7030 LOWER RIDGE RD 2018-07-25 - Laserfiche WebLink

� Y the extent feasible unless full dispersion is employed. (A review of the soils showed there was evidence of mottling at 18-inches,therefore the soils are not suitable for infiltration.In addition the driveway is locate approximately 1-foot from the property line and is higher than the adjacent property.If the pervious pavement fails the runoff will drain on the adjacent property to the north causing potential issues.The proposed design will use a 2-foot wide dispersal trench located along the south edge of the driveway to prevent any runoff from leaving the site to the north.) 3. Bioretention in accordance with Volume V, Chapter 7 of this manual. . (Not feasible due soils type, mottling and issues with maintenance and the slopes along the rear of the lot. If the bioretention pond is disturbed or not maintained it could cause a point discharge from the site eroding the slopes at the back of the lot.With the use of the dispersal trench,the runoff will sheet flow from the site. 4. Sheet Flow Dispersion in accordance with BMP T5.12, or Concentrated Flow Dispersion in accordance with BMP T5.11 in Volume V, Chapter 5 of this manual. (Will be used) To the extent possible,proposed on-site stormwater management meets the 2014 DOE SWWM Manual Infiltration Capacity:The USGS Evaluation for the site show the on-site soils are a Type C are a not suitable for infiltration. (see appendix) BMP T5.13 "Post Construction Soil Quality and Depth" The top soils will be stockpile on-site and reused per "Implementation Options #3 per BMP T5.13 "Post Construction Soil Quality and Depth" which requires "Stockpile existing top soils during grading and replace it prior to planting... " (See work sheets"List of Figures") Minimum Requirement #6 Runoff Treatment Requirements DRIVEWAYS AND PARKING PGHS AREA The combined new PGHS area is under the 5,000 sf the threshold. Therefore,no runoff treatment is required.. Minimum Requirement #7 Flow Control As discussed above,stormwater will be managed through the use of LID methods using splash blocks and 50-foot minimum flows paths through vegetation before leaving the site and has been designed using the LID applications as outlined in Volume III, Chapter 3, "Flow Control Design" of the DOE 2014 Stormwater Management Manual. The total impervious area including: home and driveway, is under the 10,000 sf threshold. Therefore the site qualifies for a small site drainage design. To the extent possible,the proposed BMP's addresses the required stormwater management as outlined City Evereet Stormwater Management including: 7030 Lower Ridge RD Full Drainage Report Revised:November 3,2017 Page 13