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Chapter XIII: Control of Phosphorus from Nonpoint Sources
- The University of Akron Press
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in the 1978 Great Lakes Water Quality Agreement, the parties had specified the target loading of phosphorus, 11,000 metric tons per annum, that would bring eutrophication under control in Lake Erie. By that time, they possessed a sound knowledge of the amounts of phosphorus being contributed by each significant municipal and industrial point source in both the United States and Canadian sections of the Lake Erie Basin, and would soon be provided with similar knowledge about phosphorus from diffuse sources by the International Joint Commission’s study of pollution from land use activities and the U.S. Army Corps of Engineers study of phosphorus loadings to Lake Erie from agricultural lands. The parties would then be in a position to decide by how much and by when each country would be required to reduce its loading to Lake Erie so as to achieve the target loading. In its final report, in 1970, on the pollution of Lake Erie and Lake Ontario , the International Joint Commission (IJC) had recommended that the United States and Canada jointly undertake an integrated program of phosphorus control to include “the reduction of phosphorus discharged to these waters from agricultural activities.”1 The commission had learned Control of Phosphorus from Nonpoint Sources 220 C H A P T E R X I I I from the report of its International Lake Erie Water Pollution Board that some 23 percent of the total phosphorus entering Lake Erie came from land drainage.2 The board explained that the presence of phosphorus in the drainage reflected local and regional land use practices and that phosphorus was contributed in varying amounts by the tributaries to Lake Erie.3 Urban development and replacement of forest cover by farm crops had resulted in increased soil erosion and greater fluctuation in natural stream flow. Favorable conditions had been created for the leaching and transport of soluble and suspended materials from the land surface. The board anticipated that the amount of phosphorus contributed by land drainage would increase by some 20 percent by 1986. It warned that the intensive rearing of livestock in feedlots would contribute to this increase and that counteracting it would require improved handling and disposal of animal wastes. The practice of fertilizing farmlands in winter with animal wastes also required attention, since it resulted in large pollutional runoffs in the spring. In the Ontario section of the Lake Erie Basin, wastes from beef and dairy cattle, laying hens, pullets, broiler chickens, and market hogs contributed an estimated ten thousand tons of phosphorus annually ; for the U.S. section, it was estimated that cattle, chickens, and hogs contributed some fifteen thousand tons per year. Furthermore, in 1967, twelve thousand tons of phosphorus, an increase of 90 percent since 1960, had been applied as fertilizer to cropland in the Ontario section of the Lake Erie Basin; in the U.S. section, fifty-nine thousand tons had been applied in 1964. Also, the erosion of stream banks, resulting from farmers rechanneling streams and animals grazing along the banks, was another contributing factor. Concurrently with the signing of the Great Lakes Water Quality Agreement (GLWQA) in April 1972, Canada and the United States requested in a reference that the IJC study and make recommendations both on the extent and causes of pollution from land use activities and on possible remedies .4 The reference posed several basic questions. Were the boundary waters of the Great Lakes system being polluted by drainage from land use activities ? If such pollution was occurring, by what causes, to what extent, and where was it occurring? What remedial measures would be most practicable to deal with such pollution, and what would be their probable costs? Control of Phosphorus from Nonpoint Sources 221 [54.227.136.157] Project MUSE (2024-03-19 02:38 GMT) The parties also requested the commission to assess the adequacy of existing programs and control measures for addressing nonpoint pollution. The commission responded by forming, in November 1972, the International Reference Group on Great Lakes Pollution from Land Use Activities (PLUARG), composed of nine Canadian and nine U.S. members, to carry out the study under the direction and supervision of the Great Lakes Water Quality Board.5 During the following December and January, the commission held a series of prestudy public hearings whose main purposes were to acquaint interested persons and organizations in the Great Lakes Basin with its study plans and to receive suggestions and water quality information which might be...