18 Artificial Aquatic Habitats 



wanted to provide fishing; 13 per cent, to provide irrigation water; 9 

 per cent, for swimming; 5 per cent, for wildlife; and 4 per cent for all 

 other uses.^^ Many farm families are interested in various forms of out- 

 door recreation, and the farm pond may be the center of these activities : 

 fishing, swimming, picnicking, hunting, boating, and in the north, ice 

 skating. 



Engineering Considerations for Farm Ponds 



Engineering specifications for ponds must vary for parts of the country 

 in accordance with differences in rainfall, runoff, tightness of soils, and 

 types of vegetative cover. Ponds must be deeper in the north than in the 

 south in order that the cold winters and thick ice do not result in loss of 

 fish. Increased depth is also a boon to regions characterized by long 

 periods of dry weather. In planning the shore line of the pond, water 

 areas less than 2 or 3 feet in depth should be eliminated, because shallow 

 waters may become choked with aquatic vegetation such as cattail and 

 bulrush, which may form a continuous band around a pond edge. 



A satisfactory pond must have an adequate water supply that is silt-free. 

 This water supply may be runoff from lands managed under a soil con- 

 servation program, or from springs, flowing wells, or very small streams.''^ 

 The pond should be impounded behind a well-built dam with a spillway 

 adequate to carry off flood waters. Trees and brush should not be allowed 

 to grow on the dam, or continuously around the shore of the pond. The 

 pond should be supplied with a drain pipe and valve large enough to 

 allow fish to pass through the pipe out of the pond with the outflowing 

 water (Figure 2.2). 



Much attention has been given to the regional engineering aspects of 

 pond construction by the United States Soil Conservation Service and the 

 agricultural colleges of many State universities. Information for most 

 localities of the United States is available for those wishing to construct 

 ponds, and no attempt will be made here to consider more than a few of 

 the simpler aspects of farm-pond construction. 



Engineering methods for ponds in the southeastern U.S. are much 

 different from those of northeastern, central, southwestern, or north- 

 western regions. 



In the West, certain ponds ( for example, in Colorado and Arizona ) are 

 used as sources of water for irrigation. ^^ These ponds are pumped full 

 and then are partly drained to irrigate crops during a 24-hour period. 

 These irrigation ponds fluctuate as much as 10 feet, and the water is 

 usually cold. Such ponds no not provide satisfactory fish habitats. 



However, most ponds are built for uses other than irrigation and are 

 more suitable for fish production, even though their primary function may 

 be supplying water for stock or fire protection. Even if all ponds were 



