
The Chino Basin adjudication was settled in 1978 through a stipulated agreement. Through other agreements, the Chino Basin Watermaster was required to recalculate the safe yield and other hydrologic items in 2011. Our groundwater team developed and implemented a methodology based on scientific principles and detailed numerical models to develop a complete hydrologic description of the Chino Basin over the 1960-2011 calibration period and the 2012-2071 planning period.
Watermaster was also required to calculate net Santa Ana River recharge and how the net Santa Ana River recharge changes with groundwater pumping and storage management. Working with Watermaster staff and legal counsel, our team participated in a series of workshops and two-day peer review sessions to thoroughly review the methodology, assumptions, data, and computational results. The resulting model was praised during the peer review process as one of the most comprehensive and thoughtfully developed groundwater models ever built to manage a groundwater basin. Watermaster and the Court accepted the technical work and the recalculated safe yield.
The model was updated and used to develop a storage framework (management) plan for up to 1,000,000 acre-feet of water banking activities, to develop an updated Salt and Nutrient Management Plan for the basin, and to estimate the impacts of groundwater management activities on surface water discharge and riparian habitat in the Prado Reservoir area and upstream habitat areas along the Santa Ana River. The model is currently being updated to include a subsidence module and is being recalibrated to estimate the safe yield for 2021 through 2030.
Team Spotlight

Mark Wildermuth, PE
Principal III

Mark Wildermuth, PE
Principal III
“At this point in my career, what excites me the most, what revs me up in the morning, is working with younger talented staff on really important groundwater management problems. While my grey hair often puts me in a teaching mode, their youth and enthusiasm really elevate my spirit.
My greatest accomplishment was being able to lead the development and implementation of the 2000 Chino Basin Optimum Basin Management Program. This program is responsible for: the sustainable management of one of the largest groundwater basins in southern California serving agricultural and municipal water users and about a million people; development of innovative management strategies; providing over $1 billion in benefits; and attracting $100s of million in grant funding.”

Eric Chiang
Principal Scientist II

Eric Chiang
Principal Scientist II
“It is exciting to overcome new challenges in modeling works by finding innovating solutions.
I am proud to accomplish the modeling works of the San Juan Creek Watershed and San Juan Valley Groundwater Basins with GSFLOW by creating a graphical user interface for the Processing Modflow application and putting all required data together.”

Mike Blazevic
Supervising Scientist

Mike Blazevic
Supervising Scientist
“I’m fortunate to be able to work on projects that vary in terms of geography, geology and hydrogeology and each have their own unique set of challenges and problems to be solved. This keeps my work days interesting, keeps me on my toes, and creates opportunities for me to cross-pollinate my knowledge base across multiple projects and with our younger geologists.
I’ve grown up visiting Mammoth Mountain each year as far as I can remember. I’ve skied their slopes and drank the water supplied by Mammoth Community Water District. Over the last ten years, I’ve had many opportunities to support the District on various hydrogeologic projects ranging from installing a new domestic production well to assessing potential geothermal impacts to the Town’s water supply. With this level of support to the District, I not only appreciate that drink of water more each time, but can also trace each sip to its raw source.”