Changes in irrigation technology may lead to water quality gains

Dr. Andrew Gray earned his PhD in Hydrologic Sciences at UC Davis under the supervision of Professor Greg Pasternack before becoming a professor in his own right at UC Riverside. Recently Dr. Gray’s PhD research received attention for a new discovery about how changes in agricultural practices are bringing an unanticipated benefit to aquatic environments.


Sedimentation is a common water quality problem in California. So, it's a big deal that a new study indicates that changes in irrigation technology might help. Researchers have found that large-scale adoption of drip irrigation techniques likely played a considerable role in reducing suspended river sediments in one of the state's largest agricultural areas.

“Widespread conversion from furrow irrigation to less erosive drip techniques in the early 1990's seems to be helping decrease suspended sediment concentrations in Salinas River watershed,” says Andrew Gray of the University of California, Riverside, who led the study.

In arid to semi-arid climates, like those that exist across much of California, river sediments are a product of large-scale hydrologic and climate factors like wildfires and flooding. At the same time, human activities like urbanization and agriculture also contribute. Upstream dams can lead to sediment impoundment, and lowland agricultural practices can intensify sedimentation through erosion. Gray says that means “changes in agriculture can have big ramifications for river sediments in those watersheds, with further implications for people and ecosystems.”

Drip irrigation lines being installed for lettuce in the Salinas Valley, California. Photo courtesy of Tim Hartz.

Drip irrigation lines being installed for lettuce in the Salinas Valley, California. Photo courtesy of Tim Hartz.

Read full article at: http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=20751

Read the full study: Gray, AB, GB Pasternack, EB Watson, MA Goñi, JA Hatten, and JA Warrick. 2016. Conversion to drip irrigated agriculture may offset historic anthropogenic and wildfire contributions to sediment production. Science of the Total Environment, doi:10.1016/j.scitotenv.2016.03.018.