Tex. Water Code § 15.004

Money on deposit in a fund created under Article III, Section 49-d-3, of the Texas Constitution shall not be used to finance or in aid of any project under this chapter that contemplates or results in the removal from the basin of origin of any surface water necessary to supply the reasonably foreseeable future water requirements for the next ensuing 50-year period within the river basin of origin, except on a temporary, interim basis.