JW6 J C F 1m 1'1 N F p Ed r oio 0 II m S i 0 N O b J H Ils EN y N 0 c o 0 0 r E o 0 0 e j)`000 � r 000 Jm z000 c E o 0 0 0 0 0 N ` d. r O O O O O O ~ J C O O O r J O Eo00 r E 0 P ` O O O O O O r M r r J Z O O O z c E m o 0 0 0 0 J i m w � =rim r N N O 0 �p a ma �.E E 000 N> N N 0 O r J t Q m 0 Z F C W N w 3 0 LL O rN p Otml1 OI ZZO o00 Or K �ooN Z N N N N 0- J 5 r Z J Y m 0 'c 3a �„w3m m O E 9 J`, Client �'n / ! P C t U Job p v2 / s-�/ . 00 Project AAc-4-:e_r LA.�J M r Arreftd. Celcutetions for Made by Dot, 10 1 I Checked by Dnte Sheet _of LAMP RYNEARSON & ASSOCIATES r Cc h.-Gki +-10Y�. iC0.�iVr\.�. L; �.4.� Gv L4—+.o k—S n \A/ . j7tu K P (0 —j Ci = C- A ; A 0•9.9 0, G �0.0 77,-m` OA C--e.fr✓\0r / e— 7 g. 3'M.I. =} VSa- Sihie%. aye �enS;�3r P.5.5 ,'n/Ar 13a.s'h w 1 - a y✓' ck - (0, 3 ti) ( a.g.r)( 0, �1-s j IScis-n Ljtl - io0=`9.,e o . OILY <fr J` Client + P-o }f C S T� r L L L Job # 0 a 1 S 0 IS-. ©J Project /L C+v'L✓- „fl AA;nP,- Ame-rd Calculations for Made by C-r Date 10/ Checked by Date Sheet LAMP RYNEARSON & ASSOCIATES DQ.vP.l.ok 4-i0Q0-4;9y.c�L f- C-,jLc.-fitntis • l�i4s�.. W� f7ecK` �[o Q� c: A Q A 0C Cr-C,5 CZ' = 0' 3�-' C-loo O. SS -r•r'1 e. op [o1�h. if-r�. �-:oh l TG = a' 3 min =� Vs¢ .S:- 2yr i`-,4•cps1'4y l00 y 1:'�'.Akr jS 0.S•'n in11 — l00 (0.ss) (ti.s s)(0,a.4) ,; ;1, '7$'C-fr F ILL) LAMP RYNEARSON & ASSOCIATES Client ^nPie.T �'o�J2r�"IP..t 1al-� LC. Job# Os1..�SO�S,Od Project Ah &+B✓ LAw A& 0A o r l)., m Calculations for Made by Date / I I )� Checked by Date Sheet _ of �a S E �ewK F lo�a Q Z c- c- 1z = D.3y G I oo O . SS of .0 T,- = 3 , S,. Iy� usa. -.QAs•�r, � 1 — �y r y.- s 0,21 cfs 0.'3a.19 cFs PLL LAMP RYNEARSON & ASSOCIATES Client I PMA.c.+i:o 10 l,L G Job # 0 7- i S a ).f 00 Project __ . %�i�-:-� P.V La W AA 4, 0 9- Ar"B1". Calculation for Made by L' S _ Date / O ! Checked by Date Sheet _ of yevQ- Lop eC. Co`4 ;t7ert /Zcf-i0 l Gatcam`Lo,4-ion S A a _ 0.3 c z = 0. 3 1;?- ` C T rn� O f C o 1 c�aw�'rc ion. / % - :02 . (c :.r, • t u S2 S ,M 1 y. . lOJyr` tirtiP.tiSi�.j = i."rlS�nA., 13a5i ►-1 y Q s I. 2-S_ (0, 5-') (9, gs-) (o.3.z� Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD® Civil 3D®2014 by Autodesk, Inc. 00.3 Hyd. No. 1 Developed Condition Hydrograph type = Rational Peak discharge Storm frequency = 100 yrs Time to peak Time interval = 1 min Hyd. volume Drainage area = 0.320 ac Runoff coeff. Intensity = 7.337 in/hr Tc by User OF Curve = 100-Yr OF from 87 Report.IDFAsc/Rec limb fact Q (cfs) 3.00 wire] 1.00 0.00 --k 0 East Parking Lot Detention Developed Condition Hyd. No. 1 -- 100 Year 1 2 3 4 5 Hyd No. 1 Hyd Volume Wednesday, 09 / 30 / 2015 = 2.270 cfs = 3 min = 409 cult = 0.967 = 3.00 min = 1/1 Vol (%) milli] 67 33 N 0 6 Time (min) Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD® Civil 3D®2014 by Autodesk, Inc. 00.3 Tuesday, 10 / 20 / 2015 Hyd. No. 2 Developed Condition Hydrograph type = Reservoir Peak discharge = 0.529 cfs Storm frequency = 100 yrs Time to peak = 5 min Time interval = 1 min Hyd. volume = 359 cuft Inflow hyd. No. = 1 - Developed Condition Max. Elevation = 5006.88 ft Reservoir name = East Parking Lot with Bioret. Max. Storage = 324 cuft Storage Indication method used Q (cfs) 3.00 2.00 1.00 0.00 -A 0 East Parking Lot Detention Developed Condition Hyd. No. 2 — 100 Year 2 4 6 8 10 12 14 16 18 20 22 24 26 Hyd No. 2 Hyd No. 1 1 1 1 Total storage used = 324 cuft Hyd Volume Vol (%) 100 67 33 0 28 Time (min) Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2014 by Autodesk, Inc. v10.3 Hyd. No. 2 ' Developed Condition Hydrograph type = Reservoir Peak discharge ' Storm frequency = 100 yrs Time to peak Time interval = 1 min Hyd. volume Inflow hyd. No. = 1 - Developed Condition Max. Elevation Reservoir name = East Parking Lot with Bioret. Max. Storage Storage Indication method used. 1 ' Elev (ft) ' cnne 1n 1 0 2 4 6 8 10 14. East Parking Lot with Bioret. ' Hyd Volume East Parking Lot Detention Developed Condition Hyd. No. 2 — 100 Year Tuesday, 10 / 20 / 2015 = 0.529 cfs = 5 min = 359 cuft = 5006.88 ft = 324 cult 12 14 16 18 20 22 24 26 Vol (%) 100 67 33 0 28 Time (min) Pond Report 2 Hydraflow Hydrographs Extension for AutoCAD(@ Civil 3D0 2014 by Autodesk, Inc. v10.3 Pond No. 14 - East Parking Lot with Bioret. Pond Data Contours -User-defined contour areas. Average end area method used for volume calculation. Begining Elevation = 5005.50 ft Stage / Storage Table Stage (ft) Elevation (ft) Contour area (sqft) Incr. Storage (cuft) Total storage (cuft) 0.00 5005.50 59 0 0 0.10 5005.60 59 6 6 0.20 5005.70 59 6 12 0.30 5005.80 59 6 18 0.40 5005.90 59 6 24 0.50 5006.00 59 6 30 0.60 5006.10 59 6 36 0.70 5006.20 65 6 42 0.80 5006.30 97 8 50 0.90 5006.40 165 13 63 1.00 5006.50 267 22 85 1.10 5006.60 399 33 118 1.20 5006.70 596 50 168 1.30 5006.80 944 77 245 1.40 5006.90 1,245 109 354 1.50 5007.00 1,427 134 488 Tuesday, 10 / 20 / 2015 Culvert A is orifice plate flow. Weir A is over flow to south property where it is to be detained and released at 0.09 cfs. Weir B is over flow into top of outfall structure. Culvert / Orifice Structures Weir Structures [A] [B]Rsr] TOO [A] [B] [C] [D] Rise (in) = 3.80 0.000 Crest Len (ft) = 5.00 8.00 0.00 0.00 Span (in) = 3.80 0.000 Crest El. (ft) = 5006.80 5006.94 0.00 0.00 No. Barrels = 0 Weir CoeH. = 2.60 2.60 3.33 3.33 Invert El. (ft) = 5006.11 0.00 0.00 0.00 Weir Type = Broad Broad - - Length (ft) = 10.50 0.00 0.00 0.00 Multi -Stage = No No No No Slope (%) = 1.00 0.00 0.00 n/a N-Value = .010 .013 .013 n/a Orifice Coeff. = 0.60 0.60 0.60 0.60 Exfil.