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HomeMy WebLinkAbout03.07 Binder - Appendix H• • • SPRING VALLEY RANCH PUD - PHASE 1 GARFIELD COUNTY, COLORADO SOIL MANAGEMENT PLAN October 15, 2007 PREPARED FOR: Spring Valley Holding, LLC. 4000 County Road 115 Glenwood Springs, Colorado 81601 PREPARED BY: Gamba & Associates, Inc. Consulting Engineers and Land Surveyors 113 Ninth Street — Suite 214 Glenwood Springs, Colorado 81601 Phone: (970) 945-2550 Fax: (970) 945-1410 •,`1,,,,,i ,,,! ,�� ItEG r ip yr n : =�z . • ....• A ,,,,,,,i,,,\ T. Carter Page, P.E. 35161 INTRODUCTION AND LOCATION This report was prepared to meet the requirements of the Garfield County Board of County Commissioners Preliminary Plan Resolution 2005-84, regarding the requirement that a Soil Management Plan be included with any final plat application. AREAS OF PRINCIPAL CONCERN FOR SOIL MANAGEMENT The areas which will require soil management are largely the same as the areas which will require dust control during the construction phase of this project. More specifically, these are mostly, though not entirely, limited to proposed utility corridors (where they are outside of roads), proposed new roads, existing ranch roads that will be used as access or temporary roads, a portion of County Road 115 west of the County Road 114 intersection, County Road 114 from Spring Valley Ranch to U.S. Highway 82, materials and equipment storage and staging areas inside Spring Valley Ranch, and the disturbed area outside of the proposed water tank site. SOIL MANAGEMENT METHODS Prior to construction, and within the maximum and minimum time limits established by the Colorado Department of Public Health and Environment (CDPHE), Water Quality Control Division (WQCD) for the filing of a Stormwater Management Plan (SWMP), a formal SWMP amendment will be submitted. A SWMP exists for some repair work done last year to re -grade and repair the existing ranch roads within Spring Valley Ranch property. The permitted SWMP was approved for Niebur Golf, for the project entitled Ranch Access Roads Re -grading. Following is an outline of the SWMP amendment that will be submitted to the CDPHE-WQCD prior to commencement of construction activities: 1. Site Description a. The construction activity will be both on the Spring Valley Ranch property, and off, on the adjacent County Roads (C.R.) 114 and 115. The primary areas with significant potential for impacts on soil management will consist of the deep and shallow utility placement, road grading and the water tank construction b. Major construction activities relative to Phase 1 of the Spring Valley Ranch P.U.D. are currently expected to follow this sequence: i. Staging & Mobilization ii. Construction of Vehicle Fueling site storage containment berms. This will only apply if on-site fuel storage is used. Construction of Portable Toilet facilities containment berms will necessarily be an on-going work item, as a central location will probably be too far for practical application. iii. There are two possible entrances for construction equipment that will both require washed rock treatment areas to reduce off-site tracking of soil. The primary entrance is near the intersection of County Road 115 (aka Red Canyon Road) and County Road 114 (aka CMC road), (Latitude 39° 29' 26" N; Longitude 107° 13' 12" W). The secondary access is at the intersection of County Road 115 (Red Canyon Road) and the Landis Creek ranch road, (Latitude 39° 30' 44" N; Longitude 107° 14' 41" W). The rock tracking areas should be a minimum of 24 -ft. wide, and 200 -ft. Spring Valley Ranch PUD — Soil Management Plan October 15, 2007 Page 2 of 5 long, with at least 1 -ft. of screened rock (11/2 -inch preferable). These areas must be maintained and replaced when soils begin to fill them, and tracking of materials begins to occur. iv. Placement of Silt and Erosion Control Structures at the outlets. v. Placement of protective fencing around all wetlands as mapped in Appendix M of Binder 3 of the Phase 1 Final Plat application. vi. Road grading and re -grading operations and concurrent construction of shallow and deep utilities. vi i. Placement of Silt and Erosion Control Structures at the outlets of all Water Diversion Devices. These may be constructed concurrently with the construction of the Water Diversion Devices. viii. Revegetation shall be required in accordance with the Revegetation Specifications attached. c. The total area of the site, is shown on the plans. The total area of disturbance is estimated to be approximately 58 -Acres. d. The pre -developed runoff coefficient has been estimated as 0.35. e. The existing vegetation on the site is variable, based on the existing ground slope and the degree of previous ranch work. Large areas exist of relatively undisturbed gambrel oak, aspen, spruce/fir, sagebrush, serviceberry, pinon pine, juniper, and native grasses, as well as areas that have been extensively farmed for hay/dryland wheat, in the past. The entire site continues to be grazed by cattle, as in the past. Agricultural areas have been identified on the maps. The total percentage of ground cover is estimated at 75% to 85%. f. The only anticipated potential pollution sources will be the vehicle fueling facilities and the portable sanitary toilet(s). The contractor will be required to construct separate containment berms for the portable toilet(s), and any materials that might produce any sort of material runoff. The minimum volume contained within the berms shall be equal to, or greater than, the total volume of