Enhanced Tailwater Recovery System

A plethora of research has been conducted in the Midsouth to document the depletion of the Mississippi River Valley Alluvial Aquifer [MRVAA], which is the underground source of water used to irrigate most of the crops in the region. Much has been written about ways to lessen the impact of water withdrawal from the MRVAA in order to ensure its long-term sustainability as the primary source of irrigation water for crops growing in the Delta. This is especially important since present estimates are that only about half the water withdrawal from the MRVAA is sustainable.

Tailwater recovery, or capturing irrigation water runoff from crop fields so that it is available for future irrigation[s] of the same crop/site, is one of several irrigation water conservation tools that can be used to increase surface irrigation efficiency. Major obstacles to the development of a tailwater recovery system are 1) getting the captured water pumped back to the site of irrigation application, 2) producer concerns about getting excess irrigation water off a field, and 3) a lack of recognition of the importance of conserving MRVAA water that has been/still is free except for the cost of pumping it from the ground.

Dr. Chris Henry and colleagues at the Univ. of Arkansas have developed and patented a pit-less tailwater recovery system that addresses the first obstacle listed above. This system is described in a Mar. 2024 Delta FarmPress article titled “Tailwater recovery system delivers gold standard in furrow-irrigated rice” by Whitney Haigwood and in a Univ. of Arkansas news release by John Lovett. Pertinent details about this system follow.

•    According to Dr. Henry, furrow-irrigated rice offers 1) increased no-till options, 2) the ability to plant cover crops to potentially improve soil health at the site of production, and 3) an enhanced ability to rotate to other crops such as soybeans at the site of production. Research results indicate that it can result in as much rice production at a site as the standard flood irrigation system, but with much less water applied to the rice crop.

•    Information in both articles indicates that this pit-less tailwater recovery system was devised for row-irrigated rice. This is an important development since nearly 2 million acres [5-yr. average] of rice are grown in the Midsouth states of Arkansas, Louisiana, Mississippi, and Missouri, and an increasing portion of the rice crop is now being row-/furrow-irrigated as a water-saving measure.

•    This system is portable, which allows it to be moved to different fields based on crop rotation and irrigation needs.

•    It is easily installed and keeps the soil moisture more consistent across the rice field.

•    Once installed, the system allows a rice field to be irrigated continuously.

•    The system is based on a high-flow, low-head pump that recirculates the irrigation water back to the top of the field being irrigated. Thus, all irrigation water remains on the field being irrigated.

•    The efficiency of this system is high because it captures the tailwater and returns it to the top of the field to be returned down the furrow.

•    This tailwater recovery system is available through local NRCS offices.

•    Since a large portion of the region’s rice is rotated with soybeans that are surface-irrigated, conservation of irrigation water will be enhanced even further if this system can be adapted/modified to use with furrow-irrigated soybeans.

Composed by Larry G. Heatherly, Apr. 2024, larryh91746@gmail.com