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Home My WebLink AboutINVERNESS INNOVATION PARK FIRST FILING (ROCKY MOUNTAIN INNOVATION INITIATIVE) - PDP - 30-09A - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTPreliminary Drainage, Erosion Control and Water Quality Report Rocky Mountain Innovation Initiative IX. APENDICES Appendix I • Hydrology and Pipes Appendix II ■ Detention ■ Infiltrometer Test Results Appendix III • FEMA Firmette ■ Drainage and Erosion Control Plan Preliminary Drainage, Erosion Control and Water Quality Report Rocky Mountain Innovation Initiative VII. CONCLUSIONS A. Compliance with standards I. All drainage design will conform to the criteria and requirements of City of Fort Collins Storm Drainage and Design Criteria and Construction Standards. 2. Proposed sediment/erosion control measures will conform to the recommendations of City of Fort Collins Storm Drainage and Design Criteria and Construction Standards and generally accepted erosion .control procedures. B. Drainage Concept I. The proposed drainage plan concept for the RM12 project will be effective for the control of stormwater runoff and water quality for the proposed site. VI11. REFERENCES • City of Fort Collins Storm Drainage and Design Criteria and Construction Standards • Urban Storm Drainage Criteria Manual Volume 1 • Urban Drainage and Flood Control District, Denver, Colorado, March, 1969. • Urban Storm Drainage Criteria Manual Volume 2; Urban Drainage and Flood Control District, Denver, Colorado, March, 1969. • Urban Storm Drainage Criteria Manual Volume 3 Best Management Practices; Urban Drainage and Flood Control District, Denver, Colorado, September, 1999. Preliminary Drainage, Erosion Control and Water Quality Report Rocky Mountain Innovation Initiative VI. SEDIMENT/EROSION CONTROL A. General Concept I. Temporary erosion control measures will be installed with this project. These measures will include: a. Silt fence along the property lines. b. Inlet filters at all inlets. c. Water trucks and soil terracing to address construction dust abatement. d. Vehicle tracking pad at the construction entrance. e. The detention pond will act as a sediment basin during construction. 2. Permanent sediment\erosion control measures will include riprap forebays at all storm sewer outfalls. a. All disturbed areas will be paved, landscaped or revegetated to prevent soil erosion and sedimentation. 3. Maintenance of all sediment\erosion control devices will remain the responsibility of the contractor until the project is completed. B. Fiscal Surety I. Opinions of probable cost will be provided with the Final Drainage Report to serve as the basis for the required fiscal surety. Preliminary Drainage, Erosion Control and Water Quality Report Rocky Mountain Innovation Initiative D. Specific Details — Inlets and Storm Sewer 1. Runoff from the project site is collected by storm drain inlets and conveyed to the regional infiltration pond. Inlets are placed in sumps as dictated by the grading plan. The inlets are not sized for preliminary design. Detailed inlet sizing calculations will be provided with the Final Drainage Report. 2. Inlets are also provided along East Vine Drive at the ends of the proposed street improvements. These inlets will serve to intercept flow from the RM12 improved area for conveyance to the pond. 3. It is expected that the storm drain system will be extended into Vine Drive and future UP developments as those projects are constructed. A preliminary layout for the future storm drainage system is provided on the Drainage and Erosion Control Plan located in Appendix. The trunk systems within Vine Drive are designed to accommodate the future runoff from this future development. Conservative assumptions were made regarding future hydrologic parameters. These assumptions are documented in the runoff calculations contained in the appendix. Preliminary Drainage, Erosion Control and Water Quality Report Rocky Mountain Innovation Initiative B. Specific Details -Detention I. Stormwater detention for RM12 will be provided in a regional infiltration pond located south of Vine Drive. Although it is anticipated that this pond will provide storm water management for much of the IIP site, it is only sized for RM12 at this time. 2. Outflow rate from the infiltration pond is calculated to be 1 /2 the measure infiltration rate. The reduction factor of 50% is used to account for potential clogging of the filter media. The infiltration rates were measured by CTUThompson using double ring infiltrometer testing. The results of those test are included. in the appendix. 3. Detention volume required for RM12 is 0.82 acre-feet. This was determined using the measure infiltration rate over the bottom area of the pond. 4. Water quality volume is not calculated separately since the entire 100-year event is being treated through the process of infiltration. Therefore, the total design volume of the pond is 0.82 acre-feet. 5. Water quality pre-treatment will be provided in the various inlets in the stormwater collection system. The bottoms of the inlets will be deepened by 2.5 feet to allow for sedimentation. Additionally, oil interceptor devices (such as the Nyloplast "Snout" or equivalent) will be placed in each inlet to separate oil and other floatable contaminants from the storm water runoff. Details for these will be provided at final design. 