City Hall

New Seawall Cost Estimate: $56 Million Over McGinn Prediction

By Erica C. Barnett October 28, 2011

Another reason to believe Mayor Mike McGinn's proposed $241 million ballot measure to pay for the downtown seawall was premature: During this Wednesday's city council budget meeting, council members were told that the waterfront seawall---originally estimated at $274 million---is now expected to cost $330 million, a $56 million jump. And that estimate itself is only based on 10 percent design---as the design gets more refined, the costs could go up (the current estimate, as we reported earlier this year, is a range from $310 million all the way up to $390 million, depending on what elements---fish viewing areas? beaches?---the city wants to incorporate into the design).

The reasons for the increase, according to council staffers: The new proposal includes ecological upgrades to the downtown shoreline; the city has extended the project from Pine Street to Virginia; and the construction method has been changed to accomodate unstable soils on the waterfront. The new construction method involves using drilled shafts instead of jet grouting to drive the piles that support the seawall, which is "less risky for soil conditions in this area," central staffer Norm Schwab told the council.

Additionally, the downtown waterfront improvement project, originally estimated at $123 million for a "bare bones" upgrade, has been revised upward to $234 million, and could go higher as the James Corner Field Operations design firm refines its proposal, staffers said. The city estimates it could raise only about $225 million from a local improvement district (a special taxing district in and around downtown), so it would have to come up with some other source of revenue to pay for rest of the waterfront upgrade.
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