GEI provided complete turnkey design, permitting, and construction phase services to rehabilitate an existing 925-linear-foot historical seawall at Cold Spring Harbor Laboratory.
The existing sandstone block seawall experienced frequent damage and chronic deterioration due to its age and its location along the harborfront. A few sections of the seawall collapsed over time; some repairs had been made, and additional repairs were needed. Stormwater runoff from the upper portion of the campus runs downhill, discharging to the harbor through and over the wall during heavy rainstorms. The high-water table behind the seawall and localized springs were also problematic. This recurrent action caused further instability to the wall, since the hydraulic flow carries the fines from the backfill through the open joints of the stone.
The seawall is subjected to daily tidal fluctuation and wind-driven wave energy during coastal storms, and the wall commonly overtopped during severe coastal storms. GEI worked to repair the seawall quickly and prevent any further deterioration; in addition, to offset future sea level rise, GEI recommended that the wall be raised as high as possible without changing its character or significantly increasing the cost of repair. The historical character of the wall was maintained while repairs were made.
Another one of the project’s unique considerations was its environmental impact. The harbor is home to winter flounder, which lay millions of eggs in the water during the spawning season. GEI investigated whether the construction would affect the fish and their breeding patterns. When the tides are low, the shoreline of the inner harbor becomes too dry for flounder eggs to survive, so the fish lay their eggs in deeper water, away from the seawall. Therefore, the construction was not anticipated to affect the flounder population.
GEI performed the following services: Field investigation and verification of site conditions; regulatory review and permitting; 30%/60%/100% design; bidding and construction phase services. Construction was completed in December of 2022.
