A wate control structure in a water management system that conveys water, controls the direction or rate of flow, or maintains a desired water surface elevation.
Water control structures are in open channels or water use areas usually as part of an irrigation or drainage system.
In Ohio this standard applies to subsurface drainage control structures as well as open channels. However, the primary focus of this standard is structures other than water level control structures that are installed in subsurface drainage systems. Typical structures are drops, chutes, turnouts, surface water inlets, head gates, pump boxes and stilling basins.
They control the stage, discharge, distribution, delivery, or direction of flow of water in open channels or water use areas.
Water control structures are also used for water quality control, such as sediment reduction, temperature regulation, and/or reducing the discharge of flow containing nutrients. These structures can also used to create or protect fish and wildlife habitat and other natural resources.
Vegetation complying with Critical Area Planting standard (code 342) shall be established on all disturbed earth surfaces. Where soil, climate or site specific conditions preclude establishing permanent vegetation, other protective means such as mulches or gravels, shall be used. The structure shall be fenced, if necessary, to protect the vegetation. Structures shall not be installed that have an adverse effect on septic filter fields. The water level upstream of water control structures shall not be raised on adjacent landowners without their permission.
Structures to control the elevation of water in drainage or irrigation ditches include checks, flashboard risers and check dams.
Other structures that might be used in some applications include water division boxes, bridges, culverts, flumes, sluices, and inverted siphons.
The NRCS Conservation Practice Standard 587 provides a lengthy list of important considerations that relate to preventing potential adverse impacts associated with the installation and use of structures for water control.
The effectiveness and water quality benefits of structures for water control is very site specific. In many applications the primary purpose of a water control structure is not associated with improving water quality but providing some other function such as being an integral part of an irrigation system.
Costs are site-specific and will depend on the size and type of water control structure needed at a location. These costs might range from a few hundred dollars to many thousands of dollars. In some case, such as drainage water management, cost-sharing funds might be available.
Structures for water control are hydraulic control structures that are used to manage water flows in channels and pipes. Often they slow down the water and act like a dam. However, they can also be used to speed up the velocity of the flow or divide the flow into more than one flow stream.
An operation and management plan shall be provided to and reviewed with the land manager. The plan shall be site specific and include but not be limited to the following: Structures will be checked and necessary maintenance, including removal of debris, shall be performed after major storms and at least semi-annually. Water level management and timing shall be adequately described wherever applicable.
- Consult your SWCD, NRCS or a drainage contractor as proper sizing and construction are critical. Often a structure for water control will need to be design by an engineer and in some applications, such as installation of a structure in a ditch, a permit might be required.
- Sizing and installing prefabricated water level control structure for use with subsurface drainage systems usually do not require the services of an engineer.