Study of the Virginia V-notch weir-box culvert combination gaging station

Abstract

A Virginia V-notch weir·box culvert combination gaging station is a discharge measuring device to record the runoff from small watersheds, usually less than two thousand acres in area.

The station is composed of a prebuilt highway culvert, a one-foot thick triangular shaped weir placed between wing walls of the culvert entrance and a water level recorder placed 10 feet upstream from the weir. Water runs over the weir and enters the culvert, its surface elevation is controlled by the weir for low stages and, by the culvert, for high stages.

The advantages of this kind of gaging station are: l. to make low flow measurable and accurate, 2. to permit free passage of debris and, 3. economical.

The main purpose of this thesis is to determine the relationship between the discharge and the measured flow stage.

Scaled model studies have been previously made for the same gaging station and the result is found practically agreeable.

Theoretical analysis shows that the weir is hydraulically short-created. A suggestion, to place the flow stage measuring section within the wing walls of the culvert entrance, is recommended in this thesis.