6. The required volume of 0.82 acre-feet is achieved at elevation 56.67 in the pond. The emergency spillway for pond is at elevation 58.00. The additional storage volume between these elevations is reserved for future development within IIP. ® 5. A dewatering manhole is provide for the temporary installation of a pump should the pond need dewatering for maintenance purposes. Long term maintenance will be addressed with a operation and maintenance manual to be developed during final design. 6. An emergency spillway is provided to convey the 100-year undetained flowrate safely through the pond. The spillway general discharges towards the Gustov- Swanson Natural Area to the south. An easement for this discharge has been provided by the City. Additionally, an emergency spillway is proposed near an existing break in the dike constructed along the river on, the south side of Natural Area. This spillway is also designed for the 100-year undetained event. Riprap calculations will be provided for these at final design. Preliminary Drainage, Erosion Control and Water Quality Report Rocky Mountain Innovation Initiative IV. DRAINAGE DESIGN CRITERIA A. Development Regulations Design criteria from the City of Fort Collins Storm Drainage and Design Criteria and Construction Standards were followed for this drainage report. B. Hydrological Criteria I. Peak flow rates for the 10-year and 100-year storms have been calculated in accordance with the City of Fort Collins Storm Drainage and Design Criteria and Construction Standards. Please see these calculations in the Hydrology section of the Appendix. D. Hydraulic Criteria I. The City of Fort Collins Storm Drainage and Design Criteria and Construction Standards are used to determine the adequacy of the culverts, storm sewers, inlets and street capacities throughout the project. 2. Analyses are performed using methodologies presented in Urban Storm Drainage Criteria Manual Volumes I and 2; Urban Drainage and Flood Control District, Denver, Colorado, September, 1999. Please see the various computation spreadsheets in the Hydraulics section of Appendix 1. V. DRAINAGE FACILITY DESIGN A. General Concept I. Stormwater runoff from the proposed project will be collected by a system of curb/gutter, storm drain inlets and storm drain pipes. 21 Runoff from Vine Drive will be collected by storm drain inlets and conveyed via storm drain piping. The storm drain piping along Vine Drive is oversized to provide storm drainage conveyance for the future improvements along Vine Drive adjacent to the future phases of Inverness Innovation Park. 3. Stormwater will be managed using a regional infiltration pond located on the south side of Vine Drive. This pond will provide both water quality and water quantity treatment for the developed flows for phase I (RM12) and for future projects within IIP. This pond will also provide treatment for future phases IIP, although analysis for those uses will be provided along with future development applications. At the present time, the regional pond will be used for phase I only. u Preliminary Drainage, Erosion Control and Water Quality Report Rocky Mountain Innovation Initiative 111. DRAINAGE BASINS AND SUB -BASINS A. Major Basin Description 1. The project site lies within the Cache La Poudre Basin. 2. Portions of the project site lie within the FEMA 100-year floodplain (Zone AE) of the Cache La Poudre River, as shown on FIRM panel #08069C0977G, dated June 17, 2008. Additional portions of the site lie within the FEMA 500-year floodplain (Zone X). There are no new critical facilities or expansion of existing critical facilities proposed with this project. A Floodplain Use Permit will be required for the work proposed within the 100-year floodplain. B. Existing Conditions I. As previously' mentioned, the existing site is currently developed as an industrial development, consisting of several metal buildings and a large gravel storage. area. The site is fairly flat with the terrain sloping gently to the south and southeast at approximately 0.33%. 2. Existing vegetation is minimal on the project site, with the exception of the areas along the Lake Canal, which flows west -to -east along the northern boundary of the site. This area is protected by an environmental buffer, and will not be disturbed by the project. 3. Existing soils generally consist of clayey sands and top soil overlying sands and gravels, as expected from the location of the project site near the floodplain of the Cache La Poudre River. The soils report • for the project, entitled "Geologic and Preliminary Geotechnical Report, 300-500 East Vine Drive", dated September 15, 2008, was prepared by CTL/Thompson. 4. There are no off -site flows into the RM12 site. C. Developed Conditions I. The proposed RM12 project consists of two office/industrial buildings to house the Rocky Mountain Innovation Initiative. The parking areas will be paved with asphalt and internal concrete walks and plaza areas will serve pedestrians. 