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HomeMy WebLinkAboutDrainage Reports - 12/20/2013tDecember 19, 2013 City of Ft. Collins AprPlans ' Approved By Date FINAL DRAINAGE AND ' EROSION CONTROL REPORT ' Mail Creek Crossing Fort Collins, Colorado t ' Prepared for: Everitt Companies 3030 S. College Ave. Fort Collins, Colorado ' Prepared by I NORTHERN ENGINEERING ' 2W South College Avenue, Suite 10 Fort Collins, Colorado 80524 Phone: 970.221.4158 Fax: 970.221.4159 vww.northemengineedng com �j This Drainage Report is consciously provided as a PDF. Please consider the environment before printing this document in its entirety. When a hard copy is absolutely necessary, we recommend double -sided printing. Project Number: 110-061 NorthernEngineering.com /I 970 221 4158 I NORTHERN ENGINEERING December 19, 2013 1 Larimer County Engineering 200 West Oak Street, Suite 300 ' Fort Collins, Colorado 80521 ADDRESS: PHONE:970221.4158 200 S. College Am Suite 10 WEBSI�� rthernengineering am Fort Collins, C080524 FAX.970.221.4159 ' RE: Final Drainage and Erosion Control Report for MAIL CREEK CROSSING ' Dear Staff: Northern Engineering is pleased to submit this Final Drainage and Erosion Control Report for your review. This report accompanies the Final Development Plan (PDP) submittal for the proposed Mail ' Creek Crossing development. This report has been prepared in accordance with the Fort Collins Stormwater Criteria Manual ' (FCSCM), and serves to document the stormwater impacts associated with the proposed Mail Creek Crossing project. We understand that review by Larimer County and the City of Fort Collins is to assure general compliance with standardized criteria contained in the FCSCM. ' If you should have any questions as you review this report, please feel free to contact us. ' Sincerely, NORTHERN ENGINEERING SERVICES, INC. Q�p N . T ' Nicholas W. Haws, PE U ll ron t�'va ,r.Jt Project Manager L;E,� �je�t Eng'ur2QF;' 1 NORTH ERN NORT ENGINEERING LJ TABLE OF CONTENTS MAIL CREEK CROSSING ' IV. DRAINAGE FACILITY DESIGN.........................................................................................5 A. General Concept..............................................................................................................................5 ' B. Specific Details.................................................................................................................................5 V. CONCLUSIONS.............................................................................................................8 A. Compliance with Standards.............................................................................................................8 ' References.........................................................................................................................9 ' APPENDIX A — Hydrologic Computations APPENDIX B — Hydraulic Computations B.1 — Storm Sewers B.2 — Riprap ' B.3 — Street Flow B.4 — Inlets B.5 — Detention Facilities ' APPENDIX C — Water Quality Design Computations APPENDIX D — StormWater Management Model (SWMM) ' APPENDIX APPENDIX E F — Drainage Addendum Letter — Erosion Control Report ' MAP POCKET: DR1 — Overall Drainage Exhibit Final Drainage and Erosion Control Report �S I NORTHERN ENGINEERING I. GENERAL LOCATION AND DESCRIPTION A. Location 1. Vicinity Map MAIL CREEK CROSSING Figure 1 - Vicinity Map 2. The Mail Creek Crossing project site is located in the South half of the Northwest quarter of Section 8, Township 6 North, Range 68 West of the 6th Principal Meridian, City of Fort Collins, County of Larimer, State of Colorado. 3. Mail Creek Crossing (i.e., Lehman Property) is comprised of ±45.19 acres; however, the Mail Creek Irrigation Ditch serves as a natural drainage divide. There are ±39.60 acres of the total project site area situated north of the irrigation ditch which could drain to McClellands Creek. Tract A, which is situated West of the project site, is not a part of the work included herein. 4. The project site is bound to the north by Kechter Crossing (proposed); to the south by the Mail Creek Ditch and The Timbers; to the east by Kechter Farm (proposed); and to the west by Bacon Elementary School and South Timberline Road. 5. The project site is undeveloped. Final Drainage and Erosion Control Report 1 NORTHERN ' ENOINEFUNC MAIL CREEK CROSSINC ' 6. The existing groundcover primarily consists of native grasses. Existing runoff generally drains northeast across flat grades of between one and three percent. Much of the property historically drains to the Edelweiss Pond. 7. According to the United States Department of Agriculture (USDA) Web Soil Survey website, USCS soil group CL is predominant on -site. These soils are inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays and lean clays. ' 8. There are no major drainageways within or adjacent to the project site. Mail Creek Irrigation Ditch, which is managed by the New Mercer Ditch Company, borders the property along the south and southwest property lines. ' 9. The proposed Mail Creek Crossing development will consist of ±137 single-family residential lots at a density of ±3.03 lots per acre. There are no commercial lots planned with this development. ' 10. The project site is currently zoned FA-1. The proposed zoning is Planned Land Division - LMN. 1 1 1 1 1 B. Floodplain The subject property is not located in a FEMA regulatory or City of Fort Collins designated floodplain (refer to Figure 2). Mail Creek Crossing 1110481 FFMA FYNMNIWi f Fy F4xn�YaYn �n- fey Um6 1 11,952 ® I Nab. �I-a4 �YMO f my ms..oxw um.nuaowawinom,�. on mFmcw.m Fcx.w wo8_t68.-WmJ.emaar�Yo-piir . ImvmammmMm.naa.ornmvme ma. McayN[.nY mwvrmme. oN mFencamv. me n mr a mrmi e..aumv..unnt wm�mwe b.b Figure 2 - FEMA and City of Fort Collins Floodplains Final Drainage and Erosion Control Report 2 NORTHERN ENRINEERINR MAIL CREEK CROSSING , II. DRAINAGE BASINS AND SUB -BASINS t A. Major Basin Description Mail Creek Crossing is located in the McClellands Basin. According to the City of Fort Collins (http://www.fcgov.conVutilities/what-we-do/stormwater/drainage-basins/mcclellands-basin), "The , McClellands Basin encompasses approximately 3.4 square miles in southeast Fort Collins. The storm runoff from the basin originates northeast of College Avenue and Harmony Road and drains southeast through Oakridge, Willow Springs, Stetson Creek and Harvest Park ' developments. A single major drainageway, McClellands Creek, conveys flows from the upper end of the basin to the downstream discharge point along Fossil Creek Reservoir Inlet Ditch. The majority of the basin is either developed, or is being developed, with residential , and commercial land areas." The project site is included in a mini -master plan, which was prepared by the City of Fort ' Collins in February 2006, for the Homestead PUD area within McClellands Basin. In particular, the undeveloped Mail Creek Crossing project site is a part of Basin 901-3, Basin 901-4 and Basin 901-5. ' B. Sub -Basin Description The following is excerpted from a drainage addendum letter (Northern Engineering I Dated: 1 09.10.2012) which addressed the Mail Creek Crossing storm drain outfall and the allowable developed release rate for the project