The URL can be used to link to this page

Home My WebLink AboutPOUDRE SCHOOL DISTRICT 2004 HIGH SCHOOL - SITE PLAN ADVISORY REVIEW - 43-01A - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTB E Y O N D E N G I N E E R I N G 3.0 1 1 Preliminary Drainage & Erosion Control Study 2004 High School HISTORIC DRAINAGE BASINS 3.1 Major Basin Description The 2004 High School Site lies within the McClellands Creek Master Drainage Planning Area. An updated master drainage plan for McClellands Creek, McClellands Creek Master Drainage Plan Update (Dated: November 30, 2000), was completed by ICON Engineering, Inc. According to the update, McClellands Creek is located in the south part of Fort Collins. It begins near the northeast comer of the intersection of College Avenue and Harmony Road. McClellands Creek flows in a southeasterly direction to Swift Pond. The mandated developed release rate for this area is 0.5 cfs per tributary acre. 4 NAFC0I94\Drainage\Word\Fc0194_DrainageRepon.doc NCUM BE Y ON D E N G IN E E R ING REFERENCES Preliminary Drainage & Erosion Control Study 2004 High School 1. Storm Drainage Design Criteria and Construction Standards (FC-SDDCCM), City of Fort Collins, Colorado (Revised January 1997). 2. Drainage Criteria Manual (Manuao, Urban Drainage and Flood Control District, Wright - McLaughlin Engineers, Denver, Colorado, June 2001. 3. McClellands Creek Master Drainage Plan Update, City of Fort Collins, Colorado, prepared by Icon Engineering, Inc., November 30, 2000. (Draft Report) 4. Flood Plain Modeling Report McClellands Channel Improvements, for Fossil Lake P.U.D. Second Filing, City of Fort Collins, Colorado, prepared by Northern Engineering Services, Inc., November 30, 2000. 10 NAFC0194\Drainage\Word\Fc0194_DminageReport.doc I u BEYOND ENGINEERING Preliminary Drainage & Erosion Control Study 2004 High School up to the adjacent sidewalk, and eventually be routed to D.P. 403 through a grass - lined swale. Undeveloped runoff in basin 500 (4.92 ac) will continue to flow overland through existing fields toward the northwest parking lot. Proposed curb and gutter will route the runoff to D.P. 313. Runoff in basin 501 (4.95 ac) will flow overland and into an existing irrigation ditch to the south of the basin. Storm water that is not routed to the ditch will be routed to D.P. 312. Basins 502 (1.94 ac) and 503 (0.64 ac) will route runoff via curb and gutter to inlets at locations still to be determined. The designs of these inlets are being coordinated with the design of the Ziegler Road improvements. Basin 504 (2.60 ac) will flow overland through existing fields and landscaped areas and be routed by curb and gutter to D.P. 312. Developed runoff in Basin 600 (1.68 ac) flows overland through landscaped areas and playing fields to Cambridge Avenue. The flows are caught by curb and gutter that route the flow west to D.P. 301. The inlet at D.P. 301 will capture a small portion of the runoff while the majority of runoff will continue along curb and gutter to D.P. 601. A Type `R' curb inlet will capture the water and route it into storm drainage system `A'. The developed runoff from Basin 601 (1.99 ac) will flow overland through landscaped areas and playing fields to Cambridge Avenue. This runoff will also be routed by curb and gutter to D.P. 601. Basin 602 (1.10 ac) will capture half street flows from Cambridge Avenue and route the runoff to D.P. 602 where the storm water will be captured by a Type `R' curb inlet. These flows will be routed to the detention/irrigation pond via storm drainage system W. 8 NAFC0194\Drainage\Word\Fc0194_DrainageReport.doc ' P4C4=TE BE Y ON D E N G IN E E R ING Preliminary Drainage & Erosion Control Study 2004 High School 305b (3.35 ac) are designed to capture runoff in dry wells that capture the minor storm runoff and route major storm runoff into the sub -surface drainage system. Runoff from Basin 308 (0.51 ac) will enter a curb chase at D.P. 308 and continue to be routed along curb and gutter to D.P. 302. The parking areas will act as local detention facilities. Basins 306 (2.84 ac), 307 (3.89 ac), 311 (4.01 ac), 312 (6.52 ac), and 313 (6.57 ac) will capture runoff in bioswales located in the center of each basin. Runoff will enter the swales through curb cuts and flow overland to area inlets. These inlets route the runoff to storm drainage system `B' at a rate of 0.5 cfs per tributary acre. The