Geotechnical

Lawrence Karp, PhD, BRIG’s geotechnical expert, concludes that the developer’s analysis does not address the unusual circumstances potentially giving rise to significant impacts as a result of building the project’s structures on marshland that was dredged, filled, and flooded in the 1950s, and that is highly prone to settlement. The developer did not undertake a subsurface exploration to assess foundation features for the apartment building, nor did it perform physical field tests or index borings to support its conclusions. Notably, the developer did not provide actual foundation design and construction recommendations for the project’s structures.

These omissions are significant. The existing duplex structures are settlement-forgiving, meaning they have length-to-width aspect ratios that are close to equal, such that settlement occurs uniformly across the structure. By contrast, as Dr. Karp notes, the project’s apartment building would be approximately five times as long as it is wide, with no structural or design features that would accommodate large differential settlements. He concludes that the apartment building will likely experience differential settlement and subsidence unless major subgrade foundation systems are implemented. Installing such systems, which may include pile-driving, is environmentally intrusive, and will very likely cause significant adverse impacts on neighboring structures and the lagoon, as well as cause significant noise impacts.