COLIFORM DENSITIES IN URBAN WATERS OF WEST TEXAS

Playa lakes are an integral part of the surface water management plan for the city of Lubbock, Texas. Most have been enlarged to increase vo lume. Surrounding streets are designed to direct runoff into local bas ins, so the once-ephemeral wetlands are now permanent urban impoundmen ts. A variety of recreational activities bring people into contact wit h these playas. This study found coliform densities 10 to 100 times gr eater than recommended for human contact (i.e., swimming or wading). A nalyses of water quality characteristics and landscape features sugges t that total-coliform densities are diluted by the greater water input s of larger watersheds and by overflow from adjacent basins. Both tota l-coliform and Escherichia coli densities appear to be unrelated to ot her environmental parameters. The source of coliforms, the reason for such high densities, and factors responsible for their persistence rem ain uncertain.