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HomeMy WebLinkAboutDrainage Reports - 02/20/1995I C eiPwiW1 ffllffy""O Prepared For: U.S. West Prepared By: Northern Engineering Services, Inc. 420 S. Howes, Suite 202 Fort Collins, Colorado 80521 (303)221-4158 Project Number: 9428.00 Northern Engineering Services, Inc. 1 1 IDecember 28, 1904 ' Mr. Glen Schlueter City of Fort Collins Stormwater Utility 235 Mathews tFort Collins, Colorado 80522 RE: U.S. West Garage Facility Fort Collins, Colorado Project Number: 9428.00 Dear Glen: ' Northern Engineering is pleased to re -submit this Final Drainage Report for the U.S. West Garage Facility for your review. ' We have addressed your comments contained in the red -lined Drainage Report dated November 28, 1§94. Landstar Surveying is in the process of revising the retention easement exhibit to submit along with the Deed Of Dedication For Easement. It is my understanding that the Drainage Plan and report will be signed upon receipt of a copy of the signed deed. If you should have any questions or comments as you review this revised report, please feel free to contact me at your ' convenience. Sincerely, NORTHERN ENGINEERING SERVICES, INC. Via... f3_ vV ►�` Q,W EGi'h�hi Mary B . Wohnrade , `���Q�•.�` f°•. dj��,,� Proj ct En ne p� �,P ✓p•Fy 25033 N Sipe ram: Michael F. Jo s, P.E. y�.c�•. k,� 1 420 S. Howes • Suite 202 • Fort Collins, Colorado 80521 • (303) 221-4158 • Fax (303) 221-4159 Colo. Hwy. 287 I 1 j i Long Pond C�C'P -'• �o'L. Lo Willox Ln. Lindenmeier Lake Zm .o y Lee �� o'�o �•.. �P• r�P� Lake I Vine Dr. ' Final Drainage Report for U.S. WEST GARAGE FACILITY Fort Collins, Colorado November 28, 1994 GENERAL LOCATION SITE DESCRIPTION ' General Location This report summarizes the results of a storm drainage investigation for the proposed U.S. West Garage Facility improvements. The project is located in the SE Quarter of the NE Quarter of Section 13, Township 7 North, Range 69 West of the 6th ' Principal Meridian in Fort Collins, Colorado. The project is bounded by East Laurel Street on the north, Colorado Street on the west, and South Lemay Avenue to the east. (See Vicinity Map). Site Description 1 The 1.91 acre site is located in downtown Fort Collins and is currently a storage and garage facility for U.S. West vehicles and equipment. The site is partially paved, on the west and south ' sides of the existing building, and the remainder is gravel. The site generally slopes from west to east at approximately 1%. Surrounding land use patterns are residential to the north and west and, commercial to the east. Laurel Street Elementary School is adjacent to the site on the south and southwest. ' H. HISTORIC DRAINAGE Major Basin Description The project is located in the Old Town Drainage Basin which has almost entirely undergone urban development. The existing storm sewer system within the Old Town Basin is in generally good condition according to the "Old Town Master Drainage Basin Plan for ' Final Drainage Report November 28, 1994 U.S. West Garage Facility Page 2 ' II. HISTORIC DRAINAGE. con't the City of Fort Collins, Resource Consultants & Engineers, Inc. ' (RCE), January 7, 1993. ' Historic Drainage Patterns The historic drainage pattern of the proposed site can be divided into three small