any holding tank or other material containment(s) within the berm, plus a 1 -foot freeboard. g. There is not anticipated to be any disruption to the flow of existing springs or irrigation features. The location of all known water sources on the site are shown on the map. The locations of wetlands are identified on the site map. h. The name of the receiving waters for the area that is subject to disturbance is the Roaring Fork River. All flows from this site will follow natural existing drainages. Principal drainages are shown as light blue lines on the Site Map. 2. Site Map • The site map includes the construction site boundaries within Phase 1, and the waterline and sewer line extensions as shown on the construction plans. • The areas of soil disturbance are limited to the shallow and deep utility work, and road grading areas. The total area equals approximately 58 Acres. • There are numerous areas of major cut and/or fill. These are shown on the plans. • There are no defined areas for the storage of fuel. It is anticipated that re -fueling will be accomplished by bringing fuel to the equipment on the roads, with fuel trucks, due to the length and difficult terrain on the site. Placement of portable sanitation stations is anticipated to follow the road work, and must be accompanied by construction of containment berms. Spring Valley Ranch PUD — Soil Management Plan October 15, 2007 Page 3 of 5 • There will not be any areas needed for dedicated asphalt or concrete batch plants. • The location of erosion control facilities such as water turn -outs, broad-based dips, cross -drain culverts and water bars will be established in accordance with the attached tables and formulae, taken from the U.S. Forest Service Guidelines for the construction of Forest Roads and Associated Water Diversion Devices. • The location of all known springs, streams and other surface waters are shown on the Site Map, as light blue lines. Wetland areas have been mapped and are so identified. • The overall site contemplated for road grading activities is a high meadow, well outside the known 100 -year flood plain boundary of the Roaring Fork River, the closest body of water for which such information is available at this time. 3. BMs for Stormwater Pollution Prevention Anticipated sequence of construction: Road grading activities will be coordinated with placement of Water Diversion Devices. All Water Diversion Devices shall be constructed along the road alignments in accordance with the tables attached to these documents. All Water Diversion Devices will be equipped with silt mitigation devices consisting of Silt Fences, Rock & Fabric Silt Barriers or Hay -Bale Dikes in accordance with the details provided on the attached sheets. Screened -rock "tracking -reduction" areas will be constructed at each of the two entrances to the site, consisting of an 8 -inch thick layer of 1 Y2 -inch screened rock layer. Each area shall be 24 -ft. wide by 200 -ft. long. Since County Road 115 (Red Canyon Road), which provides access to both project entrances, is an unpaved gravel road, off-site tracking of dirt will be dealt with by blading any tracked material off of the County Road. County Road 114 (the CMC Road) is also an unpaved gravel road near the entrances, so off-site tracking of dirt will be dealt with by blading also. Portable sanitary facilities will be placed within berms at locations convenient to the crews working the site. On-site storage of any road base will be in areas not subject to major flooding, and shall be surrounded as applicable with silt fences. The contractor shall be responsible for providing absorptive and other cleanup materials onsite, which shall be readily accessible to promptly deal with any fuel or other spill that should occur on the site, in accordance with all applicable Federal, State and Local laws. Any earth contaminated with any such material shall be removed from the site and disposed of in accordance with all applicable Federal, State and Local laws. 4. Final Stabilization and Long-term Stormwater Management Any vegetated areas disturbed during construction, will be revegetated with native drought - tolerant grasses similar to the indigenous species found on the property in accordance with the Erosion Control, Stabilization and Revegetation specifications included in the final plat application. 5. Other Controls Spring Valley Ranch PUD — Soil Management Plan October 15, 2007 Page 4 of 5 Because of the limited nature of the work proposed, it is not anticipated that any "Other Controls" will be required. 6. Inspection and Maintenance The contractor shall be required to inspect all silt fence, rock and mesh filters, and all other erosion control features at least every 14 -days. In addition, all features shall be inspected after any period of snowmelt or precipitation event that causes any sign of surface erosion. Any deficiencies or damage to the features shall be repaired. Personnel familiar with the intent and language of the SWMP and the associated SWMP map shall perform this work. Any problem areas, or leaks, breaks or deficiencies in the BMPs shall be reported to the Contractor's manager as well as the Engineer. Records shall be kept by the contractor of all repairs or problems, including any spills, leaks or overflows of any fuel, sanitary waste, solid waste, or chemical of any description. Records shall show the time and date of the problem as well as the weather conditions at the time of the problem. Spring Valley Ranch PUD — Soil Management Plan October 15, 2007 Page 5 of 5