Final Report Summarizing 2020 Sampling

This research was sponsored by the GVSU Student Summer Scholar Program through the Office of Undergraduate Research. 

ABSTRACT:  The Grand River (GR), Michigan’s longest river, stretches 422 km from the headwaters to the mouth. The Grand River Watershed (GRW) comprises 13% of the entire Lake Michigan drainage basin with a drainage area of 14,431 km2, the second largest drainage basin system in Michigan. The Grand River Expedition (GRE) launched by Verlen Kruger in 1990, documented GR water quality. The 2020 expedition was postponed due to COVID-19, which required changes to our sampling plan. The 2020 water quality sampling, originally planned for the 2020 GRE, was completed using a modified sampling plan and methods with the following goals: 1) collect a complete, multi-parameter, water quality dataset; 2) compare collected data to other available datasets to evaluate water quality changes spatially along the river and over time; and 3) make data available to the public, policy makers, and river managers to raise awareness of water quality issues in the GR. In the summer of 2020, discrete water samples were collected at 1990 sampling locations and analyzed for: E. coli, chloride, nitrate, ammonia, total phosphorous, and orthophosphate. Additional data were collected using an In-situ Aqua TROLL 500 Multiparameter Sonde, which provided high resolution temperature, dissolved oxygen (DO), pH, salinity, conductivity, total dissolved solids (TDS), and oxidation reduction potential (ORP) data. Preliminary comparison of 1990 and 2020 water quality data show that DO and total phosphorous concentrations remained essentially unchanged while pH, temperature, TDS, chloride, nitrate, ammonia and E. coli concentrations decreased. Average temperatures for the entire GR decreased (0.24℃) since 1990, with a decrease in temperature at the headwaters and an increase in temperature downstream of Grand Rapids. Average total phosphorous levels, although largely unchanged (+2.6%) between 1990 and 2020, significantly decreased in some reaches. E. coli reductions were notable in 2020 data compared to the 1990 data (-93.8%), particularly downstream of concentrated urban areas such as Grand Rapids. 2020 nitrate concentrations also exhibited a reduction (-75.2%), while maintaining a similar trend to the 1990 nitrate levels. Compilation and analysis of high-resolution Sonde data is ongoing and will likely yield additional insights and explanations for observed water quality changes.

The complete report including data and appendices can be downloaded here 

Ashton_Wampler_Kneeshaw_S3_Report_Final_w_appendices