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Home My WebLink AboutDrainage Reports - 03/10/1996OPERTY of Find Fteport FI--T �LL�NS UTYLrrtF.�� to 6 DRAINAGE AND EROSION CONTROL REPORT FOR COLLEGE AVENUE WIDENING NORTH BOUND TURN LANE TO HORSETOOTH ROAD FORT COLLINS, COLORADO \&I �. \1/ VA V C�■ C 6 WELSH ENGINEERING SCIENCE & TECHNOLOGY. INC. 11 DRAINAGE AND EROSION CONTROL REPORT FOR COLLEGE AVENUE WIDENING NORTH BOUND TURN LANE TO HORSETOOTH ROAD FORT COLLINS, COLORADO PREPARED FOR: CITY OF FORT COLLINS, COLORADO DEPARTMENT OF ENGINEERING PREPARED BY: W ESTEC 2629 REDWING ROAD, SUITE 200 FORT COLLINS, COLORADO 80526 SEPTEMBER 1, 1995 WELSH ENGINEERING SCIENCE & TECHNOLOGY. INC. September 1, 1995 WESTEC #95435 ' Mr. Glen Schlueter City of Fort Collins Stormwater Utility 235 Mathews ' fort Collins, CO 80522 RE: DRAINAGE AND EROSION CONTROL DISCUSSION RELATIVE TO THE COLLEGE AVENUE TURN LANE. Dear Mr. Schlueter: ' Enclosed is a copy of a Drainage Discussion and Erosion Control Report for the referenced project. All calculations for this report have been made in accordance with criteria established by the City of Fort Collins. If there are any questions please call me. ' Sincerely, WESTE �a '�yp` ��. �• HIV .°..: _ - ��L�, iQ J. Thomas Knostman, P.E. Project Engineer ' JTK/sea 1 ' 2629 Redwing Road, Suite 200, Fort Collins. Colorado 80526-2879, Ph. 970 226 3535 Fox 970 226 6475 Reno Tucson Elko Winnemucca Plecsonron Englewood ' Nevada Arizona Nevada Nevada California Colorado I I I 1 I 1 11 n DRAINAGE AND EROSION CONTROL REPORT FOR COLLEGE AVENUE WIDENING NORTH BOUND TURN LANE TO HORSETOOTH ROAD FORT COLLINS, COLORADO DEVELOPMENT LOCATION AND DESCRIPTION Location The proposed turn lane will be in the north bound section of College Avenue at Horsetooth. The turn lane will allow traffic to turn to the east bound lanes of Horsetooth Road. The site lies in the Northeast Quarter of Section 36, Township 7 North, Range 69 West of the Sixth Principal Meridian, City of Fort Collins, County of Larimer, State of Colorado. Property Description The turn lane will cross three developed properties that are now east of the east College Avenue flowline. These consist of 1" Choice Bank, Showtime Video and Palmer House Flowers traveling from the intersection south. New right-of-way (R.O.W.) will need to be dedicated by the later two properties. The location of the project is shown on Figure 1. DRAINAGE BASIN IDENTIFICATION Description The site lies in the Foothills Drainage Basin. Drainage south of the Larimer Canal No. 2 is partially cut off by an inlet to the Canal. DRAINAGE DESIGN CRITERIA Regulations The City of Fort Collins Storm Drainage Design Criteria [1 ] is being used as the basis for this report. Development Criteria Constraints Drainage into the Larimer Canal No. 2 shall not exceed that currently entering the canal through the existing 5 foot curb inlet at the bridge. Hydrologic Criteria The Rational Method was used to predict the peak and cumulative runoff from the proposed development. Calculations are included in Appendix I. 95435200 09/01/95 95435F01.DWG EAST HORSETOOTH ROAD Q st CHOICE BANK F FORT COLLINS W S WZ Q w C9 w J o SHOWTIME c� VIDEO r 0 0 n n PALMER FLOWERS WENDYS DEVOE PAINTS SCALE IN FEET 0 100 200 viw�� ■ tea.. COLLEGE AVENUE WIDENING FIGURE No. 1 NORTHBOUND TURN LANE TO HORSETOOTH ROAD SITE MAP Calculations All calculations for this report have been made in accordance with criteria established by the City of Fort Collins. Variances ' No variances are requested. DRAINAGE DESIGN Concept ' Drainage from the north bound lanes of College Avenue South of Horsetooth Road flows north from a high point at Bockman Drive in the east gutter of College Avenue. This drainage currently is intercepted by an existing 5 