The Danger of Hypertrophic Status of Water Supply Impoundments Resulting from Excessive Nutrient Loads from Agricultural and Other Sources

Vladimir Novotny



The effect of agricultural operations on nutrient losses with a specific focus on creating eutrophic and hypertrophic water quality in lakes and reservoirs providing water supply has been outlined. As a result of the intensification of agriculture and installing sewerage to growing communities, nutrient loads into receiving surface and ground waters have dramatically increased throughout the world. The article compares nonpoint loads of nitrogen and phosphorus in several countries. Two specific cases will illustrate the dilemma. The presentation will focus on the Švihov Reservoir on the Želivka River in the Czech Republic which is a primary source of potable water for Prague and Lake Tai (Taihu) in China. These impoundments are either threatened by or are already suffering from excessive nutrient loads by nonpoint agricultural and by point industrial and municipal sources. The problem is the hyper-eutrophic status exhibited by harmful algal blooms of cyanobacteria (Cyano-HAB) which is becoming endemic to many impoundments in Europe and Asia. The need for coordinated interdisciplinary research and an implementation remedial plan is outlined, discussed and developed into a concept of an ecoregion for multiple uses and purposes for water bodies and watersheds providing water supply to communities.