RECYCLED WATER: BOON OR BUST FOR DEGRADED URBAN STREAMS IN THE ARID WEST?
Abstract:The City of San Jose (City), located in the semi-arid climate of central California, has seen unprecedented growth in the last two decades with the success of Silicon Valley. This urbanization of the Santa Clara Valley Watershed has necessitated the development of creative solutions for maintaining the biological integrity and sustainability of the local environment. One proposed solution is using recycled water from an existing pipeline, to augment the flow in a degraded urban stream. This streamflow augmentation concept has been discussed and debated for many years, however improvements to the quality of the recycled water, and the increased demand for water supply, have made the concept of streamflow augmentation using recycled water a potentially viable option.
This option is already being implemented in many areas of California. Using recycled water for streamflow augmentation is what dischargers of secondary and tertiary treated wastewater have been doing for decades in California. Many projects in southern California have created effluent-dominated streams during the dry weather season. Many of these streams have recently had their wastewater discharges upgraded to tertiary treatment. This higher quality water produced multiple benefits for fish, wildlife and humans. So important are many of these benefits, that regulatory agencies have begun seeking to enforce minimum flows to be maintained by dischargers, in order to protect the established beneficial uses. Frequently, the discharger has made plans to remove all recycled water flows to the streams for land applications of this new, high quality recycled water. It seems that it is just as difficult to obtain permits to release recycled water into the stream as it is to obtain permits to divert recycled water out of the stream.
The City has been developing the support of public stakeholders, regulatory agencies and academic researchers to gain the necessary approvals to implement the Coyote Creek Streamflow Augmentation Pilot Project (Pilot Project). The Pilot Project would test the potential benefits of having recycled water augment flows in Coyote Creek, which is the drainage basin for eastern San Jose. CEQA compliance documentation is currently under review and an NPDES permit application is being developed. Comprehensive baseline monitoring has proceeded during the dry weather season (May through October 1999). There is, however, continued debate among stakeholders, as to the appropriateness of using recycled water to “enhance” streamflow throughout the dry season in this semi-arid climate. The debate over the use of recycled water in degraded urban streams includes issues of water quality, water supply, groundwater impacts, endangered species, aesthetics, historical flows and habitat modifications. While some issues can be addressed through data collection and investigation or resolved during permit negotiations, other issues cannot be answered until the recycled water is released into the stream.
Document Type: Research Article
Publication date: January 1, 2000
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