site. An updated copy (Dated: 11.27.2012) of the drainage addendum letter is included in Appendix E. ' "The McClellands Basin drainage master plan prescribes a 100-year release rate of 0.50 cfs/ac. Much of the Mail Creek Crossing (i.e., the Lehman Property), historically drains to the Edelweiss Pond, as indicated in the 2008 Kechter Crossing , drainage Report. However, the preferred stormwater outfall for these properties, when developed, is north of Kechter Road into McClellands Creek. As such, the off- site outfall pipe for Kechter Crossing has been re -analyzed with the development of ' these properties taken into consideration." Mail Creek Crossing will release into an existing 18" storm drain pipe in Tilden Street at a ' 'self-imposed' unit release rate of 0.20 cfs/acre during the 100-year storm event. The total release rate from the project site will be approximately 7.50 cfs (based on ±37.5 acres tributary area). , The project site does not receive notable runoff from contiguous off -site properties. Runoff from the south is blocked by the Mail Creek Irrigation Ditch. ' 1 1 Final Drainage and Erosion Control Report .: t 1 1 1 1 1 .�I NORTHERN ORTRN ENGINEERING THE III. DRAINAGE DESIGN CRITERIA MAIL CREEK CROSSING A. There are no optional provisions outside of the FCSCM proposed with Mail Creek Crossing. B. Development Criteria Reference and Constraints 1. The subject property is not part of an Overall Development Plan drainage study. 2. The site plan is constrained on two sides by the Mail Creek Irrigation Ditch and undeveloped project sites (i.e., Kechter Crossing and Kechter Farm) along the remaining two sides. C. Hydrological Criteria 1. The City of Fort Collins Rainfall Intensity -Duration -Frequency (IDF) Curves, as depicted in Figure RA-16 of the FCSCM, serve as the source for the rainfall intensities in the attached hydrologic computations. Tabulated data contained in Table RA-7 has been utilized for Rational Method runoff calculations. 2. The Rational Method has been employed to compute stormwater runoff utilizing coefficients contained in Tables RO-11 and RO-12 of the FCSCM. 3. The EPA Stormwater Management Model (SWMM) Version 5.0 (Build 5.0.022) has been used for preliminary detention pond sizing calculations. 4. Two separate design storms have been utilized to address distinct drainage scenarios. The first event analyzed is the "Minor," or "Initial" Storm, which has a 2-year recurrence interval. The second event considered is the "Major Storm," which has a 100-year recurrence interval. D. Hydraulic Criteria 1. The drainage facilities proposed with the Mail Creek Crossing project are designed in accordance with criteria outlined in the FCSCM and/or the Urban Drainage and Flood Control District's (UDFCD) Urban Storm Drainage Criteria Manual. 2. As stated in Section I.B, above, the subject property is not located in a FEMA regulatory or a City of Fort Collins designated floodplain. F. Floodplain Regulations Compliance 1. As previously mentioned, this project is not subject to any floodplain regulations. G. Modifications of Criteria 1. No modifications are requested at this time. Final Drainage and Erosion Control Report n 1 NORTHERN ENGINEERING MAIL CREEK CROSSING ' IV. DRAINAGE FACILITY DESIGN ' A. General Concept 1. The main objective of the Mail Creek Crossing drainage design is to follow the previously established outfall location and allowable release rate guidelines, while not adversely impacting adjacent properties. 2. The project site has been divided into four (4) tributary areas (i.e., A, B, C and D). The ' sub -basins comprising tributary areas A, B and C will drain to Pond 1 (sub -basin P1), Pond 2 (sub -basin P2) and Pond 3 (sub -basin P3), respectively. The sub -basins that comprise tributary area D are situated along peripheral regions of the project site. These , sub -basins are described more fully in Section B (see below). In general, each of the main tributary areas is divided into sub -basin areas (e.g., B1 ' through B9) for the purposes of evaluating street capacities, sizing inlets and sizing storm drain pipes and overflow swales (with future submittal). The minor and major storm event runoff in each sub -basin was estimated with the Rational Method. ' 3. Extended detention Water Quality Capture Volume (WQCV) will be provided within each of the detention ponds. With this preliminary submittal, we sized the respective WQCV for each tributary area and added it to the required 100-year storage volume. In the ' context of the SWMM model and at the start of the 100-year storm event, the starting water surface elevation was set equal to the WQCV water surface elevation. ' 4. No notable runoff passes directly though the project site. 5. Appendix A contains detailed Rational Method calculations (i.e., composite runoff ' coefficients, Tc calculations and developed runoff estimates) for the 2- and 100-year storm events (i.e., minor and major) reflective of the proposed Mail Creek Crossing development plan. Aggregated areas and impervious values for the tributary areas were ' input into SWMM, and the results of which can be found in Appendix D. Additionally, WQCV computations utilizing the,Best Management Practices criteria outlined by the Urban Drainage and Flood Control District are included in Appendix C. , 6. Detailed street capacity and inlet sizing computations were also performed and are included in Appendix B. A full-size copy of the Drainage Exhibit can be found in the Map Pocket at the end of this report. ' B. Specific Details 1. The tributary areas are similar in composition, design and prevailing flow patterns. In ' general, sheet flow from the developed single-family lots will drain into the adjoining street section (i.e., local street classification with roll-over curb and gutter or collector street classification with vertical curb and gutter). The developed runoff from aggregated , sub -basin areas will drain into CDOT Type 13 combination inlets or swales and then into one of the three on -site water quality/quantity ponds. ' 2. The proposed street sections will provide adequate street capacity during the minor and major storm events. The 2-year street capacity is limited by flow spreading to the crown or the top of the curb. Herein, the curb height controlled. During the 100-year storm ' event, the right-of-way was used to establish maximum flow depths within the street sections. Final Drainage and Erosion Control Report 5 , NORTHERN ENGINEERING MAIL CREEK CROSSING ' 3. The inlets at design points Al/A2, and 135/67 are designed to receive and convey the 100-year storm event. The inlets at design points C2 through C5 receive and convey the partial 100-year storm event. In a 100-year event, a combined flow rate of 40.2 cfs ' will be intercepted by the inlets, and a flow rate of 10.8 cfs will overtop the inlets. Flow will be conveyed overland directly into Pond 3. 