Water Control Structure

Purpose/Function:

These structures are built across a watercourse to help prevent gully erosion, manage water to improve crop production and reduce the movement of pollutants to downstream waters. Benefits include being used to control flooding and reduce nutrient runoff and can be used to manage water levels for crop production or fish and wildlife habitat.

Initiation protocol:

Contact the local Soil Conservation District or University of Maryland Extension for assistance. Currently, Maryland credit for this practice is only granted on the Eastern Shore and in a ditch (not available for sallow water impoundments, for example). 

Tile Breaks: An inexpensive way to restore wetland hydrology is to break, plug or remove subsurface drainage tiles. Drainage tiles are usually made of clay or plastic and are buried in areas to sufficiently drain lands for conversion to farmland. For precise water level control, risers or uprights containing debris guards can be attached to functioning drainage tiles. 

Ditch Plugs: Like a tile break, surface water ditches allowing drainage of low areas can be plugged or filled. Water levels may need to be managed by installing water control structures or emergency spillways to prevent extensive flooding of adjacent lands.

Public acceptance:

A properly designed and implemented water control structure should not significantly impact the public as these practices should only adjust the immediate agricultural land.  

Implementation Factors (level of difficulty):

Difficult. Government agencies and private organizations such as Ducks Unlimited (DU) are available for technical and financial assistance. For example, Ducks Unlimited contributes to numerous private land restorations by handling project costs, offering land protection in perpetuity through conservation easement contracts, providing consultation with biologists and supplying engineering design and construction services.

Funding Sources / Options:

Funding for this practice is available through local Soil Conservation Districts programs such as the Maryland Agricultural Water Quality Cost-Share Program and the Environmental Quality Incentives Program. State departments of agriculture and environment and private non-profit organizations such as Ducks Unlimited and The Nature Conservancy also offer funding assistance.

Costs:

Cost estimate for installation is $ per acre treated per year.

Note: EPA figure based on an average system size of 167 acres. EPA figure seems too low. MDA estimates $13,500 for 26 acres of this practice.

Load Reduction Efficiency:

Average Total Nitrogen removed per acre of practice per year

Cost per pound removed = between $8 and $12

Average Total Phosphorous removed per acre of practice per year = 0.0 lbs.

Cost per pound removed = N/A

Average Total Suspended Solids removed per acre of practice per year = 0.0 lbs.

Cost per pound removed = N/A

Operation & Maintenance:

Check structures after major storms and at least twice a year. Remove debris as necessary. Dikes need to be mowed on a yearly basis to prevent woody plant growth. This should be performed after August 15 to avoid destroying nests during the breeding season. Any leaks or breaches in a dike must be quickly repaired to avoid washouts. Muskrats may burrow in dikes, resulting in leaks that require immediate attention. Woody debris deposited by beaver near water control structures and emergency spillways will also need to be removed to reduce extensive flooding. Water control structures, spillways and associated pipelines need to be checked for proper function on a regular basis.

Climate Change Considerations:

This measure to reduce the impacts of climate change are “low risk” because they are justified on other grounds such as pollution control, flood control and outdoor recreation. One suggested practice to reduce climate change impacts is to install and maintain water control structures as water levels may be controlled to maintain saturation much of the year, which is conducive to storage of carbon. However, a small aerated zone in the soil may be maintained to encourage bacterial destruction of methane.

Planning Questions to Consider:

How will the structure affect the property or nearby water budget? Will the structure impact downstream flows or aquifers? How will the structure affect wetlands or other water-related wildlife habitats?

Technical Notes:

Work with the Natural Resource Conservation Service and the Soil Conservation District to develop an engineering design and an operation and maintenance plan. If applicable, install fencing to exclude livestock and wildlife to protect vegetation. The water level upstream of the structure and associated impacts should not be raised on adjacent lands without landowner permission.

Helpful Links:

• https://www.youtube.com/watch?v=pYyhEjLJi3k
• https://www.youtube.com/watch?v=Gl4tI48YT4k