Lake and River Restoration


Start of the Problem

Industrial / commercial and residential development within watersheds increases yearly, and many ponds, lakes and rivers have been subjected to an ever-increasing load of nutrients and sediments to industrial pollutants or even raw sewage. This has resulted in decreased water quality. Increased nutrient loading’s are most commonly due to excessive use of fertilizers, malfunctioning septic systems, industrial contamination and improper waste disposal within the watershed. As development continues, the amount of total hard–surfaced area also increases, and the volume and velocity of the water moving through the watershed into surface waters is increased. This run-off erodes soils and transports organic materials and nutrients from surface soils. Inorganic materials in the form of sand, silt, and clay are also transported to receiving waters, further contributing to decreased water quality.

Controlling Input

In an ideal world, controlling contamination load and limiting the quantity of run-off should be the best solution. However, control is limited and seldom 100% effective. The elevated nutrient loading’s that find their way into streams, lakes and ponds cause many environmental problems. These include: algae blooms, proliferation of rooted aquatic plants, low Dissolved Oxygen levels, increased water temperature, odor’s, increased bacteria levels, and stunted fish populations or fish kills. Many studies have shown that some watershed management systems and typical pond aerators only reduce pollutants in ponds by about 5-35 percent. This usually is not enough to make noticeable difference in aquatic pond weeds and algae growth; it does little or nothing to improve fish health, nothing to reduce mucky lake bottoms, or to reduce disease bacteria or odor,s

Natural Cleansing Capacity

Healthy water bodies have a natural capacity to cleanse themselves. Every pond, lake & river is an individual or inter-connected ecosystem, with a food chain of organisms that assimilate the incoming nutrients. The food chain moves nutrients up from the simplest single-celled bacteria, to healthy plants and fish life. This natural system works very well without any aeration system or chemicals to improve water quality, keeping the ecosystem in balance until excessive nutrient / industrial pollutants or agricultural run off inflow overwhelms the ability of the ecosystem to assimilate the nutrients. Once this occurs, the excessive nutrient levels and pollutants adversely affect the aesthetics and quality of the water-body by stimulating the growth of nuisance algae and plant life. Further deterioration of water quality causes other problems like slow killing of aquatic life and algae blooms; the latter is one result that can quickly turn a pond or lake to “pea soup” green or cause the formation of “smelly” floating algae mats.

Water Treatment Chemicals

One way to treat aquatic pond weeds or pond algae problems has been using water treatment chemicals in place of pond aeration systems. Chemicals are applied at the water surface. The chemicals kill the weeds and algae, and the dying vegetation sinks to the bottom of the water-body where it decomposes. As the vegetation decays, nutrients in the plants are released back to the water column and become nutrients for the next weed growth or algae bloom. But something far worse occurs; at the same time, that decaying vegetation uses up the oxygen at the bottom, creating an anoxic zone. Many studies have shown that an average of about three times as much nutrients are released from anoxic sediment on pond bottoms than what typically comes in from the watershed each year. The effectiveness of the water treatment chemical is quickly reduced as it settles to the bottom and is diluted by pond inflow and mixing with waters from untreated portions of the pond. The dead mass of vegetation accumulates on the bottom of the pond adding to the mass of organic sediments already there. Herbicides and algaecides do more harm to water quality than they do good. They sometimes cause fish kills and add toxic substances to the water and sediments.

The Beginning of the Problem

If there is oxygen present, the accumulated organic sediments begin to decompose aerobically. This organic material serves as food for bacteria and organisms that live in the substrate (bacteria, insect larvae, worms, etc.). These organisms require and consume Dissolved Oxygen as they digest the organic sediments. As sediments and biological activity increase, Dissolved Oxygen levels are depleted and become limiting. Low or no Dissolved Oxygen conditions can occur quickly, eliminating aerobic organisms and slowing the breakdown of the organic sediments. Then the growth of anaerobic bacteria, the bacteria that thrives in an environment of low or no Dissolved Oxygen, increases. Anaerobic digestion of the organic sediments begins, releasing toxic gases into the water that kill beneficial aerobic bacteria and insects.

The Real Problem

Anaerobic digestion of pond sediments is a much slower process than aerobic digestion. Aerobic digestion can result in the control or reduction of organic sediment levels, anaerobic digestion usually allows organic sediment levels to increase. During anaerobic digestion, bacterial enzymes and lack of oxygen make the nutrients on the bottom sediments soluble. Then the nutrients return to the water column and are available to support new weed and algae growth. Anaerobic conditions on the pond bottom have a damaging effect on the food chain that supports fish populations. This situation escalates to the point where fish habitat is reduced or eliminated. Fish quality, size and quantity are greatly affected.

Treating the Symptoms

Traditional chemical treatment for algae and aquatic plant control can be a valuable tool in the aesthetic management of ponds, lakes and rivers. However, it does not eliminate the condition that causes the problem. Water treatment chemicals cannot be applied to prevent an algae bloom. High capacity, portable aeration is the most effective system for naturally maintaining and restoring the quality of the water. Chemicals can only be applied to eliminate the bloom. The bloom captures dissolved nutrients from the water column and creates algae. The chemical treatment kills the pond algae, and the dead and dying organisms settle to the bottom where they decompose, using up available oxygen and releasing soluble nutrients back to the water column. Once the biomass is formed, nutrients are effectively locked into the pond’s ecosystem to be recycled indefinitely. Some chemical treatment elements, copper in particular, can accumulate in pond sediments when used year after year. Accumulated copper can reach levels that are toxic to aquatic organisms, or result in the growth of algae that is resistant to the effects of copper. Herbicides for aquatic weed control create similar problems.

Restoration – Dealing with the Problem

To restore a water body to its original pristine condition, we must restore the natural processes that allow it to assimilate the nutrient load that it receives. Ideally, nutrient inputs should be reduced or eliminated wherever possible. Also, understanding our limited ability to accomplish this task is important, we must then supplement and support natural assimilation of the nutrient load as it exists until the aquatic environment can maintain itself.

The Natural Process

The natural assimilation of nutrients in an aquatic ecosystem begins to breakdown when these natural processes are limited or eliminated by low oxygen levels. Aerobic organisms are much more efficient at digesting organic material than anaerobic organisms. Aerobic organisms feed on organic material contained in the sediments and assimilate these nutrients into increased body mass and reproduction. Aerobically assimilated nutrients become part of the food chain, rather than being recycled within the water column, as they are when anaerobic conditions exist. By maintaining aerobic conditions at the bottom and throughout the water body, (fish) the top consumer will also improve in quantity and quality. Maintaining the aerobic environment will also reduce or prevent the accumulation of organic sediments. Aerobic conditions at the bottom benefit all aspects of the aquatic environment.

The Solution

The solution to lake and river restoration is Aeration: the process of adding Oxygen to improve water quality. Oxygen is needed by all aquatic life, as well as aerobic bacteria to decompose organic matter. Aeration increases the process of oxidizing or eliminating pollution. The AquaCannon is the only system capable of consistently delivering 25,000+ GPM (36 million gallons per 24 hrs) of highly oxygenated water to the locale. This unbeatable new standard in Aquatic Habitat Restoration is now available. Our aeration systems are custom designed and built by Seeley’s Cove Research Center Inc. in New Brunswick Canada. The AquaCannon is the largest and most efficient, yet portable mechanical aeration system made to date, and is the result of many years of ongoing Canadian research and development.