Much consideration should be given to the pond layout before construction begins. Crawfish ponds, as with most aquaculture ponds, are constructed above ground with the use of levees, or dikes. This aids in keeping unwanted fish and water out of the ponds. These levees can be of varying sizes depending on the need. The minimum size levee should have at least 12 inches of freeboard above the full pond water level. The top width needs only be wide enough to comfortably walk on. The slope of the levees should be at least a 2:1 ratio. Hence, the minimum levees dimensions can be considered to be 30 inches tall, with a 10 foot base to it.
Most crawfish producers in North Carolina construct ponds with fairly substantial levees. These levees are usually a minimum of 3 feet tall, 12 feet wide at the crown, and have a 36 foot base. Although there is more cost involved in constructing these levees, there are also several advantages. First, the producer has vehicle access to the entire perimeter of the pond since the levee is wide enough to drive upon. This is important for when the need for repair arises, as well the need for transportation of heavy loads from remote areas of the pond. Second, there is considerably more levee for burrowing animals, such as nutria and muskrats, to have to undermine before serious damage results. This gives the less observant manager more time to locate potentially disastrous pond draining holes in the levee before a washout can occur.
Many producers are also constructing internal baffle levees to aid in the maintenance of the pond's water quality. The baffle levees are minimal levees built within the pond's perimeter levee and function as a way to direct water circulation throughout the entire pond. These baffle levees are rarely more than 2.5 to 3 feet tall with rounded crowns. In larger ponds, where water is more inclined to follow the path of least resistance from the water supply to the drain, areas of "dead" water can occur. These areas of stagnated water tend to contain lower dissolved oxygen levels and because of this, lower production. Baffle levees direct water flow to these "dead" areas increasing their productivity as well as providing additional levee areas for the crawfish to burrow.
The majority of the crawfish ponds built in the northeastern part of the state are constructed with backhoes or draglines. Dirt is excavated from just outside where the perimeter levee of the pond is to located and deposited to form the levee. The resulting ditch generally fills with water from the abundant shallow ground water forming essentially a moat around the pond. This moat, or canal, in most cases becomes a water supply for the pond. The producer can put a pump into the canal, and at least partially fill the pond before depleting the water in the canal. By turning off the pump for a period of time, the canal recharges with water, and additional water can be pumped. For many crawfish producers, this is their only water supply.
Ponds can also be built with the use of bulldozers, land planes, and levee plows to move the dirt. Bulldozers should be used only when the distance the dirt needs to be pushed is 100 feet or less. Beyond this distance, bulldozers are not efficient. Conversely, land planes are only efficient in the construction of larger ponds. Long runs are needed by the land plane so that they can efficiently scrape the soil with the metal blade into the hopper, in a manner similar to a wood plane. The soil is then transported to the levee site to be dumped and packed. Finally, the levee, or terracing plow, can be used for the smaller designed perimeter levees as well as the internal baffle levees. A levee plow is simply a large plow designed to pull dirt from the outer reaches of both of its extended arms inward to an area directly behind the pulling vehicle. This action results in a piling and slight compaction of soil, thus making a levee. Normally, the maximum size of a levee resulting from the use of a levee plow is 3 feet with a rounded crown.
When it is possible, it is also important to incorporate a water recirculation system to the pond. The number one killer of crawfish in a pond is due to low dissolved oxygen. The low dissolved oxygen is due to the decomposition in the fall of the flooded organic matter that was planted in the pond during the dry summer for the crawfish to feed on. The only way to counter this oxygen demand being placed on the water is to flow aerated water through the pond. This aerated water can be in the form of fresh well water, or recirculated pond water. Many producers are utilizing their canals around their pond as recirculating canals, as well as a water source, so that they can reuse the water being discharged from the pond. The water is then simply relifted into the pond. This is much more energy efficient than pumping fresh well water from the depths necessary to get adequate volumes of water. Some producers have added paddlewheel recirculators to their ponds that have been built into the internal levee system to recirculate the water just within the pond. Some of these homemade paddlewheels are effectively recirculating 10,000 gpm using only 3 hp. In the shallow crawfish ponds, it is more important to move large amounts of water efficiently through the pond than it is to aerate.
The average size crawfish pond in North Carolina is 5 acres but ranges from a low of 1/2 acre to a high of approximately 60 acres. There is not is not a fast rule as to what is the best size crawfish pond. Each individual producer must determine this by taking into account the lay of the land, the availability of water, and how much labor and fiscal resources each individual is willing to dedicate to the operation.