Lake Red Rock is known for its scenic views and recreation opportunities, but what about its denitrification potential? Fed by the Des Moines River, the lake’s water comes from both the Des Moines Lobe and the Southern Iowa Drift Plains. While this provides an ample supply of water to keep the lake full, it also aids in the transport of nitrate and sediment. In this week’s webinar, Using Delta Sediments and Pool Levels to Increase Nitrate-Nitrogen Reductions at Lake Red Rock, Matthew Streeter and Keith Schilling share about their project to determine the effect of water levels on water quality.
Understanding how water levels will affect nitrate reduction begins by looking at historical data. Luckily, Lake Red Rock has nitrate load data going back to 1978. Utilizing this data Streeter and Schilling found that a majority of the nitrate load can be attributed to the Des Moines River, with only 3% coming from tributary areas. They also discovered a 12.4% reduction in nitrates as water moved through the lake. In addition to incoming nitrates from the Des Moines River, sediments also play a key role. Using satellite imagery and hand collected soil samples, Streeter and Schilling were able to create a map of the delta that offered insight into the denitrifying abilities of the soil.
With the top 4 feet of sediment accounting for 8% of eroded soil since 1992, the denitrification potential has increased greatly. Find out more about increased nitrate load reduction in Lake Red Rock by watching this week’s full webinar. Also, tune in next week as we hear from Abigail Schulte from Iowa State University discuss Solid-State Anaerobic Digestion of Prairie Biomass and Beef Manure and check out our archive to watch past webinars.
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