HAMILTON ARMY AIRFIELD COASTAL SALT MARSH EXCAVATION

  • SALT-MARSH-EXCAVATION2
  • SALT-MARSH-EXCAVATION1
  • SALT-MARSH-EXCAVATION3
  • Client: US Army Corps of Engineers
  • Location: Novato, CA
  • Date: 2006
  • Contract #: W912P7-05-C-0003
  • Value: $5,223,998

The Coastal Salt Marsh at the former Hamilton Army Airfield required remediation to address elevated levels of contaminants by removing contaminated soil from the marsh.  Soil was excavated in the outboard marsh from several specific sites ranging in size from a few hundred square feet to several acres and as much as three hundred feet outboard of the bay front levee.

Minimization measures were implemented to protect the salt marsh harvest mouse, the California clapper rail and other fauna and flora from the effects of remedial actions.  A contract biologist kept daily notes of the mouse relocation, vegetation removal and barrier fence erection work at each site documenting minimization measures taken.  A total of 31 salt marsh harvest mice were successfully relocated

Bay water tidal influences into the excavation areas were a major concern.  Control measures such as sediment traps and a barrier placed at the downstream end of the drainage ditch were devised to eliminate migration of contaminants into the bay by receding tide water.  The barrier also eliminated the potential of fish entering the excavation sites.

Cerrudo Services excavated, stockpiled and disposed 33,208 cubic yards of contaminated soil from a total of 10 separate sites located within the coastal salt marsh tidal zone.