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Projects Worked On

Project Name Description

The Middle East and North Africa have longstanding water supply and sanitation challenges.  In 2011, US Agency for International Development (USAID) partnered with Development Alternatives Inc. to end the global freshwater crisis by implementing the Furthering the Blue Revolution Initiative (FABRI). This program helps create Middle East and North Africa Network of Water Centers of Excellence (MENA NWC). Designed and launched by USAID through FABRI, DAI has partnered with the UC Davis College of Agricultural and Environmental Sciences International Programs office to provide critical guidance on water resource and wastewater management in the formation of MENA NWC. The Center for Watershed Sciences is spearheading UC Davis participation in FABRI. UC Davis, along with four other U.S. public universities, is providing strategic guidance and research assistance to developing countries in these regions. It is the beginning of a long-term relationship with USAID and a continuation of the Center’s work in support of international research.



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.



Water resource management in California is often extensive and complex and deserves a comprehensive data and modeling approach. The Hobbes Project is a new effort to provide a venue for modelers in California and elsewhere to create an open, organized and documented quantitative representation of the state's intertied water resources system. Geocoded elements in this database can be interactively converted into tiered networks able to be solved by multiple modeling platforms depending on user preferences, with the appropriate translators. Many Hobbes tools will be web-based with exporting capabilities to the most common analytical and modeling software.

The Hobbes Project will include:

  • Database standardization and data documentation

  • Geocoded data element representations

  • Open platform with web access

  • Ability to transform database elements into documented model inputs via co-development

  • Focus on data and database structure, organization, documentation, not specific models

As shown in Figure 1, users of the Hobbes Project will be able to visualize different documented elements in a common web-based mapping application, run specific modeling networks using either the Hobbes basic database, network managers scenario manager software pieces and visualize model outputs in tabular form, chart templates, maps or simply exporting the modeling network, its input data and/or its modeling output to be used in other platforms.

For more information, please see the project website at


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.  



Water Quality and Hydrodynamics

Hydrodynamics and Water Quality in the Sacramento San Joaquin Delta

Sea level rise, large-scale flooding, and new conveyance arrangements for water exports may increase future water salinity for local agricultural production in California’s Sacramento-San Joaquin Delta.  Increasing salinity in crop root zones often decreases crop yields and crop revenues.  Salinity effects are nonlinear and vary with crop choice and other factors including drainage and residence time of irrigation water. Here, we explore changes in agricultural production in the Delta under various combinations of water management, large-scale flooding and future sea level rise.  Water management alternatives include through-Delta water exports (current conditions), dual conveyance (through-Delta and a 6,700 Mm3yr-1 [or 7500 cfs] capacity peripheral canal or tunnel) and the flooding of five western islands with and without peripheral exports. We employ results from previous hydrodynamic simulations of likely changes in salinity for irrigation water at points in the Delta. We connect these irrigation water salinity values into a detailed agro-economic model of Delta agriculture to estimate local crop yield and farm revenue losses. Previous hydrodynamic modeling work shows that sea level rise is likely to increase salinity from 4% to 130% in this century, depending on the increase in sea level and location.  Changes in water management under dual conveyance increase salinity mostly in the western Delta, and to a lesser extent in the north, where current salinity levels are now quite low.  Because locations likely to experience the largest salinity increases already have a lower-value crop mix, the worst case losses are less than one percent of total Delta crop revenues. This result also holds for salinity increases from permanent flooding of western islands that serve as a salinity barrier. Our results suggest that salinity increases could have much smaller economic effects on Delta farming than other likely changes in the Delta such as retirement of agricultural lands following large-scale flooding and habitat development.  Integrating hydrodynamic, water salinity, and economic models can provide insights into controversial management issues. 


