Study launched to probe how water temperature affects stream health

Posted October 27, 2023

SCCWRP and its partners have kicked off the technical work for a study seeking to improve managers’ understanding of how water temperature affects the health of sensitive aquatic life in Southern California streams where treated wastewater effluent is being discharged.

The study, which kicked off in October following stakeholder approval of the workplan, focuses on the Upper Santa Clara River watershed, and complements a similar ongoing study in the San Gabriel watershed. Treated wastewater effluent is typically discharged into streams above the stream’s ambient temperature.

Unlike much of the San Gabriel River watershed, the Santa Clara River naturally receives inputs from groundwater. Groundwater is thought to have a cooling effect on river temperature, meaning the groundwater in the Santa Clara River has the potential to help offset increased temperatures from the treated wastewater discharges.

The investigations are motivated by a new generation of treated wastewater discharge permits that have lowered the maximum temperature at which receiving water is required to be maintained.

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