PART VIII — AQUATIC ECOSYSTEMS 



balance study of one of the Great 

 Lakes, preferably Lake Michigan be- 

 cause it lies entirely within U.S. 

 boundaries, simplifying operational 

 logistics and interdisciplinary study, 

 or Lake Ontario, which is the object 

 of the International Field Study on 

 the Great Lakes of the International 

 Hydrological Program. This would 

 involve a study measuring the input 

 from industrial and urban sources, 

 land drainage, and the atmosphere. 

 The output would include measure- 

 ments of loss through outlets, reten- 

 tion by sediments, removal of biota, 

 and loss to atmosphere. Other as- 

 pects of the study would be directed 

 toward the dispersal of input ma- 

 terials in the lake by currents and 

 general water circulation, and the 

 interaction between input materials 

 and the biota. The major problem 

 to be solved by this study is the 

 assimilation capacity of the lake wa- 

 ter — that is, the amount of material 

 it can receive without deterioration 

 in quality. The object would be to 

 prevent inputs above the assimilation 

 capacity, as well as to determine the 

 costs for maintaining a given water 

 quality. This would require estab- 

 lishment of water-use priorities, a 

 political decision yet to be made. 

 Also, information on the kinds, quan- 

 tities, and concentration of materials 

 entering the lake would make it pos- 

 sible to evaluate the relative impor- 

 tance of a pollution source and to 

 identify the sites where pollution- 



control measures would be most ef- 

 fective. Moreover, it would produce 

 high-quality information essential for 

 predictive capabilities (modeling) con- 

 cerning the nature and rates of eu- 

 trophication, and it would serve as 

 a model for studies of the other Great 

 Lakes. 



A large part of the required data 

 for this materials balance is presently 

 being collected by several federal and 

 state agencies and regional univer- 

 sities conducting investigations on 

 Lake Michigan and its drainage basin. 

 Success of this study would require 

 cooperation among these organiza- 

 tions. The organizational structures, 

 personnel, and facilities are in exist- 

 ence; only a coordinated effort is 

 needed. Such a study would not 

 lessen the present need to deal with 

 urgent local problems by federal and 

 state agencies, but it would produce 

 new and exciting possibilities for 

 attacking pressing Great Lakes prob- 

 lems on the basis of a total system 

 and long-term planning. 



In the second example, the pro- 

 posed study would focus on a major 

 river system, such as the Grand River 

 in the Lake Michigan basin, aimed 

 at determining the impact of its dis- 

 charge on the inshore lake waters 

 receiving it, and alternative methods 

 of reducing this impact. A materials 

 balance of the river and the source 

 of materials would be determined for 



the entire river. The accompanying 

 systems analysis, among other things, 

 would determine the benefit/cost im- 

 plication of maintaining an acceptable 

 water-quality standard and would 

 pinpoint alternatives for solving the 

 local water-resource problems. The 

 impact of river discharge on the in- 

 shore area would involve studies of 

 currents, thermal-bar phenomena, 

 and biochemical interactions. The 

 significance of such a study is evident 

 when it is realized that approximately 

 90 percent of the pollutants entering 

 the lakes do so through river systems. 

 This would serve as a model for at- 

 tacking the problems of other major 

 rivers entering the lakes. 



Expected Results — These sug- 

 gested attacks on Great Lakes eu- 

 trophication would identify rather 

 specifically: the need for new instru- 

 mentation such as automatic monitor- 

 ing devices; the application of remote 

 sensing methods to water-resource 

 investigations; the prevailing socio- 

 economic and political problems; and 

 the need for an interdisciplinary ef- 

 fort involving the cooperation of 

 personnel from universities, industry, 

 and government. It would also make 

 possible reasonable estimates of costs 

 involved in establishing a manage- 

 ment program for the entire Great 

 Lakes basin. The high rate of Great 

 Lakes eutrophication argues for im- 

 mediate action on the general prob- 

 lems presented in this discussion. 



Pollution and Recovery in Lake Washington 



The city of Seattle lies between 

 Puget Sound and the west side of 

 Lake Washington. Early in this cen- 

 tury, the lake was used for disposal 

 of raw sewage, and unsatisfactory 

 conditions developed. In the early 

 1930's, most of the sewage was di- 

 verted to Puget Sound, and for a few 

 years the pollution of the lake was 

 considerably reduced. But Seattle was 



expanding and smaller towns around 

 the lake were growing. In 1941, a 

 two-stage biological sewage-treatment 

 plant was established on the lake, and 

 by 1954 ten such plants had been 

 built. Another one was built on one 

 of the inlets to the lake in 1959. 

 In addition, some of the smaller 

 streams were heavily contaminated 

 with drainage from septic tanks. 



Studies of the lake in 1933, 1950, 

 and 1952 showed increases in the 

 content of algae and nutrients and 

 decreases in the amount of oxygen in 

 the deep water during summer. 



In 1955, a conspicuous growth of 

 the alga Oscillatoria rubescens de- 

 veloped. This event attracted atten- 

 tion because this species had occurred 



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