(in/hr) = 0.000 (by Wet area) Multi -Stage = n/a No No No TW Elev. (ft) = 5006.30 Note. Culvert/Onfice outtlows are analyzed under Inlet (ic) and outlet (oc) control, Weir nsers checked for onfice conditions (ic) and submergence (s). Stage / Storage / Discharge Table Stage Storage Elevation Clv A Clv B Clv C PrfRsr Wr A © Wr C Wr D Exfl User Total ft cuft ft CTS cfs cis cfs cfs cfs cfs cfs cfs cfs cfs 0.00 0 5005.50 0.00 - - 0.00 0.00 -- - 0.01 1 5005.51 0.00 - - 0.00 0.00 - - 0.02 1 5005.52 0.00 - -- - 0.00 0.00 - - 0.03 2 5005.53 0.00 - - - 0.00 0.00 - - 0.04 2 5005.54 0.00 - - -- 0.00 0.00 - -- 0.05 3 5005.55 0.00 - -- - 0.00 0.00 0.06 4 5005.56 0.00 - - - 0.00 0.00 - - 0.07 4 5005.57 0.00 - - - 0.00 0.00 - - 0.08 5 5005.58 0.00 - - - 0.00 0.00 - - 0.09 5 5005.59 0.00 - -- --- 0.00 0.00 - --- 0.10 6 5005.60 0.00 - - - 0.00 0.00 - - 0.11 7 5005.61 0.00 - - - 0.00 0.00 - - 0.12 7 5005.62 0.00 - - - 0.00 0.00 - - 0.13 8 5005.63 0.00 - - - 0.00 0.00 - - 0.14 8 5005.54 0.00 - - - 0.00 0.00 - - 0.15 9 5005.65 0.00 - - -- 0.00 0.00 - - 0.16 9 5005.66 0.00 - - - 0.00 0.00 - - 0.17 10 5005.67 0.00 - - --- 0.00 0.00 -- - 0.18 11 5005.68 0.00 - -- - 0.00 0.00 - - 0.19 11 5005.69 0.00 - - - 0.00 0.00 - - 0.20 12 5005.70 0.00 - - 0.00 0.00 - - 0.21 12 5005.71 0.00 - - - 0.00 0.00 - - 0.22 13 5005.72 0.00 - - - 0.00 0.00 - - 0.23 14 5005.73 0.00 - - - 0.00 0.00 - - 0.24 14 5005.74 0.00 - - - 0.00 0.00 - - 0.25 15 5005.75 0.00 - - - 0.00 0.00 - - 0.26 15 5005.76 0.00 - - - 0.00 0.00 - 0.000 - - 0.000 0.000 - - 0.000 - - 0.000 0.000 - - 0.000 0.000 - - 0.000 0.000 0.000 0.000 - - 0.000 - - 0.000 0.000 - 0.000 0.000 - - 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Continues on next page 3 East Parking Lot with Bioret. ' Stage / Storage / Discharge Table Stage Storage Elevation Clv A Clv B Clv C PrfRsr Wr A Wr B Wr C Wr D Exfil User Total ft cuft ft cfs cis cfs cfs cis cfs cfs cfs cfs cfs cfs ' 0.27 16 5005.77 0.00 0.00 0.00 0.000 0.28 17 5005.78 0.00 _ _ _ 0.00 0.00 ___ ___ _ = 0.000 0.29 17 5005.79 0.00 -- -- - 0.00 0.00 - - - - 0.000 0.30 18 5005.80 MO - -- - 0.00 0.00 - - -- - 0.000 0.3 18 5005.81 0.00 0.00 0.00 0.000 ' 0.32 19 5005.82 0.00 - _ - 0.00 0.00 - _ - = 0.000 0.33 20 5005.83 0.00 0.00 0.00 0.000 0.34 20 5005.84 0.00 - - - 0.00 0.00 - - - - 0.000 0.35 21 5005.85 0.00 - - - 0.00 0.00 - - - - 0.000 0.36 21 5005.86 0.00 - - 0.00 0.00 - 0.000 ' 0.37 22 5005.87 0.00 _ 0.00 0.00 _ _ _ 0.000 0.38 23 5005.88 0.00 - - - 0.00 0.00 --- - - - 0.000 0.39 23 5005.89 0.00 - - - 0.00 0.00 - - - - 0.000 0.4 24 5005.9 0.00 0.00 0.00 0.000 0.41 24 5005.91 0.00 - _ - 0.00 0.00 - _ _ - 0.000 0.42 25 5005.92 0.00 0.00 0.00 0.000 0.43 25 5005.93 0.00 - - - 0.00 0.00 - - - - 0.000 0.44 26 5005.94 0.00 - - - 0.00 0.00 - - - - 0.000 0.46 27 5005.96 0.00 0.00 0.00 0.000 ' 0.46 27 5005.96 0.00 - _ - 0.00 0.00 - _ _ - 0.000 0.47 28 5005.97 0.00 0.00 0.00 - 0.000 0.48 28 5005.98 0.00 - - - 0.00 0.00 - - - - 0.000 0.49 29 5006.00 0.00 0.00 0.00 0.000 0.50 30 5006.00 0.00 - _ - 0.00 0.00 - _ _ - 0.000 ' 0.51 30 5006.01 0.00 0.00 0.00 0.000 0.52 31 5006.02 0.00 - - - 0.00 0.00 - - - - 0.000 0.53 31 5006.03 0.00 - - - 0.00 0.00 - - - - 0.000 0.55 32 5006.05 0.00 0.00 0.00 0.000 ' 0.55 33 5006.05 0.00 - _ - 0.00 0.00 - _ _ - 0.000 0.56 33 6006.06 0.00 0.00 0.00 0.000 0.57 34 5006.07 0.00 - - - 0.00 0.00 - - - - 0.000 0.58 34 5006.08 0.00 - - - 0.00 0.00 - - - - 0.000 0.59 35 5006.09 0.00 - 0.00 0.00 - 0.000 ' 0.60 36 5006.10 0.00 _ _ 0.00 0.00 _ _ _ 0.000 0.61 36 5006.11 0.00 - - - 0.00 0.00 - - - - 0.000 0.62 37 5006.12 0.00 - - - 0.00 0.00 - - - - 0.000 0.63 37 5006.1 0.00 0.00 0.00 0.000 ' 0.64 38 5006.14 0.00 - _ - 0.00 0.00 = _ _ = 0.000 0.65 39 5006.15 0.00 0.00 0.00 0.000 0.66 39 5006.16 0.00 - - - 0.00 0.00 -- - - - 0.000 0.67 40 5006.17 0.00 - - - 0.00 0.00 - - - - 0.000 0.68 41 5006.1 0.00 0.00 0.00 0.000 0.69 41 5006.19 0.00 - _ - 0.00 0.00 = _ _ = 0.000 0.70 42 5006.20 0.00 0.00 0.00 0.000 0.71 43 5006.21 0.00 - - - 0.00 0.00 - - - - 0.000 0.72 43 5006.2 0.00 0.00 0.00 0.000 0.73 44 5006.23 0.00 - _ - 0.00 0.00 - _ _ = 0.000 ' 0.74 45 5006.24 0.00 0.00 0.00 0.000 0.75 46 5006.25 0.00 - - - 0.00 0.00 - - - - 0.000 0.76 47 5006.26 0.00 - - - 0.00 0.00 -- - --- - 0.000 0.7 47 5006.2 0.00 0.00 0.00 0.000 0.78 48 5006.28 0.00 - _ - 0.00 0.00 = _ _ = 0.000 0.79 49 5006.29 0.00 0.00 0.00 0.000 0.80 50 5006.30 0.00 - - - 0.00 0.00 - - -- - 0.000 0.81 51 5006.31 0.03 oc - - - 0.00 0.00 - -- - - 0.028 0.82 53 5006.32 0.04 oc - 0.00 0.00 0.042 ' 0.83 54 5006.33 0.05 oc _ _ 0.00 0.00 = _ _ = 0.054 0.84 55 500&34 0.07 oc - - - 0.00 0.00 - - - - 0.065 0.85 56 5006.35 0.08 oc - - - 0.00 0.00 - - - - 0.076 0.87 58 5006.37 0.10 oc 