Master of Science (MS)
Semester of Degree Completion
Charles L. Pederson
Kickapoo Creek, a tributary of the Embarrass River in Central Illinois, has undergone a stream restoration that included the construction of two artificial riffles. These structures were designed to slow flood waters, increase channel and substrate stability, and increase habitat heterogeneity in a stream impacted by erosion and sediment deposition. They may also provide stable substrates that affect the algal community, leading to shifts in algal community composition, increases in the biomass of primary producers, and subsequent increases in nutrient retention. I explored the effects of the restoration on instream nutrient retention by measuring and comparing phosphate uptake lengths, velocities, and areal uptake in restored and unrestored reaches of Kickapoo Creek. I employed a pulse method with a mass balance approach to measure phosphate uptake dynamics. I also used single station in situ dissolved oxygen assays to measure gross primary productivity, and analyzed the relative concentrations of chlorophylls a, b, and c, as well as ash free dry masses of algal communities on different substrates such as sand, natural rocks, and restoration rip rap. I was able to demonstrate shorter uptake lengths, higher uptake velocities, greater areal uptake, and greater primary production in the restored reaches of the stream, suggesting that the restoration structures enhanced nutrient retention by increasing algal activity. Results of chlorophyll analysis demonstrated statistically significant differences in the quantity and relative ratios of chlorophylls a, b, and c on the different substrate types, suggesting that the stable substrates provided by the artificial riffles and bank stabilization rip rap enhance the growth of different algal taxa compared to the unstable sandy substrates found in unrestored reaches of the creek.
Hughes, Adam Thomas, "Do Artificial Riffles Enhance Nutrient Retention in Restored Streams?" (2014). Masters Theses. 1297.