Written by Industry Expert Paul Dorsett, Fisheries Biologist
I could hear his excitement when Mike called requesting a consultation on plans to build ponds and lakes on the ranch he intended to purchase. Upon arrival at the ranch to evaluate the potential for several 1- to 20-acre impoundments, and after consulting a topographic map, I quickly realized Mike’s excitement was about to be severely diminished. The entire area he wanted to develop into scenic lakes and trophy bass fisheries was fed by over 1,600 acres of watershed. This watershed may be suitable for a 150-acre lake in this area but for the relatively small impoundments Mike envisioned, this watershed would have resulted in unmanageable fisheries with expensive and difficult dams to build and maintain. In short, his lakes would have flushed like a Texas tube chute every time a sizable rainfall event occurred.
Disasters, such as droughts and floods, typically cannot be avoided. Much of your ability to recover your aquatic assets following a disaster may hinge on the planning you do during the design and construction phase and management prior to these events. While droughts can lead to low water levels and eventually fish kills, floods can be equally damaging by washing valuable fish downstream and unwanted “rough” fish into your lake. Even lakes that have no rough fish in their watershed are potentially subject to immigration of rough fish as they swim upstream against the current. If you don’t believe me, conduct a simple test by putting various species of fingerling fish into a 5-gallon bucket with a few inches of water. Push the bucket into a larger container filled with water until water slowly spills over the bucket’s edge and watch as a few of these small fish are able to swim straight up the flow of water running down the interior of the bucket.
During the planning and construction phase, it is important to plan the lake to fit the watershed or vice versa. The appropriate watershed size will vary regionally, depending primarily on rainfall. You should consult a professional dirt contractor, or engineer to properly size your dam and overflow structure. In many states, or more populated areas within others, design work must be submitted and permits provided before construction can begin.
Once construction is complete, slopes around the perimeter of a pond should be monitored and maintained for erosion, especially along the dam and overflow structures. In most cases, beneficial vegetative buffers should be introduced to hold the soil in place. In more extreme cases, rock, concrete, erosion blankets or other suitable erosion resistant material may be utilized. A small amount of erosion can lead to a major breach in your dam during a storm event. I witnessed this first hand in 2004 when my community was hit with 17 inches of rain over a 7-hour period. Many dams in our area had water not only flowing through the spillways, but over the top of the entire length of their dams. Many of these dams failed.
This isn’t a drought, but rather the devastation left following a 30” rain that breached a dam and drained the lake. Nothing can be done, except rebuild and start over from scratch.
To maximize their usefulness, overflow structures and spillways should be maintained to minimize impedance of water flow. Excess vegetation, beaver dams, and other debris that could obstruct water flow should be removed. Construction, tree planting or other changes to a spillway or dam should not be made without review by a professional to ensure they do not result in an unintended reduction in flow during a storm event.
Like storm preparation, preparation for drought should also be considered in the design and construction phase. Impoundments in drier climates are often built deeper so that water will remain during periods of drought. Though adding groundwater may save your fishery, this activity is illegal in many areas where it would be most beneficial due to this resource’s limited supply and greater purposes. Check with your local officials and well drilling companies for potential restrictions before you plan to maintain your lake with well water.
Pond aeration is a great way to minimize the loss of fish during a low water event. Aeration is classified into two general forms: Bottom diffused aeration and surface aeration. Surface aeration can exist in the form of a high-volume pump or agitator though many fountains with attractive patterns also provide valuable aeration. The key to adequate surface aeration is the volume of water that is moved. The greater the volume of water, the more aeration benefit. If the pond is deeper than 8 feet, bottom diffused aeration should be a consideration. Bottom diffused aeration consists of a compressor that pumps air through diffusers placed on the pond bottom. The air moving through the water column not only adds oxygen directly to the water, it also performs the far greater purpose of moving water vertically, destratifying the water column and exposing more water to the surface for oxygen uptake.
Whether you are planning a lake construction project, managing a lake or fishery, or in the aftermath of a catastrophic event, professional lake managers and fisheries biologists are a great resource to evaluate, prevent, or begin the rebuilding process. In Mike’s situation, we not only stopped the catastrophic event before it took place, we prevented him from investing in a property that would not have suited his goals.
Contact the experts at 888-480-LAKE (5253) for all of your lake, pond, wetland and fisheries management needs.
SOLitude Lake Management is a nationwide environmental firm committed to providing sustainable solutions that improve water quality, enhance beauty, preserve natural resources and reduce our environmental footprint. SOLitude’s team of aquatic resource management professionals specializes in the development and execution of customized lake, pond, wetland and fisheries management programs that include water quality testing and restoration, nutrient remediation, algae and aquatic weed control, installation and maintenance of fountains and aeration systems, bathymetry, mechanical harvesting and hydro-raking, lake vegetation studies, biological assessments, habitat evaluations, and invasive species management. Services and educational resources are available to clients nationwide, including homeowners associations, multi-family and apartment communities, golf courses, commercial developments, ranches, private landowners, reservoirs, recreational and public lakes, municipalities, drinking water authorities, parks, and state and federal agencies. SOLitude Lake Management is a proud member of the Rentokil Steritech family of companies in North America.