0.00 0.00 0.087 ' 0.87 59 5006.37 0.10 oc - _ 0.00 0.00 - _ _ - 0.098 0.88 60 5006.38 0.11 oc 0.00 0.00 0.108 0.89 62 5006.39 0.12 oc - - - 0.00 0.00 - - - - 0.118 0.90 63 5006.40 0.13 oc - - - 0.00 0.00 - - - - 0.129 0.91 65 5006.41 0.13 oc 0.00 0.00 0.134 ' 0.92 67 5006.42 0.13 oc - _ - .00 0 0.00 = _ _ - 0.135 0.93 70 5006.43 0.13 oc 0.00 0.00 0.134 0.94 72 5006.44 0.14 oc - - - 0.00 0.00 - - - - 0.140 0.95 74 5006.45 0.15 oc - - - 0.00 0.00 - - - - 0.146 0.96 76 5006.46 0.15 is - - 0.00 0.00 0.151 0.97 78 5006.47 0.16 is _ 0.00 O.DO - _ _ _ 0.156 0.98 80 5006.48 0.16 is - - - 0.00 0.00 - - - - 0.160 1 Continues on next page... 4 East Parking Lot with Bioret. ' Stage / Storage / Discharge Table Stage Storage Elevation Civ A Clv B Clv C PrfRsr Wr A Wr B Wr C Wr D EMI User Total It cuft ft Cfs cfs Cfs Cfs Cfs Cfs cts cfs Cfs Cfs Cfs ' 0.99 83 5006.49 0.16 is 0.00 0.00 - 0.164 1.00 85 5006.50 0.17 is _ _ _ 0.00 0.00 _ _ _ 0.170 1.01 88 5006.51 0.17 is -- - - 0.00 0.00 - - - - 0.174 1.02 91 5006.52 0.18 is - - - 0.00 0.00 - - - - 0.178 1.03 95 5006.5 0.1is 0.00 0.00 0.182 ' 1.04 98 5006.54 0.19 is = _ - 0.00 0.00 - _ _ = 0.185 1.05 101 5006.55 0.19 is 0.00 0.00 0.189 1.06 1 D5 5006.56 0.19 is - - - 0.00 0.00 - - - - 0.193 1.07 108 5006.57 0.20 is - - - 0.00 0.00 - - - - 0.196 1.08 111 5006.58 0.20 is 0.00 0.00 - - 0.200 ' 1.09 115 5006.59 0.20 is _ - _ 0.00 0.00 _ _ 0.2D4 1.10 118 5006.60 0.21 is - - - 0.00 0.00 - - - - 0.20E 1.11 123 5006.61 0.21 is - - - 0.00 0.00 - - - - 0.211 1.13 133 5006.63 0.21 is 0.00 0.00 0.214 ' 1.13 133 5006.63 0.22 is - _ - 0.00 0.00 - _ _ - 0.218 1.14 138 5006.64 0.22 is 0.00 0.00 0.221 1.15 143 5006.65 0.22 is - - - 0.00 0.00 - - - - 0.224 1.16 148 5006.66 0.23 is - - - 0.00 0.00 - - - - 0.227 1.18 153 5006.68 0.23 is 0.00 0.00 0.233 ' 1.18 158 5006.68 0.23 is = _ - 0.00 0.00 - _ _ - 0.233 1.19 163 5006.69 0.24 is 0.00 0.00 - - - - 0.236 1.20 168 5006.70 0.24 is - 0.00 0.00 - - - - 0240 1.21 183 5006.72 0.24 is 0.00 0.00 0.243 ' 1.22 183 5006.72 0.25 is = _ - 0.00 0.00 - _ _ = 0.246 113 191 5006.73 0.25 is 0.00 0.00 0.249 1.24 199 5006.74 0.25 is - - - 0.00 0.00 - - - - 0.251 1.25 206 5006.75 0.25 is - - - 0.00 0.00 - - - - 0.254 1.27 222 5006.77 0.26ic 0.00 0.00 0-257 ' 1.27 zzz soos.n 0.26 is - _ - 0.00 0.00 - _ _ - o.zso 1.28 229 5006.78 0.26 is 0.00 0.00 0.262 1.29 237 5006.79 0.26 is - - - 0.00 0.00 --- --- - - 0.265 1.30 245 5006.80 0.27 is - - -- 0.00 0.00 - - - - 0.268 1.31 256 5006.81 0.27ic - 0.01 0.00 - 0.283 ' 1.32 267 5006.82 0.27ic _ _ 0.04 0.00 _ V = 0.309 1.33 278 5006.83 0.28 is - - - 0.07 0.00 - - - - 0.341 1.34 288 5006.94 0.28ic - - - 0.10 0.00 - - - - 0.379 1.3 5006.8 0.28 is - 0.14 0.00 0.421 1.36 310 5006.86 0.28 is - � 0.18 0.00 - 0.468 1.37 321 0.23 0.00 0.518 1.38 332 500688 .7N-- 0.28 0.00 - 0.572 1.39 343 5006.89 0.2 - - 0.34 0.00 - 0.629 1.4 36 5006.9 0. 0.41 0.00 0.705 1.41 368 5006.91 0.3 _ - 0.47 0.00 - 0.770 1.42 381 5006.92 0.30.54 0.00 0.836 1.43 394 5006.93 0.3 - - 0.61 0.00 - 0.906 1.44 4 5006.9 0.3 0. 0.0 .7 1.45 421 5006.95 0.30.75 _ - 0.02 _1.070 1.46 434 5006.96 0.30.82 0.05 1.182 1.47 448 5006.97 0.3 - 0.90 0.10 - 1.308 1.48 461 5006.98 0.3- 0.98 0.15 - 1.445 1.49 474 5006.99 0.3 1.06 0.22 - 1.592 1.50 488 5007.00 0.3- = 1.16 0.31 1.788 End Culvert A is orifice plate flow. Weir A is over flow to south property where it is to be detained and released at 0.09 cfs. Weir B is over flow into top of outfall structure. Max. flowrate at 100-year water surface elevation Stormwater Detention and Infiltration Design Data Sheet Metier Law Detention Facility 001 Stormwater Facility Name: 4828 South College Avenue, Fort Collins, CO; East Parking Lot Facility Location & Jurisdiction: User (Input) Watershed Characteristics Watershed Slope = 0.040 Watershed Length -to -Width Ratio = 1.50 Watershed Area = 0.32 Watershed Imperviousness= 61.0% Percentage Hydrologic Soil Group A = Percentage Hydrologic Soil Group B = 100.0% Percentage Hydrologic Soil Groups CID = Location for 1-hr Rainfall Depths (use dropdown): User Input V User Input: Detention Basin Characteristics WQCV Design Drain Time = 40.00 hours I After completing and printing this worksheet to a pdf, go to: httos•//maoerture diaitaldatasemices com/evh/?viewer-- dif create a new stormwater facility, and attach the pdf of this worksheet to that record. Design Storm Return Period = Two -Hour Rainfall Depth = Calculated Runoff Volume = OPTIONAL Override Runoff Volume = Inflow Hydrograph Volume = Time to Drain 97% of Inflow Volume = Time to Drain 99%of Inflow Volume = Maximum Ponding Depth = Maximum Ponded Area = Maximum Volume Stored = User Defined Stage [ft] User Defined Area [ft-21 User Defined Stage [ft] User Defined Discharge [cfsl 0.00 0 0.00 0.000 0.08 6 0.08 0.000 0.18 38 0.18 0.005 0.28 106 0.28 0.121 0.38 1 208 0.38 1 0.161 0.48 349 0.48 0.197 0.58 552 0.58 0.227 0.68 907 0.68 0.254 0.78 1,215 0.78 0.368 0.84 1,400 0.84 0.380 0.90 1,450 0.90 6.600 WQCV 2 Year 5 Year LO Year 25 Year 50 Year 100 Year 0.53 0.98 1.36 1.71 2.31 2A1 3.67 0.006 0.015 0.023 0.032 0.048 0.063 0.084 0.006 0.014 0.023 