Building Ponds for Commercial Aquaculture
Pond construction planning must take into account engineering requirements, the biological needs of the species that is being cultured, and the cost of construction. When exceptions are made in these areas, catastrophic results can occur. Some examples of pond failures include: dam failure due to improper compaction or soil type, rapid sedimentation and levee erosion when levee slope is to steep, and bankruptcy when pond construction costs are excessive for the potential return from aquaculture. Experts must be consulted when constructing a pond in order to minimize the risk associated with pond construction errors. The Soil Conservation Service, now the National Resource Conservation Service, has been the best source of this information in the past. Now, fewer NRCS engineers are available for assistance, but this agency is still a very good source of assistance. The Cooperative Extension Service can provide information about pond construction requirements for aquaculture. Many county extension agents have a great deal of knowledge of pond construction. The ultimate responsibility for pond construction decisions falls on the potential pond owner. In large pond projects, hiring a licensed engineer may be the best decision.
We are fortunate, in Georgia, to have several competent and ethical contractors who are currently building ponds for aquaculture. The ponds that have been constructed are built in an efficient manner and exceed the minimum engineering requirements without excessive cost. Soils on each site are considered and worked so that seepage is minimized. These contractors consider the requests of the land owner, counseling when the owner is making a poor construction decision.
Levee height and top width are variables that can improve the quality of the pond or add to the cost of pond construction. Minimum engineering requirements are recommended as follows: Top width at least 8 ft for levees less than 10 ft tall, freeboard of at least 1 ft on levee ponds (not watershed filled ponds) that are less than 656 ft long, levee slope of 3:1 (unstable soils require 4:1 to prevent excessive erosion) (Wheaton 1985). Levee-type ponds require 1,100 to 1,200 yards of dirt per acre when built on level land (Wellborn 1988a). Catfish pond levee top width is recommended as 16 ft to allow vehicle passage (Wellborn 1988b). A square (660' X 660') 10 acre pond can require 2,569 linear feet of levee. A 3 ft increase in levee height must be added at the bottom of the levee, so that a change from 6 ft to 10 ft levee height adds at least 1,798 cubic yards of dirt per acre to the soil needs for building a pond. When amortized over a 10 year period, the added cost of this additional pond depth would amount to an additional $300 to $450 per acre per year in cost of operation. To pay for such a design, an additional 400 to 600 pounds of catfish must be produced each year. Similar relationships can be shown for increases in levee width or levee slope.
Wellborn, T. L. 1988a. Site selection of levee-type fish production ponds. SRAC Publication No. 100. Southern Regional Aquaculture Center, USDA. 2 pp.
Wellborn, T. L. 1988b. Construction of levee-type ponds for fish production. SRAC Publication No. 101. Southern Regional Aquaculture Center, USDA. 4 pp.
Wheaton, F. W. 1985. Aquaculture Engineering. Robert E. Krieger Publishing Company, Inc., Malabar, FL. pp. 414-462.