4. Thel on -site detention ponds were sized with EPA SWMM Version 5.0. • Detention Pond 1 receives runoff from sub -basins Al, A2, and the back half of several single-family lots in sub -basin P1. • Detention Pond 2 receives runoff from sub -basins B1 through B9 and the back half of several single-family lots in sub -basin P2. Detention Pond 3 receives runoff from sub -basins Cl through C5 and the back half of several single-family lots in sub -basin P3. Two of the on -site detention ponds are linked (refer to Appendix D for a SWMM Schematic). Detention Pond 1 drains into Detention Pond 2. Detention Pond 2 and Detention Pond 3 combine at a proposed manhole in Tilden Street. The orifice plate sizes were determined iteratively to balance the allowable release rate of 7.50 cfs and the available detention pond area and depth. TABLE 1 - Pond Summary Pond ID Detention Water Quality Total Volume Water Quality 100-yr Peak Volume Capture Volume WSEL WSEL Release Rate (AC -FT) (AC -FT) (AC -FT) (FT) (FT) (CFS) 1 1.23 0.12 1.35 4942.53 4946.24 2.20 2 4.36 0.37 4.73 4937.10 4940.90 1.50 3 1.61 0.20 1.81 4935.90 4940.90 6.10 Emergency spill from Ponds 1 and 2 will be safely col nveyed along the north property line of the project site from these ponds in an easterly direction into Tilden Street. The Kechter Farm project, which is currently under construction, has a concrete pan and swale section running along this property line. Lots running parallel to this property line within Kechter Farm drain to this swale, and a minor amount of drainage from the proposed project goes into this Swale as well. Any emergency spill from Ponds 1 and 2 will be directed into this swale. Emergency spill from Pond 3 will be safely conveyed via sheet flow through open property to the northeast of the pond. 8. Sub -basin D2 will sheet flow to the northeast and off -site into Kechter Farm (proposed). A preliminary drawing prepared by the Kechter Farm engineer (JVA, Incorporated) shows an existing basin on the Mail Creek Crossing project site of approximately 2.16 acres in size. Premised on the assumption of 'no -ditch', it drains onto the Kechter Farm project site. The current plan for Mail Creek Crossing shows sub -basin D2 (0.51 acre) draining to the east and onto the Kechter Farm project site. The proposed condition Final Drainage and Erosion Control Report 6 .v NORTHERN ENGINEERING MAIL CREEK CROSSING includes developed runoff from future undeveloped area, one single-family lot and approximately 0.06 acre of Piney Creek Drive. The proposed developed flows (i.e., Q2=0.77 cfs and Q,00=3.35 cfs) from this area are comparable to the existing flow ' estimates (i.e., Q2=0.0.64 cfs and Q,00=2.95cfs). In general, we anticipate the impact from our developed runoff to be negligible. ' 8. Sub -basin D3 wraps around the northeast corner of the project site. It is comprised of the back half of fifteen single-family lots. The current proposal shows the developed runoff from D3 draining into a swale along the east property line and sheet flowing ' across the north property line. The existing runoff draining to these property lines generally flows overland and into shallow swales. At the confluence of these swales, which is the northeast property corner, the existing runoff flows north in an existing , concentrated flow path. The character of the proposed drainage patterns is generally consistent with the existing condition. Additionally, the minor and major storm event flows that we propose to drain at D.P. D3 are considerably less than existing flow rates. ' The entirety of the existing property (38.7 acres) historically drains to the northeast corner of the site. This historic basin generates 9.7 cfs in the 2-year event, and 44.4 cfs in the 100-year event. Developed sub -basin D3 (1.78 acres) generates1.8, and 7.8 ' cfs in the 2- and 100-year events. 9. Sub -basin D4, which includes the front half of two single-family lots and 0.11acre of ' Tilden Street will drain to a portion of Tilden Street that was designed with Kechter Crossing. The additional flows should have no adverse impact during the 2- and 10-year storm events. During the 100-year storm event, the additional flows may cause ±lcfs , to bypass the proposed on -grade inlets at the intersection of Tilden Street and Kechter Road. 10. We are working with the New Mercer Ditch Company on the Mail Creek Irrigation Ditch ' crossings designs. Mail Creek Crossing will cross the Mail Creek Irrigation Ditch at three locations: ' • Tilden Street • A pedestrian crossing to the east of Piney Creek Drive t 1 Final Drainage and Erosion Control Report 7 (NORTHERN ENGINEERING V. CONCLUSIONS A. Compliance with Standards 1. The drainage design proposed with the Mail Creek Crossing development complies with the City of Fort Collins' Stormwater Criteria Manual, as well as previous drainage studies from which downstream stormwater infrastructure was constructed. 2. The drainage design proposed with the Mail Creek Crossing development complies with the City of Fort Collins' McClellands Basin master drainage plan. 3. The drainage plan and stormwater management measures proposed with the Mail Creek Crossing development are compliant with all applicable state and federal regulations governing stormwater discharge. Final Drainage and Erosion Control Report 8 .V I NORTHERN ENGINEERING References 1. City of Fort Collins Landscape Design Guidelines for Stormwater and Detention Facilities, November 5, 2009, BHA Design, Inc. with City of Fort Collins Utility Services. 2. Fort Collins Stormwater Criteria Manual, City of Fort Collins, Colorado, as adopted by Ordinance No. 174, 2011, and referenced in Section 26-500 (c) of the City of Fort Collins Municipal Code. 3. Final Stormwater Management Plan, September 3, 2008, Benchmark Engineers, P.C. 4. Homestead/McClellands Mini -Master Plan, February, 2006, City of Fort Collins. 5. Larimer County Urban Area Street Standards, Adopted January 2, 2001, Repealed and Reenacted, Effective October 1, 2002, Repealed and Reenacted, Effective April 1, 2007. 6. Soils Resource Reoort for Larimer County Area, Colorado, Natural Resources Conservation Service, United States Department of Agriculture. 7. Urban Storm Drainage Criteria Manual, Volumes 1-3, Urban Drainage and Flood Control District, Wright -McLaughlin Engineers, Denver, Colorado, Revised April 2008. 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N LL LL M a In m b M m U In U a IB.1 — Storm Sewers G 1 1 B.2 — Riprap B.3 — Street Flow BA — Inlets 8.5 — Detention Facilities NorthernEngineering.com // 970.221.4158 1 1 1 1 1 1 NorthernEngineering.com // 970.221.4158 i i i i i 1 i i i i i N 1 i 7 Storm Sewer Summary Report Page 1 Line Line ID Flow Line Line Invert Invert Line HGL HGL Minor HGL Dns No. rate size length EL Dn EL Up slope down up loss Junct line (cis) (in) (H) (h) (ft) N (ft) (ft) (ft) (ft) No. 1 Pipe 1.1 21.10 24 c 152.0 4944.39 4945.15 0.500 4946.02' 4947.38' 0.11 4947.48 End 2 Pipe 1.2 12.70 18 c 30.0 4945.14 4945.29 0.500 4947.48' 4947.85' 0.80 4948.66 1 Project File: STORM_1.slm Number of lines: 2 Run Date: 08-02-2013 NOTES: c = cir; e = ellip; b = box; Return period = 2 Yrs. ;'Surcharged (HGL above crown). Hydmflm StDM Sewers 2005 \ I I I I I I I I I 1■ c 0 ` S |! ; ci . ! $ _ §!