0.031 0.048 0.062 0.083 1 1 1 1 1 1 1 2 1 1 1 1 2 1 2 0.33 0.63 0.78 0.84 0.85 0.86 0.87 0.004 0.017 0.028 0.032 0.032 0.032 0.033 0.000 0.003 0.006 0.008 0.008 0,009 0.009 n rcre-ft rcre-ft rcre-ft tours tours t Icres lore-ft SDI_Design_Data_FC_Rainfall_Detention Basin(003).xlsm, Design Data 1O/1/2015, 12:10 PM I Stormwater Detention and Infiltration Design Data Sheet - 100YRIN I I --100YR OUT � rr 15 `u Z 3 0 1 ' o.s ' o 0.1 1 c TIME [hr) 0.9 0.8 0.7 0.6 G i 0.5 n 0.4 ' 0.3 ' 0.2 0.1 ' 0 0.1 1 DRAIN TIME [hr] 10 100 SDI_Design_Data_FC_Rainfall_Detention Basin]003).xlsm, Design Data 10/1/2015, 12:10 PM yQ£ 9aFDEN,� iN MG m 9519 RVN CNiOEN BISIN NFA W] I' . I I I — wn— - - mEncx ■ I — _ ■ . � RiDPD9ED 0.NN GNmO1 / / • ' I ■ I �«■ i■ ��■■■■■■■■ME■■■■■■■■■■■a��� ■�■■■i■■■■■ ��•;■ I � I I � m I I .9ze 9 CMU" AYE E%6 9YL➢Illf EF�GG COMDVR '.000SED C.LNIN 910RE,E Ni PtN B 'N . ■ ■ ■ ■ . R N f MN 8 IN . ■ ■ ■ ■ . M.IP D IL. APQM C-J NEL.IED FLO M'NGw !- BORElE1RCIN TRENCH e11Y1Yw [BLIN Ell' B N N IYPERrMUS: ILR C2-0z. ctm . D.W Dz-D.13 a. DIDO D.97 0. RN1fiWOD1 SB1tlYYf (B�4N ■a 9w�L t �cER.+Dus 21Z Cz - D.Iz C1D0 - D.H W . Oo . DIDD � DO d nQ FV = m m f°n C 0 o c N O v n c m a w p 0 w m 9 N _J w N c w v D C J w W `o N 1O m O � >o w a m 06 o Km m a w w m p � a O O r a � a N w O r O m h m C Y H C O C w v O 4) O w w C w 6 U w 0 a O n `c U � o o c w c m y > N oow 6 Li F U m =m ya a o a 3 O O eF j d O! O O. E N m o 0 d 9 N o m O Tn m N e m J n J a c A N 53� m w 0 m o� j O O a L^ bbd o N � a mm o a U � � a O H O a A N A N O H O � C d a `m U c c o n � d _ `u m m u Q ❑ r d s a e d U c am w 0 m c m m a m o `m m Q m }m � 3 Design Procedure Form: Rain Garden (RG) 1 of 2 Designer: Charles Sonnier, PE Company: Lamp Rynearson 8 Associates Date: August 28, 2015 Project: Metier Law Location: 4820 South College Ave., Fort Collins, CO 80525 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, I, I, = 21.0 % (100% if all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = I,/100) i = 0.210 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.10 watershed inches (WOCV=0.8-(0.91-0-1.19' t2 ,0,78'0 D) Contributing Watershed Area (including rain garden area) Area = 4.443 sq ft E) Water Ouality Capture Volume (WQCV) Design Volume Vwocv = 35 cu it Vol = (WQCV / 12) ' Area F) For Watersheds Outside of the Denver Region, Depth of de = in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region, Vwocv .,TER = cu it Water Oualiy Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VwpCV USER = Cu ft (Only it a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth (12-inch maximum) Dwocv = 12 In B) Rain Garden Side Slopes (Z = 4 min., hertz. dist per unit vertical) Z = 4.00 ft / ft (Use "0" if ram garden has vertical walls) C) Mimimum Flat Surface Area A.„ = 24 sq ft D) Actual Flat Surface Area Aqi„= = 361 sq ft E) Area at Design Depth (Top Surface Area) AT. = 756 sq ft F) Rain Garden Total Volume VT= 559 cu ft (Vr ((Arm - Ae w) / 2) ' Depth) Choose One 3. Growing Media 018" Rain Garden Growing f4H1ia QOther (Explain)_ 4. Underdrain System Choose One A) Are underdrains provided? 0YE5 ®NO B) Underdrain system orifice diameter for 12 hour drain time i) Distance From Lowest Elevation of the Storage y= Ni ft Volume to the Center of the Onfice it) Volume to Drain in 12 Hours Vol,,= WA cu ft in) Onfice Diameter, 318" Minimum Do = WA in ' Copy of UD-BMP_v3.03.x1sm, RG 8/28/2015, 5:01 PM Design Procedure Form: Rain Garden (RG) Sheet 2 or 2 Designer: Charles Sonnier, PE Company: Lamp Flynearson & Associates Date: August 28, 2015 Project: Metier Law Location: 4820 South College Ave., Fort Collins, CO 80525 S. Impermeable Geomembrane Liner and Geotextile Separator Fabric Choose One OYES A) Is an impermeable liner provided due to proximity #NO of structures or groundwater contamination? 6. Inlet / Outlet Control Choose One 05heet Flow- No Energy Dissipation Required A) Inlet Control Flow- Energy Dissipation Provided 7 Vegetation r*Oor,:entrated I OSeed (Plan for frequent wed Control) ®Plantings OSand Grown or Other High Infiltration Sod 8. Irrigation Choose One *YES A) WIII the rain garden be irrigated? ONO Notes: Copy of UD-BMP_v3. 03.xlsm, RG 8127/2015, 10:56 AM Stormwater Detention and Infiltration Design Data Sheet Metier Law Rain Garden 001 Stormwater Facility Name: Facility Location &Jurisdiction: 4820 South College Avenue, Fort Collins, CO; West Side of Building User (Input) Watershed Characteristics Watershed Slope = 0.060 ft/ft Watershed Length -to -Width Ratio = 2.00 L:W Watershed Area = 0.10 acres Watershed Imperviousness = 21.0% percent Percentage Hydrologic Soil Group A = percent Percentage Hydrologic Soil Group B = 100.0% percent Percentage Hydrologic Soil Groups C/D = percent Location for 1-hr Rainfall Depths (use dropdown): LW I'pu, V User Input: Detention Basin Characteristics WQCV Design Drain Time = 12.00 hours After completing and printing this worksheet to a pdf, go to: httos://maaertum.dieitaidatas mices.com/"h/7viewer--cswdif create a new stormwater facility, and attach the pdf of this worksheet to that record. Routed Hydrograph