Evapotranspiration (ET) within the riparian zones of streams and rivers of arid and semi-arid regions can be a major source of depletion of surface water flows. ET also can influence interactions between surface waters and ground waters through impacts on the water table along river corridors. Eight years of riparian ET measurements utilizing eddy covariance methodology and continuous water table elevation measurements (2000-2007) have been made for a 320 km reach of the Rio Grande in central New Mexico, USA. Rates of annual ET ranged from ~70-130 cm y^-1. Water table drawdowns up to 3 m occurred in dense monotypic stands of non-native salt cedar. Estimates of the responses of annual ET and groundwater recharge through the riverbed to a 2^oC temperature increase have been calculated and an overall water budget developed for the middle Rio Grande in central New Mexico under present conditions and under a warming scenario of 2^oC. Climate change in the form of temperature warming will substantially increase the rates of both ET and groundwater recharge along riverine corridors in arid and semi-arid regions of the world.