Irrigation accounts
for 42% of the total freshwater withdrawals
in the United States. Climate change, the pressure of a growing population,
degrading water quality, and increased competition from other sectors
could constrain continuous supply to meet future agricultural water
demand. This study presents an evaluation framework to assess the
potential reuse of agricultural drainage water for crop irrigation.
Using a regional approach, we review the current state of agricultural
drainage treatment and reuse and the institutional, economic, and
other barriers that can influence the reuse decision. In the 31 eastern
states, agricultural drainage contains valuable nutrients that can
be reused for irrigation with minimal treatment, while the 17 western
states struggle with large volumes of saline drainage that can contain
constituents of concern (e.g., selenium), preventing reuse without
treatment. Using a new decision-support tool called WaterTAP3, a potential
treatment train for saline agricultural drainage was analyzed to identify
treatment challenges, research needs, and the potential implementation
at a larger scale. As demonstrated by our case study, desalination
of agricultural drainage is costly and energy intensive and will require
sizable investments to fully develop and optimize technologies as
well as manage the generated waste and brine.