Results Design Storm Return Period = Two -Hour Rainfall Depth = Calculated Runoff Volume = OPTIONAL Override Runoff Volume = Inflow Hydrograph Volume = Time to Drain 97% of Inflow Volume = Time to Drain 99% of Inflow Volume - Maximum Pending Depth = Maximum Ponded Area = Maximum Volume Stored = 1 ' SDI_Design_Data_FC_Rainfall_RainGarden(003).xlsm, Design Data User Defined Stage [ft] User Defined Area [W2] User Defined Stage (ft) User Defined Discharge [cfs] 0.00 361 0.00 0,00132 0.10 396 0.10 0.00132 0.20 432 0.20 0.00132 0.30 469 0.30 0.00132 0.40 507 0.40 1 0.00132 0.50 546 0.50 0.00132 0.60 586 0.60 0.00132 0.70 627 0.70 0.00132 0.80 669 0.80 0.00132 0.90 712 0.90 0.00132 1.00 756 1.00 0,00132 1.50 800 1.50 6.60000 WQCV 2 Year 5 Year 10 Year 25 Year 50 Year 100 Year 0.53 0.98 1.36 1.71 2.31 2.91 3.67 0.001 0.001 0.003 0.005 0.010 0.014 0.020 NN/A 0.001 0.003 0.005 0.010 0.013 0.019 pN/A 11 30 50 100 115 113 MN/A 12 30 51 102 117 116 r1N/A 0.13 0.32 0.51 0.90 1.01 1.03 #N/A 0.009 0.011 0.013 0.016 0.017 0.017 aN/A 0.001 0.003 0.005 0.010 0.013 0.013 n acre-ft icre-ft cre-ft tours tours t cres cre-ft 10/1/2015, 12:17 PM Stormwater Detention and Infiltration Design Data Sheet ' 0.6 ' 0.5 oa 0.3 0 02 ' o.l ' o 1 —100VR —50YR 1 0.8 x a 0 ' p 0.6 z 6 ' 04 7) ' 0 o.l TIME [hr] 1 10 100 DRAIN TIME [hr] SDI_Design_Data_FC_Rainfall_RainGarden(003].xlsm, Design Data 10/1/2015, 12:17 PM q � ■ a 0 a � @ � E k 0 a ■ w ƒ $kc ,{CL�E 0 f 2 » a f 7 �i A « � !■» � §!C § « ow $ .2 tS = \ I®§ f & i �;2 tIL �IL § I$ B E � I cli ee /f L$ /e qe , 0 6 ci COCD \ Iq \) {. \ [ '_£ \ \ § \ § ) C� ) 7 3 $ \ } \ ; § j sK§�] sE # a k } \ ) (D 0 � Weir Report ' Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Typical Curb Cut Bio-Retention Trench Rectangular Weir Crest = Broad t Bottom Length (ft) = 0.50 Total Depth (ft) = 0.50 ' Calculations Weir Coeff. Cw = 2.60 Compute by: Known Q ' Known Q (cfs) = 0.21 1 Depth (ft) 0.50 ' 0.00 -0.50 Highlighted Depth (ft) Q (Cfs) Area (sqft) Velocity (ft/s) Top Width (ft) Assume each curb cut captures 25% and 75% is bypass. This results in needing 4 total curb cuts to capture 0.85 cfs. Typical Curb Cut Bio-Retention Trench Thursday, Aug 27 2015 = 0.30 = 0.210 = 0.15 = 1.42 = 0.50 Depth (ft) 1.00 0.50 MIX -0.50 0 .1 .2 .3 .4 .5 .6 .7 Weir W.S. Length (ft) Weir Report ' Hydraflow Express Extension for Autodesk® AutoCAD® Civil 31D® by Autodesk, Inc. ' South End of Bio-Retention Trench Rectangular Weir Crest = Broad Bottom Length (ft) = 1.50 Total Depth (ft) = 0.50 ' Calculations Weir Coeff. Cw = 2.60 Compute by: Known Q ' Known Q (cfs) = 0.85 Depth (ft) 1.00 0.50 ' 0.00 ' -0.50 t Highlighted Depth (ft) Q (cfs) Area (sgft) Velocity (ft/s) Top Width (ft) South End of Bio-Retention Trench 0 .5 1 1.5 2 Weir W.S. Thursday, Aug 27 2015 = 0.36 = 0.850 = 0.54 = 1.57 = 1.50 Depth (ft) 1.00 0.50 Sri -0.50 2.5 Length (ft) ha�ust 27, 1987 City of Fort Collins Storm Drainage Utility P.O. Box 580 Fort Collins, CO 80522 ATTN: Mr. Glen Schlueter RE: Drainage Report Congregation of the Living God Building 4820 South College Avenue Project No.: 206.23 GENERAL The project is a remodel of an existing building at 4820 South College, converting the facility from a commercial building to one more appropriate for religious pursuits. Aside from the removal of an existing deck on the northeast corner of the building, the remodel is internal. The onsite parking available will be expanded considerably due to the change in use. This report addresses the drainage improvements needed to comply with City Criteria. The site is located on the east frontage road of College Avenue approximately a quarter mile south of the intersection with Harmony Road, in the northwest quarter of Section 1, T6N, R69W. The property is 0.574 acres in extent, bordered on the north by a similar commercial building, on the south by an empty lot, and by residential property to the east. The westerly portion of the site drains to the frontage road; the easterly portion drains to a swale running southerly to Fossil Creek. The western portion of the site consists of lawn and paved parking, and will receive only minor modification. The eastern portion of the property, as well as a 5 foot access easement on the south boundary, is covered with scrub grass which will be replaced with paved parking and landscaping. Slopes are 4 to 15%. HYDROLOGY The property is zoned BL which indicates a minor design frequency of 10 years, however as the site involves no conveyances to be sized the minor design storm evaluated was the 2 year event. The Rational method was utilized; rainfall intensities were taken from the Criteria curves. The western basin is 0.274 acres in extent including some offsite lawn to the north. Proposed improvements to the western basin include widening the onsite drive by 5 feet to the south and the addition of a landscaped island on existing pavement. Existing composite C was taken to be 0.575 and the developed composite C is 0.600 based on the proposed site plan. Existing peak flows are 0.43 CFS ENGINEERING PROFESSIONALS INC. 2000 Vermont Dr, Fort