£ 6 ) WS ! ( � J \ § § t k o � iz ts M O N N O OD O N N N C J O Z N N H N LL U N O Storm Sewer Summary Report Page 1 1 1 1 1 1 Line Line ID Flow Line Line Invert Invert Line HGL HGL Minor HGL Dns No. rate size length EL Dn EL Up slope down up loss Junct line (cfs) (in) (ft) (ft) (ft) N (ft) (ft) (ft) (ft) No. 1 Pipe 2.1 25.10 30 c 154.1 4936.11 4936.88 0.500 4937.78 4938.59 0.11 4938.70 End 2 Pipe 2.2 17.60 24 c 36.0 4936.88 4937.06 0.500 4938.95` 4939.14' 0.49 4939.62 1 Project File: STORM_2.stm Number of lines: 2 Run Date: 08-02-2013 NOTES: c = cir; e = ellip; b = box; Return period = 2 Yrs. ; 'Surcharged (HGL above crown). Hyft low Sloan sewers 2005 J 1 O N C N p c o 2.2 O d o .- M W OWN N b ° W o o m t U m cc a in Qy, G o p c — o 0 J > M N 0.2 W d 5 m Obi a a v O O N b V N d � � � E t 0 z J > m N a a m o > = x n M — a v c _ m M m t0 V% e N N G O J > m N m co m m W 0 m m a v j mr m a c O N N c c a O N n m p C G � N J � m v a Y >dx n M m N f V1 N G N N O O m N ii U d d C 2 J N d I J 1 11 1 M M J Z M O N N 9 co O UI C J O Z M i 0 5 U x E N oaa) z ii U a) O Storm Sewer Summary Report Page 1 1 1 1 1 1 Line Line ID Flow Line Line Invert Invert Line HGL HGL Minor HGL Dns No. rate size length EL Dn EL Up slope down up loss Junct line (cfs) (in) (ft) (ft) (ft) 1%) (ft) (ft) (fill (ft) No. 1 Pipe - (37) 40.20 30 c 33.1 4935.06 4935.23 0.514 4937.18 4937.63 0.17 4937.80 End 2 Pipe 3.1 40.20 30 c 49.9 4935.23 4935.48 0.501 4937.83' 4938.24' 0.18 4938.42 1 3 Pipe 3.2 20.10 24 c 38.0 4935.48 4935.67 0.500 4938.82' 4939.08' 0.64 4939.71 2 Project File: New.stm Number of lines: 3 Run Date: 08-02-2013 NOTES: c = cir; e = ellip; b = box; Return period = 2 Yrs. ;'Surcharged (HGL above crown). Hydm low Storm Sewers 2005 1 h 10 P C. P W ,J �go o L 1.2 ' L � O � T w y l0 Ol [m V O 4n O N C m K N a N N O � W m O L V W N1 0 0 o p 0 0 0 J > o m n N r rn m m a a a _o a > d x o o e L ..- o N a - o o c m m a a vi E 0 L z m � a voi o G N N N J > M V (O N 9 O m O V a V N O rm c rn o v m n 0 0 0 � m ao rn W m� m m rn a v a O d N tp O� O o a a d Oa a V V C) 0 Z_ d Y m N O C V N N [V OJ (+1 N x a— m rn m v e e 0 0 o E N N N N a V N m z m N C N O O V LL N a G O I s e [l n [l g� 8 V S. 0 3 1 1 1 1 Storm Sewer Summary Report Page t Line No. Line ID Flow rate (cfs) Line size (in) Line length (ft) Invert EL Dn (ft) Invert EL Up (ft) Line slope N HGL down (ft) HGL up (ft) Minor loss (ft) HGL Junct (ft) Dns line No. 1 Pipe - (29) 8.60 15 c 360.7 4932.11 4933.91 0.499 4933.25' 4938.42' 0.76 4939.18 End Project File: STORM_4.stm Number of lines: 1 Run Date: 08-02-2013 NOTES: c = cir; e = ellip; b = box; Return period = 2 Yrs. ; 'Surcharged (HGL above crown). Hydmf ow Slmm Sewers 2005 [1 1 I O N G Z r 2.0 J m -+ O Y o u � N ^ _O N N V m m L O p c o J > m a a _ > d L � O N � d n � O. � y S ry O d a V E L Z y � N G J > N O C7 N ^ m v C > = x n _ c C _ m N e _N � m A Wudr m � W V _ a m ME Z: 7 LO E m N ; a m N d C at G L n r a o N t7=x m 0 td m V d N vi O ai O y N LL d U m C O J � d iJ 1 I �J I I l 1 Storm Sewer Summary Report Page 1 Line No. Line ID Flow rate (cfs) Line size (in) Line length (ft) Invert EL Dn (ft) Invert EL Up (ft) Line slope N HGL down (ft) HGL up (ft) Minor loss (ft) HGL Junct (ft) Ons line No. 1 Pipe 5.1 2.00 15 c 35.0 4938.72 4939.05 0.943 4939.19 4939.62 n/a 4939.62 End Project File: STORM_5.slm Number of lines: 1 Run Date: 08-02-2013 NOTES: c = cir; e = ellip; b = box; Return period = 2 Yrs. Hydraflow Storm Sewers 2005 I I 1 O N i � c J y Y u o � o al N � O N N O r N u W O o m o v C p c (q a co V K O J > M m W W N.Z. � v 9 > N O E N > am m a c = N m O L Z ad N p O J > 0 U' a p 2 0 cm� m _ v c _ O M e a 0 J > N 0.2 Y+ M a 9 WE O N of E m a d _ C y G N O O p L m r a p o m p=x n a r a o > m m E m � N �I n N 0 U N C N u m u a � � o NorthernEngineering.com // 970.221.4158 t N N O p d' S 9 o000 m N io itlp m 0000 0000 N U �i Y V 0 10 EiQ A N O O -.. T N LL J J J J K L7 0 2 R O U E r F F F 3 inmm � N O O V O 11 'Y v m p0 x°K nveioP W e _ C3 E Coco Z min moo aa¢¢ N Z Z Z Z W g glad E6 x a a a a T Z Z Z Z a z N O w q— m Q Y O O O O J t O000 Q 3 a,Y m o o in r Y t 3 = Y Z Y E q K dm > 00 r — Y o` x U 2 V 1- w` dU z m` N 6_ E2 � d N ON�nN N N N ti M q .L O.vti00 O O Y -+NmV o U U 0 OR Ham €E€E o000 N N N N LJ 1 �I ' NorthernEngineering.com // 970.221.4158 NORTHERN ENGINEERING Street Capacity Calculations I Drive -Over Curb & Gutter - Minor Storm Event Project: 110-061 Calculations By: H. Feissner Date: 5/1612013 ums¢ab ^a c a wR�rtmR art..R ��• ttv srJ 'EI \ 0-R rtJ Can "a �1 \ s !L R ' S.• - Ill• I \ ' Y • M. sR y 1 SY • :R• ` b. b J_ • a \ I�r Isa---'- N clavE-tnEa ate. Ea)TreR aRo SloEwaEx liennings Formula for flow in shallow triangular channels: Q = 0.56(ZJn)Spl2yer3 Where: Q Thepretical Gutter Capacity, cis y Depth of Flow at Face of Gutter, N n Roughness Oee8lclern, see below So Longitudinal Channel Slope, Wit 5, Cross -Slope of Gutter Pan, tWt So Cmss-Slope of Gutter Pan, JIM Sc Cross -Slope of Asphalt, Wit Z Reciprocal of Cross Slope. Wit Inputs S. 27.94-b Z. - 1/S, 3.58 So 9.82. ZY = 1/% 10.18 Sr 2.00% 4 = 1/S, 50.00 FL to FL Distance :Et. Select y 0.39 water depth at flowline, ft y' 0.28 water depth at EDP, ft So = See Below longitudinal slope of street, % Results 0. 56(Z/n)y8/3 = 34 77 n ZJn 223.69 Zdn 636.46 Z,yn 3125.00 10,27 29.23 1158 56.84 Mail Creek Crossing Design Point Street Name Width FL to CL ftStreet Classification Developed Qi its Longitudinal Grade S % Calculated 0, cIs Reduetidr Factor (See Figure ST-2) Allowable Q, eta Al Spruce Creek Drive 15 ocai 2-83 0.60% 6,57 1-00 657 A2 Spruce Creek Drive 15 Local 1.92 0.60% 6.57 1.00 6.57 81 Spruce Creek Drive 15 focal 2.58 0,80% 7.58 1.00 7.58 E12 Spruce Creek Drive 15 Local 1,74 0.80% 7.58 1,00 7.58 B3 Lotlaole Creek Drive 15 Local 3.98 0,60% 6.57 1,00 6,57 B4 Lotl a ale Creek Drive 15 Local 2.54 0.60% 6.57 1.00 6.57 87 1 Piney Creek Drive 1 15 1 local 1.45 1.00% 8.48 1 1.00 8.48 88&B9 Piney Creek Drive 1 15 Loral 4.95 1,00% 8.46 1 1.00 8.48 C2 Sand Creek 15 Loral 2.30 0.80% 7.58 1.00 7.58 CI & C3 Owl Creek Drive 15 Local 6.11 0.65% 6.83 1.00 6.83 C4 Sand Creek 15 Local 2.77 0.80% 7.58 L00 7.58 C5 Owl Creek Drive 15 1ecal 2.65 0.65% 6.83 1.00 6.83 5/16/2013 3:49 PM D:IPm/ectslll0-0611DrainagelSfrtCaplllO-061Street Capecity_ROCG-Mmocx/sxRollover C&G Channel Report , Hydraflow Express Extension for Autodesk0 AutoCAD® Civil 3DOO by Autodesk, Inc. Thursday, May 16 2013 Drive Over Curb and Gutter (Major Storm Event) I Slope=0.55% ' User -defined Invert Elev (ft) = 4999.40 Highlighted Depth (ft) = 0.60 , Slope (%) = 0.55 Q (cfs) = 35.65 N-Value = 0.018 Area (sqft) Velocity (ft/s) = 14.12 = 2.52 , Calculations Wetted Perim (ft) = 53.13 Compute by: Known Depth Crit Depth, Yc (ft) = 0.57 Known Depth (ft) = 0.60 Top Width (ft) = 53.00 ' EGL (ft) = 0.70 (Sta, El, n)-(Sta, El, n)... (0.00, 5000.00)-(4.50, 4999.91, 0.016)-(10.08, 4999.80, 0.025)-(11.50, 4999.40, 0.016)-(12.67, 4999.51, 0,016) -(26M. 4999.79, 0.016)-(40.33, 4999.51, 0.016)' -(41.50, 4999,40, 0.016)-(42.92, 4999.80, 0.016)-(48.50, 4999,91, 0.025)-(53.00, 5000.00. 