This estuarine lagoon is fed by a number of small rivers and a canal and is linked to the sea by a narrow channel to the north, near Negombo city city.
It is surrounded by a densly populated region region containing rice paddies, coconut plantations and grassland. The land is used for fishing and agriculture. The lagoon has extensive mangrve swamps and attracts a wide variety of water birds including cormorants, herons, egrets, gulls, terns and other shorebirds.