20091002092601128.pdfMessage Page 1 of 2
Zulauf, JoAnne
From: Zulauf, JoAnne
Sent: Friday, October 02, 2009 12:26 PM
To: 'ptiegs@yahoo.com'
Subject: FW: Tiegs Drainage
Please find Stormwater review comments below.
Engineering review is suspended until drainage issue is resolved.
Thank you
JoAnne Zulauf
-----Original Message -----
From: Shuster, Jerry
Sent: Friday, October 02, 2009 12:05 PM
To: Zulauf, JoAnne
Subject: Tiegs Drainage
JoAnne,
Her is my review of the Tiegs drainage submittals dated 9123109:
o The modeling documentation shows the facility meets the City's flow control
requirements. The plans, however, do not reflect the modeled pond.
o The model uses an effective depth of 3 feet. The effective depth is equal to 0.4
times the depth of the gravel plus the soil, plus the water (ponding) depth, plus the
freeboard (extra embankment height above the water surface). In Detail 2, the
gravel plus the soil is 5 feet, the ponding depth is one foot and the freeboard is 6
inches. This equates to a effective depth of 3.5 feet. The soil depth can be
decreased from 4 feet to 2.75 feet. This will make the effective depth 3 feet to
match the model.
o The model uses a riser height of 2.5 feet (above the top of the soil layer). Detail 2
shows the top of the riser 1 foot above the top of the soil. The riser must be raised
to match the model (see addition comment below on the outlet,structure for further
information the riser)
o The model used an orifice elevation of 0.9 ft (above the top of the soil layer). Detail
2 shows the orifice 0.2 ft above the top of the soil layer. In addition to not matching
the model, this is too close to the soil level and will be susceptible to clogging.
• Following review by maintenance staff, the designed outlet structure needs to be
changed to help prevent clogging of the orifice and better performance of the overflow
pipe. The outflow structure must be in a catch basin/yard drain to facilitate
maintenance and reduce the chance of clogging. See the attached drawing.
. All pipes, vegetation lined ditches and other stormwater conveyances should be drawn
showing their slope and arrows for flow direction so they can be constructed and
inspected properly.
10/2/2009
Message
Jerry Shuster, P.E.
Stormwater Engineering Program Manager
City of Edmonds
121 5th Ave N.
Edmonds, WA 98020
Desk Phone: 425-771-0220 x1323
Fax: 425-672-5750
shuster@ci.edmonds.wa.us
10/2/2009
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