The Arkansas Basin Water Forum Program recently held at Otero Junior College addressed many water issues, but improving water quality was among the most important for the general public.
An extensive research project is underway with the guidance of Tim Gates and Dana Hoag, professors at Colorado State University. The study is taking place along the Lower Arkansas River, above and below John Martin Dam. Gates grew up in McClave, where a major project is being conducted by Michael Weber for the Lower Arkansas Valley Water Conservancy District. The session was moderated by Blake Osborn, Colorado Water Institute and Colorado State University Extension Service.
Best Management Practices were modeled and discussed by Gates and Hoag, then an opinion survey was taken by use of a questionnaire answered on the cell phones of the participants.
“We all enjoy our green valley,” began Gates, a native of this very valley. “But we must admit those green fields we enjoy are enabled by irrigation, which alters the hydrology and geology of the land and affects the return flow to the river.” The impacts of irrigation return flow diminish groundwater quality and cause shallow water tables, affecting crop yield and non-beneficial water consumption. Irrigation drive solutes to streams and alters concentrations. Thus collections of salt, nitrates, selenium, and uranium occur in the return flow.
Some best management practices may help to allay these problems. The ones studied in this project are reduced irrigation, canal sealing, lease-fallowing, reduced fertilizer, and enhanced riparian buffers. However, none of these will reduce the natural concentration of selenium and uranium in Colorado soil, Gates reminded the audience.
Hoag continued the explanation. The most effective of the methods was lease fallowing. In this program, the farmer does not irrigate about a portion of his land and is able to sell these water rights to a municipal user. He quite possibly makes more money this way than by harvesting a crop on that portion of his land. He rotates the area to different parts of his land, gaining the advantage of replenishing natural fertilizing without the expense of artificial fertilizers.
Canal sealing and enhanced riparian barriers (larger tracts of trees and native plants along the riverbed) are most effective single practices for reducing selenium in the river. Enhanced riparian barriers and reduced fertilization are most effective for lowering nitrates in the river. The combination of canal sealing/reduced fertilization, reduced irrigation/land fallowing/canal sealing/reduced fertilization/enhanced riparian barriers, and canal sealing/reduced fertilization/enhanced riparian barriers are most effective for lowering both selenium and nitrates in streams while also decreasing soil salinity. Canal sealing is the most effective single best management practice for lowering water table elevations and soil salinity while increasing crop yields and boosting net returns.
At the end of the session, participants were asked their opinions on the subjects discussed by way of questions answerable on cell phones. Most of the participants were technically adept and answered the questions. A prime objective of the program was to gain feedback from the farmers/ranchers directly involved.
The results indicated the audience is introducing best management practices into their fields as rapidly as economically feasible and that they know where to go for information to manage environmental concerns. Hoag cautioned that uniformly applied best management practices take about 10 years to show full impact. He also said storage and release from reserve accounts will be required to meet the Colorado-Kansas Compact requirements.