Evapotranspiration (ET) is the largest flux in the water balance after precipitation. Direct measurements of ET using micrometeorology and eddy covariance are expensive and require a lot of staff time for station maintenance and data processing making it cost-prohibitive for the USGS. Last fall, Li-Cor introduced the LI-710 as a simpler and more economical one-dimension ET sensor. Through the Next-Generation Water Observing Systems R&D program, the USGS and Desert Research Institute have been evaluating the LI-710 against traditional eddy covariance measurements. The presentation and demonstration will highlight some of our current results and provide hands-on look at the sensor.