"Project" means any physical structure or facility proposed or constructed under this chapter for the conservation, storage, regulation, reclamation, treatment or transportation of water to replenish, recharge, or restore a ground water basin, or to prevent, stem, or repel the intrusion of sea water therein, or to improve the quality of the waters thereof, when such basin is relied upon as a source of public water supply.
Ca. Water Code § 12921.3