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HomeMy WebLinkAboutNEW BELGIUM, 4TH FILING, PACKAGING HALL & BUCKINGHAM ST. - PDP & AMENDED ODP - 1-95F - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTIM dn II. M ri id= a PROJECT SITE . . . . . . . . . . . . . . WADO-3 - M rATE T-yl MULBERRY ED RU ��F R-rp'l al N MWE ff �;>�NIT�YMAP FORT COWNS DOWNTO" AJRPARK STATE HIGHWAY 14 E I APPENDIX A VICINITY MAP I a I I 0, 7. REFERENCES 1. City of Fort Collins, "Storm Drainage Criteria Manual", (SDCM), dated March, 1986. 2. Urban Drainage and Flood Control District, "Urban Storm Drainage Criteria Manual", Volumes 1 and 2, dated June 2001, and Volume 3 dated September 1999. 3. "Final Drainage and Erosion Control Report for New Belgium Brewery First Filing" dated July 8, 1997 by JR Engineering and subsequent updates by North Star Design, Inc. I i i 5.2 Specific Details To limit the amount of silt leaving the site several erosion control measures shall be implemented during construction. Wattles will be used in the swales and where appropriate, and the north, south and east boundaries shall have silt fence installed. A vehicle tracking pad shall be installed at the proposed connections to Buckingham Street to control the mud being tracked onto existing pavement. During overlot grading, disturbed areas are to be kept in a roughened condition and watered to reduce wind erosion. The detention pond will be used as a sediment trap during construction. 6. CONCLUSIONS 1 6.1 Compliance with Standards All computations within this report are in compliance with the City of Fort Collins Erosion Control Reference Manual for Construction Sites, the Storm Drainage Design Criteria Manual. Requirements placed on the site related to the new rainfall criteria have been followed. No drainage variances are required for the project. 1 6.2 Drainage Concept I I The proposed drainage concepts presented in this report and on the construction plans adequately provide for stormwater quality treatment of proposed impervious areas. Conveyance elements have been designed to pass required flows and to minimize future maintenance. If, at the time of construction, groundwater is encountered, a Colorado Department of Health Construction Dewatering Permit will be required. 6 �J I P Basin 6 includes the south portion of the proposed building, the volleyball courts and the commons area. The detention pond is also encompassed in this basin. Runoff from the roof in this basin will discharge via downspouts into gravel areas and into the permeable interlocking concrete pavers. The water will percolate through the gravel and pavers, will be collected in perforated pipes and will enter the detention pond in the commons area. Runoff from the Commons Area will flow south to a swale and west to the pond outlet. The detention pond is limited to a release rate of 1.15 cfs which was established with earlier reports on this site. This limit was imposed because of inadequate downstream facilities. Basin E is an existing basin that encompasses a majority of the existing brewery, pavement and tank farm. The basin was assumed to be unchanged with this report although there are some small areas of imperviousness that are being added to this basin. The basin boundary was also assumed to remain as was established with the previous reports on this site to show continuity and provide clarity for the drainage calculations 4.3 Drainage Summary Drainage facilities located outside of the right of way (including. the ponds, bioswales, permeable pavement, storm drain system and the pond outlet) will be maintained by the owners of the property. The storm system in the right of way for Buckingham will be owned and maintained by the City of Fort Collins. 1 5. EROSION CONTROL 5.1 General Concept This site lies within the Moderate Rainfall and Wind Erodibility Zone per the City of Fort Collins Zone Maps. The potential exists for silt movement from the site and into the existing swale along the north side of Lincoln Avenue. A potential also exists for tracking of mud onto existing streets which could then wash into existing storm systems. The required performance standard and the erosion control escrow amount will be determined with the final drainage calculations for this site. i 5 C i i I I P I D D I 0 I I D I been utilized extensively in the Fort Collins area, the potential benefits from these measures have not been incorporated into the runoff and detention calculations. Therefore, the calculations included with this report are assumed to be conservative. 4.2 Specific Flow Routing A summary of the drainage patterns within each basin is provided in the following paragraphs. Basin 1 includes the majority of the proposed building. Runoff from this basin will be routed east and will discharge in downspouts on the east side of the building. This runoff will flow south to the proposed bioswale in Basin 2 and be conveyed south to Basin 3. Basin 2 includes the area on the north and east sides of the proposed building. The runoff on the north side of the building (truck dock area) will be conveyed east via surface flow to the bio swale on the east side of the proposed building. This swale will be constructed at a shallow slope and will be lined with a permeable soil mix which will encourage infiltration into the subsoils. This bioswale will convey runoff