0.016) Elev (ft) Section Depth (ft) 1.60 , 5001.00 T 5000.50 1.10 ' - ' 5000.00 0.60 - 0.10 ' 4999.50 1 -0.40 4999.00 � 1 4998.50 -- - -0.90 , -5 0 5 10 15 20 25 30 35 40 45 50 55 60 , Sta (ft) Channel Report Hydra m Express Extension for Autodeska0 AutoCAD® Civil 3D® by Autodesk, Inc. Thursday, May 16 2013 Drive Over Curb and Gutter (Major Storm Event) I Slope=0.60% User -defined Invert Elev (ft) = 4999,40 Highlighted Depth (ft) = 0.60 Slope (%) = 0.60 Q (cfs) = 37.23 ' N-Value = 0.018 Area (sqft) Velocity (ft/s) = 14.12 = 2.64 Calculations Wetted Perim (ft) = 53.13 Compute by: Known Depth Known Depth (ft) = 0.60 Crit Depth, Yc (ft) Top Width (ft) = 0.58 = 53.00 EGL (ft) = 0.71 (Sta, El, n)-(Sta, El, n)... ' ( 0.00, 5000.00)-(4.50, 4999.91, 0.016)-(10.08, 4999.80, 0.025) 411,50, 4999.40, 0.016)-(12.67, 4999.51, 0.016)-(26.50, 4999.79, 0.016)-(40.33, 4999.51, 0.016) -(41.50, 4999,40, 0.016)-(42.92, 4999.80, 0.016)-(48.50, 4999.91, 0.025)-(53.00, 5000.00, 0.016) Elev (ft) ' 5001.00 5000.50 5000.00 4999.50 4999.00 1 4998.50 1 Section 0 5 10 15 20 25 30 35 40 45 50 55 Sta (ft) Depth (ft) 1.60 1.10 LI 9 0.10 -0.40 Channel Report , Hydraflow Express Extension for Autodesk®AutoCAD® Civil 3D® by Autodesk, Inc. Thursday, May 16 2013 Drive Over Curb and Gutter (Major Storm Event) I Slope=0.80% ' User -defined Highlighted Invert Elev (ft) = 4999.40 Depth (ft) = 0.60 ' Slope (%) = 0.80 Q (cfs) = 42.99 N-Value = 0.018 Area (sqft) Velocity (ft/s) = 14.12 = 3.04 ' Calculations Wetted Perim (ft) = 53.13 Compute by: Known Depth Known Depth (ft) = 0.60 Crit Depth, Yc (ft) Top Width (ft) = 0.60 = 53.00 ' EGL (ft) = 0.74 (Star El, n)-(Sta, El, n)... (0,00, 5000.00)-(4.50, 4999.91, 0.016)-(10.08, 4999.80, 0.025)-(11.50, 4999.40, 0.016)-(12.67, 4999.51, 0.016)-(26.50, 4999.79, 0.016)-(40.33, 4999.51, 0.016)' -(4L50, 4999.40, 0.016)-(42.92, 4999.80, 0.016)-(48.50, 4999.91, 0.025)-(53.00, 5000.00, 0.016) 1 1 Elev (ft) Section Depth (ft) 5001,00 ll 1.60 , 1.10 5000.50 - -� I - - ' j ' 5000.00 - 0.60 i I 0.10 4999.50 ' 1 4999.00 - -0.40 1 4998.50 I � -0.90 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 Sta (ft) ' Channel Report Hydraflm Express Extension for Autodeska0 AuWCAD@ Civil 3D© by Autodesk, Inc. Thursday, May 16 2013 ' Drive Over Curb and Gutter (Major Storm Event) I Slope=1.00% User -defined Highlighted Invert Elev (ft) = 4999.40 Depth (ft) = 0.60 Slope (%) = 1.00 Q (cfs) = 48.06 ' N-Value = 0.018 Area(sgft) Velocity (f /s) = 14.12 = 3.40 Calculations Wetted Perim (ft) = 53.13 Compute by: Known Depth Crit Depth, Yc (ft) Known Depth (ft) = 0.60 Top Width (ft) = 0.60 = 53.00 EGL (ft) = 0.78 El, n)-(Sta, El, n)... '(Sta, ( 0.00, 5000.00)-(4.50, 4999.91, 0.016)-(10.08, 4999.80, 0.025)-(11.50, 4999.40, 0.016)-(12.67, 4999.51, 0.016)-(26.50, 4999.79, 0.016)-(40.33, 4999.51, 0.016) -(41.50, 4999.40, 0.016)-(42.92, 4999.80, 0.016)-(48.50, 4999.91, 0.025)-(53.00, 5000.00, 0.016) Elev (ft) ' 5001.00 '000,50 ' 5000.00 ' 4999.50 4999.00 t ' 4998.50 -5 Section 0 5 10 15 20 25 30 35 40 45 50 55 60 Depth (ft) 1.60 1.10 1.o 0.10 M Sta (ft) Project: Inlet ID: 11 ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm) 11 T. y a Allowable Width for Spread Behind Curb a Behind Curb (leave blank for no conveyance credit behind curb) Roughness Behind Curb typically between 0.012 and 0,020) of Curb at Gutter Flow Line :e ham Curb Few to Street Crown Width Cross Slope (typically 2 inches over 24 inches or 0.083 Nf) Longitudinal Slope - Enter 0 for sump condition hg's Roughness for Street Section (typically between 0,012 and 0.020) Allowable Spread for Minor & Major Storm Allowable Depth at Gutter Flowline for Minor & Major Stone Flow Depth at Street Crown (leave blank for not at Depth without Gutter Depression (Ea. ST 2) ical Depth between Gutter Lip and Gutter Flowline(usually 2") at Depression (dc - (W " S, " 12)) at Depth at Gullet Flowtine ,vable Spread for Discharge outside the Gutter Section W (T- W) at Flow to Design Flow Ratio by FHWA HEC-22 method (Eq. ST-7) :harge outside Me Gutter Section W, cameo in Section T. :harge within the Gutter Section W (01- Ox) :harge Behind the Curb (e.g., sidewalk, driveways, & lawns) :imum Flow Based On Allowable Spread v Velocity within the Gullet Section Product: Flow Velocity times Gutter Flowllne Depth oreltwl Water Spread oretical Spread for Discharge outside the Gullor Section W (T - W) tar Flaw to Design Flow Ratio by FHWA HEC-22 method (Eq. ST-7) oretical Discharge outside the Gutter Section W. fomed In Section Tx Ta let Discharge outside Ole Gutter Section W. (limited by distance Tcnowx) :harge within the Gutter Section W 0,,- OK) :harge Behind the Curb (e.g., sidewalk, driveways, & lawns) it Discharge for Major B Minor Storm (Pre -Safety Factor) rage Flow Velocity Within the Guitar Section Product, Flaw Velocity Times Gutter Rawlins Depth ne-Based Depth Safety Reduction Factor for Major& Minor lid > 6"I Storm Flow Based on Allowable Depth (Safety Factor Applied) ullant Flow Depth at Gutter Floss ine (Safely Factor Applied) ullanl Flow Depth at Street Craven (Safety Factor Applied) TMr« = 10.0 fl Sw,�r= 0.020 Gift n. = 0.016 Hoets= 6.D0 Indhas Tceovm it W = Sx =5207 IOf Sw=3 fun So =55 full nrhohsr '1 0.016 Minor Storm Major Storm T. - 18.0 18.0 dxwx =J 5.84 1 8.40 linchers crack = yes y= de = a= it Tx: E. Ox' Ow' Q. = O1' V= V'd = Tm . Tx cur = Ed: Ox 1n= Ox° Qw' Oevcx' O= V+ V'd R= Oe' it dcaoww' Minor 4.32 4.32 2.0 2.0 1.52 1.52 5.84 5.84 16.0 16.0 0.331 0.331 6.2 5.2 3.1 3.1 0.0 0.0 9.3 9.3 3.8 3A .9 1 1 9 Minor St.. Major Sir. 18.0 28Y 16.0 2fi 7 0.331 0.204 62 24.3 62 22.2 3.1 6.2 0.0 1.8 9.3 30.2 3.8 5.0 .9 1 3.5 1.00 1.00 9.3 30.2 5.84 2,40 0.00 2.56 riches itches riches itches k cis is cis oft ps cis cf5 Is .is :1s fps off, nches notes STORM Allowable Capacity is based on Spread Criterion Minor Stone Major Storm STORM Allowable Capacity is based on Depth ri 0.s.. • 9.3 30.2 cb vG. MINOR STORM max. allowable capacity is less than flow given on shset'O-Peak' 1 1 1 I I L 1 11 110-061_UD-Inlet_v3.12_Tllden Strest.xlsm, O-Allow 5/16/2013. 4:03 PM , k 1 1 1 1 1 1 1 North ernE ngineering.com // 970.221.4158 I 1 1 1 1 INLET CAPACITY SUMMARY Project: 110-061 By: ATC Date: 7/1/2013 Inlet ID Inlet Type Inlet Condition Design Storm Design Flow CFS Inlet Capacity (CFS 1.1 Single Combination Sump 100- r 8.40 8.70 1.2 Double Combination Sump 100-yr 12.70 20.10 2.1 Single Combination Sump 100-yr 7.50 8.70 2.2 Double Combination Sump 100-yr 17.60 20.10 3.2 IDouble Combination Sump JPartial 100-yr, Overflow to Tract 128.60 120.10 3.3 IDouble Combination JSump 100-yr 122.40 120.10 I INLET IN A SUMP OR SAG LOCATION Pmfe , • Combination Inlet Capacity Inlet ID • Single Combination Inlet Sump Con Oitlon d L.(C)—� N-Curb XNmt We W n Information tried m I., lies, Type = Depmamemoutionllo minwutglnardepmaclon'a' lmm' !IoW) 4.` er of UM IXNa Grels or Cum Openig) Ne Depth A R.W.- (m6de of but oepreaawn) fbW Difi l• Ilbrmatlwr n of o Unit Gale "(G)= of a Un Grate W. ` D,Nlg Rotor for Is G. (Wploel value 0.150. W) Ar ` I,Fa t., for a Sege Grab(Npbal vale D.W-D 70) G(G) Weir CoafOceni(typlwl value 2. 15-3.W) C. (G)• Co. CoeRxle t nypmel value O.W -0.W) Co (G)- Opening Mormatlpn II of a Unit Cub Opening 4 (C) t of V..l C.Opening In I.. Nm!= I of Cue OMin TM1OH In I., St.. of TIaast (aes USDCM Fugue ST51 Tirane: NMm for Deprepi Pon (typical, Ito over, amO of 2 feat %- pig Feet., fora Sil Cure Cle, Ilyp¢al retie 0 ID) Ct fC) _ Opening WY Coealueni INpleal rem 2 3-3 6) C• IG) oper.Ig oMke Coenmmn Iryplral velm 0 so - 0 ]O) C. (Cl II Inlet Interception Capacity (assemtn clogged condition( NING. NInI GYeek for MNor and Motor St.