Open Lake Water Quality Conditions for Lake Erie's Western, Central and Eastern Basins, 1986

摘要

The 1986 Lake Erie open lake surveillance/monitoring program followed the plan recommended and sanctioned by the Water Quality Board of the International Joint Commission, Great Lakes Regional Office. The study included twelve western basin, six central and three eastern basin surveys. Several conventional physical and chemical parameters were measured on all surveys. The western basin data set has the greatest seasonal coverage, spanning from April through November. Based upon total phosphorus, chlorophyll and secchi transparency, the western basin is classified as eutrophic. The central basin epilimnion was similar in nutrient concentration and trophic classification (mesotrophic) as was reported for 1985. Seasonal median total phosphorus and chlorophyll concentrations were 13 ug/1 and 2 ug/l respectively. In contast with 1985, the central basin hypolimnion was not found to have gone anoxic. However, the oxygen depletion rate was 4.7 mg/l/month, the highest rate calculated in recent years. Only limited seasonal information was collected for the eastern basin during the 1986 field season. Based upon the available information, phosphorus and chlorophyll concentrations were similar to those recorded in previous studies.