Workshop Summary

California faces many challenges to meet the future water demands from continued population growth. These include reduction of the Colorado River water allotment as well as water quality issues related to further contamination, analytical technology improvements, and potential lowering of water quality standards. Of the tools California has to manage the challenges, artificial groundwater recharge will continue to be important and will grow in application over the next decade. This workshop provided presentations on the status of artificial recharge in California, including the intricacies and challenges faced to implement and manage artificial recharge projects, case histories, and the political and policy issues.

• Overview of current and planned artificial recharge in California - inventory and categorization of current activities, the role of artificial recharge in long-term water-resource planning for the state, status of grant programs and other mechanisms for funding/facilitating artificial recharge programs.
  
  
• Hydrologic challenges - saturated and unsaturated flow considerations (including facility design and operation), use of models (simulation and optimization) to evaluate project benefits and potential impacts, surface-water/ground-water interaction, variability and uncertainty in surface water supplies, and monitoring design and instrumentation.
  
  
• Water quality challenges - organic and inorganic chemistry issues, changed environmental conditions and potential for mobilization of natural or man-made contaminants, use of tracers to evaluate disposition and effects of recharge operations, disinfection byproducts, reclaimed water quality issues, role of emerging contaminants.
  
  
• Microbial challenges - evaluating and monitoring bacteria and viruses, including transport of viruses and bacteria, new analytical methods, and design and operation issues.
  
  
• Policy challenges - water rights, funding (federal, state, local, private), economics (cost-benefit analysis), water transfers, public perception, legislation.

Overview of Santa Clara Valley Water District Artificial Recharge Facilities

Concern over significant water level drops and subsidence in Santa Clara Valley in the 1920's led to the formation of the Santa Clara Valley Water Conservation Committee, the first focused-area studies of causes and plans for mitigation, and the subsequent forming of the Santa Clara Valley Water Conservation District. Since the 1930's, Santa Clara Valley has had an artificial recharge program to assist in restoring water to the underlying aquifers, reduce subsidence and minimize further declines in groundwater elevations. The water district currently operates 18 major recharge systems, which consist of a combination of off-stream and in-stream facilities. The total annual average recharge capacity of these systems is nearly 160,000 acre-feet. The Santa Clara Valley Water District hosted a tour of its groundwater recharge facilities.