— Grp/rtlrtgmry MINOR M LICR 0emer No. 16 C.2! Y!lon 300 Ilrly 1 60 t3o IniMa MINOR MAi M3.00 1. in 0.31 ae MINOR MAJOR 3,W B.W 3,35 0.W 2.00 0.10 0A0 370 DN .in ncM ICIbe regne, en UD Inlet 3.1-m etimplet-single, inlet In Sump 712612012 1:51 PM , INLET IN A SUMP OR SAG LOCATION project Combination Inlet Capacity MM O • Doable Combination link - Sump Condition .� to (C)—,a HZwE H.Van Wo WP w LO (G) 1"t uober of UM IOab (Gcne or Cub Opemp) WSW, GqM IS Fbvlme (oWNe of In. tlepmeelpn) reb IMunMbn aplbaf a Unit Ore. MM of a UNI Greta Ite Ooeat RaIIo for a Grna(Iyp"vapsa 0.16 M) at FPnor for a Slrtn Gas itil nvate 0.SO-0.NO War Web Coelf Awe (typal vMs 215-J 90) OMa CanfHen (to" vW 0.00 -O.m) CUM opanMp Momnlbn of a Urn Cut, 0 oran0 fleigh of Ventral Cub Oneep In IT.Ibs I-Nmight of Cub Ott. Thoet In Imhu cgn of Thor Nor USOCM Fgln ST-e) ne Worth for Deplmabn Pan ( WWW)y Iti yWlwaitlM of 2 Son) b0011O Factor for a SIIpn Cub 0WWW; Oyopo vnuo It 10) Cwb DOW, Web Coafflclere Ori vane 2.S06) ub correct OMIa CorflhnN (typical vna 0,SO .0.70) Total Inlet Interception Capacity (auumea clogged condition) CmW IS SWO for nlnor uW pYor St.. 1.0 PEMI Wnmin4 tD"—. eMrnn la not a rypkal r—Won for Ina. type apaCNNE. WamNB J Cbo9M0 hcfa k nm In Mn reenmmann•cl rnu• for 1.10Ini.1.. IN. Type- Gemar Na. 16Comblm0on No -1 2 Fbw OepM• SO 120 Ifml6 MWOR MAJOR 1.•(G)•w We=Cr(G1=Cw (G)•Do(G)• MWOR PI L. (C) ry� a Hws• rreh= Wn. Cr(C)= C..(C)= C. (0)= J.00 8.50 425 000 2.00 O.lo 0.10 3,10 0.IS 1S0 M Imllee Imae aegnae Ian UO InInI J I-cornbnnw 0.0 O1 Inlet In 5rmp 72W2013. 1:60 PM I 1 1 1 1 i 1 1 1 1 1 1 1 i 1 1 NorthernEngineering.com 11 970.221.4158 LJ I 1 I 1 I 1 1 1 1 I Stage - Storage Calculation Project Number: , , .. :.. Project Location: Fort Cuiir-- Calculations By: ATC Pond No.: F:, ! 1 Required Volume !',aa�a^n Date: 12/19/2013 Water Surface Elevation (WSE) Design Point Design Storm Required Volume— Design Storm FAA Volume= SWMM Volume= �214 n 377.3 ft' ft' ft' 4942.53 ft. N/A ft. 4946.24 ft. Contour Elevation (Y values) Contour Area Depth Incremental Area Avg. End Cumulative Volume Avg. End Incremental Volume Conic Cummulative Volume Conic (X- values) ft ft. ft w ft 4,941 166 0.00 0 0 0 0 4,942 8778 1.00 4472 4472 1476 1476 4,943 11740 1.00 10259 14731 7096 8572 4,944 13801 1.00 12771 27502 11377 19949 4,945 15970 1.00 14886 42387 13676 33625 4,946 18239 1.00 17105 59492 15822 49448 4,947 20609 1.00 19424 78916 18069 67517 4,948 230791 1.00 21844 100760 20416 87933 Stage - Storage Calculation Project Number: Project Location: Calculations By: Pond No.: Required Volume Date: 729 201 Water Surface Elevation (WSE) Design Point Fz Design Storm WQCV Required Volume= 16076 ft3 Design Storm 100-y1 FAA Volume= N/A ft3 SWMM Volume= 205890 ft3 4937.10 ft. N/A ft. 4940.94 ft. Contour Elevation (Y values) Contour Area Depth Incremental Area Avg. End Cumulative Volume Avg. End Incremental Volume Conic Cummulative Volume Conic (X- values) ft ft. ft 3 ft ft, ft3 4,935.4 0 0.00 0 0 0 0 4,936.0 5931 0.60 1779 1779 1186 1186 4,937.0 19671 1.00 12801 14580 12134 13321 4,938.0 39197 1.00 29434 44014 28878 42199 4,939.0 55695 1.00 47446 91460 47205 89404 4,940.0 60357 1.00 58026 149486 58010 147414 4,941.0 64469 1.00 62413 211899 62402 209816 4,942.0 686821 1.00 66576 278475 66564 276381 i 1 1 1 I 1 I I 1 i 1 1 1 1 1 t Stage - Storage Calculation Project Number: Project Location: . i Co)Iwis, Coic. Calculations By: "C Pond No.: Required Volume Date: 7/29/2013 Water Surface Elevation (WSE) Design Point Design Storm 4Uy Required Volume— 8759 Design Storm 100-yr FAA Volume= N/A Required Volume= 78925 ft' ft ft3 4935.92 ft, N/A N/A ft. 4940.88 ft. Contour Elevation (Y values) Contour Area Depth Incremental Area Avg. End Cumulative Volume Avg. End Incremental Volume Conic Cummulative Volume Conic (X- values) ft ft. ft ft ft 4,934.4 0 0.00 0 0 0 0 4,935 6456 0.60 1937 1937 1291 1291 4,936 9894 1.00 8175 10112 8115 9406 4,937 11542 1.00 10718 20831 10708 20114 4,938 13303 1.00 12423 33253 12412 32526 4,939 15175 1.00 14239 47493 14229 46755 4,940 17160 1.00 16168 63660 16158 62912 4,941 192571 1.00 18209 81869 18199 81111 4,942 21468 1.00 20362 102232 20352 101464 1 I 1 I 1 1 1 1 1 1 1 1 North ernE ng meering.com i/ 970.221.4158 1 1 1 1 t ATC a: 7.29.13 STORAGE & OUTLET BASIN AREA = 6.860 <-- INPUT from impervious calcs BASIN IMPERVIOUSNESS PERCENT = 38.00 <-- INPUT from impervious calcs BASIN IMPERVIOUSNESS RATIO = 0.3800 <--CALCULATED WQCV (watershed inches) = 0.174 <-- CALCULATED from Figure EDB-2 WQCV (ac-ft) = 0.120 <-- CALCULATED from UDFCD DCM V.3 Section 6.5 WQ Depth (ft) = 1.600 <-- INPUT from stage -storage table AREA REQUIRED PER ROW, a (in2) = 0.398 <-- CALCULATED from Figure EDB3 CIRCULAR PERFORATION SIZING: dia (in) = 5/8 <-- INPUT from Figure 5 - number of rows = 5 t (in) = 0.500 <-- INPUT from Figure 5 number of rows = 1.000 <-- CALCULATED from WD Depth and row spacing QUALITY POND DESIGN ATC t- 7.29.13 REQUIRED STORAGE & OUTLET WORKS: BASIN AREA = 18.870 <--INPUT from impervious calcs BASIN IMPERVIOUSNESS PERCENT = 46.00 <-- INPUT from impervious calcs BASIN IMPERVIOUSNESS RATIO = 0.4600 <--CALCULATED WQCV (watershed inches) = 0.196 <-- CALCULATED from Figure EDB-2 WQCV (ac-ft) = 0.369 <-- CALCULATED from UDFCD DCM V.3 Section 6.5 WQ Depth (ft) = 2.200 <-- INPUT from stage -storage table AREA REQUIRED PER ROW, a (in Z) = 0.962 <-- CALCULATED from Figure EDB-3 CIRCULAR PERFORATION SIZING: dia (in) = 1 <-- INPUT from Figure 5 number of rows = 7 t (in) = 0.500 <-- INPUT from Figure 5 number of rows = 1.000 <-- CALCULATED from WD Depth and row spacing 1 1 1 1 1 WATER QUALITY POND DESIGN CALCULATIONS POND 3 Project: 110-061 By: ATC QUIRED STORAGE & OUTLET WORKS: BASIN AREA = 9.370 <-- INPUT from impervious calcs BASIN IMPERVIOUSNESS PERCENT = 53.00 <--INPUT from impervious calcs BASIN IMPERVIOUSNESS RATIO = 0.5300 <--CALCULATED WQCV (watershed inches) = 0.215 <-- CALCULATED from Figure EDB-2 WQCV (ac-ft) = 0.201 <-- CALCULATED from UDFCD DCM V.3 Section 6.5 WQ Depth (ft) = 1.700 <-- INPUT from stage -storage table AREA REQUIRED PER ROW, a (in2) = 0.623 <-- CALCULATED from Figure EDB-3 TION SIZING dia (in) = 7/8 <-- INPUT from Figure 5 number of rows = 5 t (in) = 0.500 <-- INPUT from Figure 5 number of rows = 1.000 <-- CALCULATED from WD Depth and row spacing I 1 1 u ' NorthernEngineering.com /1 970.221,4158 m a N I N I O I I ' O I I � I a N I H I ] I m I I O 1 N I Z I O 1 I m I m I W I > I I I I 1 a 1 W 1 o I E Z I W I £ I W I O I al I I I I (Y I W I F I 3 1 O 1 F 1 ' W I I Q I m I W I N 4 . ro d N «++++ ,C N I O�Omml`t W.Y 1 O#0000(Im O�OO si v 1 eorrn E m l o.+0000Porlo 4 N dL momro ] O 1 OmOOO.-I ('ION�O Y O N U I N I dN v E d# O C �+1OONO H I OO 1ONOOO.YOOOfi >o y 00 ~ N N Y O O I + L N d! x O O r W c E x o 0 O N ♦ C -1 V a O IO "I N 00 Nu 1 POONOP v+J I OPOOOPO OI+IOr O« E v l .-lo m E v o 000mro^.+ « Pore.. 1n a v I o�n000�noo 0 w I T dYI N E V f oo U N N O O O N O I tiolV m > N i4 O O I I C m C; l.y000o > N 1 # 1 O O f W 1 I O O O N 4 4 1 d u d• z> m m ••• u I u I 0z 000o ro N x DNL« I woow000raa�oo::o o >• z z>. z z x ❑nn0000rl « u w m« 41 f T r + u T1 40 « Y G « « aTJ Y . . . 