2. East Vine Drive will be improved to minor arterial standards along the frontage of the project. Preliminary Drainage, Erosion Control and Water Quality Report Rocky Mountain Innovation Initiative I. INTRODUCTION This report presents the pertinent data, methods, assumptions, and references used in analyzing and preparing the final drainage, erosion control and water quality design for the Rocky Mountain Innovation Initiative (RM12) at the Inverness Innovation Park (IIP) in Fort Collins, Colorado. The RM12 project can be considered phase I of the overall UP project. This report is prepared in support of the Preliminary Development Plan for RM12, and the Overall Development Plan for IIP. II. GENERAL LOCATION AND DESCRIPTION A. Property Location I. The project site is located along the north side of East Vine Drive. The current address of the parcel is 300 East Vine Drive, Fort Collins, Colorado. y a err a i Legary Pazt gee MarLrez TE Park ' SI� i ` s � hbrea Rndersonville uii CeNn Pni ,. � _J GD Buddnahan Lrk FJ G�eers: -'„ L a ' q Go f Coorsa:� 3A� E Mrberey Si 7t 9. i Ccloraao Sate za7 Vicinity Map, NTS B. Description of Property I. The existing site is currently developed as industrial, with several metal buildings and a large gravel storage area. The proposed project is located on the western portion of the overall Inverness Innovation Park project site, in the area currently uses for outdoor storage. r Preliminary Drainage, Erosion Control and Water Quality Report Rocky Mountain Innovation Initiative TABLE OF CONTENTS Title Page Engineer's Certification Table of Contents I. INTRODUCTION.......................................................................................:.... 3 ,0 11. GENERAL LOCATION AND DESCRIPTION ............................................. 3 A. Property Location......................................................................................................................3 B. Description of Property............................................................................................................3 Q� Ill. DRAINAGE BASINS AND SUB -BASINS .............:........................................ 4 A. Major Basin Description......:....................................................................................................4 B. Existing Conditions....................................................................................................................4 C. Developed Conditions..............................................................................................................4 _ IV. DRAINAGE DESIGN CRITERIA....................................................................5 A. Development Regulations........................................................................................................5 B. Hydrological Criteria.................................................................................................................5 D. Hydraulic Criteria......................................................................................................................5 V. DRAINAGE FACILITY DESIGN.................................................................... 5 _ A. General Concept ......................................... ............................................................................... 5 B. Specific Details — Detention .................................................................................................... 6 C. Specific Details — Swales.......................................................................................................... 6 ` D. Specific Details — Inlets and Storm Sewer...........................................................................7 V1. SEDIMENT/EROSION CONTROL................................................................8 _ A. General Concept.......................................................................................................................8 B. Fiscal Surety ...................... :....................................................................................................... 8 _ VII. CONCLUSIONS ...............................................................................................9 A. Compliance with standards ..................... ......... ....................................................................... 9 B. Drainage Concept......................................................................................................................9 ' VIII.REFERENCES ..................................9 ............................................................. IX. APENDICES..................................................................................................... 10 Preliminary Drainage, Erosion Control and Water Quality Report Rocky Mountain Innovation Initiative ENGINEER'S CERTIFICATION I hereby state that this Preliminary Report for the drainage, erosion control and water quality design of the Fort Collins Brewery project was prepared by me or under my direct supervision for the owners thereof and meets or exceeds the criteria in the City of Fort Collins Storm Drainage Design Criteria and Construction Standards. Stacy J. Gowing Registered Professional Engineer State of Colorado No: 34290 Preliminary Drainage, Erosion Control and Water Quality Report For Rocker Mountain Innovation Initiative at Inverness Innovation Park Fort Collins, Colorado Prepared for: URBAN DEVELOPMENT PARTNERS C/O MICHAEL BELLO 1212 S. COLLEGE AVENUE FORT COLLINS, CO 80524 Prepared by: ENGINEERING 171 NORTH COLLEGE AVENUE FORT COLLINS, CO 80524 970-219-2834 AUGUST 12, 2009