Idaho Code § 42-702: Measuring devices above reservoirs.

Any person, firm or corporation using the channel of any stream or streams or any tributary of such stream or streams in this state as an impounding reservoir shall place therein at a point above and as near as practicable to the backwater of such reservoir such system or device as the department of water resources may require for measuring the flow of water at such point and in accordance with plans and specifications which shall be furnished by the department.