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I ti •-I 4 •i L I 0 0 J U O m E l o 0 N a I u I I I 3 I ti ti I Jwl N W I .4 IP M N I O m O 7 E I O N 5 O 4 4 Z I I I N 1 I 1+ I PO I L I 1 I I C I 1 � 1 I ti I 0 0 .i E I io J N I O N N N L I 1`l 1't M N I O'J I 00 5 I I N N I N I �O ry I D I �00 I C 1 10 ID 1 fil 1 P O N N 1 I ti 1 L I J J •• 101 hho I Cl I O I n.ti I 440 1 W W O I I Q) c c E I o o '•i I L I c D I J W D I W b N I u U c N N Iaa awa N I l O I �•1 '•1 N N D I D D •-I --I N C 1 C C N N U O 1 O O C C O U I U U 4 4 F NorthernEngineering.com // 970.221.4158 1 I NORM HERN ENGIt EERING Drainage Addendum Letter ADDRESS: PHONE:970.221.4158 20, S. College Ave. Suite 10 WEBSITE: Fort Collins, CO80524 FAX:970.22L4159 wwwnorthernengineering.com Date: November 27, 2012 ' Project: Kechter Crossing Project No. 110-061 Regional Storm Sewer Revisions ' Attn: Mr. Wes Lamarque City of Fort Collins Stormwater Utility 700 Wood Street Fort Collins, Colorado 80521 Dear Wes: ' This letter serves to document the storm sewer revisions associated with the. Kechter Crossing development. Said revisions have primarily been made in order to provide a more regional stormwater ' ouffall capable of serving multiple properties in the vicinity of Kechter Crossing. The changes involve the addition of an 18" RCP storm sewer in Tilden Street, as well as the upsizing of the off -site ouffall line from 24" to 36" diameter. The Final Stormwater Management Plan for Kechter Crossing, Amended September 3, 2008, by BenchMark Engineers originally designed the ouffall to McClellands Creek to accommodate 17.8 cfs. However, based upon further analysis and consultation with the City of Fort Collins Stormwater Staff, the methodology previously employed with Kechter Crossing was deemed invalid if additional properties were to be connected to the system. In order for the City to consider the drainage outall a regional facility, it must sufficiently comport to the McClellands Basin drainage master plan. ' While the off -site ouffall pipe had the potential to serve multiple properties, there was insufficient evidence to justify whether or not the system had adequate capacity. A marked -up copy of the Overall Basin Map ' from the 2008 Kechter Crossing drainage report is attached to this letter. The area highlighted in yellow is the approximate boundary of properties assumed to utilize the off -site drainage outall pipe to be constructed with Kechter Crossing. The overall tributary area was further divided into the following rough ' sub -basins; Kechter ROW (5.76-ac), Northwest (28.08-ac), Kechter Crossing (30.54-ac), Northeast (19.75-ac), and Lehman Property (37.63-ac). The McClellands Basin drainage master plan prescribes a 100-year release rate of 0.5 cfs/ac. However, the Kechter Crossing development has already been designed and approved for a peak discharge of 8.6 cfs. Therefore, this rate has been maintained. The Kechter ROW was assumed to be developed; and thus, a fixed 100-yr historic discharge of 11.2 cfs was held as a pass -through in both scenarios. The other ' basins were evaluated for both a 0.2 cfs/ac and a 0.5 cfs/ac release rate. The resultant pipe sizes for each scenario are depicted on the attached color -coded exhibit. 1 1 A 36" diameter outall pipe was selected in order for this stretch to remain a regional system, and potentially be eligible for ownership and maintenance by the City of Fort Collins Stormwater Utility. This affords the ability for properties within the Northwest and Northeast sub -basins to release at 0.5 cfs/ac when they develop in the future and connect to the Kechter Crossing off -site outall. D Projec& 110 061 @amnge 4er rk,D,amage RexrH 30-05'. Drainage -Addendum Letter 2012 '.1 26 de-, Page 1 of 2 .V INORTHERN ENGINEERING The Lehman Property, however, agreed to a self-imposed 0.2 cfs/ac restriction in the 100-year developed condition. Since the Lehman property bears the sole burden, and is the sole benefactor, of constructing the new storm sewer in Tilden Street, it was decided that a lower release rate was a reasonable offset for the cost of installing a smaller diameter pipe. In this case, an 18" storm sewer was selected. This concept was agreed to in a meeting with Fort Collins Stormwater staff on October 5, 2012. Stan Everitt with the Everitt Companies was present representing the development interests of the Lehman Property, which currently has a pending development proposal through Larimer County under the Mail Creek Crossing application. As originally approved with Kechter Crossing, Tilden Street was to be stopped approximately 30-feet short of the southern property line. The interim condition provides an interceptor Swale to divert upstream flows from the southwest around the Kechter Crossing development and towards the historic flow path on City - owned property. The approved plans include an inlet and RCP storm sewer (SD-6) to allow stormwater to pass under Tilden Street in the ultimate condition. However, the assumption is that the runoff previously intended to utilize SD-6 will now be conveyed in the new 18" storm sewer (Line A6-1) in Tilden Street. Therefore, Storm Line A6-1 will provide a pipe stub and flared -end section to the west to intercept flows from the southern boundary of Kechter Crossing. It is anticipated that the Mail Creek Crossing development (Lehman Property) will connect into the system at the southern terminus of Tilden Street (STMH A6-5) at a future date. The addition of an 18" RCP storm sewer in Tilden Street will provide a restricted outfall with 7.5 cfs capacity to the Lehman Property for future development. STMH A6 will be shifted east approximately 17- feet to accommodate the 18" RCP storm sewer incoming from the northwest corner of the City property. The off -site outfall has been upsized from 24" to 36" diameter. This provides sufficient capacity for the remaining undeveloped properties enclosed by the yellow line on the attached Overall Basin Map to release at 0.5 cfs/ac. No additional analyses or modifications are expected with this proposed drainage revision. Please do not hesitate to contact me if you have questions or require additional information. Nicholas W. Haws, PE qp cc: Traci Shambo - Larimer County Engineering Dave Oswandel - Brinkman Partners Stan Everitt - Everitt Companies (Cloud Peak Ranch, LLC) Michael Bird - Mentage Homes enc. I 1 1] DRe.ad-:10061 Dmnage-Wdendoil-Lute, 201211-25.doa Page 2 of 2 ' 0 0,2_cfo/a_c 0.5 cfs/ac 30" 36" ' 18"' 30" 18" 24" 'selected pipe size EILI� I I 11" NorthernEngineering.com // 970.221.4158 W INORTHERN ENGINEERING EROSION CONTROL REPORT MAIL CREEK CROSSING A comprehensive Erosion and Sediment Control Plan and associated details will be included with the final construction drawings. It should be noted, however, that any such Erosion and Sediment Control Plan serves only as a general guide to the contractor. The staging and/or phasing of the Best Management Practices (BMPs) depicted, and additional or different BMPs from those included may be necessary during construction, or as required by the authorities having jurisdiction. It shall be the responsibility of the contractor to ensure erosion control measures are properly maintained and followed. The Erosion and Sediment Control Plan is intended to be a living document, constantly adapting to site conditions and needs. The contractor shall update the location of BMPs as they are