This watershed is about 1,800 acres in size. The neighborhoods of South Beach, Linden Park, Grasmere and Arrochar fall within the South Beach watershed either in whole or in part. At the lower elevations, the South Beach neighborhood contains a pond and large area of marshland, dominated by common reed plants called phragmites. The pond was a branch of a vast tidal wetland system of spartina grass prior to the construction of Father Capodanno Boulevard and Seaview Avenue. The construction of these roads and deposition of dredge spoils in the adjacent federal land obstructed tidal flow inland and isolated the pond.