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Home My WebLink AboutMONTAVA - PHASE E - TOWN CENTER RESIDENTIAL - BDR220003 - DOCUMENT MARKUPS - ROUND 3 - EROSION CONTROL LETTER/REPORT· · · · · · City of Fort Collins, Colorado UTILITY PLAN APPROVAL APPROVED: City Engineer, APPROVED: Water & Wastewater Utility, APPROVED: Stormwater Utility, APPROVED: Park Planning and Development, APPROVED: Traffic Operations, APPROVED: Environmental Planner,Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date City of Fort Collins, Colorado UTILITY PLAN APPROVAL APPROVED: City Engineer, APPROVED: Water & Wastewater Utility, APPROVED: Stormwater Utility, APPROVED: Park Planning and Development, APPROVED: Traffic Operations, APPROVED: Environmental Planner,Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date · · · · · · City of Fort Collins, Colorado UTILITY PLAN APPROVAL APPROVED: City Engineer, APPROVED: Water & Wastewater Utility, APPROVED: Stormwater Utility, APPROVED: Park Planning and Development, APPROVED: Traffic Operations, APPROVED: Environmental Planner,Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date · · · · · · City of Fort Collins, Colorado UTILITY PLAN APPROVAL APPROVED: City Engineer, APPROVED: Water & Wastewater Utility, APPROVED: Stormwater Utility, APPROVED: Park Planning and Development, APPROVED: Traffic Operations, APPROVED: Environmental Planner,Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date · · · · · · City of Fort Collins, Colorado UTILITY PLAN APPROVAL APPROVED: City Engineer, APPROVED: Water & Wastewater Utility, APPROVED: Stormwater Utility, APPROVED: Park Planning and Development, APPROVED: Traffic Operations, APPROVED: Environmental Planner,Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date · · · · · · City of Fort Collins, Colorado UTILITY PLAN APPROVAL APPROVED: City Engineer, APPROVED: Water & Wastewater Utility, APPROVED: Stormwater Utility, APPROVED: Park Planning and Development, APPROVED: Traffic Operations, APPROVED: Environmental Planner,Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date · · · · · · City of Fort Collins, Colorado UTILITY PLAN APPROVAL APPROVED: City Engineer, APPROVED: Water & Wastewater Utility, APPROVED: Stormwater Utility, APPROVED: Park Planning and Development, APPROVED: Traffic Operations, APPROVED: Environmental Planner,Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date · · · · · · City of Fort Collins, Colorado UTILITY PLAN APPROVAL APPROVED: City Engineer, APPROVED: Water & Wastewater Utility, APPROVED: Stormwater Utility, APPROVED: Park Planning and Development, APPROVED: Traffic Operations, APPROVED: Environmental Planner,Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date · · · · · · City of Fort Collins, Colorado UTILITY PLAN APPROVAL APPROVED: City Engineer, APPROVED: Water & Wastewater Utility, APPROVED: Stormwater Utility, APPROVED: Park Planning and Development, APPROVED: Traffic Operations, APPROVED: Environmental Planner,Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date Approved Sheets Date 1-1 | Page Stormwater Management Plan (SWMP) For Montava Subdivision Phase E: Town Center July 2022 submitted to: City of Fort Collins, Colorado 748 Whalers Way Montava Subdivision Phase E: Town Center Stormwater Management Plan Page 1 1.0 - Site Description 1.1 Introduction The following Storm Water Management Plan (SWMP) has been prepared for use during the construction of the Montava Subdivision Phase E project. This plan describes recommended procedures and best management practices, BMP’s, to assist the contractor in complying with the Colorado Water Quality Control Act and the Federal Water Pollution Control Act. A copy of the CDPHE General Permit for discharge is attached in Appendix A. The general permit is the State law that requires this report and is provided for reference. A copy of the permit application is provided in Appendix B for submittal to the State at least 10 days prior to beginning grading activities. The intent of this plan is to provide the contractor a place to consolidate records, logs, permits, applications etc. as well as guidance on water quality protection. It is critical that the contractor understands that this plan is a living document that must be updated and maintained throughout the construction process. 1.2 Project Location and Description The Montava Subdivision Phase E: Town Center project site is located in Section 32, Township 8 North, Range 68 West of the 6th Principal Meridian, within the City of Fort Collins, Larimer County, Colorado. The proposed site is bounded on the north by farmland and Future Montava Subdivision phases, on the east by farmland, N. Giddings Road, and Future Montava Subdivision phases, on the south by Mountain Vista Drive and farmland, on the west by the Number 8 Outlet Ditch and Montava Subdivision phase G and Future Montava Subdivision phases. The Montava Subdivision Phase E: Town Center project site contains approximately 39.00 acres and consists of the Multi-Family, Townhomes, Duplex, Single Family, Mixed-Use, and Open Space. The Montava Subdivision Phase E: Town Center is currently zoned as Low Density Mixed-Use Neighborhood District Flexible Overlay Zone (LMN). A vicinity map illustrating the project location is provided in Figure 1.1. Montava Subdivision Phase E: Town Center Stormwater Management Plan Page 4  Stoneham loam (101) – 1 to 3 percent slopes.  Stoneham loam (102) – 3 to 5 percent slopes.  Stoneham Loam (103) – 5 to 9 percent slopes. The characteristics of the soil found on the project site include:  Moderate infiltration rate when thoroughly wet.  Moderately fine texture to moderately coarse texture.  