basins. Basin H1 drains the southern most ' portion of the site to the south, into an existing drainage swale which then runs east to existing curb and gutter behind Longs Drug Store. Basin H2 drains the majority of the site to the east into ' an alley adjacent to the east property line. Basin H3 currently drains north out to Laurel Street and into an existing drop inlet in the south flowline of Laurel (See Historic Basin Map in ' Appendix). A minor amount of off -site runoff enters the site along the south and west property lines from Laurel Street Elementary School. ' There are no existing drainage facilities on -site. ' III. DEVELOPED DRAINAGE Developed Conditions ' The proposed site improvements include paving the gravel parking lot on the south and east sides of the existing garage facility. ' Design Criteria and References ' Drainage criteria outlined in both the City of Fort Collins Storm Drainage Design Criteria Manual (SDDCM) and Storm Drainage Criteria Manual by the Urban Drainage and Flood Control District have been used for this Final Drainage Study. The Old Town Master Drainage Basin Plan has also been referenced. ' Final Drainage Report November 28, 1994 U.S. West Garage Facility Page 3 111. DEVELOPED DRAINAGE con't ' Hydrologic Criteria The Rational Method was used to estimate peak stormwater runoff from the proposed site improvement. An initial 2-year design storm and major 100-year design storm was used to evaluate the proposed drainage system. The proposed retention facility has been designed for the 100-year storm frequency. Rainfall intensity ' data for the Rational Method was taken from Figure 3-1 of SDDCM. Hydraulic Criteria ' The City of Fort Collins Storm Drainage Design Criteria has been used for all hydraulic calculations. General Drainage Concept Under developed conditions, Basin H3 will remain unchanged due ' to conditions remaining the same in this basin. Developed runoff from Basin D1 will increase slightly over historical rates due to the increased imperviousness caused by additional paving, but would ' not warrant detention. Basin D2 will experience the most dramatic increase in runoff and will require on -site parking lot retention. Specific Details Developed stormwater runoff will sheet flow across the paved parking area of Basin D2 and into a twenty (20)-foot wide, 0.46' ' deep gravel swale along the east property line. The minimum proposed grade along the east property line is 4960.50. Water will be retained in the gravel swale and paved parking area up to this ' minimum elevation. Above this elevation, water will spill to the east as is has done historically. ' Storage provided by the swale and parking area below an elevation of 4960.50 has been calculated to be 7,479.94 cubic feet. The anticipated volume of developed runoff from the 100-year storm is 6,337.5 cubic feet. The estimated volume of the proposed retention then, would be 1.5 X 6,337.5 = 9,506.25 cubic feet. The 2-year historic volume of runoff from Basin H2 has been estimated to be 2,689.5 cubic feet. The volume of spill to the east from the ' U.S. West - site during the 100-year event would be 9,506.25 - 7,479.94 2,026.31 cu-ft which is less than the calculated historic volume. These figures are based on the Rational Formula using a block rain, which