Credit: Unsplash/CC0 public domainA recent study by Oregon State University revealed that greater buffer zones around water bodies and more consistent enforcement for water protection regulations are necessary to reduce agricultural-based pollution in the Western U.S.Research has shown that agricultural pollution from both croplands and rangelands is responsible for 48% of the impairments in water quality in U.S. surface waters. This in turn affects fish and insect habitats and decreases biodiversity in aquatic environments.The OSU paper reviewed 40 cases studies that examined the effects of agriculture on water quality. It was featured on the cover of Water earlier this month. Researchers focused on studies that examined the relationship between agricultural management practices and aquatic responses in rivers, streams, and livestock rangeland use to biotic responses in rivers, streams, and riparian zones, which are areas bordering streams and rivers.According to the most recent national assessment of streams in the lower 48 U.S. States, only 26-30% of their lengths were in good condition for the fish and insects that live in them. Researchers are hopeful that the U.S. can restore aquatic habitat and improve the health of water-dwelling animals by implementing appropriate mitigation."What I see, is that there are still a number of pretty good places; however, there are still a few places where, regardless of regulations and mitigation actions, there is still some work to be done," stated Robert Hughes, the lead author. Hughes holds a courtesy appointment in OSU's College of Agricultural Sciences as an associate professor in Department of Fisheries, Wildlife and Conservation Sciences. "We can do better. We already know how."According to the same national assessment, 44% and 37% respectively of the total lengths of stream and river were in poor condition for fish and insects.The study authors state that pollution from point sources is relatively easy to treat and identify. However, agricultural pollution can occur over large areas of land, particularly in the Western U.S. This includes the row crop fields that drain into streams and rivers, and rangelands where cattle graze or defecate in and around bodies of water.Robert Vadas, Jr., a Washington researcher, co-authored the study. He highlighted that Washington regulation of agricultural polluting is behind regulation of urban or forestry land use.Hughes stated that "the best solution would be for the riparian sections back to the streams", referring to floodplain areas that extend a short distance from riverbanks. We could offer easements to farmers; they could be paid to remove the land from crop production.He said that better fencing and better herding would make a big difference in keeping cattle from rivers and streams.Hughes stated that sites in good condition are those that have had protected watersheds and riparian zones. They're not perfect, they're still being used by farmers, ranchers, and loggers but they're significantly better.A 2009 study in Oregon found that agricultural lands were responsible for 80% of impaired stream lengths in the Willamette Basin despite only representing 30% of the total length.Hughes mentions the Willamette River, however, as an example for positive change. Numerous rehabilitation projects have been undertaken to clean up pollution points and improve fish habitat. These include planting trees, widening side channels, and removing road crossings that block fish migration.He said, "You can now fish and swim in the Willamette. It was an open sewer 70 years ago." We still have problems, of course. But we have made great strides.Hughes understands the obstacles farmers may face in allowing some of their farmland back to nature. He also recognizes the need for infrastructure to protect rivers and streams.He said that the solutions must come from within local communities and not from external agencies.Hughes stated that watershed councils are the most successful thing Oregon has done. They allow local people to get together, decide what they can do and then discuss, "We tried this; it can be improved." That's how you do it. "We are wired not to listen to anything that comes from above."Continue readingMore information: Robert M. Hughes et. al., Agricultural Effects on Streams & Rivers: A Western USA focus, Water (2021). Robert M. Hughes et. al., Agricultural Effects on Streams and Rivers - A Western USA Focus, (2021). DOI: 10.3390/w13141901
