Email, Kevin Wagner, PhD, associate director, Texas Water Resources Institute, Texas A&M Institute of Renewable Natural Resources, April 9, 2015

11:58 a.m.

…

First, I'm not sure about the context that Commissioner Miller was speaking, but with drip irrigation, a 98% efficiency is possible. I suspect that was what he was referring to. However, drip irrigation has only been implemented on 3% of irrigated acres (as of 2008). The most efficient center pivot systems can achieve a 95% efficiency, but again, not all farms have implemented the most efficient systems on the market. See the following report I did in 2012 regarding more specifics (http://twri.tamu.edu/docs/education/2012/em115.pdf).

I will agree with Commissioner Miller that significant strides have been made and we are getting "more crop per drop." Because center pivots have been adopted in much of the state, most irrigation is in the range of 88-95% efficiency.

However, we continue to work with producers to improve irrigation efficiency and timing. New irrigation technology is being tested and we continue to develop tools to help producers better schedule irrigation events and also provide education on these tools and methods.

Which leads me back to the final point that Commissioner Miller made regarding irrigation conservation potential being maxed out. Here's my take on that, past advances have improved efficiency by 20-30% due conversion from furrow irrigation (which is 60% efficient) to sprinklers and drip (which are 88-98% efficient). Looking forward, improvements on the vast majority of irrigated acres are going to be much smaller as we now tweak technology and management. So in a sense, "the low hanging fruit has been picked."

Moving forward, I see the best opportunities for improving agricultural irrigation being:

·         Continuing Conservation Practices Adoption

o   Encourage adoption of low pressure center pivot systems (13% of sprinklers in 2007 were not low pressure systems)

o   Encourage adoption of subsurface drip irrigation where feasible

·         Improving Irrigation Scheduling (<10% Use)

o   Provide farmers with education and better tools such as an evapotranspiration Network, soil moisture sensors, controllers, etc.

·         Adopting Drought Tolerant Crop Varieties (many are being developed commercially)

·         Improving Irrigation Conveyance Systems (this applies to irrigation districts providing surface water)

I hope that some of this is helpful. It may be a little more than you wanted. However, if you have any follow up questions please let me know.

Best regards,

Kevin Wagner, PhD

Associate Director

Texas Water Resources Institute | Texas A&M Institute of Renewable Natural Resources