represents the average intensity of the most intense portion of the rainstorm. ' Final Drainage Report November 28, 1994 U.S. West Garage Facility Page 4 ' Specific Details. con't ' Water retained on -site in the parking and swale areas would eventually infiltrate thru the clay fill and into the natural sand stratum located approximately two(2)-feet below existing grade (See ' Soils Report). The retention pond would be temporary until such time as the ' Master Drainage Plan improvements are constructed down Laurel Street. At that point, the pond would be converted to detention and stormwater released at a 2-yr historic rate to the flowline of Laurel. It is anticipated that Laurel Street will be lowered ' approximately 1.0 foot from information given in the Old Town Master Drainage Basin Plan. ' A future land acquisition along the east propertyline of 16.8' would enable the pond to be enlarged to accommodate additional detention volume. From the rational method mass diagram, using an assumed future release rate of 2.5 cfs, the required detention volume would be approximately 11,265 cu-ft. Expansion of the pond would be required to increase the volume from 7,479.94 cu-ft (retention) to 11,264 cu-ft (detention). Should the land acquisition fail, additional volume could be acquired by raising the top of berm along the east property line to an elevation of 61.0 or greater. ' Developed conditions in Basin H3 will remain the same as historic. ' Developed conditions in Basin D1 will be altered slightly from historic. Additional paving will contribute to a slight increase in basin imperviousness from a composite runoff coefficient of 0.43 ' to 0.50. The minor increase in developed runoff would not warrant a detention facility. ' IV. EROSION CONTROL Due to the brief and unobtrusive nature of the project, ' erosion control will not be necessary. V. CONCLUSIONS Compliance with Standards All drainage analyses have been performed according to the City of Fort Collins Storm Drainage Design Criteria Manual (SDDCM) and the Urban Drainage and Flood Control District's Drainage Criteria Manual. ' Final Drainage Report November 28, 1994 U.S. West Garage Facility Page 5 Summary of Drainage Concept ' Tentatively, the City of Fort Collins and U.S. West are coordinating a land swap in order to accommodate a future ' neighborhood park adjacent to Laurel Street Elementary School. The southern portion of the existing project site would become park area, and in turn, an equal square footage of the parking and ' storage area would be relocated east of the existing east property line where an alley is currently located. Measures have been taken to ensure adequate drainage ' facilities have been provided with consideration given to public health and safety, and the temporary nature of the proposed improvements. Properties upstream and downstream of the proposed ' site improvement will not be adversely impacted by developed runoff. The overall concept set forth in the Old Town Master Drainage Plan has been considered in the preparation of this Final Drainage Report U.S. West Garage Facility REFERENCES November 28, 1994 Page 6 1. Storm Drainage Design Criteria and Construction Standards. City of Fort Collins, Colorado, May, 1984. 