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By Richard Pasquill, Manitoba Water Services Board, Brandon
One of the most common problems faced by dugout owners is how to control the growth of algae in their water supplies. In the past, the standard method involved dosing the dugout with chemicals such as bluestone and/or Reglone "A". While this provided some means of control, most often the treatment was too late or poorly applied, and the results achieved questionable.
To devise a course of action which will have some chance of success, we must first look at what algae needs to grow. The two basic needs of algae are sunlight and food. Past attempts to control the amount of sunlight penetrating the water have only been partially successful; new technology which is being developed for this purpose, however, shows greater promise. Controlling the food available to the algae offers an alternative to reducing sunlight.
One of the best means of controlling the nutrient levels in the water is to take steps to prevent the nutrients from reaching the water in the first place. This is done through the removal of all trees and shrubs within 60 feet of the water (deciduous trees should be at least 150 feet from the water), stabilizing the banks and providing a 50 - 100 foot grass buffer around the dugout, seeding down runways, and installing water diversions around the dugout to control water levels. If these measures fail, the nutrients in the water can be settled out with the use of lime.
In some cases, however, the problem will persist. This generally occurs with older dugouts that have accumulated a fair bit of organic matter on the bottom over the years. This matter not only decreases the depth of water stored, but also contains a wealth of nutrients that can be reabsorbed into the water. If this is the case, the dugout may have to be cleaned.
To properly clean a dugout, it is best if the water can first be removed to allow direct access to the organic build-up on the bottom. While it is possible to clean out a great deal of the matter with the water still in place, results are questionable. If the water cannot be removed to allow cleaning, the installation of a second dugout should be considered.
One of the major problems often associated with cleaning dugouts is how to dispose of the sludge. In many cases, this sludge is left on the banks of the dugout and simply washes back in over time. The sludge must be removed from the area and away from the drainage path supplying the dugout.