foot curb inlet in the bridge buttress over the Larimer Canal No. 2 (the canal). The new flowline of the turn lane will connect to a new 5 foot curb inlet opening which was constructed with the 1" Choice Bank Box Culvert [2]. Existing storm 1 drainage flows to the canal and flows through the new 5 foot curb inlet will be approximately the same. The existing inlet is located at station 1 +60 feet. The longitudinal grade along this reach is ' approximately flat. The inlet is located in a semi -sump condition with the drainage flowing south to the inlet from a high point approximately 50 north of the inlet 1 inch above the inlet flowline. Under the present conditions, during the 100-year storm event, the peak flow is Details estimated to exceed the depth of the curb south of the existing inlet and flows east, over the curb and landscaping, into the Showtime Video parking lot and to the canal. The storm drainage remaining in the gutter flows to the inlet with any carry-over flowing north to Horsetooth Road and then east. The new curb inlet will be in the buttress of the existing bridge approximately at station 1 +69. The new inlet will be located in a sump 2 inches below the high point in the flow line at station 1 +00 north of the inlet. The longitudinal grade both north and south of the inlet will be 0.4 percent with a cross slope between 2.0 and 2.5 percent. Storm flows during the 100-year storm will exceed the gutter depth but will be restricted from flowing east to the canal, through the Showtime Video Parking Lot, by landscape berming. Stormwater overflows will spill over the highpoint at station 1 +00 and flow north to Horsetooth Road. Support for the following discussion will be found in the calculations in Appendix I and on the drawings furnished with this report. As stated above, the Rational Method was used for drainage estimates. Basin A s Basin A consists of the north bound College Avenue roadway area between Bockman Drive and the high point in the gutter at station 1 +00 and the western two-thirds of Devoe Paints. The drainage from Bockman Drive to College Avenue is routed through Western Auto as detailed in Attachment A. This area drains Point A at the new curb inlet at station 1 +69. The basin is entirely impermeable with a runoff coefficient of 0.95. Time of concentration for Basin A is estimated to be 10 minutes with a rainfall intensity of 7.15 inches per hour. The area of the 1 basin is 1.70 acre without the new turn lane and 1.84 acres with the new lane. The peak 100-year storm flow from Basin A is 12.25 and 13.28 cubic feet per second (cfs) with and without the turn lane, respectively. Under present conditions, during the 100-year storm event, the existing inlet at Point A as modeled with UDINLET will take approximately 8.64 cfs with a depth in the gutter of 0.73 feet. The actual depth of the gutter is only 0.5 feet and thus the flow will breach the top of the gutter flowing east into the Showtime Video parking lot and to the canal bypassing the inlet and effectively increasing the flow to the canal. During the 100-year storm event, the new inlet at Point A as modeled with UDINLET, will take approximately 8.50 cfs with a depth in the gutter of 0.64 feet. A landscape berm above the top of the new curb will increase the depth of flow to 1 foot to assure that flows will be routed 1 to the inlet and overflow (13.28 - 8.5 = 4.78 cfs) will travel onto Horsetooth Road. Basin B I Basin B consist of the remaining portion of north bound College Avenue from the high point at station 1 +00 north to the intersection of College and Horsetooth Road. The area of Basin B with the new turn lane is 0.19 acres and the entire area is impermeable. Using the maximum rainfall intensity of 9.0 inches per hour, the 100-year peak flow