1728 100TH ST SW 2024-01-04 - Laserfiche WebLink

EXISTING SITE CONDITIONS The project site is located on the southeast corner of the intersection of Dakota Way and 100" Street Southwest in Everett, Washington, within City of Everett limits (Parcel #'s: 00552400602500 & 00552400602600). The project site is approximately 0.53 acres. Existing ground slopes range from 2 to 8 percent (Figure 1: Existing Site Plan). The topography slopes towards the south. There are no existing buildings on site. Swamp Creek passes through the southeastern portion of the property via an existing enclosed pipe. The parcel is covered in lawn (Figure 2: Site Photographs). ' National Resources Conservation Service (NRCS) Soil Map (Refer to Section IV, USDA NRCS Soil Map and Description) indicates on -site soils consistent with Alderwood materials. Alderwood-Urban soils are a gravelly ashy sandy loam material that was derived from basal till ' and is commonly found on till plains. Alderwood-Urban soils are moderately well drained material with a hydrologic soil group "B'"; However. SMMWW Table III-2.4 classifies Alderwood soils as group "C." ' Mac Engineering dug Test Pits (TP) in the northern portion of the site (Refer to Section IV: Mac Engineering Soil Logs). On -site soils were found to be consistent with Alderwood soils. Mottling was found at 16 inches below the ground surface in TP-2 indicating the seasonal presence of groundwater, and groundwater was encountered at a depth of 34 inches. A topsoil sample was collected and sent to Northwest Agricultural Consultants to determine the organic content (6.83%) ' and cat -ion exchange capacity (15.7 meq/100g). Based on test results, existing topsoil meets requirements from SMMWW Volume V, Chapter 11, BMP T5.13; therefore, topsoil will be stock piled for final stabilization (Refer to Section IV: Northwest Agricultural Report). Based on on -site field observations, stormwater runoff sheet flows to the south through existing lawn and infiltrates into the ground, thus recharging the water table. There are no erosion issues present within the project site area. DEVELOPED SITE CONDITIONS ' The proposed project consists of construction of two SFRs with driveways and parking areas. Stormwater drainage analysis and flow controls, used to achieve best management practices (BMPs). designed for this proposed development will comply with the requirements set by the Everett Municipal Code and SMMNN'W. ' The proposed two SFRs (t3,420 sf w/overhang) are classified as non -pollution generating impervious surfaces (NPGIS). The proposed SFRs will be located in the northern portion of the property (Figure 3: Developed Site Plan). Stormwater runoff will collect in gutters and utilize downspouts. The proposed SFRs will have a minimum of 3 downspouts each per SMMWW Volume V, Chapter 4, BMP T5.1013 Downspout Dispersion Systems. The downspouts will tightline south to a proposed Dispersion Trench, which will have a minimum 25 ft flowpath from the discharge point to the nearest downstream property line. in accordance with BMP T5.1013, Design Criteria for Dispersion Trenches. u