Winterkills occur during periods of ice and snow cover. Ice usually allows enough light penetration for photosynthesis, but a layer of snow can block out most light. This light blockage prevents oxygen production, but respiration and decomposition continue, resulting in an oxygen shortage. Aquatic vegetation is seldom a problem in the rivers and streams of Kansas. In fact, vegetation along the banks is beneficial in that it protects the banks from erosion.
Problems can occur in canals, however, which are designed to transport water.
Plants growing along the edge, especially trees, can impede water flow. Aquatic plants usually are not a major problem in these areas. Encroaching vegetation may impede flow in drainage ditches. Marshes and seep areas usually cannot be used for conventional Kansas agriculture so the vegetation can be left alone for wildlife habitat. Weed problems can occur in cultivated fields that border these wet areas, especially in abnormally wet years.