Tex. Water Code § 11.330

The owner of any works for the diversion or storage of water shall maintain a substantial headgate at the point of diversion, or a gate on each discharge pipe of a pumping plant, constructed so that it can be locked at the proper place by the watermaster, or a suitable outlet in a dam to allow the free passage of water that the owner of the dam is not entitled to divert or impound. The commission shall adopt rules, and the executive director shall enforce the rules, governing the type and location of the headgates or gates and the outlets to allow the free passage of water.