HomeMy WebLinkAboutPermit File BLD-2021-0313 2711 Oakes Avenue (9)ANACORTES PUBLIC WORKS DEPARTMENT
Steven Lange, Senior Engineering Tech
P.O. BOX 547, ANACORTES, WA 98221 PHONE: (360) 299-1983
E-MAIL: stevel@cityofanacortes.org CELL: (360) 661-3468
Drainage Review Memo
Date: June 147 2021
To: Dave Oicles, Permitting
From: Steven Lange
Subject: 2700 Block of Oakes Avenue (P58268)
cc: Eric Shjarback, Justin Symonds, Libby Grage, Don Measamer
The Public Works Engineering Department completed a review of the June 3, 2021
submittal for the above referenced project on June 14, 2021. Below are the comments:
1. Project Description and Summary:
- Development Type: Please revise. Proposed is Single Family
Number of Lots: Please revise. Proposed is two
Site Sediment Transport Score: Need to complete. See Appendix 4
Depth to ground water: Provide this information. You will need this
information to design the BMP's selected.
- Infiltration Rate: You will need this information to design the BMP's selected.
- Regarding the SF, the Ecology Manual recommends using 4200 SF when
designing, this way there is room to expand on the impervious area over time,
without having to redo the drainage report. If you say 1,889 SF maximum
impervious, then the site is unable to expand at a later date, without having to
do additional upsize of the facilities and paperwork.
- BMP's (required in MR#5: The project is considered Flow Control Exempt.
Most, if not all projects select BMP T5.10C Perforated Pipe connection. No
specific sizing, other than what the detail calls out.
2. Drainage Basin: Please revise. Basin G10. No downstream deficiencies found
3. Applicability Flow Chart (Figure I-2.4.1) —Accepted
4. Applicability Flow Chart (Figure I-2A.2) — Not needed. Please remove.
5. Minimum Requirement 1: Step 1-3.1.3 — Please revise. Project is considered
Flow Control Exempt, therefore there is no need to perform an off -site analysis.
6. Minimum Requirement 1: Step 1-3.1.5 — Applicant needs to select the
appropriate BMP for this project. So far there is 1) BMP T5.10A — Downspout
•Water •Wastewater •Streets •Storm Draina e • En meerin a Solid Waste
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Full Infiltration, 2) BMP T5.10B — Downspout Dispersion System, and; 3) BMP
T5.14A Rain Gardens. Rain Garden is not an option for Flow Control Exempt.
Most project select BMP t5.10C — Perforated Pipe Connection
7. Minimum Requirement 1: Step 1-3.1.6 — The 13 elements of a the SWPPP needs
to match the Erosion and Sedimentation Plan in Appendix 5.
8. Minimum Requirement 1: Step 1-3.1.7 — Need to complete. Are all the items
included in the report?
9. Minimum Requirement 1: Step 1-3.1.8 —Did the applicant review the document
to ensure compliance with the Ecology Manual?
10, Minimum Requirement 2: Applicant needs to select the best BMP's specific to the
project, using the provided Tables in Tab 2. Then show the BMP on the site
plans. Please revise.
11. Minimum Requirement 3: Accepted.
12. Minimum Requirement 4: Accepted,
13. Minimum Requirement 5:
- Flow Control Exempt is accepted. Although, the reason provided is not
accepted. Applicant needs to locate the section that discusses a manmade
conveyance system to the Bay. Please insert that paragraph.
Pick one BMP from the list.
- Remove List 41 from the report.
14. Appendix 1: Accepted.
15, Appendix 2: Project will need to have the existing soils tested to verify
compliance with the requirements under BMP T5.13 — Soils. Then provide the
test reports for soils modification.
16. Appendix 3: See comments under Appendix 2.
17. Appendix 4: More than 5,000 SF will be disturbed on this project. Not just the
house and driveway foot print. Item B = 30.
How is the ground water entering the site going to be intercepted? There was no
perimeter drains identified on the site plan provided. Item F = 25
Score = 80.
18. Appendix 5: Revise the site plan to match Minimum Requirement 2 — 13
elements.
19. Appendix 6: Provide documented photos of the site.
20. Appendix 7: This depends on the BMP's the applicant decides to move forward
with. More to follow.
T nks,
Steven Lange
Senior Engineering Tech
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