Olde Towne Flooding Update
February 5, 2010
Another winter storm has just pushed Crawford Bay into Olde Towne and flooded Dinwiddie Street, Waverly Place, and Hampton Place again. More damage to the seawall and Crawford Parkway may have occurred. What is the City of Portsmouth doing to prevent this from happening in the future?
* The City is proceeding with the project to replace the existing seawall along Crawford Parkway. Construction will begin in June, 2010.
* The City has commissioned an update of the existing study of the Dinwiddie Street Stormwater Pumping Station.
History Portsmouth City Council has voted to use some of the money budgeted for the Holiday Inn infrastructure improvements to replace the seawall along Crawford Parkway from Tidewater Yacht Marina to Swimming Point. The project is proceeding forward as rapidly as possible.
Crawford Parkway Seawall Replacement.
Bulkhead replacement will be sheet steel pilings with a formed concrete cap and a tie-back system. The tie-backs will help keep the pilings in place and will be buried in the two west-bound lanes of Crawford Parkway (the lanes nearest the water).
The new bulkhead will be two feet further out into the bay than the existing one. The new bulkhead will average 1.3 feet above the level of the existing seawall – the level of the surrounding terrain.
It is not necessary to build the seawall any higher because water from the bay would just flow around the ends of the seawall into Olde Towne through Tidewater Yacht and Swimming Point.
NOTE: It is impractical and cost-prohibitive to build a structure massive enough to prevent even the largest storm from flooding Olde Towne. In fact, the proposed seawall is designed to prevent flooding from events the size of most (but not all) historical storms– but there are no guarantees.
Crawford Parkway Roadway Project
The existing two west-bound lanes of Crawford Parkway (nearest the water) are going to be closed permanently. The existing two eastbound lanes are going to be marked for two-way traffic.
Phase One of the project is the closure of the two west-bound lanes. This may happen before June due to the damage to the roadway sustained during the 2006 Nor’easter.
After the completion of the seawall project, the closed westbound lane area will be grassed over and essentially become a waterfront park.
Phase Two of the project is raising the two remaining lanes of Crawford Parkway to the approximate height of the new seawall. This will provide an additional barrier to storm-driven water from Crawford Bay. Plans for the Crawford Parkway Roadway Project will be completed in 90 days.
Dinwiddie Stormwater Pumping Station Study
A study was done in 1998 following the hurricane and flooding the previous year. This study is being updated to include a complete hydrological model of the Dinwiddie drainage basin. This is the area drained by the former creek that lay roughly where Dinwiddie Street is now.
The study will consider two different locations for the pumping station and take into account tidal changes and long-term changes in sea level due to climate change.
Future Events
30 Days (March 8 Council Work Session) City Engineer presents more fully-developed plans and schedule for the Seawall Project to Council. This is tentative: refer to City website for Agenda.
90 days (April 26th Council Work Session) City Engineer presents more fully-developed plans and schedule for the Roadway Project to Council. This is tentative: refer to City website for Agenda
120 Days (May 24th Council Work Session) City Engineer presents results of the Dinwiddie Pumping Station Study to Council. This is tentative: refer to City website for Agenda
References and Sources
CityCouncil Work Session Video January 26th, 2010. Presentation by City Engineer Richard Hartman. http://www.portsmouthva.gov/council/video.aspx
City Council Schedules: http://www.portsmouthva.gov/council/schedule.aspx
City Council Agendas: http://www.portsmouthva.gov/council/agenda.aspx
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