CA Water Code Section 1051

The board for the purpose of this division may:

(a)

Investigate all streams, stream systems, portions of stream systems, lakes, or other bodies of water.

(b)

Take testimony in regard to the rights to water or the use of water thereon or therein.

(c)

Ascertain whether or not water heretofore filed upon or attempted to be appropriated is appropriated under the laws of this State.