Collins, CO 80525 (303) 226-3852 P'c7o t�-a t11 SouthTejon, Suite 300, Coior000 Springs, Colorado 80903 (303) 634-5006 I tand 1.38 CFS for the 2 and 100 year events. Developed flows are 0.44 CFS and 1.44 CFS respectively. These flows historically ' drain to the eastern double gutter in the frontage road and thence southerly to the draw behind the Fred Schmid building and into Fossil Creek. Due to the nature and grades of the existing ' onsite improvements an onsite detention facility is impractical. Since the proposed improvements do not appreciably increase the historic flows, no detention is proposed for the western basin, and an attempt was made to provide additional detention volume ' for the eastern basin to compensate. The eastern basin encompasses 0.403 acres including some ' offsite land to the north. Existing composite C was taken to be 0.312 and the developed composite C is 0.668 based upon the proposed site plan. The 2 year existing flow is 0.29 CFS, and the ' 100 year existing flow is 1.10 CFS. Developed peak flows are 0.77 CFS and 2.36 CFS. Detention is in the parking lot as shown on the grading plan. The grading plan was developed with the intent of maximizing the detention volume available without overly ' affecting the function of the parking lot. The available volume for detention is 2185 CU FT at a maximum pool depth of 12 inches. The inflow curve was plotted and the release rate determined to be 0.27 CFS, slightly less than the existing 2 year flow of 0.29 ' CFS. while this does not provide for any appreciable excess detention, it does appear to be the maximum the site will allow. i IMPROVEMENTS The eastern portion of the site will be paved for parking. The grading plan depicts the lowpoint in the southeast corner of the proposed parking. The parking detention as shown on the plan contains a total volume of 2185 CU FT. Discharge is through an steel orifice plate with a diameter of 3-7/16 inches feeding a concrete chute accessing the irrigation lateral. The design discharge rate is 0.27 CFS, appreciably the same as the 2 year existing flow of 0.29 CFS. Excess flow will overtop the plate, if necessary. This lateral ditch lies in the natural thalweg and currently receives runoff from the site and surrounding property. Construction of the proposed parking lot will not change the historic runoff patterns or volumes. The irrigation lateral is owned by the west Fairway Estates water Association and lies in a dedicated bridle path and utility easement as shown on the plat. Negotiations have commenced concerning acceptance of the proposed improvements by the Water Association and a signoff block has been added to the grading and drainage plan. No grading or drainage improvements are proposed for the western basin since it is impractical to regrade the existing parking lot and lawn to provide detention based on the historic conditions prior to the initial development of this property. An attempt was made during the design process to provide additional detention volume in the eastern basin to compensate; however, the rear parking lot cannot accommodate any additional detention without creating overly flat slopes in the parking lot and ponding depths in excess of 12 inches. This problem could have been addressed when the site was initially developed, but was not a requirement at the time it was platted under County jurisdiction. Therefore a variance is requested concerning detention for the western basin. Calculations are attached; please refer to the grading and drainage plan for particulars. ENGINEERING PROFESSIONALS, INC. Robert W. Schil� P.E. Enc. `�'yulnsCy''�♦. P�,. to", •••O�♦i •s'� ��10 :�V� i � ♦ O � • t• i •. ♦/� . t� a V ; �ii �s • G l ". l : �� i G •• II 2o(o.f3-400 I &S 1 15/20167 , I / 000 �88 NA�-c C�\CCS %2 G�Iu2C�l IZL�t000- @ 4z3ZD 5. CauECt (-CFT lS too' XZS2:� s 0.S74 aclzr=S I MINoE oFFt.,r( c(>j-,7F-iF3u-,wf! Z $e�S1NS IDES-T ri CAST. L1 MI�IOIZ 51oRM L�K we-57 r-As1 r� DQL1NS WGS 1 TO j bL4 LZ C-U7 tZ N Z87 RZ-)NJ<\C-E r4oAi), 1Ok-NCE 5OU7%-I TO 1=oSSlC. 4',20 C . DNLl( IMP2aN/ H&, i t>-n.4"1tIL--D IS sMaLt_.,�1�SCAt=ED �r�FFIL ICU. Exls-r tNi& coKoi 1 i c*-Is viZ DIMb 51or1S - 15-t 2FAc C AKEA C kooF, P0.4 i 0,95 GrASS �4'/� 559zo 0.15 1(4Z4 ° ' = o. 7,74 ac . f 45' TZ = 1,67 0.1- 0.S75 ii IDS) - 3.41 3 = 79 MW 1 Z�= Z.1 v Gloo= Lai( I I - (LZSXO�?S��(145)Z�3.4 3= 5.� M1til�� 700=1 �Pz= D, 43 cFS Qloo - ( I.ZS 0,214) = I- 33 6F5 PQoPotE� 66NO17I DNIS Su2FACt: 4\Q CA c kor-, PVM-j LOnl612(: I� "P331- 105 ° (ozr 0 0.95 �nl:�f� tStAN� IOSJ, 0.15 tjc-w PvM 's 97' - 4SG0 0.95 Grass, <4'��, ,591 - 4Js = sto-7o 0.15 C = D, (Poo I 97q-12 20(0. Z3 - qoo aws I Oizol57' Y,�, RMI = 145' s = 3.4 °/ f. S7( I.I- D. f45) ° /3.4'3 z 7..5 ✓rli✓1 5/.�� $ I2= Z% in%rr f f - (f. ZS x O 0Yl49) `z- 3.4.r s = 5 3 �✓� I ° ,�(hr- t9z = (D.zoX z?X0. z74) = 0.44- c-Fs Q,00' 0.z&0-(,Y?XD.z74)= 1.44 op EAST BASIN EVA!NS C457JE)ZLY TO -SWALC SOC.lT�IrTcL� "r0 j�SSIL G1ZEt1G.