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STORMWATER MANAGEMENT PLAN (SWMP) <br />AND EROSION AND SEDIMENT CONTROL REPORT <br />~- FOR <br />'' ST. VRAIN LAKE GRADING IMPROVEMENT PLANS <br />Page 2 <br />~, <br />it <br />i- <br />' D. Construction Activities <br />Construction for the lake grading plans includes the grading required to <br />' ' reshape the lakes north of the St. Vrain River. Soil disturbing activities will <br />include: clearing and grubbing; installing a stabilized construction entrance, <br />diversion dikes, silt fences, and other erosion and sediment controls; <br />` grading; excavation for sediment basins, installation of storm sewer; and <br />. , preparation for final planting and seeding. <br />1' Clearing and grubbing will be necessary to allow for the proposed grading <br />• i and storm sewer installation. Construction activities associated with this <br />type of development typically require the use of heavy earthmoving <br />equipment, dump trucks, generators, concrete mixers, and other assorted <br />- ~ equipment. Best Management Practices (BMPs) will be followed to provide <br />storm water quality and minimize erosion and sediment runoff. Temporary <br />mulching and seeding will be required in areas of grading in the interim <br />~ condition. The lakes in the south portion of St. Vrain Lakes development <br />will also be utilized for detention and an outlet structure will be provided to <br />:~ <br />control the flow to the 5-year undeveloped release from the site. <br />BMPs will be installed in two general phases that correspond to the <br />progression of construction. Phase 1 BMP installation will occur prior to <br />- ~ grading operations on the site. Phase 1 BMPs include vehicular tracking <br />control devices, silt fences, temporary sediment ponds and diversion dikes. <br />A vehicular tracking control device shall be installed prior to the mobilization <br />of construction equipment on-site. Prior to the clearing and grubbing of the <br />construction area, localized clearing shall be performed for the placement of <br />perimeter erosion control measures (silt fences, diversion dikes, etc.). Site <br />clearing and grading shall commence only after phase 1 erosion control <br />measures are in place. Phase 2 BMP installation will occur after grading <br />operations are complete. Phase 2 BMPS include mulching, temporary <br />seeding, surface roughening, and permanent seeding. Once the lake <br />grading sequence of construction activities has been completed, areas <br />where construction will not begin within 30 days will be surface roughened <br />~ : to reduce erosion potential and promote infiltration and will be temporarily <br />