major storm event ponding limits are shown on sheet DRO1. Basin 314 (0.61 ac) is located adjacent to the west side of the building. This area will serve as the truck dock/loading area. A trench drain is proposed at the bottom of the dock to capture runoff within the basin. Developed runoff in basin 400 (2.79 ac) flows overland through the northeast parking lot. The runoff is caught by curb and gutter that routes the storm water to the midpoint of the north end of the lot. Runoff will enter a local detention pond through curb cuts. An outlet structure is proposed to control the release of storm water to the existing culvert system within Rock Creek Drive. Basins 401 (1.86 ac) and 402 (1.86 ac) are delineated around the proposed athletic field and track. The drainage for this facility is currently being coordinated with the landscape architect. Areas along the north and east side of the building will be primarily landscaped and graded for playing fields. Basin 403 (10.93 ac) will attenuate runoff from these landscaped areas to the northeast comer of the basin. An outlet structure is proposed to regulate the flow to the pond in basin 400 to 0.5 cfs per tributary acre. This corner of the basin will act as a detention facility during major storm events. Storm water from Basin 404 (1.63 ac) will travel overland through landscaped areas to a dry well at D.P. 404. Nuisance flows will be recharge the drywell while major events will cause overtopping of the inlet. Flows will pond 7 NAFCO194\Drainage\Word\FcO194 DrainageReport.doc 1 C FJC43M BE YON O E N G IN E E R ING 4.2 Basin Descriptions Preliminary Drainage & Erosion Control Study 2004 High School Basins 100 through 104 pertain to the building's roof drainage. The basins are split in correlation to each area's finished floor elevation. The exact location of roof drains has not yet been determined. Basins 200-204 border the Site to the east and north. These basins are bounded by the centerline of the adjoining streets and neighboring high points. The developed runoff in Basin 200 (1.23 ac) and Basin 202 (4.40 ac) sheet flows across landscaped areas, playing surfaces, and sidewalks and enters existing curb and gutter that routes the runoff east to D.P. 200. A CDOT Type `R' inlet will be designed to accept the runoff that enters the on -site drainage system through an 18" CL III RCP. Basin 201 (1.33 ac) sheet flows across landscaped areas and sidewalks to a low point in the landscaping. An area inlet will capture the runoff and route it to the on -site sub -surface drainage system. Runoff from Basin 203 (1.39 ac) flows overland across landscaping and enters curb and gutter that routes the runoff to D.P. 203. A CDOT Type `R' curb inlet will be designed to accept this flow, however the routing of this storm water is still to be determined. Basin 204 (3.03 ac) borders the Site to the north and encompasses the south half of Rock Creek Drive. Runoff will be routed by curb and gutter to a Type `R' curb inlet located at the east end of the basin. This runoff will be captured in detention facilities located in the northeast comer of the Site. Basins 300-314 are located on the interior of the Site. The developed runoff in Basins 300 (0.56 ac), 301a (1.34 ac), 301b (1.63 ac), 302 (0.27 ac), 309 (2.11 ac), and 310 (1.54 ac) traverse landscaped areas and half street areas and enter curb and gutter that routes it southeast to the respective design points. This storm water will be captured by Type `R' curb inlets and routed to storm drainage system `B'. Runoff from basins 303 (3.94 ac), 304 (1.39 ac), 305a (3.38 ac), and 6 NAFC0194\Drainage\Word\Fc0194_DrainageReport.doc Preliminary Drainage & BEY ON D E N G IN E E R ING Erosion Control Study 2004 High School 4.0 DEVELOPED DRAINAGE CONDITIONS 4.1 General Concept In general, the majority of on -site developed runoff will sheet flow across landscaping or asphalt to a local area inlet that outlets to the sub -surface storm drainage system. More specifically, roof drainage will be captured by gutter systems and dispersed to one of four sub -surface conveyance systems that are located around the four areas of the building. From here, the developed runoff will enter the sub -surface storm drainage system that will transport it to an on -site detention/irrigation facility. Each on -site parking area will act as a local detention facility and release developed runoff