The salt which is contaminating water in the Red River Basin today was laid down in the Permian geologic age, 220 to 270 million years ago. An inland sea became isolated and evaporated, leaving the salt behind. Over geologic time, the salt was covered with rock and silt. Ground water now runs through the salt deposits dissolving some of the salt, creating brine. This brine surfaces as springs and contaminates the local rivers. The brine that contaminates the South Fork of the Wichita River contributes approximately 200 tons of chloride pollution daily. This brine is collected and pumped down a 22-mile pipeline to the Truscott Brine Lake. Construction of the pipeline and lake began in 1976 and was completed in 1987. The lake level is maintained relatively constant through the action of evaporation on the pool.