1. The department may, of its own motion, make or cause to be made such surveys and investigations as it may deem advisable and necessary for the discharge of its duties under this article.

2. The department, upon its own motion, or upon a petition presented to it by a person or public corporation pursuant to provisions of this article, may in its discretion, extend the scope of such proceeding to any improvements or developments of natural resources which may be done under any provisions of this article, and if any part of the procedure governing the matters concerning which the petition is presented cannot be made applicable in all respects to the subject matter of the proceedings as thus extended, then the procedure peculiar to such additional matter as provided for in this article may be adopted to the extent necessary.

3. The department shall make or cause to be made continuing investigations of the water resources of the state so as to accumulate comprehensive data as a basis of providing for their proper conservation, development, regulation and use.

4. The department shall conduct systematic gauging of rainfall and stream flow throughout the state when moneys shall have been appropriated therefor.