2013 Sandy Flood saline impacted tree survey by Eymund Diegel for the NYC Parks Department

Text on map:

"Gowanus / Red Hook Flood Impacts:  Post Sandy Flood Tree Leaf Out Percentages.

Trees impacted by salt water ponding and salt water flooding. June 25, 2013 survey.

Field Notes:  Mainly London Planes (Platanus acerfolia) and Dawn Redwoods (Metasequoia glystroboides) were impacted by salt water intrusion to their root areas.   277 trees were mapped as impacted. 

Recommendations:

Do nothing. Let tree go through full annual leaf out cycle to see which ones survive before replacing anything.

As capital restorations permit, eliminate salt ponding locations to allow for better draining of flood salt waters.

DEP currently has Green Infrastructure draining reconstruction project on Columbia Street between Sigourney and Bay which should be informed of Sandy’s lessons before replanting.  There is also a proposal for a new park and regrading of Gowanus Bay Terminal as part of EPA Gowanus Superfund Cleanup that should integrate Halleck Street and Columbia salt water draining issues.

Most impacted areas are Red Hook Houses at Dwight and King Street and Red Hook Park.

These were built on the old Seabrings Tidal Mill ponds, so settlement and ponding of salt water in these locations was variable on tree health.

Draft Map"