|Description||The problem. It was felt that a comprehensive analysis of the seasonal variations of physical and chemical parameters of a small Iowa artificial lake was needed. Such a study would establish a reference point for future developments in terms of water quality and useage of the defined area.
Procedure. Lake Easter, Polk County, Iowa, was studied from April 18 to July 2, 1969. Samples of the water were taken from three sites and from the top and bottom water. Samples were tested for temperature, light penetration, turbidity, specific conductance, oxygen, alkalinity, hardness, nitrate, nitrite, ortho-phosphate, and pH. Chemical tests were performed with a Hach DrEL (Engineers Portable Water Testing Laboratory).
Findings. The lake was found to have no pronounced thermal stratification. Light penetration was good, turbidity was near 0 mg/l, and specific conductance was similar to other hard alkaline lakes in the area. No sustained chemical stratification occurred although during periods of warm, calm air occasional low reading of dissolved oxygen were recorded. High levels of nitrate, nitrite, and ortho-phosphate were recorded.
Conclusions. The lake was found to have only temporary thermal and chemical stratification. Variations of physical and chemical parameters were found to be related to wind and rainfall. The lake is suspected to be receiving pollutants from some source and is in danger of rapid eutrophication due to the high level of plant nutrients, clear water, and large euphotic zone.
Recommendations. A year long study of physical and chemical parameters would be useful as would a study of the productivity in view of the high nutrient levels and large euphotic zone. The source of pollutants should be studied. A survey of aquatic plant and animal species is also recommended.||en_US