2. Old Town Master Drainage Basin Plan for the City of Fort Collins, Resource Consultants & Engineers, Inc., Fort Collins, Colorado, January 7, 1993. 3. Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual, Wright - McLaughlin Engineers, Denver, Colorado, March, 1969. 4. Geotechnical Engineering Report, Proposed Paved Parking Lot U.S. West Maintenance Facility, Empire Laboratories, Inc., June 2, 1994. Final Drainage Report U.S. West Garage Facility APPENDIX November 28, 1994 Page 7 Historical Drainage ........................... Developed Drainage ............................ Developed Detention ........................... PAGE 1 - 4 5 - 9 10 - 11 0 CL a: w N 0 W W LLI W o: 3 Z 0 0- 0_ M 2 H1 RESIDENTIAL /,J RESIDENTIAL ... �, . J ... . ... ... J .. _ ... U Q2= 1.2 CFS I EAST LAUT 4.5 CFS F�EL-STREE -EXISTING --"-� '�._._._•--' �-...,�� o DROP INLE 1 X _. c- KA 4771 _ , ■ �r` 1 ; ■ NORTH t ■ f' 1 "� SCALE 1• _ 60, A } "■ s # z■ r � Ld f W o ■ r �. ! J■ ( 1 i om i —■ / t 1 s m J = � ai M ■ V. ■ ■ z■ to ■ H3 59 x j w■ EXIST. % CONCH . PADS H2 FL s a 0 PAD ..7 j MATS. �1•.i';�.% :�• r H1 MISTIN�b �• J CbNCRETE y �p\ .t j \ ��. ELEM NTE EAF2YSC OOL A i --- DaSTING STORM SEWER _ _ = OaSTNG STORM DRAINAGE INLET HISTORICDRARNGE BASIN O BOUNDAEXISTING ROWUNE i HISTORIC FLAW PATTERN -----N.....-..- DUSTING CONTOUR H 1 rHl BASIN DE'afANTOR 0.2 AREA IN ACRES © DESIGN POINT 02= 2.2 CFS 010O= 8.9 CFS ■ GIST. STORAGE F'TRAILERS, '(NO OUNDATIONS) 02= 0.3 CFS Q1OO= 1.1 CFS FLOW TO EXIST. CURB POND GUTTER /(1 r$ HISTORIC DRAINAGE U.S. WEST GARAGE FACILITY, Fort Collins, CO. File Number: HSTBSNHI.WQ1 O Calcs Bv: MBW I TOTAL AREA = A (ac)= 0.278 RUNOFF COEFFICIENTS: (From Table 3-3) Area of Roofs (ac)= 0.0026 C for Roofs = 0.95 Area of Concrete (ac)= 0.0304 C for Concrete = 0.95 Area of Gravel Parking (ac)= 0.127 C for Gravel = 0.50 Area of Lawn & Landscape(ac)= 0.118 C for Gravel = 0.20 COMPOSITE RUNOFF COEFFICIENT: C = 0.95(0.0026+0.0304ac)+ 0.50(0.127ac)+ 0.20(0. = 0.43 0.278 If = 1.00 (Frequency Adjustment Factor; Storm Return Period of 2. Years) ;f = 1.25 (Frequency Adjustment Factor, Storm Return Period of 100- Years) OVERLAND FLOW: (Across Gravel Parking) Total Overland flow length = 81' L (ft)= 81 S(%>= 64.4-62.36= 81 C = 0.50 SWALE FLOW: (From West to East in Existing Swale) L (ft)= 216 S (%) = 6236 - 61.18 = 216 T2 = 1.87 (1.1 -CCf) SQRT(L) = 7.4 min CUBRT(S) 252 T100 = 1.97 (1.1- CCf) SQRT(L) = 5.9 min CUBRT(S) Tt = L = 2.7 min 0.55 V(fps) = 135 (From Figure 3-2) 2-YEAR TIME OF CONCENTRATION, Tc2 = 7.4 + 2.7 = 10.1 min 100-YEAR TIME OF CONCENTRATION; Tc100 = 5.9 + 2.7 = &5 min RAINFALL INTENSITY: FROM FIGURE3-1: i2(in/hr)= 2.5 i100(in/hr)= 7.4 Q2(cfs) = CCf x Q x A = 0.3 Q100(cfs) = CCf x i100 x A = 1.1 orthern enaineerina services. inc. 1 , HISTORIC DRAINAGE ' U.S. WEST GARAGE FACILITY, Fort Collins, CO. File Number: HSTBSNH2.WQ1 ' BASIN 112: TOTAL AREA = A (ac)= ' Area of Roofs (ac)= Area of Concrete (ac)= ' Area of Gravel Parldng (ac)= Ca)cs Bv: MBW 1.88 RUNOFF COEFFICIENTS: (From Table 3-3) 0.2170 C for Roofs = 0.95 0.1530 C for Concrete = 0.95 1.510 C for Gravel = 0.50 COMPOSITE RUNOFF COEFFICIENT: ' C = 0.95(0.217+0.153ac)+ 0.50(l.5lac) = 0.59 1.88 ' Cf = 1.00 (Frequency Adjustment Factor; Storm Return Period of 2- Years) Cf = 1.25 (Frequency Adjustment Factor; Storm Return Period of 