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 

Water Funds for the Ensenada Region

The Center for Watershed Sciences in Collaboration with researchers from the Universidad Autonoma de Baja California in Ensenada conducted a Pre-feasibility Assessment for a Water Fund in the Region. A Water Fund in the Ensenada Region may result an attractive water management tool for government agencies, water utilities, urban and agricultural water users and non-governmental or conservation organizations. Improved water management and governance, higher local involvement, compensation for environmental services provision, and enhanced groundwater management supple are among the incentives for the various groups in the Ensenada Region. Costs of activities in a Water Fund for the Ensenada Region and the revenue generating tools require more detailed economic and financial analyses. Furthermore, estimation of net water supply gains from Water Fund activities through hydrological studies is in place.   Conclusions from the study include:

  1. The Ensenada Region provides ecosystem services including water resources that sustain population needs, agriculture and other economic activity. These ecosystem services should be protected as part of the current governmental plans and locally raised conservation initiatives without great conflict.
  2. Water resources management in Mexico faces infrastructural, institutional and financial challenges. There is a need to coordinate planning and funding to embrace and financially sustain local initiatives.
  3. Water issues in the Ensenada Region include aquifer overdraft, over allocation of water use concessions, saline intrusion and a poor institutional infrastructure to address these problems in organized manner. Hence the opportunities for a Water Fund to help are present.
  4. Ecosystem services can coexist with current and future development in the Ensenada Region. Key areas to target with a Water Fund are protection of land practices and the basins that contribute headwaters and recharge to aquifers, water quality in the aquifers, and augmentation of water supply via water use efficiency, demand reduction, or sustainable water supply sources.
  5. The stakeholder potential support, the legal infrastructure, and the economic context for a Water Fund in the Ensenada Region exist.
  6. Involvement of stakeholders and especially the CONAGUA through workgroups is fundamental and encouraged in the early states of the process.
  7. More research is needed on how the stakeholder, legal and economic trio can be formalized in a Water Fund, in the areas if hydrologic modeling, economic and financial analyses, creation of work groups and drafting bottom up initiatives and objectives in a fund. 

Collaborators: Leopoldo Mendoza-Espinosa

Integrated Environmental Modeling

Integrated Modeling for Adaptive Management of Estuarine Systems


May 21-22, 2015, UC Davis Campus

Like many estuarine systems, California’s Sacramento-San Joaquin Delta needs to revolutionize how models and data are developed and integrated to support adaptive management. Durable and adaptive solutions must account for a cascade of interacting social, economic, and ecological effects.

The National Science Foundation is sponsoring an Integrated Modeling Workshop to explore ways to improve the development and application of modeling for multipurpose management of changing estuarine systems. The two-day workshop will bring together experts from Europe, Asia and across the U.S. Potential solutions will be identified and discussed from multiple perspectives: government, academia, NGOs, consultants and stakeholders.

Approaches to be discussed include:

Community modeling leverages the expertise of many public, private, NGO, and academic researchers for understanding complex environmental problems and supporting adaptive management. Community modeling is a way to connect experts on each of the system components through a common framework. Community modeling requires a sustainable business model that works across agencies, universities, NGOs and the private sector.

Public domain models and data can include open source and more proprietary and controlled approaches to develop software and data. Such approaches are especially important where a broad common understanding must be developed among many interests and where alternatives must be compared with transparency and minimal cost.

Integrated Environmental Modeling (IEM) uses information technologies to couple independently developed models. Modular modeling components are assembled flexibly to explore, explain, and forecast the behavior of various system purposes. IEM systems around the world include diverse stand-alone applications and high performance computer clusters.

Workshop Program (Updated May 19, 2015)

  • Integrated Environmental Modeling
  • Decision support systems: science/modeling organizations that bridge the science-policy gap
  • Directions for improved integrated modeling of estuarine systems

The workshop is organized by the Delta Stewardship Council/Delta Science Program and UC Davis Center for Watershed Sciences. The National Science Foundation is sponsoring the event in partnership with the California Water and Environmental Modeling Forum and the International Association for Hydro-Environment Engineering and Research.


