BIOTIC RESPONSES TO STREAM POLLUTION DURING 

 ARTIFICLAL STREAM REAERATION 



By A. F. BARTSCH 



WISCONSIN COMMITTEE ON WATER POLLUTION 



AND 



WARREN S. CHURCHILL 



WISCONSIN CONSERVATION DEPARTMENT, MADISON, WIS. 



Introduction 



During lumbering days, the Flambeau River carried logs of majestic 

 pine and hardwood, and even now the water is shaded occasionally by 

 virgin timber. Its natural beauty is an annual attraction to the fisherman 

 and vacationist. Aside from these values, the river is ej05ciently wash- 

 ing away pulp and paper mill wastes equal in strength to the domestic 

 sewage from a city about the size of Omaha, Richmond or Oklahoma City. 

 This report is primarily an account of the way in which the living things in 

 the stream are affected by this natural clean-up job. 



Hydrographic and Cultural 



The Flambeau River is located in the north-central part of Wiscon- 

 sin (Figure 1) and drains southwesterly into the Chippewa. The drainage 

 area of the North Fork, considered in this report, is about 1,150 square 

 miles with 720 square miles above the city of Park Falls. This area is 

 mostly cut over land, relatively undeveloped and with a low human popu- 

 lation. The most prominent cultural feature is Park Falls with a popula- 

 tion of about 3,200. 



Domestic sewage is treated efficiently by the activated sludge process 

 (Figure 2). Daily B.O.D. population equivalent from this source is 150. 

 Critical pollution of the North Fork by waste sulphite liquor originating 

 at a Park Falls mill has been a serious problem for more than 10 years. 

 The daily B.O.D. contribution from this source was about 189,000 popu- 

 lation equivalent during the summer of 1946. In years of low stream 

 flow, conditions became severe as far downstream as Oxbo — 25 to 30 miles 

 from the pollutional source. Dilution by river water alone as a source of 

 dissolved oxygen has been adequate only when flows approach 2,000 c.f.s. — 

 almost three times average flow. 



These conditions led to selection of the Flambeau River as the subject 

 for experimental artificial reaeration. The project was undertaken as a 

 cooperative one by the Sulphite Pulp Manufacturers' Committee on Waste 



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