at Point B from Basin B is 1.69 cfs. The combined 100-year peak flow from Basins A and B at Point B is 6.47 cfs. I I I I I 1 WIND AND RAINFALL EROSION EVALUATION Site Soils ' The Larimer. County, Soil Conservation Service Soils Report identifies the soils overlaying the site as belonging to Thedalund Loam having slight to moderate rainfall erodibility ' characteristics. The rainfall erosion season as detailed in the City of Fort Collins, Erosion Control Reference Manual [11 Ithe Manual) is between May 1 and October 31. The Manual details the site as having moderate wind erodibility characteristics and states the predominant wind direction is from the west-northwest in this area. The wind erosion season as detailed in the Manual is between November 1 st and May 31 st. The disturbed area of less than one acre exempts the project from wind erosion controls. Construction at the site is estimated to begin in March 1996 and continue through April 1996. This schedule places the project within the wind erosion season. 1 Erosion Controls Due to the small size of the disturbed area, the short period during which soils will be exposed for erosion, the developed nature of the basin and the necessary access to all construction areas the only available area from controls are at the drainage outlets. Gravel filter inlets will be constructed over the area inlet in the Showtime Video parking lot and across the new inlet ' to the canal. I 1 2. I 1 1 City of Fort Collins, Colorado, Storm Drainage Design Criteria and Construction Standards, May 1984, Revised January 1991. Water, Waste & Land, Inc., Drainage Discussion and Erosion Control Resort for 1 st Choice Band of Fort Collins Box Culvert. Bridges and Fill Construction, January 25, 1995. I I L I ova kI I HYDROLOGY AND HYDRAULIC CALCULATIONS 1 1 1 11 I I KENO, NEVADA ' `W vv C WINNEMUCCA,NEVADA WELSH ENGINEERING SCIENCE & TECHNOLOGY, INC. ENGLEWOOD, COLORADO O FORT COLLINS, COLORADO BY- /"72' DATE SUBJECT �IY 2C9i__G CT �f SHEET NO. OF CHKD. BY DATE PROJECTre`y�L EaL Ilex'` Q� 7,i�a2t4Jfj PROD. NO. S�-� ' Tug LAaE= / (�qAL Nr,w Az =, 33 u 1 1 1 /bc) - Ar S,Uzn / t/�-_AJTI_ _ ?, o NAJ5 `•/_ - AW - -- -. ® VV 1= RENO, NEVADA WINNEMUCCA, NEVADA I WELSH ENGINEERING SCIENCE & TECHNOLOGY, INC ENGLEWOOD, COLORADO FORT COLLINS, COLORADO O 1 BY-TT-k—__ DATE SUBJECT _f1 CHKD. BY DATE PROJECT Coy-{ `!vim bt-0 (-, `/ +'i-, % / = 74i SHEET NO. OF PROJ. NO. g5EL 1 ht)utt-f E_ o , 1 �►� �Lp-�V _ to /P5)�,00� rI 1 1 1 1 1 KENO, NEVADA ELKWINONEMUCCA, NEVADA ' WELSH ENGINEERING SCIENCE 3 rECHNOLOGY, INC. ENGLEWOOD, COLORADO O FORT COLLINS, COLORADO BY T7 DATE el SUBJECT //Y./2e_4IA t_Zr_ j _ SHEET NO. OF CHKD. BY DATE PROJECT COI-+ = �+ I' ll)CQ E&177 16PROJ. NO. 9 �7 2 ZZA :i N C()u1=&7� /�� lei OT'- _ �o I 1 I 170 f)EE Ul,D-a�t� u� ;vL?, S717�5F—TJC�2 tlAL c� l�'1a rr. J ----------------------------------------------------------------------------- UDINLET: INLET HYDARULICS AND SIZING DEVELOPED BY DR. JAMES GUO, CIVIL ENG DEPT. U OF COLORADO AT DENVER SUPPORTED BY METRO DENVER CITIES/COUNTIES AND UD&FCD ------------------------------------------------------------------------------ SER:Water Waste and Land -Ft Collins CO.. N DATE 08-31-1995 AT TIME 13:42:12 I** PROJECT TITLE: College Avenue *** CURB OPENING INLET HYDRAULICS AND SIZING: INLET ID NUMBER: 10 INLET HYDRAULICS: IN A SUMP. GIVEN INLET DESIGN INFORMATION: GIVEN CURB OPENING LENGTH (ft)= 5.00 L �� HEIGHT OF CURB OPENING (in)= 6.00 INCLINED THROAT ANGLE (degree)= 20.00 /`,i LJ✓1 LATERAL WIDTH OF DEPRESSION (ft)= 0.00 ��^�-� SUMP DEPTH (ft)= 0.00 Note: The sump depth is additional depth to flow depth. STREET GEOMETRIES: 1 STREET LONGITUDINAL SLOPE (g) = STREET CROSS SLOPE ( °s ) = 0.20 3.00 r �� STREET MANNING N = GUTTER DEPRESSION (inch)= 0.016 