to the aforementioned system at a rate of 0.5 cfs per tributary acre. The majority of the areas around the interior of the Site will also discharge into this system. The basins to the north of the proposed building will sheet flow to either Rock Creek Drive or to the local detention facility that is located in the northeast corner of the soccer fields. This detention pond will release at 0.50 cfs per tributary acre to the east and into another detention facility. From here, an outlet structure will restrict the release of storm water to an off -site system located in Rock Creek Drive. Basins along the southern half of Cambridge Avenue will drain to Type `R' curb inlets and release into the proposed on -site detention/irrigation facility. ' Developed runoff along the Site's undeveloped west side will continue to sheet flow across existing terrain and drain into the existing irrigation ditches. At the time of development of these areas, on -site detention will be required with a release of 0.5 cfs per tributary acre. ' The main sub -surface drainage system will route storm water runoff to a large detention/irrigation facility located in the southeast corner of the Site. This pond twill provide for water quality capture volume, detain the 100-year storm event and maintain a permanent water surface elevation below which irrigation water will be ' stored. The pond will release to McClellands Creek at a rate of 0.5 cfs per tributary acre. 5 NAFC0194\Drainage\Word\Fc0194_DrainageReporl.doc ' B E Y O N D E N G I N E E R I N G ' 2.0 METHODOLOGY Preliminary Drainage & Erosion Control Study 2004 High School 2.1 Compliance with Standards The preliminary drainage and erosion control study that follows was prepared in ' accordance with the requirements and procedures for storm drainage design set forth in the City of Fort Collins Storm -Drainage Design Criteria and Construction Manual (i.e., FC-SDDCCM) and the Urban Storm Drainage Criteria Manual (i.e., Manuao. ' 2.2 Analytical Methods The Rational Method was used to analyze the minor and major design storm runoff (i.e., 10-year and 100-year). This method is widely accepted for drainage design involving small drainage areas (<160 acres) and short times of ' concentration. The Rational Method relates peak discharge to the runoff coefficient, rainfall intensity, and drainage area. The rainfall intensity and runoff ' coefficients were taken from the FC-SDDCCM. This method is ideal for storm sewer sizing and simple detention pond sizing or ' design situations where only the peak flow rate and/or the total volume of runoff are needed. ' The FAA Method was used to estimate the preliminary detention pond size requirements. In addition to the methods mentioned above, this preliminary drainage study was hydraulic from prepared using a few other hydrologic and software packages Haestad Methods and the Urban Drainage and Flood Control District, including: StormCAD, FlowMaster and HydroPond. 3 NAFC0194\Drainage\Word\Fc0194_DrainageReport.doc Nk�>= Preliminary Drainage & ' B E Y O N D E N G I N E E R I N G Erosion Control Study 2004 High School 1.3 Proposed Project Description The proposed 2004 High School will consist of one two-story, predominantly ' brick building that covers 258,746 ftZ (5.94 acres). Four separate parking areas will provide the school with 1200 parking spaces. The two largest parking areas ' are located south of the proposed building. A third, yet smaller parking area, lies to the west of the proposed building. The fourth parking lot will be located in the northeast corner of the Site. The north portion of the Site will be heavily landscaped and contain a meandering ' pedestrian walkway. The area on the east side of the building will consist of numerous athletic fields and a running track. A truck docking area has been designed for the west side of the building. ' Vehicle access for the Site will be from west via Ziegler Road, from the east via Cambridge Avenue and from the north via Rock Creek Drive. C 1 I 2 NAFC0194\Drainage\Word\Fc0194_DrainageReport.doc BEYOND ENGINEERING Preliminary Drainage & Erosion Control Study 2004 High School ' 1.0 INTRODUCTION 1.1 Site Location The proposed Fort Collins 2004 High School (Site) is located in south Fort Collins. The Site is bordered to the north by Rock Creek Drive; to the east by Cambridge Avenue; to the south by Kechter Road; and the to the west by Ziegler Road (Refer to Exhibit 1, Vicinity Map). More particularly, the Site (90f acres) is ' located in the Southwest Quarter of Section 4, Township 6 North, Range 68 West of the 6`h Principal Meridian, City of Fort Collins, County of Larimer, State of Colorado. 