Date:    April 25, 2017
Item No.: 6c_Supp
Terminal 18 Stormwater Outfall
Renewal and Replacement
Marine Stormwater Utility

Marine Stormwater Utility


Stormwater Utility established to protect Puget Sound
2

Utility Revenue & Goals
Utility Revenue Breakdown            Assess all 78 miles of
NWSA             infrastructure by 2019
NWSA tenants
Port                    Invest in asset
Port tenants              rehabilitation to
improve water quality
Collected $4.7 million in 2016,
~$5 million in 2017
Provide triple bottom line benefits
3

Terminal 18 Stormwater
Drainage area roughly 175 acres
(nearly 9 Safeco Fields)
Most site drainage enters Duwamish
East Waterway through 13 Port-
owned outfalls
Outfalls were installed ~50 years ago

Largest active container terminal
4

T-18 Stormwater System


East Waterway Outfall Locations
5

Existing Outfall Conditions

Ponded water in the pipes
Missing tide gates
Broken Pipes
Visible conditions under the dock
6

Current Assessment / Scope of Work
Focus from last manhole to end of pipe
Repair broken and cracked pipe
Realign pipe grade or slope
Install new tide gate valves

New tide gate installation
Current Conditions and Repair
7

Project Schedule
Commission Authorizations
Design & partial construction authorization 2nd Qtr 2017 
Full Construction authorization 4th Qtr 2017 
Construction activities
Non disruptive construction activities summer 2017
Repair and replacement construction phased between
2018 and 2020
Schedule phased over 4 years
8

2017 Construction
Activities
Cured-in-place pipe (CIPP)
Tide gate valves where CIIP
performed
Budget 
2017 design and construction
activities = $1M
Capital plan = $4M, 2017-2020 
Cure-inplace pipe installation
Perform non-disruptive work early
9