Moderate rate of water transmission. These soils consist of the following hydrologic soil groups as defined in the United States Department of Agriculture (USDA), Web Soil Survey:  Group B – 18.70%  Group C – 24.30%  Group D – 57.00% The USDA web soil survey report is included in Appendix G. 1.5 Wetlands and Receiving Waters The Montava Subdivision Phase E is located in development is a 20.8-acre undeveloped lot west of the Anheuser Busch property. According to FCSCM, runoff from the undeveloped site generally sheet flows in the southeasterly direction towards the Larimer and Weld Canal Montava Subdivision Phase E is located in. See the Martin/Martin Master Drainage Study for more information about the existing conditions. According to the Montava Master Drainage Study, Montava Subdivision Phase E is primarily located within Basin F, Basin G1, and Basin G2. The portion of Montava Subdivision Phase E located in Basin F will generally flow southeasterly into a pond designed with the Master Drainage Study. The portion of Montava Subdivision Phase E located with Basin G1 will generally flow southeast and into a pond proposed with the Master Drainage Study. The portion of Montava Subdivision Phase E located in Basin G2 will generally flow southwest into a proposed pond and outfall directly into the Number 8 Ditch. These existing drainage patterns were maintained with the development of the Montava Subdivision Phase E project. The proposed Montava Subdivision Phase E development generally maintains existing drainage patterns. The entirety of the site will continue to flow northwest through proposed storm infrastructure to the location of the existing detention pond. The existing detention pond will be increased in size to over-detain runoff from the developed condition of the site. An outlet Montava Subdivision Phase E: Town Center Stormwater Management Plan Page 5 structure will attenuate storm runoff to a historic rate of 0.04 cfs/acre. The outlet structure will outlet into an existing swale northwest of the site. 1.6 Storm Water Management Plan Administrator _________________________ shall be the designated SWMP Administrator for the Project. It will be his or her responsibility to insure the SWMP's adequacy at all times to effectively manage potential storm water pollutants throughout the course of construction. 1.7 Potential Pollutants Below is a list of potential pollution sources that can occur during the construction of site improvements and potential remedies, or the appropriate section that should be referenced for controlling these pollution sources:  All disturbed and stored soils – (Surface roughening, reseeding, mulching and silt fence)  Vehicle tracking of sediments – (Vehicle tracking pads, street sweeping)  Management of contaminated soils – (See Section 2.3.2)  Loading and unloading operations – (See Section 2.2.3 - Stabilized Staging Area)  Outdoor storage activities (building materials, fertilizers, chemicals, etc.) – (See Section 2.3)  Vehicle and equipment maintenance and fueling - (See Section 2.3.2)  Significant dust or particulate generating processes – (See Section 2.2.3 – Wind Erosion/Dust Control)  Routine maintenance activities involving fertilizers, pesticides, detergents, fuels, solvents, oils, etc. (See Section 2.3.2)  On-site waste management practices (waste piles, liquid wastes, dumpsters, etc.) – (See Section 2.3)  Concrete truck/equipment washing, including the concrete truck chute and associated fixtures and equipment - (Use concrete wash-out)  Dedicated asphalt and concrete batch plants – (Not used on this project)  Non-industrial waste sources such as worker trash and portable toilets – (See Section 2.3.2.- BMP’s for San/Septic Waste)  Other areas or procedures where potential spills can occur (See Section 2.3) 2.0 - Pollution Controls Montava Subdivision Phase E: Town Center Stormwater Management Plan Page 6 2.1 Controls Overview During construction, several control measures shall be implemented under the direction of the contractor to prevent discharge of contaminated water. Specifications and details for specific control measures are included in Appendix C of this report for use on the project. In addition to those structural measures, other controls include non-structural practices, materials management, spill prevention and management, and other miscellaneous controls as described in the following sections. 2.2 Erosion and Sediment Controls The objective of erosion control is to limit the amount of erosion occurring on disturbed areas until stabilized. The objective of sediment control is to capture soil that has eroded before it leaves the construction site. Despite the use of both erosion and sediment control measures, it is recognized that some sediment could remain in runoff, especially during very large storm events. The contractor shall utilize the best management practices (BMP’s) described in the following sections to minimize the above potential to the maximum extent practicable. During all phases of construction, the contractor should plan ahead of possible rainfall events and work to limit erosion from occurring where potential exists. Where potential does exist provide adequate conveyance, temporary or permanent, and direct runoff to BMP’s that trap sediment. The erosion and sediment BMP’s anticipated for use on the site include both structural and non-structural practices. 