To keep ponds in production, some farmers use a dragline or trackhoe to rebuild levees. They lower the pond water level to half-full and draw up the sediments near the worn levee with a trackhoe or dragline.
Perching on top of the eroded levee, the machine scoops up pond bottom materials, starting as far as possible from the levee, and drawing in material toward the bank.
Levees rebuilt this way are compacted little and erode rapidly. This method also produces a trench around the base of the levee, which can interfere with harvest. The dragline reaches farther into the pond than the trackhoe and results in less severe trenching at the levee base.
The dragline method, which costs about $300 an acre, may give relief from the worn levee for 2 to 4 years. The dragline or trackhoe method may be the most useful technique to repair a worn levee temporarily if fish prices are high or for leased ponds that the owner refuses to repair.
The best time to rebuild by trackhoe or dragline is during drier periods, which allow the sediment to dry and grass to become established before rains wash soil back into the pond. Late spring or early summer is best.
For ponds older than 10 years, draining and drying may be more suitable. A traditional way to rebuild levees is to drain the pond and wait for the pond bottom to dry enough to support the weight of a tractor and dirt pan. Typically, pond bottom soils crust over, forming a firm surface layer with moist soils below.
Disking the surface exposes deeper soils and speeds drying. A bulldozer can break up and mound the bottom soils so that they dry faster. When weather permits, use dirt pans to rebuild levees, such as in the initial construction. The principal advantage is that by this time soils have dried enough to compact well during rebuilding.
The process takes so long that an entire years crop may be lost because of the wait for sediments to dry enough for dirt pans to operate efficiently. Breaking the sediment crust the first time through the pond is essential for good drying.
Alternatively, after the pond bottom dries enough to support a wide-track dozer, use the dozer to push moist pond bottom soil to the levees. The dozer rolls up on the levee to pack the material back in place. Then use tractor drawn dirt pans (Fig. 2) to finish the pond to grade, leaving a smooth surface that slopes to the drain.
Bulldozers and dirt pans can be used to rebuild ponds as small as 1 /4 acre. Laser sights on the equipment help the operator maintain the appropriate pond bottom slope. Using a bulldozer to rebuild levees compacts the soil less than using tractor pans.
This method is suitable for ponds built from very plastic soils with high clay content, where compaction affects soil strength less than with many other soils. For best results, compact the soils in shallow layers using a sheepsfoot roller or wheeled equipment.
A new technique of some Mississippi Delta farmers uses a dragline and bulldozer only. This method is usually reserved for ponds with deep sediments (more than 2 feet deep) in ponds not drained in 10 to 15 years. The Mississippi method involves draining the pond as usual for a complete reconstruction.
After all the water is gone, the dragline digs a 3- to 4-foot-deep drainout ditch along the levee base around the entire pond, which allows water to weep from the pond sediments and leave at the drain.
Slope the drainout ditch to the drain to carry out unwanted water. When the sediments have set up to a soft consistency (usually a week if no rain falls), fill back in a section of the ditch at the shallow end of the pond to form a ramp to allow a size 65D bulldozer to cross into the soft sediments.
The bulldozer makes passes down the pond length, rowing up the soft sediment on either side of the blade on each pass. The sediment should be soft enough to still flow slightly. If allowed to dry too much, the mud pushes down the pond rather than flowing to the sides.
The goal is to row up the mud (pile the bottom sediments in rows) down the pond length for good drainage and quick drying. You may need to make more than one pass, several days apart, to complete this stage of the process.
The rows will be 4 to 5 feet high and of equal width, with the parent soil showing slightly between the rows. Rains will drain off the rows and flow down the channels left by the bulldozer.
Allow the rows to dry for 2 to 3 weeks, depending on rainfall, or until the rows are a heavy plastic consistency. Then, bulldoze across the rows starting at the pond center, moving toward the nearer levee. The push should pack the entire distance to the levee .
When all the sediment has been packed back into the levee slopes, top a small amount of the original clay from the pond bottom back over the packed sediment material. This minimizes erosion during the early period when the pond is refilled.
Expect the levee to settle some as the packed material compacts in the next few months. With this method, a pond drained in late spring or early summer can be back in use by midsummer in most years. Again, compaction is less than optimum using this method.
Rainfall determines the time needed to finish any process, but the initial trenching and rowing process of this method allows rainfall to exit the pond rather than soak into the sediments. Ponds rebuilt this way should last 10 years.
Authors:
Jim A. Steeby , Nathan Stone , H. Steven Killian and Dennis K. Carman
