Sierra Club v. City of San Antonio; New Braunfels Utilities v. City of Sanantonio, San Antonio Water Systems, City of Hondo, Texas, Onits Behalf of All Other Municipal, Industrial, Commercial,domestic and Livestock Pumpers in Medina, City of Uvalde,texas, on Its Behalf of All Other Municipal, Industrial,commercial, Domestic and Livestock Pumpers in Uvalde Andkinney Counties, City of Leon Valley, Texas, on Its Behalfof All Other Municipal, Domestic and, 118 F.3d 1580 (5th Cir. 1997)