Canary in the coal mine? In Iowa, there is mussel in the stream. Iowa’s freshwater mussels depend on good water quality and proper habitat, as well as waters that support healthy fish to carry baby mussels (glochidia) to their future homes. So the number and types of mussels in an area – or the lack thereof – can tell you a lot about the health of a stream or river. In Iowa, they’ve told Department of Natural Resources (DNR) researchers a great deal.
Along a stretch of Buffalo Creek, five segments sat on Iowa’s impaired waters list since 2008 due to problems supporting aquatic life – specifically, mussels. A 1984 survey showed a healthy number and variety of mussels in the stream, but by 1998, follow-up work found those numbers had dropped by more than 50 percent.
In 2010, local communities came together through the Upper Buffalo Creek Water Quality Project, headed up by the Buchanan Soil and Water Conservation District, to make changes on the land to improve the water flowing into Buffalo Creek. A similar effort through the Middle Buffalo Creek project added work downstream. Landowners and farmers created grassed waterways and filter strips, and used farming practices like planting cover crops to reduce erosion and runoff to the creek. It made a difference, reducing the amount of sediment reaching the creek by 4,417 tons a year. With that extra soil being kept out of the creek, mussels bounced back with improved habitat.
“Farmers and landowners really came together, and as a result, we have found threatened species where they weren’t before and are taking five stream segments off the impaired waters list,” said Chuck Gipp, DNR director.
A new DNR statewide freshwater mussel survey, which ran from 2011 to 2017, found a significant increase in Buffalo Creek over the 1998 survey, including four species of mussel on Iowa’s threatened species list. Many of the mussels were younger than five years old, suggesting that conditions had recently improved. As a result, five segments of Buffalo Creek were removed from the state’s impaired waters list for their aquatic life impairment, joining seven other stream segments in the state.
Statewide, the DNR sampled 813 sites over seven years as part of the freshwater mussel survey, finding 39 different species, including two that had been believed to have been gone from Iowa. Prior to the current statewide survey, 25 segments of Iowa streams and rivers were listed as impaired for freshwater mussel declines. As a result of the mussel survey, 12 segments have now been delisted, and another two segments will be proposed for delisting.