� ExIST�N6 CO�.tGIi�O�.iS: SuizFACt Bu>L9!NG iZooF Pave-N L-MT ON-17E 6- A.SS - SCEuF-) -i°/ OFF5re C--,ass - SC 2L! ) =- 4 v CroMfosl-TE C = 0.319 iKrec-a7l�>j C,o-Ti:---)-lal.. RuN�I„JC� tAtA C Zl�}S D, D.SS Il�ao° D,ZD Z-540 rJ of I S 1-1 559 D ' D. 403 ec IO� : &SEF,,J3T r oMP NOT INCWI)L-7,' pwtZS TO Eo-- L PI-T p4m,1= ISZ' L d.= 5)=,,5-94-o = 5,5, 5 = 3.iD'o '1'cZ = f.87(1.1-0.31zXf5Z)�� 3•� 11.9 v�!n sy� IZ IZ_ Z..5 inly- (•57(I.I- 0 ZS Y.31ZVI3?-)(a� = ID.?��,✓s �-f II 1�o= 7 in� L9.z (D.3IiX7-.3Xo.403)= OZ9 CFS Q��= CI.ZsXo.3►zX�XD.4o3�4 1,10 oFs 9Qopos�ro CpNOI-f I�>.tS a ls�AI_F/n, �rtA C 6"IL01n16n r-�F PVM I 6r�asS Z�85 ° 0.95 358p ° O, z0 CLmpmrTE G= Zo(o, Z - 400 I Zlf) I 8%zo(87 1z= 2.26W r TG,G17 = I. SI (I. I - (1. ZS o,��Si)C «4 )'Z f z.9 3 = 4.3 a2= (D.�IoSXz.8sx0.4n3)= D--17 GF5 DO S'UMNAZIZG q1C F�D�iS EAS'rA Z�r �lS i )ooyr OlsT Zqr EW I00-4K D--V >+ e5t 0,43 1,38 0,44 1,44- r lasT O,Z9 I.10 0.�� 2,5(� CALOLULA L INFLOW Wri'tll: P02 L�4Si F34S',.1 9cr70,J71,04 MIALITt3 ! In/hr SECONDS Fk 3 5 -7 goo ?o-) ID i Coco 1413 l5 (0 9cxO I S ll 10 ZIOo I Sl0 Z 3 Z Z- 30 4•Z ISOO 2-s44 !oo L 40, 31 SO 90 IS5 5400 33(�Oz. IZo ).45 '7Zoo 35I-t> 1.2 9noo 36�?4- lzx� 1.05 105C)C:> 3 3 l Co Z DCo z 3 - 400 �w5 SI`ao!sl roll �1x ILT111Dp� voutmeSs ��40 n»� ass 3000 J J v N Zoo p N W J g G I o,c5o 0 �o LSO 9b Mwt.fTc � NF1t7,�l,FJ-1ST �—ftlJ'flCh! I Zo I `-3'> ass Zoe. Z3- 400 I ��z�/8-1S �a �Guc.A 1Cc.uM� �iJal 4��1.4g1E AS f62 6%x)lx �p� z (02 ' p 9''' zS 3 O�oo V�� A= 76.2 95� v= 9(,e 19' G_7 `� 9� 96-° z/' G' �o R: S9.9 9576 ,V=.4/0.o A= 53 ' qe�� V= 23¢.9 9,�? V= 2z v= 553 95 57 yszz /71 95?z V=O 95Z7 ?7' iz'o ?5z7 A=9./ Z7 //' 9&0 9s s2 9-9.2 Zip 96 �� D' a Ot9,o 0f13 Ofj 012 Ot 97 0132 O t 9Z pt ¢2 07,59 Of75 2oG Z2�-400 a/-n1a-I k�S ?ALO UL1 ,C (ctli S- Zaic. - - S17C cAt i Ac core o�. E Z l 8 S F1-5 or: 4 S }:-2 GiZdG ► �� Fl d,�l . -1'115 15 MDS (;ETeN (Ioo ,AT CAN 13� Z YES tt3 Llit-L A SQL 2ttieASC of 29ZO FI"3 to o • Z9Z0 Ffi� 7 J. G-7 GFS < 029 C.FS 2Jv UlS � 108p0 SCGS .o PA1zy-loc. L4D-, IIJ C—,CST �ASIh.� F�G����JLS �ir���{L►.� DETeN' k,a i v�U1ME �2 L1 IVC1�� ltir. - Z �r NiST. C-a C AS RAS+fl Ft,v S A l.;bYc 131 1. s�Zc ID G-S Ft::,e Q= 0.27 cfs . Ll &C P(A t. �a J2yo 12 -Lr d asy.�ME C- D•�I - Suq�r �i�Ct� 5 �7lAiL IF IS 19 1 I.S .ZJ ,Ass-) -c �= 2 4-S (5=o-0, D,L! = I,S-d.09 1 I of (,4,4 (h-nos) I.6=�.i3Q=JDS }�_ 0•al� L= D,z2 r= OD �.la' A= 9,Wl D,3'o 0,1-� 0,0&4n h= .$57 ,Q- ©Z!% = D L1 c15 r No Text 0 GRADING LILD DRAINAGE NOTES 1. NO GRADING OR DRAINAGE IMPROVEMENTS ARE PROPOSED FOR THE WESTERN BASIN DRAINING TOWARDS THE U.S. 287 FRONTAGE ROAD. EXISTING FLOW PATTERNS AND VOLUMES REMAIN APPRECIABLY UNCHANGED, 2. HYDROLOGIC DATA ARE AS FOLLOWS: EVENT ACRES L: ft St Tc, min 1, in/hr C Q,cfs - ____________________________________________________ WEST 2 EXIST 0.274 145 3.4 7.9 2.7 0.575 0.43 100 EXIST 0.274 145 3.4 5.7 7.0 0.719 1.38 WEST 2 DEV 0.274 145 3.4 7.5 2.7 0.600 0.44 100 DEV 0.274 145 3.4 5.3 7.0 0.750 1.44 EAST 2 EXIST 0.403 152 3.6 11.9 2.3 0.312 0.29 100 EXIST 0.403 152 3.6 10.7 7.0 0.390 1.10 EAST 2 DEV 0.403 254 2.9 7.1 2.85 0.668 0.77 100 DEV 0.403 154 2.9 4.3 7.0 0.835 2.36 3. PARKING LOT DETENTION IS PROVIDED FOR THE EASTERN BASIN FOR BASICALLY THE 100 YEAR DEVELOPED - 2 YEAR HISTORIC DIFFERENCE. RELEASE RATE IS 0.27 CPS, VOLUME 1S 2185 CU FTI MAXIMUM POOL DEPTH IS 12 INCHES. 4. ALL CURB IS 6• VERTICAL, EXCEPT AT DETENTION POND WHERE MAXIMUM GDR. HEIGHT IS 12" 1 "J �A.l �MVJ.A+6l S Ihl � IL Ild ica; a,r o. J.-s=sue OVLC.-!1"1 g!.Ei NS,4401y, ftA,. I' i a� � r � I J 141E341_ i2• MIo(. ti I IF2E P1ATE I�s�l� Dw1ITEe:34��' I j!&e r 4N'£ 95QP �4P 9400 _ EYr I l'u, %Q.DIB•f% SECTION A -A p20F1 LE 7lA2Ou&-4 DIS6-A24.E CNUTE W.T S. 021FICE PLATE IS V2" 51FE1..'67 b /L'ANGNC2 BOLTS IN VE¢7.4URB FACE TO AMCUOe PLATE. 'fO CUUTE. � to °I• oII•b 4'la 0 95�° 4• o�e s a.-e e�e•. C"U-qc cgD,s6 ;EC1104 NZs. {maws IN: -, �, ■ FINAL DRAINAGE AND EROSION CONTROL STUDY FOR JENSEN HOMES OFFICE BUILDING FORT COLLINS, COLORADO May 18, 1993 Prepared for: Jensen Homes P.O. Box 1007 Fort Collins. Colorado 80522 Prepared by: RBD, Inc. Engineering Consultants 209 South Meldrum Fort Collins, Colorado 80521 (303) 482-6368 RBD Job No. 014-043 I 1 1 t t F i_ Sub -basin 4 is proposed to flow undetained from the project site. The peak 100-year flow from this sub -basin is subtracted from the project site's 2-year peak historical flow at Fairway Lane. The remaining flow was used as the basis for the total maximum release rate from on -site detention facilities. Specific Details The project site is divided into four drainage sub -basins. The sub -basins are indicated on the Drainage and Erosion Control Plan in the Appendix. A detention pond will be utiiized to detain on -site runoff from Sub -basin 1. the maximum allowable release rate from Sub -basin 1 will be limited to 0.09 cubic feet per second (cfs). The discharge from the detention pond will enter the south adjacent property's east parking lot from the southeast corner of the project site's east parking lot (refer to Drainage and Erosion Control Plan in Appendix). The runoff will then follow the historical drainage pattern. The runoff from Sub -basin 2 is proposed to flow into