630 57TH ST SW 2023-06-23 - Laserfiche WebLink

• • 4. SWPPP NARRATIVE The intent of this section is to provide the information necessary to support the engineering plans in order to implement a design that will;.reduce, eliminate or prevent the discharge of stormwater pollutants, meet or exceed the water quality and sediment management standards for the County and State, and prevent adverse impacts to the receiving waters for this project. A. SITE GRADING/EROSION CONTROL RISK ASSESSMENT Area proposed to be cleared/worked: 1.33 acres Average slope for the site: 10% (Area of Disturbance Only) Erosion Hazard of Soil Moderate Critical Areas downslope Yes Site is upstream of an ESA Stream No Based on the above information and the fact that the area of the site to be disturbed is moderate and construction site runoff will pass through silt fencing or other perimeter filtration features prior to leaving the site, and that if site conditions warrant, additional BMP's can be.implemented as corrective measures the Risk Category for this site is Moderate Risk.. B. SWPPP MINIMUM ELEMENTS 1: Preserve Vegetation and Mark Clearing Limits The first .step in the construction process is for the contractor to fence the limits of clearing/disturbance (BMP C103) prior to any other construction activity. The engineering plans locate and provide the square footages for the areas of grading, clearing, impervious surfaces.and un-disturbed areas on the proposed site. As much of the natural vegetation as possible will be preserved on this project(BMP C101). Approximately 25% of the parcel will be flagged for disturbance. . 2: Establish Construction Access 0 The SWPPP calls for the proposed construction entrance(BMP C105)to be installed as the second step after the staking of clearing limits. At this time winter work is expected during the wet season. 3: Control Flow Rates This project is below the thresholds requiring flow control for the project. 0 Seahurst SP 18-1015 May 2020 Page 6