installed, removed or modified in conjunction with construction activities. It is imperative to appropriately reflect the current site conditions at all times. The Erosion and Sediment Control Plan shall address both temporary measures to be implemented during construction, as well as permanent erosion control protection. Best Management Practices from the Volume 3, Chapter 7 — Construction BMPs will be utilized. Measures may include, but are not limited to, silt fencing along the disturbed perimeter, gutter protection in the adjacent roadways and inlet protection at existing and proposed storm inlets. Vehicle tracking control pads, spill containment and clean-up procedures, designated concrete washout areas, dumpsters and job site restrooms shall also be provided by the contractor. The Grading and Erosion Control Notes can be found on Sheet CS2 of the Utility Plans. The Final Plans will contain a full-size Erosion Control sheet, as well as a separate sheet dedicated to Erosion Control Details. In addition to this report and the referenced plan sheets, the contractor shall be aware of, and adhere to, the applicable requirements outlined in the Development Agreement for Mail Creek Crossing. Also, the site contractor for this project will be required to secure a Stormwater Construction General Permit from the Colorado Department of Public Health and Environment (CDPHE), Water Quality Control Division — Stormwater Program, prior to any earth disturbing activities. Prior to securing said permit, the site contractor shall develop a comprehensive Stormwater Management Plan (SWMP) pursuant to CDPHE requirements and guidelines. The SWMP will further describe and document the ongoing activities and inspections and maintenance of construction BMPs. 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City of Fort Collins, Colorado UTILITY PLAN APPROVAL APPROWD tlty ee0lneee Oete CHECKED BY: WN 1 e filer ! br V Wty DeY CHECKEE BY: av CHECKED BY �— DIN, ]IECKED Bl: —— -� D=te NECKED BY —� Dele (7 Z Sheet DR1 Of 54 Sheets OWNER: LIE&JAME51?AMEIA S '.. Awl nMBEwJNE RD. FORT COWNS CO `— OWNER OffifiBFA. ANDERSONJAMESIY DELGRANDE HENSTE%NNIE DEBPAL 22f7TECHTER RD 61095. nMBEPoJNERO FORT COLLINS, CO FORTCIXIIN$W y ROBOT Awl awl FO • / C \ \ SF \ V BACON UcELEMENTARY sr Too � A ZEPHYR ROAD _ IBC'ROWI -�- I IpI -7 NOTE. DO BMPS SIgWN ON THIS PLOP AflE GRAF MC flEPRESEMATION50NLY. FINALDETEWAINATIOIOESILE NO LOCATION E. BE DETERMINED BY THE COMMCTCR ND DOCIIMENEED ON THE DYNMIIG SHE PLAN. Iva A _�—EASTNG IY BEGIN ORW M L I JI IIU I II L== A 1 P SPRLICEC ,r, r 1 I MPHYRROAD (BSI ROW) .�. .. EASDNG WRIGA➢ONl STRUCTURE ��FF�gg9 EROSION CONTROL NOTES IT SHOWED BE MOM MAT MY EROSION Cd1R0. PLAN SERVES SURRWNgHG SURFACE TYPE AND CDOITCR (Lt.. STAGE-DnKll ONLY AS A GUIDELINE TO ME CONTRACTOR. HEADING STAGING AHDO SEDI MENT CONTRA. LOCH OR SILT RIGS FOR BARE WIT, BASS PHASING OF BEST MANAGEMENT PRACTICES (Ali.) IS EXPECTED. SAM EF GRAVEL SOCAS FOR PAVEMENT. Eal ADDITIONAL AND/OR DIFFERENT CNPA FROM T CD3 Y DEPICTED MAY BE NECESSARY DURING DORCHE TER DUE TO PE PUDDING EACNTES SHALL BE LOCATED AT LEAST ME WMRFn CHANGING SIZE CONDITIONS ON AS REWIRED BY LOCAL (INS) FEET EACH NATURAL HWY OF WATER W MAHD. NATURAL AUMDllnES. DRANAGE WAY DM MANMADE DRAINAGE WAY. ME FUEL TANKS D SUELING AREA UST BE CONTAINMENT R AREA M MIS EROSION CONTROL Z LM N IS SCHEMAIN MATURE. AS SUCH. NLL HOT ALLOW A NEL SPILL i0 DIRECTLYRUIN ROW, BEEP, W GRAPHICAL SBOS WAY NOT BE 10 SCALE. HER ARE THEY OFF, M BE WASHED INTO A BODY BE WATER. NEnAFO OR NECESSARILY RICAN IN THEM EXACT LOCATOR. MAMACE WAY. 3 ME CONTRACTOR SHALL BE RESPONSIBLE FOR ALL PERMITTED 11. CONSTRUCTOR WASTE STORAGE (WIKTFRS) AND PMTADE GLDISCHARGE PERMIT. STATE DI MIT. ETCM .) AND COMPLIANCE M OR SANITATION UNITS (CONSTRUCTTOIETS) SMALL HE LOCATED CAUTHORITIES C SCALE BE ME ESPONED&I BE T LEAST RELY (MG FEET FROMMy STMMWAINR INLET, ME CONTRACTOR (MPREFER) HR) TO ENSURE EROSION WEII.WD. ON MHHAGE WAY, SAD EXCITES USi BE SEi M CONTROL MEASURES ARE LATTERLY MAINTAINED AND ECLLONED A CONTAINMENT AREA MAT HALL NOT ALLOW PCLLUTANI. TO DIRECTLY FLOW. SEEP. RUN OF. M GE WASHED INTO A HWY OF •. CONTRACTOR STALL IMPLEMENT THE APPROPRIATE EROSION WATER WETLAND M DRAINAGE WAY. oVMFSTFRs 91ALL BE CONTROL MEASURES ACCORDING ME ME WASINurnM LOCATED ON FIAT. STABLE GROUND. AND CONSTRUCTION NOTES SEQUENCING AND LEVEL CF S E STABuznnM. SNARL GE STAKED DOM 5. CONTRACTOR SHALL IMPLEMENT NMMMAR INLET PROTECTION 12 ME CONTRACTOR ANSI ALL SIBCMMACTMS MUL C0.'0.4ATE M ALL STORM CHAINS SAUDI AND BONDS UNTIL SITE IS HIM ME CODES CMSIRUCnM INSPECTORS BY CEASING FULLY STAMUZEO. OPERATIONS HHEN MHDS ARE M STUmEENT K1OyTY TO CREATE MTEL PROTECTION STALL BE ADAPTED AS KOBSMY. TO ME SLOMNG DUST MTHIICH. IN M INSPECIORS CREM, IS HAZARDOUS TO HEALTH AND WELFARE, SURROUNDING p RFACE TYPE AND CENDnM N„ rrAKE-DRlgl WAYS ED FORRE SqL OR SAM Ml SCHEME BST 1], WHEREMEH SEASONAL CONSTRAINTS LEG, DURING WMAND PAAEMET NETC.) HANTER MONTHS) INHIBIT PERMANENT SEEDING CR4HATIMg ACTOR IS RESPONSIBLE FORSTABIUMG ALL STORES. DISTURBED AREAS ALL HE TREATED BUD MULCH AND MULCH TAWFIW ON OTHER MATERIALS AN REI BY EROBIM CONTROL PARTICULARLY THOSE STEEPER MAN 6:1. CRIMP MULCHING. STAFF i0 PREANT EROSON. BLAME MULCHING EROSION MATS TEMPORARY MRIG.ATM, AND ADDITIONAL WATTLES OR SET FENDING MAY SE NECESSARY To IT SEE LANDSCAPE PLANS FM ADDITIONAL IWMMAnO M ESTAMUEI VEGETATIVE COVER AND STMUTE THE SINE, STARTING, RIAMETATM. HMECAPE AND OTHER COMMENT S. ADDITIONAL MATTES. SET FNCE, M OTHER WAA % MAY BE SEE STABILIZATION MEMMS, IfQ$WY TO INSURE THAT EACH BMONG PAID IS WANTED T&DEWA1MNFSSIALL sEOMEHT BE TO MCONSTRUCTOR MSRMETR ME B CONTRACTOR SNAIL IMPLEMENT APPROPRIATE PERIMETER PRORCIIOM FOR AREAS MECTNC DRAINAGE01I FOUNDER PROTRTM SIMLL GE ADMTED AS NECESSARY. TO ME e NORTH 1WaCO 200 SWBNA IN FEET ) mm_ 1W it, LEGEND PPDPJSED SRNM 4MR PROMISED UNOERpWN W PRCPGSED INLET PROMISED CCMWR 9$ - EXISTING COW - ---• 5 — — — PROPOSED SWALE - - - PROPOSED CURB a CUTTER PROPERTY BOUNDARY SHE FENCE VEHICLE MACHINE CONTROL PAD ER09ON FABRIC EF O INLET PROIECTICR ® IP ROM SUCH STRAW WATTLE n %E W RIP RAP RP BENCHMARK/BASIS OF BEARING BENCHIMIDEM BIT, NFDA Call BentlnuM 20.94 E mMM=AMN BENCHMARK SO GNa EGA GISIM Be1MaMM2L3 Elewlm AND 18 Bass 0 DILI n umingtnWesthneoftENaMvealQuaOsadona,TON., BMW., as Tea gN WM1736-We aOSWn[ 02el5.lif" MalloNw OeannD =Ca,ledns nlelalrve Sel The Ines' clunwinaming as sn1.mM Mil an CROP 1OW'u 5, SUlrey FGI GENERAL NOTES: 1. CONTRACTOR SHALL MMEDAMLY STAL Z /1L NSNRMD SLOPES BY CRIMP MULCHING OR SIMILAR METHODS. ], SWMP Ap1N5IRATOR Conlael CemPwy P�p,,AN I CONTRACTOR TO EROMDE MUSCLE TRACING CONTROL FOR CONCRETE WASHOUT ARSA IF ACCESS IS ON PAMIENT. • KKR TO ME 'nNOL DRAINAGE AND EROSION CONTRA. REFDR FOR MAIL CREEN CROSSED' BY NORMERN ENGINEERING, DATE ME MBER IB 2013 FOR AMMONN MFCRMATON. FOR DRAINAGE REVIEW ONLY NOT FOR CONSTRUCTION cHL LnKm xomumx CENTER M • KmAMeYaOBIDW. CBIIDME.�lalp. City of Fort Collins, Colorado UTILITY PLAN APPROVAL MPRDMM EW Leo D.I. ORDERED BY: WA Wale, k W elu A MITI Oele MECNED By Ilmeelee IMMY 4 OPPOSED BYI METED BY H DY CHECKED BY: SIX, J AElf �Z LL Z W i F—z 'Ff OZ c� Zw �dl�glg'J z a J O R' U H Z Y OU W Z O ''_^^ V! LL w sh t EC1 Of 54 Sheels