5406 S 1ST AVE 2021-02-25 - Laserfiche WebLink

4. SWPPP NARRATIVE (MR #2) The intent of this section is to provide the information necessary to support the engineering plans 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-.City and State, and prevent adverse impacts to the receiving waters for this project. Note; this narrative is intended to support the SWPPP that is included with the Drainage Plans also a part of this submittal package to the City. A. SITE GRADING/EROSION CONTROL RISK ASSESSMENT Area..proposed..to_be.cleared/worked: 0.31 acres Average slope for the short plat: 10% (Area of Disturbance Only) Erosion Hazard of Soil Low Critical Areas downslope No Site is upstream of an ESA Stream No Based on the above information and the fact that the area of the short plat to be disturbed is flat and construction site runoff will pass through silt fencing or other perimeter filtration features prior to leaving the short plat, and that if site conditions warrant, additional BMP's can be implemented as corrective,measures the Risk Category for this site is Low 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 short plat. The entire project area will be cleared or disturbed for this project. 2: Establish Construction Access The SWPPP calls for the existing alley and road to be used as the proposed construction entrance(BMP C105) to be modified as needed. This shall be installed as the second step after the staking of clearing limits. The construction entrance for this project will be the alley to the west. At this time winter work is expected during the wet season. 3: Control Flow Rates The runoff from site grading will not be allowed to enter the future infiltration areas until the site has been stabilized. All on-site construction site runoff will be dispersed over the east portion of the site and no concentrated flows will be created. For the road improvements the conveyance system will be in place and can be used for controlling flows prior to connection to the existing downstream system. Zillah Lot 2 SFR 18-0605 Aug 2019 Page 7