south into Basin 3. Basin 3 includes the parking area. The parking area will be constructed of asphalt and concrete porous pavement with additional bioswales in the parking lot medians. The permeable pavement and the bioswales will also encourage runoff to percolate into the soil and will tend to decrease runoff from this basin. A lower c-value for the porous pavement was used to represent this additional percolation. Runoff from this basin will be collected in the medians and conveyed via storm pipes to the detention pond in Basin 6. Basin 4 includes the area on the north side of the parking lot. This basin is a low area that was created in an effort to save the existing trees along Buckingham. The area contributing to the low area has been minimized to the greatest extent possible and this area will not have a gravity release point. Basin 5 includes the west side of the proposed building and the parking area on the west. Runoff from the roof in this area will discharge via downspouts to the pavement. The runoff will then surface flow south in a concrete pan to a short bioswale before entering the detention pond in Basin 6. 4 i Detention and water quality will be sized to provide attenuation for the runoff from Basins E 1, 2, 3, 5, and 6. The existing release rate from this pond will be maintained. 3.3 Hydrologic Criteria Runoff computations were prepared for the 10-year minor and 100-year major storm frequency utilizing the rational method. All hydrologic calculations associated with the basins are included in Appendix B of this report. Standard Form 8 (SF-8) provides time of concentration calculations for all sub - basins. Standard Form 9 (SF-9) provides a summary of the design flows for all sub - basins and design points associated with this site. Detention volumes were determined using the FAA or Rational Method. Water quality volume was calculated using the method recommended in the "Urban Storm Drainage Criteria Manual' and will be incorporated in the pond design. 3.4 Hydraulic Criteria All hydraulic calculations within this report will be prepared with the final drainage design for this site and will be in accordance with the City of Fort Collins Drainage Criteria. 4. DRAINAGE FACILITY DESIGN 4.1 General Concept The runoff from a majority of the proposed development will be routed by sheet flow, in pipes and in swales to the proposed detention pond. The main detention pond is existing and will be enlarged with this development to accommodate the increased impervious area. The pond is located in the southwest corner of the development and encompasses the Commons Area. This pond will provided adequate detention volume and water quality extended detention. Several measures (including porous concrete pavement, bioswales and permeable interlocking concrete pavers) are proposed on site that will also provide additional water quality enhancement and will encourage percolation into the subsoil which may decrease the runoff from the site. Because these measures have not 3 I 2. DRAINAGE BASINS AND SUB -BASINS 2.1 Major Basin Description The proposed development lies within the Cache La Poudre River Drainage Basin as delineated by the City of Fort Collins. The release rate for the site was established with the Final Drainage and Erosion Control Report for New Belgium Brewery First Filing by JR Engineering, Ltd dated July 8, 1997. 2.2 Sub -basin Description Runoff from this site currently flows south to the existing detention pond along the north side of Buckingham Street or east to the culvert at Lemay Avenue. The existing drainage patterns will be maintained as much as possible with the development of this site. A majority of the runoff will be routed to the existing detention pond with a portion of the runoff flowing east to Lemay Avenue. 3. DRAINAGE DESIGN CRITERIA 3.1 Regulations This report was prepared to meet or exceed the "City of Fort Collins Storm Drainage Design Criteria Manual' specifications. Where applicable, the criteria established in the "Urban Storm Drainage Criteria Manual" (UDFCD), 1984, developed by the Denver Regional Council of Governments, has been used. This site is also in compliance with Chapter 10 (Flood Prevention and Protection) of the City of Fort Collins Municipal Code. 3.2 Development Criteria Reference and Constraints The runoff from this site has been routed to conform to the requirements of the existing approved drainage plan for the site and the City of Fort Collins Stormwater Criteria. The approved site has been broken into 5 basins and are labeled Basins A through E on the drainage plan. None of these basins have been modified in the calculations for the proposed improvements. The area of the proposed improvements has been broken into 6 basins and are labeled Basins 1 through 6. These basins are detailed in Section 4.2 of this report. 1 2 9 1. GENERAL LOCATION AND DESCRIPTION 1.1 Location The overall New Belgium Brewery site is located on the north side of Buckingham Street between Linden Street and Lemay Avenue near Old Town Fort Collins. This project is located in the northeast quarter of Section 12, Township 7 North, Range 69 West of the Larimer, State Sixth Principal Meridian, in the City of Fort Collins, County of of Colorado. See vicinity map located in Appendix A. The project site is bounded on the north by the existing City of Fort Collins Streets Department building, on the east by the existing New Belgium Brewery wastewater treatment plant and Lemay Avenue, on the south by Buckingham Street and existing residential. and on the west by the existing Brewery, warehouse and offices. 