a detention pond located in the southwest corner of the project site. The maximum release rate allowed from this pond will be 0.04 cfs and will discharge into South College Frontage Road. ;Ifter discharging from the detention pond, the flow will continue down the Frontage Road to Fairway Lane. Sub -basin 3 is proposed to drain between Jensen Homes' office building and retaining wall (see Drainage and Erosion Control Plans). The runoff is then proposed to be removed from the site by utilizing an underdrain to facilitate percolation into the surrounding soil. This drain will be designed by others. Sub -basin 4 is proposed to drain undetained into the existing irrigation ditch, to the immediate east of the project site, and the south adjoining property. The irrigation ditch flows in a southerly direction and discharges into a pond located approximately 850 feet to the south_ Flow entering the adjacent property will assume the historical drainage pattern. 3 '------�- -----__-------------- - --- ______-____ DETENTION POND SIZING BY FAA METHOD DEVELOPED BY JAMES C.Y. GUO, PHD, P.E. DEPARTMENT OF CIVIL ENGINEERING '----�---- UNIVERSITY AT DENVER --------`------------ EXECUTED ON 03-24-1993 AT TIME 14:08:27 CLIENT: DAN JENSEN ' PROJECT TITLE: JENSEN HOMES PROPOSED OFFICE BUILDING - POND 1 PROJECT NO.: 014-043 FILE: tck062\jensen\pondl.out **** DRAINAGE BASIN DESCRIPTION ' BASIN ID NUMBER = 1.00 BASIN AREA (acre)= 0.26 RUNOFF COEF = 0. 96 DESIGN RAINFALL STATISTICS DESIGN RETURN PERIOD (YEARS) = 100.00 ' INTENSITY(IN/HR)-DURATION(MIN) TABLE IS GIVEN DURATION 5 10 20 30 40 50 60 80 100 120 150 180 INTENSITY 9.0 7.3 5.2 4.2 3.5 3.0 2.6 2.1 1.7 1.5 1.2 1.0 POND OUTFLOW CHARACTERISTICS: MAXIMUM ALLOWABLE RELEASE RATE _ .09 CFS ' OUTFLOW ADJUSTMENT FACTOR = 1 AVERAGE RELEASE RATE _ .09 CFS AVERAGE RELEASE RATE = MAXIMUM RELEASE RATE * ADJUSTMENT FACTOR. V2.z ***** COMPUTATION OF POND SIZE RAINFALL RAINFALL INFLOW OUTFLOW REQUIRED DURATION INTENSITY VOLUME VOLUME STORAGE ' ---MINUTE INCH/HR ACRE -FT ACRE -FT ACRE -FT 0.00 0.00 0.00 0.00 0.00 9.00 0.02 0.00 0.01 '5.00 ' 10.00 7.30 0.03 0.00 0.02 15.00 6.25 0.03 0.00 0.03 20.00 5.20 0.04 0.00 0.03 ' 25.00 4.70 0.04 0.00 0.04 30.00 4.20 0.04 0.00 0.04 35.00 3.85 0.05 0.00 0.04 40.00 3.50 0.05 0.00 0.04 45.00 3.25 0.05 0.01 0.05 50.00 3.00 0.05 0.01 0.05 55.00 2.80 0.05 0.01 0.05 60.00 2.60 0.05 0.01 0.05 65.00 2.47 0.06 0.01 0.05 70.00 2.35 0.06 0.01 0.05 75.00 80.00 2.22 2.10 0.06 0.06 0.01 0.01 0.05 0.05 85.00 1.97 0.06 0.01 0.05 90.00 1.85 0.06 0.01 0.05 95.00 1.72 0.06 0.01 0.05 100.00 1.60 0.06 0.01 0.04 105.00 1.47 0.05 0.01 0.04 ' ---------------------------------------------------- THE REQUIRED POND SIZE = 4.855248E-02 ACRE -FT THE RAINFALL DURATION FOR THE ABOVE POND STORAGE= 75 ' ***** GEOMETRIES OF P.N EQUIVALENT CIRCULAR POND STAGE CONTOUR CONTOUR POND POND (DEPTH) DIAQMETER AREA SIDE SLP STORAGE ' FEET ----------- FEET ACRE FT/FT ACRE -FT 0.00 166.53 0.50 3.00 0.00 0.50 169.53 0.52 3.00 0.25 ' 1.00 172.53 0.54 3.00 0.52 1.50 175.53 0.56 3.00 0.79 2.00 178.53 0.57 3.00 1.07 2.50 ----------------------------------------------------- 181.53 0.59 3.00 1.37 /'c4 A 7S niuu-£ RAIufAit paRF7ic.✓ TH£ Pc.vo ✓tt✓RE ' wict CE L //s FT-1 i2LS 117 /rr _ e.53 Hips TO OVAI" TNL :CNO ' c. c 9 .T'/s 34cos .C4'S524�Aa.rt� 43�LdrT! 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P✓IL EAST PARKING LOT PIPE OUTLET DETAIL I I II CONCRETE PAN LEGEND v< - � EFI5TIN6 (l1FriDlal r '\ 4 nwcxv raNTaaa -------------- 01G}IN TINS _ 0.03 ' bdrr OCl1lIWIDN —EIF61N MlA r/`r11f6i © Da61EN FbWT sl.. I_s nlpFpa6p Clb/ATbN _ � GdHDR6R WKF INFLOW CJGp F6UR8F ' OUTFL GLMt 607T6R R r - L I Tl- � S r -, SECTION B-B _ c -� tr 1 CROSS PAN DETAIL *V"•Sn:: a .�� _ _ _ � m- - :' sv.+ an. G..-. -`I.OM.t ",'YALd .nNwA L.IVLG.� • G - • a Mr51! - �F. /—ry� F/'O- L.Llwp ppv.11 1 I/ ' � I DETENTION POND OUTLET DETAILS Nw11 rr .xe �rrEII MwfiIMD a lwe r.�n ra Lino KbALT 1P1 / W-fR1 5r • ftN CA W.N .1snVLT To I.W/ c'wmG )ximate that will flow rather than 1 OERMeN RNO L Y. NL>2 PG'I+DM rno.T 5Ltp1/uN D h Te x RFbty es/ 1'Ilera DMW. 9FL MNa DI N4NIT6R /OM1 DLTnABp IMNNI G1� 1 SECTION A -A ors OIJfFALL CI�_Aa TT91 REINT Tt1 gE�PED NMSTD SECTION ---------------------- YFFIowS detained d here at 0.09 CIS SITE PLAN release rate ENKNINAnumm�i amm�ou r nLL Y iMN+I. wewmr�"iFG Na m. u�aY x IgIR 4^NIL IO wYi YYtul �=II .�u,+lnn w In tm ro q[ rza:a nula ¢ url.In ,. . 4LT3ay mnm ' s zaW'I w ry - I.N V Yw. mIN 1i .rIMp.11T® Ifq.Iip �In Iu..,li, 11410 lv Rtfrc, ,v�.c[ �.p a1,1. ur Y,ua q rY wIA. c�iu. a. ��.Iuiaw ^•, rA511M. JR1. 1111•{UI LM.1' _ — IN,1 LIa'IN.f11f IIIIMtlH Iw.� — rGaewnLr =.Nvt .-F14rua6 !ILIn•ItTI['N DILN , Nv H w t. -Smut �­f 1 ►la rlrt curter w•! �`� � aorvuen`e errtlevLca Custewe. ssim I 1 I I z91Iw rt a LrnTeD �`nnr•F• ' FNRN6IY lflE r2FB{ �I� Tc VWNITY IMr) ie�F�eTiw —l.OHTRU;T rdcFeR 1"- 6a.LL WnN qrl wrrjLTN C< ie� CITnLj I11IyII VI n.'ale 1 _ au a w e_ _ En91n"rin9 Consultonta I OFFICE BUILDING FOR JENSEN HOMES I DRAINAGE AND EROSION CONTROL PLAN 4818 SOUTH COLLEGE AVE_ FORT COLONS. COLORADO 1 I 1