1.2 Existing Site Description ' In general, the existing Site slopes south and east along grades that vary between 0.50% and 3.00%. The existing Site is presently irrigated cropland. According to ' the results of the geotechnical subsurface exploration report that was prepared by Earth Engineering Consultants, Inc., (Dated: November 14, 2001) the existing Site ' is comprised of topsoil/vegetation underlain by light brown lean clay with varying amounts of silt and sand. ' Other pertinent on -site features include the following: • Three small buildings and a two-story farmhouse that are located near the Site's west property line. • Three irrigation ditches that traverse the Site from west to east. The first follows the north property line of the Site; the second runs through the north third of the parcel; and the third splits the parcel approximately in ' half. The City of Fort Collins Parks and Recreation will allot the area to the south of the third ditch for future development. • The McClellands Channel which runs west to east through the southern ' third of the Site. ' The existing on -site runoff currently flows overland and is captured by the irrigation ditches or McClellands Creek. 1 NAFC0194\Drainage\Word\Fc0194_DrainageReporl.doc Preliminary NONE Drainage & Erosion Control Study ' B E Y O N D E N G I N E E R I N G 2004 High School TABLE OF CONTENTS PAGE 1.0. INTRODUCTION.............................................................................................................1 1.1 Site Location.........................................................................................................I ' 1.2 Existing Site Description......................................................................................1 1.3 Proposed Project Description................................................................................1 2.0 METHODOLOGY............................................................................................................3 2.1 Compliance with Standards..................................................................................3 ' 2.2 Analytical Methods...............................................................................................3 3.0 HISTORIC DRAINAGE CONDITIONS.........................................................................4 ' 3.1 Major Basin Description.......................................................................................4 4.0 DEVELOPED DRAINAGE CONDITIONS....................................................................5 4.1 General Concept....................................................................................................5 ' 4.2 Basin Descriptions................................................................................................6 5.0 CONCLUSIONS...............................................................................................................9 5.1 Drainage Concept..................................................................................................9 REFERENCES...............................................................................................................10 ' APPENDIX A - Developed Site Hydrology • Developed Runoff Calculations APPENDIX B - Detention Pond Design APPENDIX C - Charts, Tables & Graphs BACK POCKET — Overall Drainage Plan (Sheet DRO1) i i N:\FC0194\Drainage\Word\Fc0194_DrainageReport.doc 1 i 1 1 1 1 1 1 1 1 1 1 1 1 2004 HIGH SCHOOL PRELIMINARY DRAINAGE & EROSION CONTROL STUDY for ............................. Poi die ScEiool E�Estrid:RA ............................. 2407 LaPorte Avenue Fort Collins, Colorado 80521 100 Nolte Associates, Inc. 1901 Sharp Point Drive, Suite A Fort Collins, Colorado 80525 (970) 221-2400 januanj 3rd, 2002 NJC4TEPreliminary Drainage & B E Y O N D E N G I N E E R I N G Erosion Control Study 2004 High School 5.0 CONCLUSIONS 5.1 Drainage Concept The proposed drainage concepts presented in this study and shown on the preliminary drainage plans adequately provide for the conveyance of developed runoff from the proposed development. 9 NAFC0194\Drainage\Word\Fc0194_DrainageReport.doc