20170203095546.pdfCD-V& WX-f-r-ts -I-
nOMEGA
eENGINEERING, INC.
January 27'h, 2017
2707 Wetmore Avenue
Everett, WA 043MG1
t 42S_3B7_3BZ0
f 425_259.110S0
JoAnne Zulauf
Engineering Technician RESLIB
City of Edmonds
Engineering Division
RE: RE: 1ST REVIEW COMMENTS FOR NELSON SFR BUILDING10t'F,PA IE
CI"l Cfw' E,F;)IODS
#BLD20160875
Dear JoAnne,
This letter is intended to summarize the changes made to the site plan, as well as, the engineering
package reviewed during the initial permit review for this project by the Engineering Division. This letter
addresses comments from you along with other staff members which were provided in a letter dated
December, 2016. 1 have tried to format this letter to match your comment email for easier understanding.
Sheet 1 — Cover/Site Plan
1) The location of dry utilities have been added to this sheet.
2) Lot coverage has been updated per Planning Division requirements and does not include roof
overhang. Please see revised sheet 1 for updated lot coverage calculations.
3) General notes have been updated. Please see revised sheet 1.
4) Sewer and water purveyors have been updated on cover sheet. Please see revised sheet 1.
5) Storm and fire have been added to public utility purveyor information on the cover sheet. Please see
revised sheet 1.
6) The drawing index has been updated. Please see revised sheet 1,
7) Detail E1.3 has been added to the SWPPP. Please see revised sheet 2„
8) Existing topo is shown on this sheet. The final grade will not be changing enough to show proposed
contour lines.
9) Approximate footing elevations have been added to this sheet for the existing house as well as the
new home. Please see revised sheet 2.
10) All on -site trees are to be removed from this site. As such, the clearing limits have been updated to
cover the entire site. The trees to be removed have been marked on the SWPPP. Tree protection
notes have been added to this sheet in the event that the client decides to keep any of the trees in
the back yard. Please see revised sheet 2.
11) Cut and fill grading quantities are 185 cubic yards. The SWPPP sheet has been updated to reflect
these values and for consistency. Please see revised sheet 2.
ne
OMEGA
ENGINEERING, INC.
w
2707 Wetmore Avenue
Everett, WA 98201
t 42S.387.3820
1f 425.259.1958
12) The applicant is working with OVWSD for confirmation on the proposal and utility locations.
13) Details E4.2 and E2.3 have been added to this sheet. Please see revised sheet 3.
14) The applicant will work with OVWSD to determine if the existing water meter is to be upgraded.
15) The utility note on this sheet has been revised. Please see revised sheet 3.
16) The location of dry utilities have been added to this sheet. Please see revised sheet 3.
17) This note has been added under Utility Notes on the revised Grading sheet. Please see revised
sheet 3.
Stormwater
18) Previously, WWHM was only being used to size the infiltration trench in order to meet minimum
requirement 5. Therefore the total area in the model was for the footprint of the new SFR only.
Driveway surfaces were not included because the driveway will sheet flow and not be directed to the
infiltration trench. Impervious surface calculations have been updated to reflect roof area, including
overhang. The drainage report has also been updated accordingly. The WWHM has been updated
to model the entire site as in the developed conditions compared to the entire site in the existing
conditions. Please see the revised drainage report, specifically Section 9, and WWHM calculations
provided in the back of the report.
19) The applicant will be working with the City to complete and return this form.
20) The invert elevations for the perforated pipe shown in the infiltration trench have been updated
based on the revised trench detail. Due to the additional roof area from the covered porches and
overhang, the infiltration trench was resized in order to infiltrate 100% of the roof area. Please see
the infiltration trench detail and drawing on sheet 3 of the revised plan sett.
21) A 10' minimum setback has been added to the plans for the infiltration trench. Please see revised
sheet 3.
22) Invert elevation from downspout connection has been added to the plans. Please see revised sheet
3.
23) The width of the transition zone has been added to the plans. Please see revised sheet 3.
24) Figure 5.5 from the DOE stormwater manual has been added to the plans. Sheet flow dispersion
was already called out on the plans, however a note has been added to see the detail on this sheet.
Please see revised sheet 3.
25) The maximum driveway width in any area for the new and existing concrete is 30 feet wide.
Therefore, per BMPT5.12 the minimum sheet flow path should be 15 feet. Based on the contours,
runoff from the driveway will sheet flow in a northwesterly direction. Therefore, a flow path of 15 feet
for the wider side of the driveway can be met. Please see revised sheet 3 for the vegetated flow
path for driveway runoff.
nOMEGA
ENGINEERING, INC.
2707 Wetmore Avenue
Everett, W^ 00201
t 425.387.3820
f 425_259_1958
26) The slope of the driveway and flow path have been added to this sheet. Please see revised sheet 3.
27) The applicant will be providing the City with the filled out form to approve prior to recording at
Snohomish County.
Stormw;ater Engineer Review
Minimum Requirement #1
1) All sheets have been updated.
2) The infiltration detail has been updated to say profile view. Previous comments instructed the detail
to be updated using Fig. A-3 which calls both views plan.
3) Infiltration trench detail has been updated. Please see revised sheet 3.
4) The minimum slope and inverts have been added to sheet 3.
5) Generally. one downspout connection is shown connecting to the infiltration trench. The gutters can
be routed as needed to connect to the infiltration trench. If additional connects are needed we can
show those on the plans at that time.
Minimum Requirement #2
1) Construction entrance notes have been added to sheet 2.
2) An inlet protection has been added to the downstream CB. Please see sheet 2,
3) Vehicle fueling locations will be used to limit the potential impacts from any spills. Please see
element 9 in the revised drainage report.
Minimum Requirement #3
N/A
Minimum Requirement #4
N/A
Minimum Requirement #5
1) The infiltration trench has been resized due to the additional roof surfaces that were not accounted
for previously. Please see page 7 of the revised drainage report.
2) A sieve analysis has been performed on the on -site soils per USDA method. Please see the
attached soils information. This information is also in the appendix of the drainage report.
3) As previously noted the infiltration trench was resized to account for the total roof area including roof
overhang. The infiltration trench has also been designed so that the bottom is located in the medium
sands. Please see sheet 3 and the revised drainage report as well as the WWHM calculations
provided in the appendix of the drainage report.
rA0W4k OMEGA
ENGINEERING, INC.
Minimum Requirement #7
N/A
Minimum Requirement #8
N/A
Minimum Requirement #9
N/A
Minimum Requirement #10
Maintenance requirements have been added to the report.
Minimum Requirement #11
N/A
2707 Wetmore Avenue
Everett, WA 98201
t 425.387.3820
f 425.259.1958
Thank you for taking the time to review the revised plans for this project. Please feel free to contact me
with any questions you may have.
Sincerely,
Rachel A. Jacobs, E.I.T.
Omega Engineering, Inc.