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T ECHNICAL M EMORANDUM
Date: August 8, 2016
To: Rocale Timmons
From: Kenny Booth, Andy Noone
Pre-Application Number PRE 16-000406
TWC Project Number: 150809
Project Name: Southport Shoreline Modifications
Subject: Southport Shoreline Modifications Construction Mitigation Description
Proposed Construction Dates:
Proposed construction dates for all in-water work are November 16th through December 31st of
2016. This construction window is the allowable timeframe based on fish-protection
prohibitions on in-water construction by NOAA Fisheries and USFWS. If the project cannot be
completed before December 31st, construction activities will be necessary between July 16th
through July 31st of 2017. Activities that do not require in-water work, or that can be completed
from upland locations (such as installation of the apron over the bulkhead) may occur outside
of the federal timing windows.
Hours and Days of Operation:
Construction activities may occur between 7:00 AM and 10:00 PM, Monday through Friday, and
9:00 AM to 6:00 PM on Saturday. However, since there is a limited timeframe for allowed
construction due to fish-protection prohibitions, construction outside of normal business hours
(including nights and Sundays) may be required.
Proposed Hauling/Transportation Routes:
Construction materials will be delivered by barge or truck. Materials that are delivered by
truck will arrive from Interstate 405, Exit 5. The project site is easily accessible by truck and is
only 0.6 miles from the interstate. Construction debris will be loaded onto barges or trucks and
transported to an appropriate disposal site. Construction planning has not been finalized.
More information on hauling and transportation routes will be available at the building permit
stage.
Measures to be implemented to minimize dust, traffic, transportation impacts, erosion, mud,
noise, and other noxious characteristics:
Dust: No such measures are necessary. Proposed construction activities are not expected
to result in dust.
Southport Shoreline Modifications
Construction Mitigation Description
August, 2016
Page 2
Traffic: Construction activities will occur on the shoreline and will not impact existing
roads. No traffic minimization measures are proposed.
Erosion: Construction activities will occur in water and on the shoreline bulkhead. No
exposed soils are expected, so no erosion control measures are proposed.
Turbidity: Construction activities will occur in water and on the shoreline bulkhead.
Approximately 101 pilings will be cut below the mud line and removed. A floating
sediment curtain will be installed and maintained around the work areas, as necessary,
for the duration of in-water work to limit turbidity impacts. Also, as mentioned,
construction will occur within approved fish windows to minimize impacts to
salmonids.
Noise: The removal of the existing piles and the driving of new piles as part of the
bulkhead repair activities will produce temporary noise and vibration resulting from use
of the barge, vibratory extractor/driver, and other construction equipment. Underwater
noise from vibratory extraction and driving of piles will be greater than that of other
construction equipment. Noise would be limited to normal daytime working hours and
follow all applicable regulations set forth in Renton City Code 8-7.
Any special hours proposed for construction or hauling (i.e. weekends, late nights):
Depending on the construction schedule, construction may occur on nights and/or weekends in
order for the project to be completed within the approved fish windows. However,
construction planning has not been finalized.
Preliminary traffic control plan:
Construction traffic will be directed down the Southport access road so that construction
vehicles can easily access the construction site. Since the majority of project work will occur on
the shoreline at the end of a dead end access road, it is expected that traffic control will not be
necessary. Accordingly, no traffic control plan is proposed at this time.