Senate Bill 3 established "environmental flow standards" for river basins associated with a river that flows into the Gulf of Mexico in Texas. But for some rivers in the northern part of the state, no such standards are in place.
The Texas Commission on Environmental Quality must decide on acceptable flow standards in those river basins on a case-by-case basis. River basins in Northeast Texas with no established flow standards are the Red, the Sulphur and the Cypress.