Repairing pond levees is expensive and time-consuming. The two most cost-effective measures are reducing erosion through proper pond design and soil compaction during levee construction.
Mechanical or structural treatments:
Several mechanical or structural treatments also protect pond levees effectively, including rock riprap, geotextile fabric and soil cement. Unfortunately, such methods are prohibitively expensive for most farms, except perhaps for spot treatments.
A 3-foot-high band (11 /2 feet above and below the waterline) of 4- to 5-inch diameter rock riprap alone costs about $8.75 per foot of levee protected. Adding a geotextile base where the rock riprap is placed slows erosion significantly, but raises the total cost to about $11.50 per foot of levee protected.
Geotextile material used alone has been successful on the face of levees. The fabric should extend 11 /2 feet above and below the pond waterline. Properly installed geotextile fabric should extend the life of a levee by about 5 years.
This method costs about $3.80 per foot of levee protected (about $12,500 for a 10-acre pond, which would have about 2,600 linear feet of levee). Soil-cement is a mixture of site soil and cement to resist erosion.
The cement is usually mixed at about 10 to 13 percent by dry weight with slightly plastic clays or silts. The soil-cement mixture is placed in a 6-inch layer and extends 11 /2 feet above and below the normal water line. Correctly installed soil-cement barriers control erosion for a long time. Soil cement- treated levees cost about $9 per foot of levee treated.
Vegetation:
Vegetation can stabilize stream, river and lake shores. Farmers should mulch reworked pond levees (about 100 pounds of straw per 1,000 square feet) and plant them with rye grass, centipedegrass or bermudagrass as soon as possible to reestablish vegetative cover and reduce erosion.
Contact the county Cooperative Extension Service office for information on cover grasses best suited to your location. Levee-stabilizing vegetation must not interfere with harvesting.
Most commercial ponds are harvested several times a year; any vegetation that reduces or impedes seining efficiency is unacceptable. Several types of plants are being examined as possible candidates to stabilize the side slopes of pond levees around the waterline.
Plant species such as Halifax maidencane (Panicum hemitomon) and knot-grass (Paspalum distichum) are reducing erosion with some success on pond levees in Arkansas. These plants form a margin around the pond and help dissipate wave action before it damages the levee.
They do not appear to interfere with current pond management practices, and therefore make good candidates for further research. Properly planted and managed levees can lengthen the time between levee reconstruction on commercial ponds.
Authors:
Jim A. Steeby , Nathan Stone , H. Steven Killian and Dennis K. Carman