2.00 e 1 GUTTER WIDTH (ft) = 2.00 �r T�iZ STREET FLOW HYDRAULICS: WATER SPREAD ON STREET (ft) = 18.81 GUTTER FLOW DEPTH (ft) = 0.73 FLOW VELOCITY ON STREET (fps)= FLOW CROSS SECTION AREA (sq ft)= 2.22 5.48 GRATE CLOGGING FACTOR (%-)= 50.00 CURB OPENNING CLOGGING FACTOR(g)= 20.00 INLET INTERCEPTION CAPACITY: IDEAL INTERCEPTION CAPACITY (cfs)= 10.80 BY FAA HEC-12 METHOD: DESIGN FLOW (cfs)= 12.25 ' FLOW INTERCEPTED (cfs)= 8.64 CARRY-OVER FLOW (cfs)= 3.61 BY DENVER UDFCD METHOD: DESIGN FLOW (cfs)= FLOW INTERCEPTED (cfs)= 12.25 8.64 CARRY-OVER FLOW (Cfs)= 3.61 ------------------------------------------------------------------------------ UDINLET: INLET HYDARULICS AND SIZING DEVELOPED BY DR. JAMES GUO, CIVIL ENG DEPT. U OF COLORADO AT DENVER --------------------------------------------------------------------------- kSER:Water SUPPORTED BY METRO DENVER CITIES/COUNTIES AND UD&FCD Waste and Land -Ft Collins CO ...................................... tN DATE 08-31-1995 AT TIME 13:42:18 *** PROJECT TITLE: College Avenue *** CURB OPENING INLET HYDRAULICS AND SIZING: INLET ID NUMBER: 10 ' INLET HYDRAULICS: IN A SUMP. GIVEN INLET DESIGN INFORMATION: ' GIVEN CURB OPENING LENGTH (ft)= HEIGHT OF CURB OPENING (in)= 5.00 C �� 6.00 INCLINED THROAT ANGLE (degree) = LATERAL WIDTH OF DEPRESSION (ft) = 45.00 2.00 ' SUMP DEPTH (ft)= 0.16 Note: The sump depth is additional depth to flow depth. 1 STREET GEOMETRIES: STREET LONGITUDINAL SLOPE (t) = 0.40 1 STREET CROSS SLOPE (t) = STREET MANNING N 2.50 0.016 1 GUTTER DEPRESSION (inch) = 2.00 CojL-'3 GUTTER WIDTH (ft) = 2.00 77 STREET FLOW HYDRAULICS: WATER SPREAD ON STREET (ft) = 19.00 GUTTER FLOW DEPTH (ft) = 0.64 FLOW VELOCITY ON STREET (fps)= 2.82 FLOW CROSS SECTION AREA (sq ft)= 4.68 GRATE CLOGGING FACTOR (%)= 50.00 CURB OPENNING CLOGGING FACTOR (%)= 20.00 INLET INTERCEPTION CAPACITY: ' IDEAL INTERCEPTION CAPACITY (cfs)= 10.63 BY FAA HEC-12 METHOD: DESIGN FLOW (cfs)= 13.28 FLOW INTERCEPTED (cfs)= 8.50 CARRY-OVER FLOW (cfs)= 4.78 BY DENVER UDFCD METHOD: DESIGN FLOW (cfs)= 13.28 FLOW INTERCEPTED (cfs)= 8.50 FLOW (cfs-- ---------------------------------CARRY-OVER ------------------ UDINLET: INLET HYDARULICS -----4-78- ---------- AND SIZING DEVELOPED BY DR. JAMES GUO, CIVIL ENG DEPT. U OF COLORADO AT DENVER SUPPORTED BY METRO DENVER CITIES/COUNTIES AND UD&FCD ---------------------------------------------------------------------------- SER:Water Waste and Land -Ft Collins CO.. N DATE 08-31-1995 AT TIME 11:51:16 I** PROJECT TITLE: College Avenue *** CURB OPENING INLET HYDRAULICS AND SIZING: INLET ID NUMBER: 10 INLET HYDRAULICS: IN A SUMP. - - - -- -� ® REND, NEVADA IV� C r `w WINNEMUCCA,NEVADA WELSH ENGINEERING SCIENCE & TECHNOLOGY, INC. ENGLEWOOD, COLORADO O FORT COLLINS, COLORADO BY -�T DATE S SUBJECT �1Y�2�I ��- SHEET NO. OF ' CHKD. BY DATE PROJECT CoL1 Cr PROJ. NO. E-Air"oroCr T 5goLJ ll 1/ CN�C ;� �1��►-1 0� �i.-c� t..J �� %lZ�.%I,�LrLcc�2 �1��4..t 3q iq I C I r I 1 I 1 Triangular Channel Analysis & Design Open Channel - Uniform flow Worksheet Name: Colleg Ave Widening Comment: Flow Depth at Showtime Video Entrance 6 Solve For Depth Given Input Data: Left Side Slope.. Right Side Slope. Manning's n...... Channel Slope.... Discharge........ Computed Results: Depth............ Velocity......... Flow Area........ Flow Top Width... Wetted Perimeter. Critical Depth... Critical Slope... Froude Number.... 