Changing the Flow

Abstract

One critical and ongoing challenge of groundwater management in Chino Basin has been balancing on one hand the need and desire to avoid excessive groundwater depletion and, on the other hand, the need to avoid exporting excessive and/or poor quality water from the basin and creating negative impacts on the Santa Ana River and water users downstream. Groundwater quality throughout the watershed is regulated by the Santa Ana Regional Water Quality Control Board. In the 2000s, Chino Basin parties, led by the Chino Basin Watermaster and Inland Empire Utilities Agency, negotiated with the Regional Board to design a new approach to basin management known as Hydraulic Control. This management concept involved adjusting groundwater levels within the basin to limit the outflow of poorer quality groundwater, increasing the extraction, treatment, and reuse of degraded groundwater, and enlarging the reuse of treated urban wastewater for groundwater recharge. Building, financing, and expanding the groundwater treatment facilities – known as “desalters” – and reaching agreement among the Chino Basin parties about how to lower groundwater levels in part of the basin, maintain groundwater levels in the rest of the basin, and allocate the costs and benefits of the new management approach led to the negotiation and adoption of “Peace II,” a set of additional agreements added to the earlier Peace Agreement.