A COMPARISON OF NUTRIENT CONCENTRATION AND STREAM CONDITIONS: SIX MILE CREEK AND MONEY CREEK, ILLINOIS

In the central Midwest of the United States agriculture accounts for a significant amount of land usage. Raising nutrient content of soils using fertilizer is an effective means to improve crop growth and yield, although these additional chemical nutrients and sediment freed from agriculture can cause problems as they spread through the environment. High nitrogen, phosphorous, and sedimentation of waterways may contribute to a variety of negative impacts on ecological and human health ranging from eutrophication and hypoxic dead zones in bodies of water to “blue baby syndrome”. Because of this, it is important to monitor and understand what parameters influence nutrient and sediment content of valuable bodies of water, such as the two lakes that provide drinking water to the City of Bloomington, Illinois - Evergreen Lake and Lake Bloomington. By identifying trends in nutrient concentrations that correlate to trends in stream conditions, water quality may be approximated using data that can be collected remotely with high frequency in place of lengthy analysis. We installed automated monitoring stations at two tributaries to the main drinking water reservoirs of Bloomington that drain agricultural watersheds. These stations measured discharge and turbidity at 15-minute intervals and took frequent water samples during storm events. These water samples from Six Mile Creek and Money Creek were measured for total phosphorous, reactive phosphorous, and nitrate using Flow Injection Analysis. Comparing the nutrient data to turbidity and discharge data revealed that total phosphorous fluctuations were similar to fluctuations in turbidity. Reactive phosphorous changed similarly, though there was more variation from turbidity. Our results indicate that turbidity could potentially be used to identify phosphorus inputs to the lakes in these systems.