1.2 Description of Property. The entire project site area consists of approximately 17 acres of land. The site currently has a gravel parking area, existing vegetation and a detention pond in the development area. The slopes on site range from approximately 0.5% to 10.0%. A majority of the site slopes to the south and west and into the existing detention pond. A small portion of the site slopes to the south and east toward the wastewater treatment plant. Runoff from western portion of this site flows to the existing detention pond and is released into the existing storm system in Buckingham Street. The runoff then flows south along First Street and eventually to the Cache La Poudre River. Runoff from the east portion of the site flows to the south to Buckingham Street and east to an existing culvert. This culvert conveys runoff south under Buckingham Street, along the west side of Lemay Avenue and eventually to the Cache La Poudre River. No improvements are proposed in the detention is being for this portion of the site that drains to the east, therefore, no provided area of the site. The FEMA 100yr and 500yr floodplain are located on the Flood Rate Insurance Rate Map (FIRM) Panel number 080101 0179E. The proposed building is not located within the 100yr floodplain boundaries; therefore no elevation requirements have been imposed on the building elevation. The building has been placed at an elevation to prevent flooding from onsite runoff and detention. The site and building are located within the 500yr floodplain for the Cache La Poudre River. 1 7 TABLE OF CONTENTS TABLEOF CONTENTS............................................................................................................... 1. GENERAL LOCATION AND DESCRIPTION 1.1 Location...................................................................................................................1 1.2 Description of Property............................................................................................I i 2. DRAINAGE BASINS AND SUB -BASINS 2.1 Major Basin Description..........................................................................................2 2.2 Sub -Basin Description.............................................................................................2 3. DRAINAGE DESIGN CRITERIA 3.1 Regulations..............................................................................................................2 3.2 Development Criteria Reference and Constraints....................................................2 3.3 Hydrologic Criteria..................................................................................................3 3.4 Hydraulic Criteria....................................................................................................3 4. DRAINAGE FACILITY DESIGN 4.1 General Concept.......................................................................................................3 4.2 Specific Flow Routing.............................................................................................4 4.3 Drainage Summary ...................................................................................................5 5. EROSION CONTROL 5.1 General Concept......................................................................................................5 5.2 Specific Details ........................................................................................................6 6. CONCLUSIONS 6.1 Compliance with Standards....................................................................................6 6.2 Drainage Concept.....................................................................................................6 4 7. REFERENCES....................................................................................................................7 I APPENDICES A Vicinity Map B Hydrologic & Hydraulic Computations C . Pond Sizing Calculations D Figures and Tables iii m 11 I North Star au. design, inc. August 9, 2005 Basil Hamdan City of Fort Collins Stormwater 700 Wood Street Fort Collins, CO 80522-0580 RE: Preliminary Drainage and Erosion Control Study for New Belgium Brewery Bottling Hall Dear Basil, I am pleased to submit for your review and approval, this revised Preliminary Drainage and Erosion Control Study for the proposed bottling hall at the New Belgium Brewery site located at the northeast comer of First Street and Buckingham Street. I certify that this report for the drainage design was prepared in accordance with the criteria in the City of Fort Collins Storm Drainage Manual. I appreciate your time and consideration in reviewing this submittal. Please call if you have any questions. a 4P..., President ii 700 Automation Drive, Unit I Windsor, Colorado 80550 r+ r - I I I PRELIMINARY DRAINAGE AND EROSION CONTROLSTUDY NEW BELGIUM BREWERY BOTTLING HALL Prepared for: BNIM Architects berkebile nelson immenschuh mcdowell architects 106 W. 14th Street Suite 200 Kansas City, Missouri 64105 Prepared by: North Star Design 700 Automation Drive, Unit I Windsor, Colorado 80550 (970)686-6939 August 9, 2005 Job Number l 10-10