2307 COLUMBIA AVE 2021-05-04 - Laserfiche WebLink

2. Competing Needs Criteria listed in Chapter V-5 -On-Site Stormwater Man- agement(p.903). Lawn and landscaped areas: Post-Construction Soil Quality and Depth in accordance with BMP T5.13: Size of site and Jst-Construction Soil Quality and Depth (p.911). Cannot limit max impervious impervious area to 10% of the site. coverage leaves no - room for full all Dispersion in BMP T5.30: Full Dispersion (p.939), or infiltration. Dwnspout Full Infiltration Systems in accor an MP T5.10A: Down- spout Full Infiltration (p.905) This project is 2. Rain Gardens in accordance with BMP T5.14A: Rain Gardens (p.915), cexempt from MR#7 Bioretention in accordance with BMP T7.30: Bior ells, Swales Flow Control and Planter Boxes (p.959).The rain gard °- -`- -� - acility mus avtherefore does not Infeasible due to require these LID minimum horizontal projected surfa lack of space for ierflowwhich i. least 5% of the area draining to i flowpaths. BMP s be evaluated. 3. Downspout Dispersion Syst s in accordance with BMP T5.10B: Down- spout Dispersion Systems (p.905) 4. Perforated Stub-out Connections in accordance with BMP T5.10C: Per- forated Stub-out Connections .90 Other Hard Surfaces: Yes. Flows will be directed to a 1. Full Dispersion in accordance witl combined spersion (p.939) 2. Permeable pavement1 in accordai stormwater/sewr Permeable Pavements (p.917), or Rain Gardens in accorc utility main on 4A: Rain Gardens (p.915), or Bioretention in accordaColumbia Ave. : Bioretention Cells, Swales, and Planter Boxes (p.959).The rain garden or bioretention facility must have a minimum horizontal projected surface area below the overflow which is at least 5% of the area draining to it. 3. Sheet Flow Dispersion in accordance with BMP T5.12: Sheet Flow Dispersion (p.908), or Concentrated Flow Dispersion in accordance with BMP T5.11: Con- centrated Flow Dispersion (p.905). List#2: On-site Stormwater Management BMPs for Projects Triggering Minimum Requirements #1 through #9 For each surface, consider the BMPs in the order listed for that type of surface. Use the first BMP that is considered feasible. No other On-site Stormwater 1This is not a requirement to pave these surfaces.Where pavement is proposed, it must be permeable to the extent feasible unless full dispersion is employed. 2014 Stormwater Management Manual for Western Washington Volume I- Chapter 2-Page 57