American Society of Civil Engineers

Influence of Regulators in Controlling Upstream Water Depth

by Ali R. Vatankhah, (Assistant Professor, Dept. of Irrigation and Reclamation Engineering, Univ. College of Agriculture and Natural Resources, Univ. of Tehran, P. O. Box 4111, Karaj, 31587-77871, Iran. E-mail:

Journal of Irrigation and Drainage Engineering, Vol. 137, No. 9, September 2011, pp. 620-623, (doi:

     Access full text
     Purchase Subscription
     Permissions for Reuse  

Document type: Technical Note
Abstract: Control of irrigation canals usually consists of control of water levels upstream from regulators or check structures. Regulators provide the necessary head to offtakes. Generally, influence factor is used to express the extension of the backwater curve effect within the controlled reach. This factor shows how a change in water depth exercised by a regulator can influence the water surface profile along an irrigation canal. No direct equation is available in the technical literature up until now for calculating this factor on the basis of the steady gradually varied flow theorem. In current research, using the steady gradually varied flow equation for a prismatic canal, an elegant algebraic equation for this factor is derived. Control of water levels upstream from regulators is an important application of this equation in irrigation networks.

ASCE Subject Headings:
Water levels

Author Keywords:
Influence factor
Irrigation canal
Regulators and offtakes
Backwater curve
Control of water levels
Upstream control