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Pond Constuction Considerations |
PLANNING
Careful planning in the design and construction of a pond can prevent many future problems.
It is best to consult with professionals such as the Soil Conservation Service,
Agricultural Extension, State Fish and Game Department and private engineering consultants
to ensure both the feasibility and legality of construction in the area being considered.
In some states, financial assistance may be available under water conservation or wildlife
protection programs.
SITE SELECTION
The location and size of a pond will be dictated by the type of landscape (topography),
soil structure, quantity and quality of water sources. These factors will determine whether
a pond will be an excavated (tank-type) or an embankment (dammed) impoundment.
Ponds can be constructed where groundwater supplies are near the surface, where well water
supplies or springs are available, in low-lying areas where run-off from the surrounding
watershed (drainage) area is sufficient, or at the foot of streams. Some ponds may have
to be constructed in a specific area out of necessity for storm water retention, fire protection
or decoration, thus precluding some of the factors that might be considered in choosing an
ideal site. In these situations, special measures may have to be taken such as using pond liners
or sealants, providing supplemental water sources, or designing artificial water drainage systems.
Generally, it is not recommended (nor legal) for individuals to dam permanent streams.
Groundwater supplies generally offer the highest quality water. However, if surface water sources are
used, they should come from a well-vegetated watershed area.
Supplemental water sources, such as wells, may be necessary in some areas to maintain water levels or
to periodically add fresh water. Water can be pumped in through standpipes to help function in aerating
the water.
Soil composition of a pond bottom and banks should be of a nonporous material such as packed clay to
prevent seepage. This is particularly important in dams. If suitable materials are not native to the
area, commercially available clays such as Bentonite can be used.
Construct shorelines with a minimum of 1:3 slopes to discourage vegetation growth. A sufficient portion
of the pond should be at least 10 feet deep. This will help prevent both aquatic plant growth and the
potential for winterkill of fish under the ice in northern areas.
Install a drainpipe in the pond bottom, if feasible. This will allow lowering of water levels to repair
leaks, re-excavate, or to remove trash fish.
Spillways are necessary in embankment ponds and might also be considered for excavated ponds.
They provide an outlet for excess water that would otherwise erode shorelines or cause property damage
from flooding. Determining the design, size and construction of dams and spillways are tasks best left
to professional construction engineers.
CONSTRUCTION
In constructing a pond, it is advisable to remove all topsoil, brush and trees from the basin.
Trees within 25 feet of the pond's edge should also be removed to prevent leaf litter from accumulating.
Topsoil can later be used to cover banks before sodding or seeding with a fast-establishing perennial grass.
The following are several helpful hints to be considered. A narrow path of mounded soil near the pond's edge
(called a berm) will serve to trap eroded materials, which might otherwise wash into the pond. All dams and
embankments surrounding the pond should be free of stumps and brush to prevent leakage as this material decomposes.
A filter bed of rock and rough gravel can be placed in areas where water is channeled into the pond. Finally, if
water from the watershed is more than sufficient to maintain the pond level, a diversion ditch can be constructed
to prevent some of the water from entering.
LEAKAGE
Seepage of water from a pond may become a problem when soils are too porous or are improperly compacted.
Sealing of a pond may become necessary. Techniques include compaction, application of clay sealant, addition
of chemical additives or installation of waterproof linings. Consult a soil expert or consultant to determine
the best method.
By following the practical management and maintenance procedures described elsewhere in this book, a pond can
offer many years of recreational enjoyment or functional use. Problems should be dealt with as they develop to
avoid costly renovation.
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