Site Assessment is the First Step Towards Successful Pond Construction
Pond building demands special considerations often ignored by traditional excavation companies. The first of these is an extremely thorough site assessment. Just because you want a pond does not mean it is possible; your land must conform to a few specific requirements.
A good site assessment encompasses the entire drainage area for a proposed pond not just the direct water source and immediate impact area. Everything matters – how much acreage is forest versus field, how much sun and shade an area receives, previous land use and, most importantly, soils. Unlined ponds require a heavy clay base. Without correct clay composition ponds usually devolve into expensive holes. Lining ponds is a limiting factor that adds significant costs, and a higher risk of failure.
Build Your Pond for Longevity
Once your chosen site has been deemed suitable a second tier of requirements must be confronted. Pond depth and shape, standpipe and overflow construction, aeration, habitat, access, bank stability and more. Ponds are maintenance structures that can’t be ignored for long intervals. As much as possible, you want yours to manage itself.
Your pond should not be constructed in the path of an existing waterway. In many cases this is illegal, and usually this type of construction sets the course for extreme sedimentation and thus, a short pond life. It is best if your pond is spring-fed from above or is fed from an existing stream running adjacent to or nearby the proposed site. Fresh water is pumped or fed from a settling tank or collection pond that traps sediment. This allows for periodic cleaning.
Avoid Common Pond Building Mistakes
There are many mistakes that plague bond building. Foremost among these is improper dam construction. A correctly built dam is a well-compacted dam. To create an impervious levee appropriate soils must be tightly compacted in thin layers or “lifts”, usually of 12” or less. These lifts should begin several feet below the finished grade of the proposed pond bottom to form a key-way or “core”. The core is essential for the dams strength and seal. Once water finds its way through or beneath a dam major mitigation costs are soon to follow.
Finally, the dam must also be wider at the bottom than the top, much like a pyramid. There are generally accepted slope standards for both the front and back of a dam which should be adhered to by your contractor. A dam with slopes that are too steep is a recipe for neglect and failure.
Correct Engineering Is Key
Stand pipe and overflow systems are generally the next points of failure. The purpose of the former is to regulate water level. The latter provides an evacuation route for excess during extreme weather or standpipe failure. Overflow notches are seldom placed in the center of the levee. They should be oriented to one side or the other and constructed with permanence in mind. In many cases an appropriately-sized ditch, armored with large stone (rip rap) over foundation fabric, is suitable. For larger ponds/lakes, or for dams that will double as roadways, concrete or buried drainage structures with head wall protection are advisable for overflows. All should be engineered for your specific environment and circumstances.
Maintain Control Over Your Water Level
Make sure your pond’s stand pipe has some form of clean-out so it can be lowered or drained if necessary. Periodically lowering the water level can help compress sediment and kill undesirable vegetation along banks.
For further information on dam, standpipe and overflow construction consult with USDA representatives in your area. They provide excellent examples of tax dollars at work. Representatives can help with most aspects of pond construction, sometimes even funding. There are also several good manuals created by regional universities including the University of Georgia. We have also found an excellent pond building resource in T.A.R.E Inc.of Crossville, Tn,, an engineering company specializing in aquatic resources.
Further Pond Specifics
There are many additional aspects of pond building that must be attended to to assure success. Remember, a healthy pond is one that creates a positive ecological impact, providing habitat not only for aquatic species, but nearly every type of creature from bugs to birds. For this reason, your choice of vegetation around your pond is crucial. Create a substantial buffer around your pond by planting native grasses, trees and shrubs. Cool season lawn grasses planted along the edges of ponds are generally insufficient for bank stabilization. Remember, do not plant trees on your dam! Tree roots seek water and will perforate your dam!
Where fish are concerned, make sure you choose appropriate species and correct stocking rates for your conditions. Your local USDA or wildlife agent can usually help with this. Consider building gravel-lined shelves into the pond sides for bedding. Create shelter for fish by placing boulders or dropping in old pallets tied together, Christmas trees (sans needles), old cars or appliances with oils, fuels etc. removed. Remember, a healthy aquatic environment has abundant oxygen, a correct pH range (slightly alkaline) and is devoid of damaging invasive vegetation.
You May Need Special Permitting
Depending on where you plan to build your pond and how it is to be designed you may require one or more permits. Permitting takes into account not only the safety of those downstream but environmental impacts as well. Permitting is usually much simpler on farms and in rural areas. Ponds supply huge benefits to agricultural endeavors and often receive exemptions unavailable to normal residents and commercial entities. Finally, each state has different permitting requirements. Know what is needed before you invest too much in your pond building dreams.
For more information about pond building or repair call us or email. We will be happy to evaluate your proposal or existing site. We love pond construction. Each well-constructed pond is an oasis!