Developing Wetlands: A Wetland Below a Pond

Image Above: A stop-log gate and screw-ate valve can be used to control water flow for a wetland situated below a pond. The Natural Resource conservation Service and the Conservation Department can provide help in building these structures.

Ponds or lakes make excellent water sources for wetlands located in flat areas below the dam. However, the following considerations should be taken into account:

• A drain pipe should be installed in the pond dam to provide gravity-flow water for the wetland. A simple screw-gate structure should be installed on the drain pipe to allow opening and closing. The size of the drain pipe depends on the size of the wetland and the length of time available to complete flooding of the wetland.
• An existing pond without a drain pipe can provide wetland flooding by use of siphon pipes or pumping.
• Water in ponds should be maintained at least 8 feet deep throughout the winter to insure fish survival.
• The emergency spillway of the pond should bypass the wetland. If not, the wetland should have an emergency spillway of its own, capable of discharging the pond's overflow.
• The pond need not provide all the water necessary to flood the wetland if other water sources are available. If the pond is the only water source, the wetland should not be larger than the amount of water the pond can supply. Gravity flowed water from the pond or lake can supplement other water sources to reduce pumping costs or to irrigate wetland vegetation during the summer.
• The wetland levee should have 4:1 slopes and have a minimum top width of 4 feet. A simple stop-log type water control structure will provide effective water level control and allow drainage of the wetland.

Image Above: A low-profile levee can be used to hold water for a pond-fed wetland.

Next | Previous | Home