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HomeMy WebLinkAboutSW4221101_Stormwater Narrative_20221128Narrative Protect Description The project site is located in Watauga County, NC, approximately 5.5 miles southeast of the Town of Boone, and approximately 6.0 miles northeast of the Town of Blowing Rock (36.180213°,-81.585089). The Subject Property (±28.584 ac) is located off Little Laurel Road and is identified by Parcel Id Numbers (PIN) 2839737865000 and 2839730740000. The Property is also referenced by Deed Bk 2267, Pg 660. The project site is being developed as a residential area with 14 lots to accommodate future homesites (Planning Board Pre Plat approval and NCDOT Driveway Permits have been approved). The project site (disturbed area) is approximately 3.29 acres. This includes all areas proposed for grading as well as areas necessary for construction and post -construction stormwater management. A series of permanent ditches with check dams, energy dissipaters (stilling basins), silt fence, and a temporary sediment trap will be used to collect and manage construction stormwater. Driveway construction is proposed in discrete phases with accompanying stabilization measures on all cut/fill slopes, ditches, and road corridor to meet NCGO standards. The Erosion and Sediment Control Plan and post -construction stormwater plans are included in the Site Construction Documents that accompany this application. The Sequence of Construction with operation and maintenance notes is provided in the plan. Site Description The project site is located approximately ±5.7 miles southeast of the town of Boone, NC. The site is primarily forested and moderately sloped. The applicable USGS quadrangle and NRCS soils map and descriptions for the project site are included in pages 2-4 of this narrative. The project site is located in the Yadkin Pee -Dee Basin - Elk Creek (HUC 030401010104). One stream, North Fork Laurel Creek, is located in the southeastern portion of the Subject Property, flowing northeast on -site. No wetland features are present at the project site. Adjacent land uses include undeveloped forest and low density residential. The watershed to the project site is generally undisturbed and wholly included in the Subject Property. Protect Soil Data The Subject Property is primarily underlain by Ashe-Chestnut complex of varying slopes. AcD (Ashe-Chestnut complex, 15-30% slopes, very rocky) is mapped in the northwest portion of the Subject Property. AcE (Ashe-Chestnut complex 30-50% slopes, very rocky) is mapped in the southcentral and southeast, while AcF (Ashe-Chestnut complex 50-95% slopes, very rocky) is mapped in the northeast and southeast corner. CsE (Cullasaja very cobbly loam, 30- 50% slopes very stony), is mapped beneath the North Fork Laurel Creek in the southern portion of the parcel. Soil data was obtained from NRCS Web Soil and are described in detail in the table below: NRCS Soil Unit Descriptions Soil Unit Landform Drainage Class Notes AcD - Ashe-Chestnut Ridges Somewhat Gravelly fine sandy complex, 15-30% excessively drained loam slopes, very rock AcE - Ashe-Chestnut Ridges, mountain Somewhat Gravelly fine sandy complex, 30-50% slopes excessively drained loam slopes, very rock AcF - Ashe-Chestnut Ridges, mountain Somewhat Gravelly fine sandy complex 50-95% slopes excessively drained loam slopes, very rock CsE - Cullasaja very Fans, drainageways, Well drained Very cobbly loam cobbly loam, 30-50% and coves on slopes very stony mountain slopes ESC Measures All roadside ditches will be matted as specified by the project engineer on the site plans, all fill slopes will be matted and all cut slopes with greater than 10ft in vertical relief will be matted. All cut slopes steeper than 1.5:1, and fill slopes steeper than 2:1, will also be matted, regardless of vertical relief. Stilling basins will be converted to permanent riprap aprons, post -construction, as specified on the site plans. All measures are sized to the 25yr event per the receiving water, ORW, classification. Stockpile(s) will contain silt fencing with wattle barriers. Protect Timeline Phased sequences of construction are provided with the Erosion and Sediment Control Plan provided with this application package. The estimated start date for construction is September/October 2022. The estimated length of construction to final stabilization is 1-2 months.