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History In The Making For Arkansas Irrigation
DR. CHRIS HENRY
FAYETTEVILLE, ARK.
July 16 is the first day of a series of public meetings taking place across the state on the new proposed rule, Title 24 for the Arkansas Water Plan. These public hearings will take place at 11 am at select locations in Arkansas between July 16 and August 25. The Arkansas Natural Resources Commission has developed water plans in the past, one in 1975 and another in 1990. However, the 2014 water plan marks the first time in history that the commission has committed the recommendations into rule. The water plan has been a two year process started just prior to 2012 and resulted in a comprehensive document characterizing the different demands for water and cataloguing the resources available to meet current and future demand. There has been strong public involvement in the development of the plan.
The plan documented a large shortfall, 12 million acre feet, most of which can be attributed to the largest user of water in Arkansas, agricultural irrigation. This shortfall is projected to increase to 14 million acre feet by 2050. A sustainable annual groundwater withdraw is about 8.2 million acre feet. By 2050 the irrigation gap will be about 7.2 million acre feet per year. If all of the surface water projects currently planned and being constructed are built, this could reduce this gap by 15 percent. Conservation measures may be able to reduce another 24 percent. There are three watersheds that are expected to have shortfalls of both surface and ground water, Bayou Macon, Boeuf River and L’Anguille. Left unchecked, Arkansas irrigators in the future may not have sufficient water to fully irrigate crops. There already exists water-rich and water-poor irrigator – the contrast between the two will continue to get stronger.
Building out currently planned new surface water resources, about another 3.8 million acres, and implementing conservation measures on all remaining irrigated acres only adds up to 39 percent of the 7.2 million acre feet gap attributed to irrigation. There is still another 61 percent remaining, yet there is no discussion about where this is going to come from, in the plan.
Can improvements in conservation measures take up more of this gap? To answer this question the University of Arkansas, Division of Agriculture Extension has implemented a statewide series of irrigation water management demonstrations in Mississippi, Cross, St. Francis, Crittenden, Clay, Lawrence, Randolf, Craighead, Greene, Poinsett, Lonoke, White, Lee, Arkansas, Prairie, Jefferson, Phillips, Desha, and Ashley Counties. These furrow irrigation demonstrations employ flow monitoring, computerized-hole selection, surge irrigation, ET-based scheduling, and soil moisture monitoring. The purpose of these demonstrations are to evaluate the synergy of these practices to improve irrigation efficiency and profitability. New irrigation tools are available, such as the freely available, industry developed, Pipe Planner (pipeplanner.com) by Delta Plastics and a public commitment to help promote conservation through the use of computerized hole selection (CHS) in lay flat irrigation pipe. Also Extension and NRCS have partnered to put more boots on the ground to help people implement and provide training on CHS. If you are not familiar with CHS, a video on this can be found here (http://deltafarmpress.com/soybeans/pipe-planner-video-takes-guesswork-out-furrow-irrigation-efficiency). Additionally the University of Arkansas (mobile android app through google play) and Delta Plastic (website tool through Pipe Planner) both have tools to help plan multiple inlet for rice irrigation.
Irrigation provides for yield stability, if water will be short, profitability will not be as certain as in the past.
Contact your local Extension agent or NRCS office to learn more about Irrigation Water Management. It may be time to take a closer look at how water is managed on your farm and what steps may be necessary on each field to ensure long term profitability.
Information on the dates of these meetings can be found at this website: http://anrc.ark.org/rules/proposed-rules/
More information can be found on irrigation water management at: http://www.uaex.edu/irrigation ∆
DR. CHRIS HENRY: Assistant Professor and Water Management Engineer, University of Arkansas
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