This headline could also read “Why are there dead fish in my pond?” or “Are there mosquitoes breeding in my pond?”
Shallow water, sunlight and excessive nutrients can make lake management difficult. Combine these factors with the hot temperatures and extended growing season in our area and a pond can easily turn into a nightmare if left unmanaged.
In a perfect world, all ponds would be at least 3 feet deep around the shoreline and 12 feet deep in the middle. This reduces sunlight penetration to the bottom where noxious algae and aquatic vegetation begin their growth. However, this is almost never the case in urban areas. Organic matter and sediment carried in storm-water runoff accumulates on the pond bottom over the years. This creates extensive areas of shallow water that are optimal for noxious growth.
Aquatic Growth Turns a Pond Green
Excessive algae and aquatic vegetation is not only an eyesore, but it also negatively impacts the overall water quality. It causes wide swings in dissolved oxygen levels on a daily basis. This becomes critical in the dog days of summer when water holds very little oxygen to begin with and fish survival is in the balance. Excess growth also clogs fountains, pumps, and irrigation intakes. Emergent aquatic vegetation and algae also offer mosquitoes an ideal breeding site and provide shelter for snakes and other undesirable wildlife.
Integrated Pest Management (IPM) to control algae and aquatic growth
There is no single solution for all pond problems. Therefore, noxious aquatic growth should be managed using Integrated Pest Management (IPM) practices. Integrated Pest Management in ponds includes dredging, sunlight reduction, nutrient management, supplemental aeration/fountains, algaecide/herbicide applications, and biological controls. The method or methods selected are ultimately determined by the particular use of the water body, by the available resources, and by government regulations. Ideally, aquatic plant management should be a combination of methods that work harmoniously with the environment.