7702 RAINIER DR 2022-04-05 - Laserfiche WebLink

OFF SITE ANALYSIS AND MITIGATION An Off Site Analysis and Mitigation Study meeting requirements outlined in Section 2.5.1 was performed on January 8,2016.The weather was partly clouding and cool at the time of the field inspection.See Downstream Analysis Map. TASK I: PROJECT OVERVIEW&STUDY AREA DEFINITION The proposed project is located on the Rainer Existing Site Conditions: The project consists of construction of a single family home on a 0.45 acre site.The existing lot currently has a home and shop.The majority of the sites cover is lawn with some trees. The soils at the front of the lot has been identified as McKenna series and the rear of the lot as Alderwood,both of which are type C soils and not suitable for infiltration. The site itself slopes to the west with the runoff leaving the site along the west property line to an existing drainage ditch.. The slopes for the site range from 5% to approximately 10%. TASK 2: REVIEW OF AVAILABLE INFORMATION ON STUDY AREA Resource Review: The following is a description of the resources that were reviewed for the preparation of this Level 1 Drainage Study: A. Basin Recognizance Summary:Enclosed within are downstream and upstream basin area map which clearly define the flow pass and the drainage basins related to this project. See (Downstream Analysis Map) Evidence of Existing and Predicted Problems Lack of capacity or constrictions in the existing drainage system. O On-site: No evidence of any problem. O Off-site: Stream None noted Culverts None known (no evidence of capacity or any other problems) Overtopping, Scouring,Bank, Sloughing of Sedimentation O On-site: No evidence of any problem. O Off-site: C 12-inch pipes:N/A C Stream Channel: none noted Flooding etc. O None Noted Significant Destruction of Aquatic Habitat or Organisms O None Noted B. Adopted Basin Plans: None Known Kymera 2-Lot SP Full Drainage Report Revised:April 21,2018 Page 4