SAVANNAH HARBOR EXPANSION PROJECT

CONCEPTUAL MITIGATION ACTIONS

WETLANDS

• Restore sites where tidal freshwater wetlands previously existed
• Restore sites where saltwater wetlands previously existed
  • Remove sediments deposited on Jones/Oysterbed Island outside the dikes
• Enhance restricted flows to existing tidal freshwater wetlands
  • Remove existing dikes
  • Install additional drainage pipes under roads
  • Enlarge ditches/creeks into the sites
• Enhance restricted flows to existing saltmarsh
  • Remove existing dikes
  • Install additional drainage pipes under roads
  • Enlarge ditches/creeks into the sites
• Excavate high ground areas to create sites suitable for freshwater wetlands
• Excavate high ground areas to create sites suitable for saltwater wetlands
• Increase releases from upstream reservoirs to reduce salinity in the estuary
  • Reallocate water from the Corps lakes upstream of Augusta
  • Construct upstream off-channel lagoons for additional storage of water Acquire and preserve tidal freshwater wetlands
• Acquire and preserve bottomland hardwoods
• Isolate Front River from Middle and Back Rivers to reduce salinity levels in MR and BR
  • Close lower entrance of Middle River
  • Install a flexible curtain as a barrier to block tidal flood flows up Middle River
  • Construct berms along Front River to restrict high water flows across the marsh Block Rifle Cut to eliminate higher salinity water from MR entering Back River
• Block Drakies Cut and restore flows through Steamboat River to lengthen the passage of saline tidal waters up the Savannah River
• Cease operation of the Sediment Basin to reduce movement of salinity up Back River
• Begin operation of the Tidegate with gates installed to only allow downstream flow, with no upriver movement of saltwater
• Improve flows down the freshwater canals in Savannah National Wildlife Refuge
• Increase flows down Bear Creek, Collis Creek, Mill Creek or Abercorn Creek
• Create saltwater wetlands between the navigation channel and the riverbank

FISHERY RESOURCES

• Increase dissolved oxygen levels in Front River
• Increase releases from upstream reservoirs to reduce salinity in the upper estuary during periods of lower flow
  • Reallocate water from the Corps lakes upstream of Augusta
  • Construct upstream off-channel lagoons for additional storage of water
• Increase freshwater flows down Back River to improve striped bass habitat (velocities and salinity) during spawning
• Modify the Tidegate into a fishing pier
• Install oyster shell beds in tidal creeks
• Install fish habitat structures
  • In tidal creeks
  • In nearshore area
• Construct a fishing pier to improve access
• Construct a boat ramp to improve access
• Increase flows down Bear Creek, Collis Creek, Mill Creek or Abercorn Creek

WATER QUALITY

• Add air or oxygen to low Dissolved Oxygen waters
  • Install air injection system on bottom of river
  • Install floating aerators
  • Install D.O. injection system on bottom of river
  • Construct D.O. injection system on Hutchinson Island
• Mix low Dissolved Oxygen waters on the bottom with higher D.O. surface waters
  • Inflatable weir
  • Pumps
• Increase releases from upstream reservoirs
  • To increase D.O. levels in upper harbor
  • To dilute chloride levels in upstream portion of estuary
• Block Drakies Cut and restore flows through Steamboat River to lengthen the passage of saline tidal waters up Front River (Decrease chloride levels at City of Savannah's I&D water intake)
• Relocate City of Savannah's I&D water intake to a location further upriver with lower chloride levels
• Improve the quality of industrial discharges (reduce D.O. loads on the river)
• Install oyster shell beds in tidal creeks (oysters filter turbidity and contaminants)
• Increase flows down Bear Creek, Collis Creek, Mill Creek or Abercorn Creek
  • To decrease chloride levels at City of Savannah's I&D water intake
  • To improve water quality in those tidal creeks

GROUNDWATER

• Deposit channel sediments in nearshore areas where the groundwater aquifer is near the ocean floor
• Acquire but not use a permit from the State to withdraw fresh water from the Floridan aquifer
• Reduce pumping of groundwater by acquiring - but not using -- permitted rights from industries to remove fresh water from the Floridan aquifer

SEDIMENT PLACEMENT & BEACH EROSION

• Place new work sediments into nearshore area
• Place new work sediments onto beach
• Place O&M sediments into nearshore area
• Place O&M sediments onto beach
• Place sediments from Jones/Oysterbed Island CDF into nearshore area
• Place sediments from Jones/Oysterbed Island CDF onto beach
• Construct a sand bypass system (increase sand reaching south side of entrance channel)
• Elongate north Federal groin (increase protection to a portion of Tybee ocean shoreline)
• Construct a new Confined Disposal Facility in the upper harbor
• Deposit channel sediments on nearshore areas where the groundwater aquifer is close to the surface
• Remove sediments from CDF 2A to extend it useful life
• Construct nearshore/offshore islands to provide shorebird habitat
• Create wetlands between the navigation channel and the riverbank
• Increase the wildlife value of the existing project's CDFs
• Increase public access to view wildlife at the project's CDFs
• Allow removal of sediments from the project CDFs by government agencies for use as fill in construction projects

CULTURAL & HISTORIC RESOURCES

• Document existing condition of an impacted resource
• Investigate and document the historical importance of an impacted resource
• Create public access to cultural/historic resources that will be impacted and preserved
  • Curate and display at Coastal Heritage Society
• Create a public venue to explain the historic importance of shipping to Savannah