2.2.1 Structural Practices Structural BMPs are structures that limit erosion and sediment transport. Such Practices include check dams, silt fence, inlet and outlet protection, water quality ponds, and grading techniques. The structural BMP’s that will be utilized on the subject site are described in more detail as follows: Check Dams  Can be constructed of rock, gravel bags or sandbags across a swale or channel  Used to slow the velocity of concentrated flow in a channel and reduce erosion  Used to catch sediment by capturing contaminated runoff  Most effective when used with other erosion prevention BMPs  Should not be used for basins exceeding 2-5 acres  Should be used in series with the base elevation of the upstream dam set at the same elevation or lower than the downstream dam. Sediment Control Logs (Wattles) Montava Subdivision Phase E: Town Center Stormwater Management Plan Page 10 present. Implementation of tire washing should include provisions for collecting wash water and directing it to a treatment pond  Whenever possible locate the construction entrance as far from the disturbed area as possible to allow maximum travel time for sediment removal from tires.  Public and Private roadways shall be kept clear of accumulated sediment.  Cleaning sediment shall not be accomplished by flushing with water. Sediment should be shoveled or swept from the street and placed away from storm water improvements.  Consider limiting vehicles from entering the site when conditions are wet or muddy. Wind Erosion / Dust Control  Dust from the site will be controlled using a mobile pressure-type distributor truck to apply portable water to disturbed areas. The mobile unit will apply water only as necessary to prevent runoff and ponding.  Dust control will be implemented as needed once site grading has been initiated and during windy conditions while site grading is occurring.  Spraying of portable water will be performed whenever the dryness of the soil warrants it.  At least one mobile unit will be available at all time to distribute portable water to control dust on the project area.  During high winds limit traffic speeds to 12 mph or less on areas without gravel or pavement.  Gravel can be placed on construction roads, entrances, and construction staging areas. Stone/gravel provides an effective protective cover over the soil.  In areas where wind erosion is expected soil-binding tackifiers can be applied with high success. Stabilized Staging Area  A clearly designated area where construction equipment and vehicles, waste bins and other construction related materials are stored  This area should be designated on the SWMP map.  Appropriate space to provide loading/unloading operations and parking  A stabilized surface, paved or covered in 3” diameter aggregate or larger  Perimeter controls such as silt fence, sediment control logs or construction fencing  Vehicle Tracking Control pad to be used in conjunction with a Stabilized Staging Area if this area is adjacent to a public roadway Dewatering Operations  Dewatering typically involves pumping water from an inundated area to a BMP Montava Subdivision Phase E: Town Center Stormwater Management Plan Page 17  When a bi-weekly report, an assessment of the entire property as related to SWMP issues  An estimated area of currently disturbed area.  Evaluation of all active BMPs  Actions needed to assure continued compliance with SWMP guidelines  Document all areas of potential pollution sources and how they are protected  Documentation of any needed changes  Training events  Uncontrolled releases of mud or muddy water or measurable amounts of sediment  An estimated amount of precipitation. An onsite rain gauge is suggested. 3.4 Site Maps In the back pocket of this report notebook there is an Erosion Control Plan for use during construction. The purpose of this plan is to provide the contractor a place to document and plan BMP’s used during construction. Because the placement of individual BMP’s will depend on the condition of the site and the contractor’s judgment, not all BMP’s are shown on the plans. It is the contractor’s duty as site administrator to determine the need for and placement of BMPs and mark them on the map. 4.0 - Final Stabilization / Conclusion Permanent stabilization will be achieved by establishing vegetative or permanent surface cover on all disturbed areas. The final vegetative cover is specified on the Erosion Control Plan. Vegetative cover is considered complete when 70 percent of the pre-disturbance plant density is restored. In cases where the site was already disturbed, the existing gravel ponds for example, the pre-disturbance density will be the naturally occurring cover on currently vegetated areas. The contractor shall remove all temporary erosion and sediment control BMPs after stabilization is achieved or after temporary BMPs are no longer needed. Trapped sediment (including within pipes) will be removed by the contractor or stabilized onsite. Disturbed soil areas resulting from removal of BMPs or the contractor will permanently stabilize vegetation as soon as possible. Again, this plan is a living document that will need to be updated and maintained throughout the construction process and until all areas of the site have been stabilized. This permit will remain active until an inactivation notice has been filed with the State. Additionally, this permit may be transferred to another party in the event that the contractor or sub-contractor responsible for its implementation leaves the site before stabilization has occurred. The Inactivation Notice and Reassignment Notices are included in Appendix F. 5.0 - References Montava Subdivision Phase E: Town Center Stormwater Management Plan Page 18 1. CDOT Erosion Control and Storm Water Quality Guide, Colorado Department of Transportation, 2002 2. Urban Storm Drainage Criteria Manual, Urban Drainage and Flood Control District (Rev. July, 2001) 3. Storm Water Risk Management, LLC; April 11, 2008; Pre-Construction & Engineering Training for Construction Storm Water Management Manual. 4. Construction Site Storm Water Runoff Control – National Menu of best practices, U.S. Environmental Protection Agency, 1999