40.00:1 (H:V) 30.00:1 (H:V) 0.016 0.0100 ft/ft 11.14 cfs 0.34 ft 2.83 fps 3.94 sf 23.50 ft 23.51 ft 0.36 ft 0.0066 ft/ft 1.22 (flow is Supercritical) ' Open Channel Flow Module, Version 3.41 (c) 1991 Haestad Methods, Inc. * 37 Brookside Rd * Waterbury, Ct 06708 1 I C r I I I I I ATTACHMENT A EXCERPTS FROM FINAL DRAINAGE REPORT FOR TOYS "R" US AND WESTERN AUTO STORES 1 I 1 I f-; vt4 ( �Py i Fina pproved Report Date 3 P�� FINAL DRAINAGE REPORT FOR TOYS "R" US AND WESTERN AUTO STORES SOUTH COLLEGE AVENUE AND BOCRMAN DRIVE FORT COLLINS, COLORADO JUNE 4, 1991 (REVISED JANUARY 14, 1992) PREPARED FOR: ROSENBAUM/DEAN 101 North Cascade Suite 400 Colorado Springs, Colorado 80903 719-630-0066 PREPARED BY: PARSONS & ASSOCIATES CONSULTING ENGINEERS 432 Link Lane Plaza Fort Collins, Colorado 80524 303-221-2400 PROJECT NO. 91.03 TOY ' BASIN A, (Western Auto South Parking Area) Basin A, includes the South parking lot of the Western Auto store site, the north one-half of Bockman Drive from South College Avenue to Mitchell Drive,and the west one- half of Mitchell Drive from Bockman Drive to the first driveway entrance. This basin is 1.20 acres large and will require 10,260 ft.3 of detention volume discharging at 1.17 cfs (See Table 1). ' BASIN A, (Western Auto Building and North Parking Area Basin AZ includes approximately the north parking area, ' the west one-half of the Mitchell Drive right-of-way from the southerly entrance to the northerly entrance, and the roof drainage from the proposed building.. This basin is 1.05 acres large and will require 6,840 ft.3 of detention volume discharging at 0.78 cfs (See Table 2). BASIN A3 (South College Avenue) The proposed site plan shows three graded and landscaped berms along the South College Avenue curb line along the west edge of the Western Auto site. The. area which will flow from the side of these berms .towards South College Avenue is reduced from .4 acres to .2 acres. In addition, the runoff :from these grassed areas will be substantially less than the exposed dirt and packed gravel areas which now exist. We feel that this will allow us to improve the drainage conditions along South College Avenue. Existing flows in South College Avenue will continue to flow from South to North. A valley gutter at the intersection of Bockman Drive and South College Avenue will allow flows to continue Northerly without being diverted into this site. Bockman Drive grades increase from South College Avenue at a grade of 1.67% for a distance of over 150 feet. This is reflected in the street design for Bockman Drive as part of the site construction plans. A curb inlet has been provided in the curb line along South College Avenue. This inlet has been sized to intercept and divert a portion of basin A3 flows into basin Al. The detention pond for subbasin Al will be sized to detain these flows. Only a small portion of subbasin A3 north of this curb inlet will flow offsite. -5- SUBBASIN SUMMARY Drainage Subbasin (On - site) ' Al ' A2 A3 ' A4* B1 ' B2 B3* ' B4* (On - Site) Total Drainage Subbasin (of f- t site) C Area Allowed Actual Req. Avail Ori- Remarks (Ac) Runoff Runoff Deten Deten fice (0.87 From (Ft3) (Ft3) Area CFS/ Site (S. ACRE) (CFS) F.) 1.20 1.04 1.17 10260 11056 .111 Detention in parking lot 1.05 0.91 0.78 6,840 6,925 4=:r-3 Detention in 0, 01;3y parking lot 0.37 0.32 --- None --- --- Diverted into Basin Al 0.03 0.03 0.22, None --- --- Undetained area of Mitchell Drive 2.42 2.11 2.00 16590 16305 .118 50 Year Storm Detention Underground 2.24 1.95 1.90 15180 16125 .118 50 Year Storm Detention Underground 0.38 0.33 0.68 --- --- --- Natural area North of Canal 0.03 0.03 0.22 None --- --- Undetained area of Mitchell Drive 7.72 6.72 6.97 --- --- --- --- 5.10 4.44 --- --- --- --- Flow is Q-100 detention is part of future developement '* Note: Runoff from B4 and A4 will eventually continue down Mitchell Drive and be detained in detention ponds constructed as part of Palmer House Improvements. Runoff from the north end of Subbasin B3 will be detained by future development ' along the JFK Parkway. Table lc✓ised 3-92 fa (tf6t "qs O�lf " ConAtf 1ers ' aJ rrpej ip �, Elormwaf(r U11/11/WI.19, �I 116 i SEwEL Va ki OMOMij