20150624094641363.pdfConsulting Civil Engineers
6608-216 TI Street SE, Ste #306
Mountlake Terrace, WA. 98082
Jennifer Lambert
City of Edmonds
Public Works Department
121 — 5t" Avenue N.
Edmonds, WA 98020
RE: Engineering Plan Review for Application Number: BLD20150224
Project Name & Address: Neuman — 390 Sunset Avenue N.
June 23, 2015
Jennifer,
We have completed revisions to the above noted project per your correction notice dated June 18,
2015. Below are your original review comments noted in italics, followed by our response noted in
bold.
SITE PLAN
See Architects Responses for Item's 1), 2), through 6).
TEMPORARY EROSION CONTROL PLAN (Cl OF 3
_J
Revise 'Permanent Cover BMP' notes as follows:
a. #2 — Replace the word 'detention' with 'infiltration' where applicable.
b. #4 —Replace 'esistent' with the appropriate word
c. #5 — Remove note 5. Fertilizer should not be used.
Response: Done.
DRAINAGE PLAN (C2 OF 3)_
Please show all the utilities on this plan (water, sewer, storm, gas, phone, power, etc.)
Response: Water is 10 -feet from sewer stub @ property line. Gas, power & phone are
presented as directed by others.
The elevations do not match the depth callouts in the gravel less chamber detail. Please revise.
Response: We have established an elevation at the bottom of each of the infiltrator's of 22 -Ft.
However, we have noted that the geotech representative should insure the devices are keyed
into the required layer.
,4 detail should be included that shows the connection to the StormTech Chambers for the
pipes connected to the area drains.
Response: We have provided the manufacturer's detail of the typical pipe manifolds,, used to
connect to the yard drains or inlets.
Office: (425) 744-0916 Cell: (425) 359••2717 Fax.: (425) 744-0'946"
June 23, 2015
Third Review
390 Sunset SFR
WATER — UTILITY PLAN (C3 OF 3
Please label the water service line material. Also, please note the water service line as 1-112" as
required by the fire department.
Response: ATA responds that sprinklers are not required for this project. Therefore, he stated
that the meter will be %11 and the pipe will be 1" .
The water service line shall leave the water meter and run straight into the property line
(perpendicular to the property line). Once on private property, the water service line may be
angled as needed. Please revise all plan sheets accordingly.
Response: We've drawn this accordingly.
The City requires a minimum of 10' separation between the water and sewer lines. It appears as
though the water and sewer have a 3' separation. Please revise all plan sheets to meet the City's
requirement.
Response: We have shown this accordingly on this project.
NOTE: It has been our experience with many jurisdictions that the DOE 10 -foot separation
rule usually applies up to the private property line. Usually builders have more latitude within
the building site. Is that not the case in Edmonds?
As you revise the plans to meet the minimum utility separation, please note that a minimum of 3'
separation between the water and the dry utilities (phone, power, cable, gas, etc.) is required. The
same dry utility separation requirement applies to sewer.
Response: Noted on the plan.
SEWER — UTILITY PLAN C3 OF 31
Please show the invert elevations at the main and the house so that slope and coverage can be
verified. If the slope of the pipe exceeds 20% the pipe will need to be anchored.
Response: Sewer service elevation has been provided from the owner and a building invert
has been calculated. Proposed slope is 3%.
STORM
Elevations have been provided that show several high and low spots throughout the driveway. It
is unlikely the contractor will choose to construct the driveway in this manner. Please confirm this
is the intent of the design.
Response: We have regarded the drive to a 1% surface slope from the cast end CB#3 to the
west CB #1. The grates step down to the low point at CB#1 with an emergency overflow
capability at the driveway curb cut. If any part of the system overflows it will drain to the
front via the driveway.
Office: (425) 744-0916 Cell: (425) 359-2717 Fax.: (425) 744-0946 2
June 23, 2015
Third Review
390 Sunset SFR
The sur face water runoff from the driveway shall not sheet flow into the street. Please show how
runoff from the driveway will be collected and discharged to the storm system.
Response: It will only flow to the gutter in the unlikely event of a system wide back up.The
infiltrators should all be at the same bottom elevation at a bottom depth 6 -feet below grade.