100- Years) ' OVERLAND FLOW: (Across Gravel Parldng) Total Overland flow length = 265, L (ft)= 265 1 S (%) = 64.4 - 60.64 = 265 C = 0.50 . T2 = 1.87 (1.1 - CCf) SQRT(L) ^ = 16.3 min CUBRT(S) 1.42 T100 = 1.87 (1.1- CCf) SORT(L) = 12.9 min CUBRT(S) 2-YEAR TIME OF CONCENTRATION, Tc2= 16.3 min 100-YEAR T]ME OF CONCENTRATION, Tc100= 12.9 min RAINFALL INTENSITY: FROM FIGURE 3-1: Q2(cfs) = CCf x i2 x A = Q100(efs) = CCf x i100 x A = orthern enaineerina services, inc. I i2(in/hr)= 2.03 2.2 8.9 i100(in/hr)= 6.4 O C HISTORIC DRAINAGE U.S. WEST GARAGE FACILITY, Fort Collins, CO. File Number: HSTBSNH3.WQ1 08-Se -94 Calcs By: MBW BASIN H3: TOTAL AREA = A (ac)- 0.595 RUNOFF COEFFICIENTS: (From Table 3-3) Area of Roofs (ac)= 0.281 C for Roofs = 0.95 Area of Concrete & Asphalt(ac)= 0.242 C for Concrete = 0.95 Area of Lawn & Landscape (ac)= 0.072 C for Lawn = 0.20 COMPOSITE RUNOFF COEFFICIENT: C = 0.95(0.281+0.242ac)+ 0.20(0.072ac) = 0.86 0.595ac Y = 1.00 (Frequency Adjustment Factor, Storm Return Period of 2- Years) f = 1.25 (Frequency Adjustment Factor; Storm Return Period of 100- Years) OVERLAND FLOW: (Across Laurel Street School Lawn) Total Overland flow length = 79' T2 = 1.87 (1.1- CCf) SQRT(L) = 9.6 min L (ft)- 79 CUBRT(S) S (%) = 65.5 - 615 = 3.80 T100 = 1.87 (1.1 - CCf) SQRT(L) = 9.1 min 79 CUBRT(S) C = 0.20 SWALE FLOW: (Along West Propertyline out to Existing Wet in Laurel Street) L (ft)= 194 Tt = S (%) = 62.5 - 60.78 = 0.93 184 V(fps) = 1.90 (From Figure 3-2) 2-YEAR TIlAEE OF CONCENTRATION; Tc2 = 9.6 + 1.6 = 11.2 min 100-YEAR TIME OF CONCENTRATION; Tc100 = 9.1 + 1.6 = 10.7 min RAINFALL INTENSITY: C(in/hr)= 2.4 . i100(in/hr)= 7.1 02(cfs) = CCf x Q x A = 1.2 Q100(cfs) = CCf x i100 x A = 4.5 1 orthern enaineerina Services. inc. L = 1.6 min 60M C DEVELOPED DRAINAGE U.S. WEST GARAGE FACILITY, Fort Collins, CO. File Number: DEVBSNDI.WQ1 12-Se -94 Calcs By: MBW BASIN D1: TOTAL AREA = A (ac)= 0.278 RUNOFF COEFFICIENTS: (From Table 3-3) Area of Roofs (ac)= 0.0026 C for Roofs = 0.95 Area of Concrete & Asphalt(ac)= 0.0791 C for Concrete = 0.95 Area of Gravel Parking (ac)= 0.0778 C for Gravel = 0.50 Area of Lawn (ac)= 0.1185 C for Lawn = 0.20 COMPOSITE RUNOFF COEFFICIENT: C = 0.95(0.0026+0.0791ac)+0.5(0.0778ac)+0.2(0.11 = 0.50 0.278 Cf = 1.00 (Frequency Adjustment Factor, Storm Return Period of 2- Years) Cf = 1.25 (Frequency Adjustment Factor, Storm Return Period of 100- Years) OVERLAND FLOW: (Across Paved and Gravel Parking) Total Overland flow length = 81' L (ft)= 81 S (%) = 64.4 - 62 36 = 81 C = 0.73 SWALE FLOW. (From West to East in Ejdsting Swale) L (ft)= 144 S (%) = 62.36 - 61.31 = 144 T2 = 1.87 (1.1- CCf) SQRT(L) = 4.6 min CUBRT(S) 252 T100 = 1.97 (1.1 - CCf) SQRT(L) = 14 min CUBRT(S) 0.73 V(fps) = 1.35 (From Figure 3-2) Tt = L = 1.8 min 60(M 2-YEAR TIME OF CONCENTRATION; Tc2 = 4.6 + 1.8 = 6.4 min 100-YEAR 71ME OF CONCENTRATION; Tc100 = 2.4 + 1.8 = 4.2 min (Use 5-minute minimum) RAINFALL INTENSITY: FROM FIGURE 3-1: i2(in/hr)= 2.97 i100(in/hr)= 9.0 Q2(cfs) = CCf x Q x A = 0.4 Q100(efs) = CCf x i100 x A = 1.6 lorihern enaineerina services. inc. 0 DEVELOPED DRAINAGE U.S. WEST GARAGE FACILITY, Fort Collins, CO. File Number: DEVBSND2.WQ1 ] TOTALAREA = A (ac)- 1.88 RUNOFF COEFFICIENTS: (From Table 3-3) Area of Roofs (ac)= 0.2170 C for Roofs = 0.95 Area of Concrete & Asphalt(ac)= 1.432 C for Concrete = 0.95 Area of Gravel Parldng (ac)= 0.231 C for Gravel = 0.50 COMPOSITE RUNOFF COEFFICIENT: C = 0.95(0.217+1.432ac)+ 0.50(0.231ac) = 0.89 1.88 Y = 1.00 (Frequency Adjustment Factor, Storm Return Period of 2- Years) Y = 1.25 (Frequency Adjustment Factor, Storm Return Period of 100- Years) OVERLAND FLOW: (Across Paved Parldng) MBWI Total Overland flow length = 267 T2 = 1.87 (1.1- CCf) SQRT(L) = 3.8 min L (ft)= 267 CUBRT(S) S (%) = 64.4 - 59.7 = 1.76 T100 = 1.97 (1.1- CCf) SQRT(L) = 2.5 min 267 CUBRT(S) C = 0.95 2-YEAR TIME OF CONCENTRATION, Tc2= 3.8 min (Use 5-minute minimum) 100-YEAR TIME OF CONCENTRATION, Tc100= 2.5 min (Use 5-minute minimum) RAINFALL INTENSITY: FROM FIGURE 3-1: i2(in/hr)= 3.29 i100(in/hr)= 9.0 02(cfs) = CCf x i2 x A = 5.5 0100(cfs) = CCf x i100 x A = 16.9 r iorthern enaineerina services, inc. r I I 1 1 1 Table 3-3 RATIONAL METHOD RUNOFF COEFFICIENTS FOR COMPOSITE ANALYSIS 1 Character of Surface Runoff Coefficient Streets, Parking Lots, Drives: Asphalt................................................................................................ 0.95 Concrete............................................................................................. 0.95 Gravel................................................................................................. 0.50 Roofs.......................................................................................................... 0.95 Lawns, Sandy Soil: Flat<20/6 ............................................................................................. 0.10 Average 2 to 70° 15 0.20 ' Steep >7% . ................................................................................... 0.20 Lawns, Heavy Soil: Flat<2%............................................................................................. 0.20 Average2 to7% 0.25 Steep >7% . ................................................................................... 0.35 .................... ................ 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Sawa■!/eeias•::..aea�..■ee.wevi/■..et,/■...raeel....:�GiiGGiiGaGiTifiG/ei0 i..■.arm;i.w■��■�i/.eJ��/�■�.el�.■1�.i. ■....■■.lGCIOa e�CCCC:CCCiC.�.CCi...�� ■.■�-�s.evz.r.u. ev�a■..e.�i.■u.0 u.!.'�ru■gmme..■.....n...esseo owew..!�^.r�■���'.v r�/���P�CQ S�I!lCwl�s�l.�A!!!!•!i�e�l�ll•CINI� /r/��r1■��* I�!•�����!•�� _�..■.na..s./c=..■wwmwa=�..■....e.Sew=..es.e.e.el..e.i.ess..ww........s rrr.rru.rN■■wrrrrr...r■r■r■■■■■■■■r.r■■■■■■.■■ur■■■.rr■■■r■■us■■.rr. DRAINAGE CRITERIA MANUAL RUNOFF 0 5( 3C F- 2 a z W V IY W °' 10 z W IL U5 W cc 3 n O U 2 W t- 3 1 5 - �MEN�� IA IAIIIIIIIIIIII ===W■�� II /A■I.11 //MEN 1110IM■NE■� MEIIMORION �— c •0 1 2 3 5 VELOCITY IN FEET PER SECOND 10 20 FIGURE 3-2. ESTIMATE OF AVERAGE FLOW VELOCITY FOR USE WITH THE RATIONAL FORMULA. f MOST FREQUENTLY OCCURRING"UNDEVELOPED" LAND SURFACES IN THE DENVER REGION. REFERENCE: "Urban Hydrology For Small Watersheds" Technical Release No. 55, USDA, SCS Jan. 1975. 5 -1-84 URBAN DRAINAGE & FLOOD CONTROL DISTRICT TW GA LL H l�h T% /V7 Ihl I n. v h 1✓ .R�� �O �l V «(i, ✓t 1-41 rroril L Z - YZ /2"N o VOA-- , All E ; L3s3sr J j 1-4 Z Tr-ft TEXT II STM12- �y...-rt � L3= T Mc=n-1t=7,T ALA .4-,�- 13r=rJ LAR-/'So r J .4 S / I fit- R-�Z Srp H � ! ` 05 1/0� An � O i= ,�-�..