This report contains information relating to the degree of effectiveness of the treatment of eutrophic lake sediments with a specific power plant fly ash. The treatment was preceded by the diversion of the major nutrient sources outside of the drainage basin. Data on both chemical and biological changes are documented. The study area was Lake Charles East, an 8.7 ha lake in northeastern Indiana. Treatment of approximately one-third of the sediments with fly ash and lime took place during the summer of 1975. Follow-up studies indicated reduced release of phosphorus during peak summer release periods for treated sediments. Mass balance modeling indicated a net reduction in long term phosphorus levels of 20% over levels without sediment treatment. If all sediments had been treated, the steady state phosphorus levels were predicted to decline by 61% over non-treatment levels. The phytoplankton community composition changed from one dominated by blue green species virtually year round to one in which the more classical successional pattern of diatoms-greens-blue greens took place. Cryptophytes became much more important in the post-treatment period. Zooplankton communities showed only short term effects from the treatment. Benthic organisms, dominated by midge larvae, were not affected. Total heavy metal concentrations increased slightly in the treated sediments, however, soluble levels in both the water column and the sediment interstices were not elevated.

Department of Civil Engineering, University of Notre Dame. "June 1979." Includes bibliographical references (pages 98-102).