STORM REPORT
Pgge 2 last paragraph — The proposed impervious surface area is stated as 2,689 sf for the
roof and 2,203 sf for the new pavement, totaling 4,712 sf. Page 8 states the total site
contributing impervious (proposed) is 4,625 sf. Sheet 2 of the plans list 4,713 sf effective
impervious. Please reconcile these numbers.
Response: We reconcile this by using the latest numbers on the AIA Site Plan accordingly.
This prevents us from misreading the layers and line types on the Site Plan dwg.
Page 3 — Small site Minimum Requirement #6 is Runoff Treatment, not Flow Control. Flow
Control is MR#7 and Wetland Protection is MR#8 (not #7). Correct the numbers on the Flow
Control and Wetland Protection MR's. Add the MR for Runoff Treatment and say it is not
applicable since the site does not have 5, 000 sf or more of pollution generating impervious area.
Response: This has been straightened out. We are wondering whether any of requirements 6
through 11 need to be addressed here since the impervious is less than 10,000_SF per DOE.
Page 3, MR#9 — The text states that the maintenance and operations instructions for the
proposed chambers are included in the report. Only the installation instruction are included.
Please include the maintenance instructions.
Response: Manufacturer's M&O information is included at the end of the Drainage Report.
Page 4 — Most of the "Edmonds Requirements" are incorrectly paraphrased in this section. The
site is a categorized as a Small site since it does not involve ]-acre or more of land disturbing
activity. It is further categorized as a Category 2 Small Site since it proposes more than 2, 000
square feet of new plus replace impervious surface area. Remove item 4 in this section. Item 5 is
not an Edmonds requirement but a summary of the geotechnical investigation.
Response: This has been revised.
Page 5 and Plan Sheet 2- The last sentence discussed the overflow path for the chamber system.
Area drain 44 should be raised slightly so Area Drain #3 is the overflow for the rear chamber
system. That way the oveiflow will run down the driveway and not to the neighbors to the south.
Response: Drive is re -graded at minimum grade from the rear to the front so that the
driveway can become the emergency overflow weir in the unlikely event of a flooding
condition.
Office: (425) 744-0916 Cell: (425) 359-2717 Fax.: (425) 744-0946 3
June 23, 2015
Third Review
390 Sunset SFR
Page 8 — Assuming 4, 713 sf of impervious area, based on the pre -sizing tables with a sizing factor
of 2.791o, the nth of the SC -310 chambers required is approximately 127.3 ft. Since the installed
length of each chamber is 7.12 feet (=85.4 inches; the entire chamber is 90.7 inches but there is
overlap when installed), the site will require 18 chambers not the 9 chambers presented in the text.
See; hLtp:lli4)ivi4,.stori?7tech.com/d`ownload files/pdf /cut sheet 310, pdL. Also, the text lists the
chamber width as 58 inches. The SC -310 chamber has a width of 34 inches. If the applicant
chooses to use a chamber with different dimensions than the StormTech SC -310, the pre -sizing
tables cannot be used and the chamber design must be modeled by the engineer for compliance.
Response: System is re -configured with a total of 17 gravelless chamber units.
Include the amount of impervious surface area that is draining to each chamber system (how much
is draining to the system behind the house and how much is draining to the system in front of the
house) so the number of chambers in each system can be checked.
Clearly distinguish which tightline sections and what portions of the driveway will discharge to
which chamber.
Response: While an exhibit is provided showing the proposed distribution of runoff to the
respective chambers, the system is now interconnectd so that backups in the rear can overtop
& flow to the front as required.
DRY UTILITIES
Comment was partially addressed. Underground power is shown; however, gas, phone, cable, etc.
are not shown on the civil plans. Will the dry utilities not shown on the plan sheet be in the same
trench as the power? If all dry utilities will be in the same trench, please label as such. If they will
not be in the same trench, please show the location of all the utilities.
Response: Dry Utilities are provided as directed by the Project Architect. Gas is at the south
property line. Power and phone are at the north property line and we presume they will be in
the sme trench. Construction of these items is the responsibility of the respective utility
companies not the Civil Engineer.
If you have any questions, please call me at (425) 744-0916.
Sincerely,
J.C. MCD ELL NGINEERING P.C.
J.C. McDonne l-7 .
Principal
Office: (425) 744-0916 Cell: (425) 359-2717 Fax.: (425) 744-0946 4