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Projects Worked On

Project Name Description
Addressing Nitrate in California's Drinking Water

One in 10 people living in California’s most productive agricultural areas is at risk of exposure to harmful levels of nitrate contamination in their drinking water, according to a report released today by the University of California, Davis. The report was commissioned by the State Water Resources Control Board.

The report, “Addressing Nitrate in California’s Drinking Water,” is the first comprehensive scientific investigation of nitrate contamination in the Tulare Lake Basin, which includes Fresno and Bakersfield, and the Salinas Valley, which includes Salinas and areas near Monterey. It defines the extent of the problem, suggests promising solutions and outlines possible funding mechanisms.


California’s complex water management system often defies comprehensive analysis. We summarize the results of a decade of quantification and analysis of this system from a hydro-economic perspective using the CALVIN Model.

The general approach taken dates back to Roman times, when Frontinus (97 AD) began his oversight of Rome’s water system with a systematic inventory and quantification of its water infrastructure. 

This approach has been formalized and expanded in the modern era as economists, planners, and engineers have sought to grapple with complex water management systems and problems.

In California water supply and demand is inconvenient in both space and time. Most water availability is in northern California from winter precipitation and spring snow-melt; whereas water demands are more in the south during the dry summer. Major floods and seasonal and multiyear droughts further complicate water resource management in California. The Sacramento-San Joaquin Delta is the major north-south hub for this water network.

Population growth, climate change, a vulnerable Delta, and decentralized water governance pose opportunities and challenges to water management in California. Portfolios of water management activities, including diverse general policy tools, demand management, and operations and supply expansion options, are available to manage competing demands in complex situations.

Exploring promising portfolios of actions is the main intent of the CALVIN model. The CALVIN model is an economic-engineering optimization model of California developed at the University of California – Davis. CALVIN’s major innovations are its statewide (rather than project) scale, representation of a broad range of water management options, explicit integration of broad economic objectives, and its consequent applicability to a wide variety of policy, operations, and planning problems.


Satellite Remote Sensing and Consumptive Water Use in the Delta

This study for the state Delta Protection Commission compared the effectiveness of using new remotely sensed measurement technology to estimate farmers' "consumptive water use," or the amount of irrigation water crops transpire and evaporate from the nearby soil.

Current methods of estimation and reporting of consumptive water use can be time-consuming and costly. The State Water Resources Control Board requires farmers to report the data for each water diversion every three years.


  • Calculated estimates of evapotranspiration using remotely sensed measurements collected monthly from satellite. observations [(Derived from 2007 satellite data using the Surface Energy Balance Algorithm for Land (SEBAL)].
  • Compared the above estimates with those from two well-established crop coefficient methods [Cal Poly's Irrigation Training & Research Center (IRTC) spreadsheet approach and the California Department of Water Resources' Simulation of Evapotranspiration of Applied Water (Cal-SIMETAW)]. 
  • Examined eight crops grown in 2007 on five Delta islands: Ryer, Back Tract and the Lower, Middle and Upper Roberts.


Remote sensing measurements using SEBAL:

  • Provide accurate estimates of evapotranspiration that are less susceptible to human error. 
  • Are an efficient and consistent way to acquire data for estimation; no need to aggregate crop growth characteristics, irrigation practices and other field information.
  • Offer a promising and practical alternative to crop coefficent methods of estimating evapotranspiration.

We encourage Delta farmers and water districts to collaborate on using remote sensing to reduce the time and cost of estimating and reporting consumptive water use.


Water Modeling in Agricultural Production



This  technical workshop in collaboration with the California Water and Enviornmental Modeling Forum (CWEMF). This workshop presents various alternatives for modeling the economics of water use and water scarcity within an agricultural production setting, with a particular focus on California. This 6-hour workshop at UC Davis is intended to bring experts and interested water resources professionals from academia, industry and government agencies to talk and learn about various models and optimization tools that have been used to evaluate the economics surrounding agricultural water use  in California, Australia, Chile, and México. Applications using both mathematical programming and hedonic models will be presented.  A discussion about modeling needs and future applications for the California water modeling community will be encouraged.  



Drought's Economic Impact on Agriculture

UC Davis researchers forecast the socio-economic effects of the drought on California agriculture for 2014 and beyond. Economists use computer models and the latest estimates of water deliveries, well-pumping capacities and acres fallowed. The researchers exploit new satellite remote-sensing technologies to estimate fallowed acreage as the drought unfolds.

2016 Study Downloads


Economic Analysis of the 2016 California Drought for Agriculture (California Water Blog, August 15, 2016)

Estimates of Irrigated Cropland Idled due to the 2016 California Drought: Clarifications and Supplemental Information (NEW! Memorandum, September 1, 2016)


Collaborators: Duncan MacEwan

Daniel Sumner 

California Fourth Climate Change Assessment

Economic and Environmental Implications of California Crop and Livestock Adaptations to Climate Change and Climate Policy

To more accurately estimate the threat posed by sea level rise and intense storms to coastal infrastructure, this research will provide assess coastal flood risk accounting for changing climate patterns, erosion rates, shifting beach forms, and vertical land movement. Methods will be developed to support site-specific, project level assessments of coastal vulnerabilities to sea level rise through integration of models of projected sea level rise and climate scenarios, coupled with local and regional-scale erosion rates and vertical land motion estimates.

Collaborators: Daniel A. Sumner

SWAP Model

The Statewide Agricultural Production (SWAP) model is a multi-region, multi-input and output economic optimization model of the agricultural economy in California. The current model version covers over 93 percent of irrigated production in the state with primary regions in the Central Valley, Southern California, and the Central Coast. The model is currently used for policy analysis and planning by consultants and state and federal agencies. Some of the key features of the SWAP model include:

  • Self-calibrates using Positive Mathematical Programming (PMP)
  • Constant Elasticity of Substitution (CES) regional production functions
  • Exponential PMP cost functions
  • Groundwater pumping cost module including change in depth and electricity costs
  • Regional input constraints
  • Water broken out into 6 sources
  • Endogenous crop prices
  • Technological change and exogenous demand shift modules
  • 31 agricultural production regions based on homogenous hydrologic and agronomic conditions
  • Linkage to hydrologic, agronomic, and engineering models

The SWAP model is a fully calibrated optimization model which is well-suited to estimate spatially heterogenous commodity, resource, and input specific policies. Projects span a wide range of applications over many years. Some recent examples include: 

  • Costs of Central Valley salinity
  • Effects of Delta export restrictions
  • Nitrate externalities in the Salinas Valley
  • New CVP surface water storage feasibility analysis
  • South-of-Delta water markets
  • Yolo Bypass flood date and flow volume agricultural impact analysis
  • Climate change effects on California agriculture