May 23, 2008

Research Geared To Water Needs

As the state's water issues and priorities have changed over the last decade, UNL has initiated research and programs to help ag producers have the information they need for sound decision-making.

"We really have seen a paradigm shift in water management in Nebraska, and I don't expect it to change back anytime soon," said UNL Biological Systems Engineer Derrel Martin.

Martin cited the passage of LB962, which requires a conjunctive use, sustainability analysis of all of the state's watersheds. The Natural Resources Districts are developing integrated water management plans, he said.

The price of fuel has doubled in the last five years, so what it costs an irrigator is huge compared to what it used to be, he said.

"We have down-stream or in-stream flow requirements that are beginning to dominate how we manage our watersheds. On the Platte, we have endangered species and no new depletion issues. On the Republican, we have compliance issues on flows to Kansas. We will have to manage water differently than we did five years ago."

Martin said that UNL is engaged in a number of research projects to help producers adjust to changes in water realities. An evapotranspiration study looks at irrigated crops and native range to determine water use rates for the various crops and forages, he said. A study to assess the impact of invasive species is just beginning.

Other work is trying to measure the water use of riparian grasslands to provide a baseline for managing river vegetation. If all trees were removed, grasses would become the likely ground cover along Nebraska rivers. Research is studying how much water this type of vegetation uses compared to that of trees. Another project is studying the use of satellite data to measure evapotranspiration.

Subsurface irrigation systems have been installed at the UNL Research and Extension Centers (Scottsbluff, North Platte, Norfolk) and the South Central Agriculture Lab (Clay Center) so irrigation engineers — Dean Yonts, Suat Irmak, Bill Kranz and Simon van Donk — can research and demonstrate their use.

These systems offer benefits as well as increased management and possible maintenance. That's why researchers are exploring ways to extend the life of these systems.

Simon van Donk in North Platte is beginning a study to determine how crop residues affect evaporation, Martin said. "Suat Irmak and I are looking at the same question in central Nebraska. We know that the drier it gets and the farther west we go, the less effect residues may have on evaporation," Martin said.

Another group of water researchers are studying the effects of terraces on the amount of water flow, particularly in the Republican Basin. Measurements show a substantial amount of recharge to the ground water that occurs beneath the terrace channels. Terraces catch run-off that might otherwise reach the river. Another study is just beginning to survey the basin, including the Kansas and Colorado portions, to determine the storage capacity and types of terraces that are in place.

"We encourage people to get involved in understanding all water issues," Martin said.

"The 'know how' is really important when it comes to managing our water resources."

Faith Colburn
Communication Specialist
West Central REC, North Platte