Student stipends are available on a first come first serve basis. Please fill out the student stipend request form. We can provide an stipend of $100 if located around 50 mi from Davis, $150 if located between 51 and 150 miles from Davis and $300 beyond 150 miles including out of state. 


This workshop was supported by the National Science Foundation under Award: A Workshop on Community Integrated Environmental Models (Grant Number 1464440).  The Organizing Committee acknowledges supplemental support by the Delta Stewardship Council through the Delta Science Program and the Center for Watershed Sciences. 


"Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation."

Collaborators: Christopher Enright

Peter Goodwin

Agricultural Production, Water Use and Employment

This program quantifies agricultural production, land use, water use, economic value and employment using optimization approaches such as the SWAP model (  and statistical information. Below we show some links to information

Economic Assessment of Payments of Hydrologic Environmental Services in Mexico

Payment for Hydrological Environmental Services in Mexico

By Itzel Carvajal and Remedios Hernández

Environmental services are  intangibles benefits that nature gives to humans as CO2 capture, erosion control, groundwater recharge, and others. Payment for Hydrological Environmental Services (PSAH) in Mexico dates back to 2003 and it was originally financed by a portion of the fees collected by water utilities.

Several laws, regulations, standards and guidelines comfort a framework for the PSAH establishment and operation. May agencies involved in PSAH in Mexico include the National Water Commission (CONAGUA), The National Forestry Commission (CONAFOR) and the Environment Secretariat (SEMARNAT). These three government entities are responsible to establish, fund, review and monitor each one of the programs related to payment for environmental services.

PSAH programs give an economic incentive or cash payment to owners or holders of forest land for providing  hydrological services. The lands must establish and implement a sustainable development plan and set of actions and be attractive to providers and beneficiaries of these services. In this report, a overview of payments for environmental services is presented with a case study in the region of Acayucan, Veracruz.

In Mexico, Payment for Hydrological Environmental Services is relatively a new topic, and despite the outreach work of institutions and the existing economic support to programs, poor organization and operation of these programs raise some concerns among this entities and offers ample opportunities for improvement. 

Crop Economics Map 1998-2010

California Crop Economics Map

This website provides preliminary information on irrigated land areas, water use and crop value over various hydrologic boundaries. Information from the California Department of Water Resources ( on land and water use, and economic information from the SWAP model ( for 20 crop groups are employed. You can select the hydrologic boundaries, and the parameter to display by checking the appropriate boxes. The sliding rule allows you to select the year of the information from 1998 to 2010. This will be updated as more data becomes available. Please contact Josue Medellin for any questions or comments. Last update: 1/21/2016.

Delta Consumptive Water Use Comparative Study

A Comparative Study for Estimating Crop Evapotranspiration in the Sacramento-San Joaquin Delta

Principal Investigators 
Josué Medellín-Azuara, Kyaw Tha Paw U, Yufang Jin, and Jay R. Lund
Project Contact: Josue Medellin-Azuara or Jesse Jankowski (Delta CU Main Report) Kyaw Tha Paw U (Field Campaign Delta CU Study)

(Full list of authors and contributors below)

This research project was convened by the Center for Watershed Sciences at the University of California Davis with financial support from the California State Water Resources Control Board Office of the Delta Watermaster and other agencies. Its objective is to develop a better understanding of consumptive water use in the Delta by coordinating modeling, measurement, and other information from a variety of independent research and estimation efforts. 


Consumptive water use by crops, often referred to as evapotranspiration (ET), is frequently the largest component of an agricultural region’s water balance. This study investigates crop consumptive use in the Sacramento-San Joaquin Delta (“Delta”) of California using a comparative approach with several prominent methods for estimating crop ET, including estimates based on crop coefficients, water balances, energy balance using remote sensing, and field measurements.

