Salinity in the Colorado River Basin

Abstract: Salinity in the Colorado River has increased two-fold due to anthropogenic activity in the Basin. The increased salt load constitutes a threat to wildlife (e.g. selenium) and imposes substantial economic cost to public and private sectors. Concurrent with anthropogenic salt load, future precipitation regimes may contribute to increases in river salinity that will exceed established regulatory thresholds. Here I discuss the problems, sources, and mitigation/management of salinity from a basin-wide perspective, and investigate the future flow/salinity scenarios. Currently, more than $30 million a year is spent on salinity mitigation in the basin, with an estimated $350 million in damages. Under future drought conditions, salinity mitigation expenditures may exceed $80 million, with damages approaching $1 billion annually. Even under drought conditions, salinity is not expected to pose a danger to wildlife in the river main-stem, but may threaten habitat in tributaries with significant point-source salinity inputs.