(a) A public entity that captures stormwater from urban areas, in accordance with a stormwater resource plan, before the water reaches a natural channel shall be entitled to use the captured water to the extent that the water augments existing water supplies.
(b) Nothing in this section shall be construed to do any of the following:
(1) Alter or impair any existing rights.
(2) Change existing water rights law.
(3) Interfere with, amend, or supersede any existing water rights adjudication or other legally mandated water management plan.
(4) Create a groundwater pumping right where a pumping right does not already exist.