Crop ET estimates are provided for both the Legal Delta and the Delta Service Area (DSA) for two water years (2015 and 2016) by seven methods:

  • CalSIMETAW: California Simulation of Evapotranspiration of Applied Water, by the California Department of Water Resources (DWR).
  • DETAW: Delta Evapotranspiration of Applied Water, by DWR.
  • DisALEXI:  Disaggregated Atmosphere-Land Exchange Inverse method, by the U.S. Department of Agriculture Agricultural Research Service (USDA-ARS).
  • ITRC-METRIC: Mapping Evapotranspiration at High Resolution with Internalized Calibration (METRIC), by the Irrigation Training and Research Center (ITRC) at California Polytechnic State University (Cal Poly).
  • SIMS: Satellite Irrigation Management Support System, by the National Aeronautics and Space Administration Ames Research Center (NASA-ARC) and California State University Monterey Bay (CSUMB).
  • UCD-METRIC: Mapping Evapotranspiration at High Resolution with Internalized Calibration (METRIC), by the University of California (UC) Davis.
  • UCD-PT: Optimized Priestley-Taylor approach, by UC Davis.

In addition, field-based estimates and measurements of ET using eddy covariance and estimates with surface renewal stations were developed over bare soil during the fall of 2015 and over three predominant crops in the Delta (alfalfa, corn, and pasture) in the 2016 irrigation season. One direct ET measurement station was also deployed in 2016. Five additional California Irrigation Management Information System (CIMIS) stations were deployed in the Delta in 2016 to improve the spatial representation of weather variables and accuracy in input datasets of reference ET estimates. Two annual land use parcel surveys for 2015 and 2016 were conducted by Land IQ, Inc., which provided updated land use maps over the study area with more than 30 land use classes. A total of 26 agricultural classes were used for ET estimates and analysis.

Additional Funding and Research Support from

California State Water Resources Control Board, California Department of Water Resources, Delta Protection Commission, Delta Stewardship Council, North Delta Water Agency, Central Delta Water Agency, South Delta Water Agency, Center for Watershed Sciences, and UC Water. Project managemnt support from Cathryn Lawrence at the Center for Watershed Sciences is aknowledged.

Project Documents and Datasets





Full Authors and Contributors List

Principal Investigators
Josué Medellín-Azuara1,2, Kyaw Tha Paw U3, Yufang Jin3, and Jay R. Lund1

Report Preparation and Research Assistance
Jesse Jankowski, Eric Kent, Jenae' Clay, Andy Wong, Andrew Bell, Nicholas Santos, and Jessica Badillo, University of California, Davis

Other collaborators and research support from:
Commissioned by the Office of the Delta Watermaster
Michael George, Delta Watermaster, California State Water Resources Control Board

Field Campaign Group
Kyaw Tha Paw U3, Eric Kent3, Jenae’ Clay3, Michelle Leinfelder-Miles4, Jean-Jacques Lambert3, Megan McAuliffe3, David Edgar3, Sean Freiberg3, Ruolan Gong3, Megan Metz3, Cayle Little5, Bekele Temegsen

Modeling Groups
CalSIMETAW: Morteza Orang5, Richard L. Snyder3,4, Quinn Hart1,3, Sara Sarreshteh5, and Simon Eching5
DETAW: Tariq Kadir5 and Lan Liang5
DisALEXI: Martha Anderson6
ITRC: Daniel Howes6
SIMS: Forest Melton8,9, Alberto Guzmán8,9, Lee Johnson8,9, Carolyn Rosevelt8,9, and Kirk Post8,9
UCD-METRIC: Nadya Alexander1, Nicholas Santos3, Andrew Bell1, Justin Merz1 and Quinn Hart1,3
UCD-PT: Yufang Jin3, Andy Wong3
Unmanned Aerial Vehicles: J. Andrés Morandé1, Ricardo Trezza5, Andreas Anderson2, Kyaw Tha Paw U3, Yufang Jin3, Josué Medellín-Azuara1,2, Jesse Jankowski1, Jessica Badillo1, Joshua H. Viers2, YangQuan Chen2
WRF-ACASA: Kyaw Tha Paw U3, Eric Kent3, Jenae’ Clay3, Rex David Pyles3