� o � - f�Gt-I I tit � n'1•L� /ZCT C�Tr .�iJ /-+3c.� ITL' VT f J -rTt' P-An tDL ,A -Ow *orb (M „-r ). (cr=f ) vIr Ir.l Az12- , ro �.rL !✓1 c-n-iv�` VZ = Z_Z4t3 �lle.3n �1 Gosh I.Z�) = Z,,(o89.5 3 scc / M,,j OE✓etrcmP:c7:> 1--1--tial=Mf= PPon., NlL,tr-r /2L-T-A,�l I•S(0.) = I.S(I(o.-) = Zs.35�s \ 3 V n' J r �oO Sew ) = I I70:w . L7 MIS /O rM42 tH tiJT Ta 6le P-t:?rA" ,�� I-jLR-0 wuC-V- or 4,,5vo, so = %, 4-701.'94 O, - rag- ht7- wrht r� 1491 c�-:=T < 14,rToa.,L ✓ow rv, L o f Lr L e -i . OtK 1 1 i 1 1 1 1 1 1 1 1 1 1 1 i 1 1 1 1 'C7 O 0 3 .�. O rzCD> o -It�0.�AON caz sztn �o � N ooz a.aw' (D� E E N U O N � O o 7 Cl)O U E 7 O C � L 0 Q 3 0 o i o `. M U C �s O a U N W O O M r� O O O 6666 Q1 't M N Q) O a) 0) O O) r r� r� U7 M � M O O 00 00 N 00 O (D O — U) U') o O O _ Q) N O) O 00 N U) O C6 O co O O O N U) N N O O O M U1 (D U-) O) O) O O L) U') CO CO /L RATIONAL METHOD MASS DIAGRAM PROJECT: U.S. WEST GARAGE FACILITY RUN DATE: FUTURE DEVELOPED BASIN D2 23-Nov-94 02:17:52 AM DETENTION POND C Cf AREA RELEASE. (ac) - (cfs) v.89 1.1236 2.05 2.5 Volume Storage Time i Q Volume outflow Volume (min) -------------- ----------- (in/hr) ----------- (c£s) ---------------- (cu ft) --------------- (cu ft{ ------------------- (cu ft) 0.00 0.00 0.00 0.00 6.00 7.00 14.35 5,166.02 900.00 4,266.02 12.00 6.70 13.74 9,889.24 1,800.00 8,089.24 19.00 5.50 11.28 12,177.05 2,700.00 9,477.05 24.00 4.70 9.64 13,874.46 3,600.00 10,274.46 30.00 4.17 8.55 15,387.36 4,500.00 10,887.36 36.00 3.72 1.63 16,472 23 5,400 00 11,072.23 42--�00 �: 3 40 -" 6 9.7 -17 564-G7 6 300 00: _ 11,264,47RSQOIRED STORAGE 48.00 3.10 6.36 18,302-47 7,200.00 11,102-47 54.00 2.82 5.78 18,730.51 8,100.00 10,630.51 60.00 2.60 5.33 19,188.0E 91009.00 101188.08 66.00 2.40 4.92 19,483.28 9,900.00 9,583.28 n I 00 0 0 00 00 000 0 ol 404+04 0 C) 0 C=) Co C) Ca N N II II CN 00 C:) O 0 A F-4 5 LL) 6 g C% 2 z u Z 0 z z 0 L,: LZ t/) LLI x C� O 0 0 00 -wt- Lr) 00 0 LJ C) u En 0 CIO C) LA LLI Er 4111, W < w 0 L) w En V) tn V) LD in V) O > :z (Y u u 0 Q -Cl! CD > u z az LJ Ln C) 0 0 L) 000 ww w 1— L) 2 CL t— B 1-- 0 fkf w-1L0 CL —i ��cf LLI < =) (-) Z 0 Z< CL LLJ M Li Ckf L) 0 Ln Fn w E`Y i'-I::. ,.:a s'. G, K:T 3Y e e-av .e._ ,. ... .� n r v .i. . _ ., .. a r' ... -.ev �.. I r if .$ 'w� Hitua"G `e4 ;a, a E XE.Iw_. ' , w` _ PARTNER1r iOR ESTFUTURE _ w [ TEST by a ,,yy s n 4� 4'v'y 't PN� [o EI -FUTURELL E I^ y. yam. {dyj�{A .. 1 r.I IN EIFMPDX 195992 "ra �` P �� AST LAURELS BEET tks ,., 1�; .• yN DISCHARGE LOCATION e �� 1 FOR FUTURE DETENTION POND -OFT Elr ,aY g ��t{{ ', �-� _ __ _ -3- �u P EWITH a srn - _ (� e DETAIL THIS SHEET) FUTURE 2 SUITE QULIERT Mv1fp� c iMR`�a f" _ T v, — _ �n u A JEIF � x - � �i» a +' z a i `W I', �j — T FINEV1r� _ 11 o�rt SF E. S > x-E _ If T_ _ — I ��'.� u�rjx (P x I crsr h -e �� % �_._'t_-`r"= aN4s•s1+ ✓ —r,Pr Illli fr H P E r i'-/TT•i•.F••••s4ii H�a•-•R Fai_ III ETUBE x v h ST WI 4.1 LEA wE, Ill L ;' rt r S L� wnrvi° I� �m o[rv�'y �pdg'd;t? I FUTURE DE'LENTIQN GRADING illl . sws sn IIII A #,aj .. '• } E/ 1 `+ Q2 1 F$ a 1>r } e I ^'\ p.'�„...r,,._..�"�'�°` 9124.d;TS;,: f'. w� e. T --- -- - E 1 ILL iY;%"Cl?'S"+G Ec'"FEE�r+liPJ`d3Fafb ✓, "1 ( •., pA. ". ' z< r. I /. • ? aE'c >ry h- 1 a r a T IT, { �I isII I 1d` i7 rit �L cNGOP �} . }hP„ eEa Pas r III �. �ti I�; _ Z CWALE CENTfR�IF �a50k'k�, v rr a�'� ) A IA �.