Peer Review Panel
Richard Allen10, Byron Clark11, Richard L. Snyder3,4 and Thomas Trout6


1 Center for Watershed Sciences, University of California, Davis
2 School of Engineering, University of California, Merced
3 Land, Air and Water Resources, University of California, Davis
4 University of California Cooperative Extension.
5 California Department of Water Resources
6 Agricultural Research Service, United States Department of Agriculture
7 Irrigation Training and Research Center, California Polytechnic State University, San Luis Obispo
8 NASA-Ames Research Center, Cooperative for Research in Earth Science and Technology
9 California State University, Monterey Bay
10 University of Idaho, Kimberly
11 Davids Engineering, Inc.

Advanced Hard Biofuels

Advanced Hardwood Biofuels Northwest (AHB) is a consortium of Pacific Northwest university and industry partners led by the University of Washington.  AHB is carrying out research and development to support a system that will use renewable feedstocks like hybrid poplar to produce a suite of products that are currently derived from petroleum.  AHB will focus on the development of a renewable bio-based chemical industry. Developing poplar-based biofuels including jet fuel, diesel, and gasoline that can supplement existing fossil fuels is the long term goal.  A bio-based chemical and fuel industry will revitalize rural communities through job creation and economic development, decrease the nation’s dependence on foreign oil, and move the nation toward a clean energy and product economy based on renewable materials with a low carbon footprint.

Economic Analysis of Poplar Production Adoption in Farmlands of the Northwest United States

Fuel biomass producing crops like poplar have the potential of providing renewable sources of energy with positive net carbon footprints, and economic returns. This research project explores the potential of poplar adoption in the Pacific Northwest considering an incumbent crop mix and existing economic information on crop prices, yields and productions costs. The model employs a programming approach whose objective is to maximize net returns to land and management and self-calibrates to a base dataset of incumbent crops without poplar adoption. The crop mix includes field crops, forages and grains, which have a relatively low return per unit area. Poplar both irrigated and rainfed is introduced by employing a decreasing returns to scale production function  obtained from simulated yields. The model evaluates for a range of prices of poplar, the crop mix that will maximize net returns to farm and management. Modeling results indicate that poplar can displace some of the incumbent crop groups provided farmgate price of the poplar biomass is high enough.  


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

A decision support system for water resources management: An Application to Monterrey, Mexico

This project integrates hydrologic and socioeconomic data into a water management decision support system using hydro-economic principles. Goals are to organize and exchange hydrologic and socioeconomic data; develop long-term hydrologic and socioeconomic scenarios; model a large, multi-objective metropolitan water system using hydro-economics; and identify and compare promising water management strategies.

Image Credit: Aguilar-Barajas, I., Sisto, N.P., Ramirez-Orozco, A.I. (2015)A Agua para Monterrey. Logros, Retos y oportunidades para Nuevo Leon y Mexico. Cento del Agua para America Latina y el Caribe. Agencia Promotora de Publicaciones S.A. de C.V. N.L. Monterrey, Meixico.

Collaborators: Aldo Ramirez-Orozco


An Agent-Based Model of Farmer Decision Making in Jordan

The model employs a Multi-Agent-Simulation (MAS) framework and is designed to evaluate direct and indirect outcomes of climate change scenarios and policy interventions on farmer decision making, including annual land use, groundwater use for irrigation, and water sales to a water tanker market.  Land use and water use decisions are simulated for groups of farms grouped by location and their behavioural and economic similarities.  We adapt the Positive Mathematical Programming (PMP) approach to allow explicit evaluation of the impact of pumping costs, groundwater purchase fees and a water tanker market.  The proposed approach is designed and implemented with software such that it could be used to evaluate a variety of physical and human influences on decision making in agricultural water management.

Collaborators: Steven Gorelick

Julien Harou