-rvTrt s y♦ 1r f III oYE PmN qTh +S _ r GENERAL NOTES I x< • q I HE i hI J ER54PER niw 4 A li v 5 Y au • } B6P dSrtM[MGtM MN. R..'LL VXWpMWIU PPE. IM C IEEK KMnX - /.,. >H[ E � I T . �c nE m CONTRACTOR »um E asarrawE • i rtvnu`�':F'BAm`2a'."fgb LATE)niYKS" z >»e x"o�xONNO.°N0rer#o',"�r'�a ` mr . 11 C1/1 • _ } FERRARI IT at t.r wM� ri4eaT' w 5 - . - E ' E_ EiNl ivy IF .. 9 i 1 • 2- yy T 5 [ f .. }' ii% _ C ••E'n w 1 v T T I. ' BETTERWAILT,• J..�� tr u e a 9 T! d'>, r A P5" MraTy„ _ PLO .%`` E 11 of i14°.n,%F�i:: r .�A.d'4Vkti a k: 6 a ..� P. I y� I,i 4}.yA SN IT ' NNg II 1 ' a IN "` [TMk . NEI 'd *. E a sus E, nt. 1 It� 0 �ijlll 4 Nt }tE44S .III H•'k4 � II�� w N x 1n n )lip iJ u, MA �I t At Itt 3�3� <t �, P1= a y i% Oggg¢ 4 E M ) it 'j,Je}ti# , n `, 3n rJ y. �IT ^'IThF , f''s"^R `> .. vesii!'P il,, rt' m1e � F �A+�f�SF ..R:.rS / I aw x��5 .1'r'SF,J'>T1�1`r'�"�, a t i P a„ ' f !.a ♦ t �'aP rl, FEE A S y. T ' `1.� +( , �� �•♦ - II NOTE .. "r 41 Ee��}k+1 1 ' L-L" •''' it g � 4c1EN1.LN E@rU 10 RE IEHPCIOURf PHIL LOCH LIME X M - PETER i) 3� �Y �j x ��i�( p tEU LEGEND�anE AS TIIE an OF FORT COLLINS CCNSTRVCTS MASTER xr ITf> EE cTP7'�+i , d': • ORNNACE PLAN IMPROVEMENTS IN THE OLD TOWN BASIN,ILI, %STING AORId iENEV • ' AT WHICH POINT THE MIND WILL' BE CONVERTED .FROM ,:�4a - a Y,ft /� V q K f + 'rt '„ J 7 cruvE J N'. ,,,, > T' PCP03EG SI6NM 4PEk • I -� I RETENTION TO DETEM ON PND pSCHANGEO,AT AHISTORIC" PT :I ��. J } RATE TO LAUREL ST SAT THE LOCH¶ON SHOWN ON THIS PLAN H ° ruvllMOM SOE SLOPE 5 Y . �fIT y{ N. n �•� '' '. .__� I "♦ FOR CO STRUCIION S/V iEHRES DETEENTIOI ON POND OSUTPAALL _2w 1e. t 11 7P R li �TCPM LR INP E iNLn �F /� T ,R --- FIG( C s vm ONENn,z 1 _E • ,� 8 3+'. �E/ M PIF �T own ma U N NANA'Ta;IA • -� IS — A � � SC C SEV y R'c E XM°IIIMME'i Ty •"I^° _ s ISLET K t I-J IPA^?IF Ow w 1 R/ y 'ALE" Ir. ME 1 ROP ED OWIIN • ♦ .f r P 1f " FILL m EASTVA'/ -� AI(API 1104 is • It II i A IhAIf _ . L ' LI; ETJE o=Eo ENTAI E PArTFRN air' �. ' LJ / _ 41 PR11coEC mrvTouR ..PE f v :.:, ^z- .. I, -( T ' EXISTING CONTOUR 11 L _ TRIG VISIT ) EOTI _ M . 4 1 tl s j >, �HNQ4IQ� 4�_ _ o L .... _. 51" ly a.Tt;: �A5�r...''♦ /4" ^ a GKAVF:L SW[1Lt': UL:'I'A1L � r� A MEA 'T t ! t91 1 Ay 1 ,y p�.. Y i-,... •• -a or r h; c v[ci 1 N +EEE lu r: kTr N,AQRES f 64, :J` S l h'�, • • A T 01 TAL E°V EE c NE cP CO THIN nwr�rv, '.' 4 It 9IF - i 1 1r y[ . ! y "�•� - a Js &SEEw TE AcLm BY VPPE VeCIA1QUS c •r• ' Y ` .lip' • r n ^ ".y IT 111 • 1 I T - - s iaa: $ >t yA .4N1i' t �yA FIT I IN, 4<' 4 fT1 It OE51 N OINi r .' , • _ P.. f i - !P :: ,{' ••Y • • • . �RIEPMm REQUM E4.PAKMEry1 SEVIlQ:1eIS NESS ( rnia) \... At`5 Y yv S" 4Y{Ff u raN 1 i .✓ G 1 I j� _ ` •A • • _ PX C 0295E BPM 4 5 CEMEN! TOTAL h M V Dp�jMQRp[ �{{{�y • R U MMEP CPIVNV ". T' (J' r lf/'hj^PiYlFF IdJrIfSiT 3^#T�Sr..A.. '/._�. f ' SV�VEACE 90VPSE B EV GO R"lE /(/���/ W NORTH 7 •+•-• w •-•-•-�-• sw •-•t•-• w at • • • • • • y • • • • • T P z 5 GRAPHIC SCALE q IT IT IF Feel FI -_. _..If kEl Ir a ILE,, T L I NO Re s E - L L.,1 P of ecr hl t Cote A, -- — - - NORTHERN ENGINEERING SERVICES 9428.o0 a _ U.S. WEST GARAGE FACILTY IMPROVEMENTS SCALE I 30. T - n20 SOUTH HOWE$ SUITE 202 FT. COLUNS COLOHADO B0521 DESIGNER Maw_ CIIECKEp HY MFJ - pRAINAGE AND GRADING PLAN ---(303) 221-4169 -0RAFTSMAN: ACAp PREPARED 11 /30/199a