Water Economics and Management Group

The Water Economics research program hubs collaboration among resource economists and other research disciplines to provide insights on various water uses including agriculture, urban and the environment. Economic costs of drought, policy analysis of water management and their costs are among the span of research produced in the program.



Josué Medellín-Azuara

Curriculum Vitae

Contact Information

Civil and Environmental Engineering
Center for Watershed Sciences
University of California; Davis
Davis, California 95616

Tel. (530) 754-9354
Cel. (530) 574-8019

Research Interests

  • Large scale hydro-economic modeling for water management and policy analysis
  • Water management for agricultural, environmental and urban uses
  • Agricultural production adaptation to drought and climate change
  • Consumptive water use in agriculture using remote sensing
  • Impact analysis using partial and general equilibrium models
  • Data management software systems


Ph.D. (2006) Ecology-Environmental Policy Analysis. University of California, Davis

    Dissertation: Economic-Engineering Analysis of Water Management for Restoring the Colorado River Delta, Mexico. Professor, Jay R. Lund.

M.S. (2003) Agricultural and Resource Economics. University of California, Davis.

M.B.A. (1998) Escuela de Graduados en Alta Dirección de Empresa. Instituto Tecnológico y de Estudios Superiores de Monterrey, México.

B.S. (1993) Mechanical and Electrical Engineering. Instituto Tecnológico y de Estudios Superiores de Monterrey, México.

Honors and Awards

  • International Association of Hydrogeologists, Hydrogeology Journal, Editor's Choice Article for 2015, Paper Medellín-Azuara et al. (2015).
  • American Geophysical Union, Water Resources Research. Editor’s Choice Award (2011). Paper Harou, Medellín-Azuara et al. (2010).
  • Mexican National Network of Researchers (Sistema Nacional Investigadores), Level I, September 2010 to date.
  • Mexican National Chamber of the Editorial Industry (CANIEM) award for the book: “El Agua en México”, in the category of economic essay, October 2009.
  • UC Davis Jastro-Shields Graduate Scholarship, 2005, Graduate Studies, UC Davis
  • CONACYT-UC MEXUS Graduate Fellowship, 2000-2005, Consejo Nacional de Ciencia y Tecnología (México)
  • ITESM Undergraduate Education Scholarship, 1992-1993, Instituto Tecnológico y de Estudios Superiores de Monterrey (México)
  • ITESM Academic Excellence Scholarship, 1986-1989, Instituto Tecnológico y de Estudios Superiores de Monterrey (México)

Professional Experience


2015 to present, Associate Research Engineer Step I. Dept. of Civil and Environmental Engineering. University of California Davis.

2015, Visiting Professor. Instituto de Pesquisas Hidraulicas. Universidad Federal de Rio Grande do Sul. Porto Alegre, RS, Brazil.

2013-2015, Associate Project Scientist Step II. Dept. of Civil and Environmental Engineering. University of California Davis.

2011-2013, Assistant Project Scientist Step IV. Dept. of Civil and Environmental Engineering. University of California Davis.

2009-2011, Assistant Project Scientist Step III. Dept. of Civil and Environmental Engineering. University of California Davis.

2007-2009, Postdoctoral Scholar, Professor Jay R. Lund, Dept. of Civil and Environmental Engineering, and Professor Richard E. Howitt, Department of Agricultural and Resource Economics, University of California Davis.

2005-2006, Graduate Student Researcher, Professor Jay R. Lund. Dept. of Civil and Environmental Engineering, University of California Davis.

2003-2005, Director, Aquatic Toxicology Outreach Program (ATOP). Department of Environmental Toxicology, University of California, Davis.

2002-2005, Graduate Student Researcher. Professor J. Edward Taylor. Dept. Agricultural and Resource Economics, University of California Davis.


2007, Natural Heritage Institute, San Francisco, California. Development of water management scenarios for the Rio Grande-Rio Bravo Basin.

2005-2006, El Colegio de México and The World Bank. Project: México Economic Sector Work (ESW) Economic Assessment of Policy Interventions in the Water Sector. Evaluation of policy


1997-2000, Environmental Coordinator. Navistar, formerly International Truck and Engine Corporation Mexico. Management of water treatment, waste disposal, air emission reporting and government permitting. Escobedo, Nuevo León, México.

2005-2006, Plant Engineer. Corporativo Copamex, S.A. de C.V. Supervision and plant engineering for a Pulp and Paper corporation. Garza García, Nuevo León, México.

Selected Publications

Referred Journal Papers

Fraga, C.C., Marques, G.F., Medellín-Azuara, J. (In Press). Planning for Infrastructure Expansion of Urban Water Supply Portfolios with an Integrated Simulation-Optimization Approach. Submitted to Journal of Cleaner Production.
Forni, L. Medellín-Azuara,  J. Purkey D. Howitt, R. E. and Tansey M. (2016). Integrating Complex Economic and Hydrologic Planning Models: An Application for Drought under Climate Change Analysis Water Resources and Economics, Water Resources and Economics.
Sandoval-Romero, F., Valdivia-Alcalá, R., Cuevas-Alvarado, C.M., Hernández-Ortiz, J., Medellín-Azuara, J., Hernandez-Avila, A. Voloración Económica del Agua Potable en la Delagación Iztapalapa, D.F. Revista Mexicana de Ciencias Agrícolas 7(6):1467-1475.
Medellín-Azuara, J. (2016). The California Case: Managing Groundwater in Irrigated Agriculture. Harvard College Review of Environment and Society, 3:11-12. Invited contribution.
Nelson, T; H Chou; P Zikalala; J Lund; R Hui and J Medellín-Azuara (2016). Economic and Water Supply Effects of Ending Groundwater Overdraft in California's Central Valley. San Francisco Estuary and Watershed Science, 14(1).
Nelson, T; R Hui; J Lund and J Medellín-Azuara (2016). Reservoir Operating Rule Optimization for California's Sacramento Valley. San Francisco Estuary and Watershed Science, 14(1).
MacEwan, D; R Howitt and J Medellín-Azuara (2016). Combining Physical and Behavioral Response too Salinity. Water Economics and Policy, 02(01),1650010.
Medellín-Azuara J, MacEwan D, Howitt R, Kourakos G, Dogrul E, Brush C, Kadir T, Harter T, Melton F, Lund J (2015) Hydro-economic analysis of groundwater pumping for irrigated agriculture in California’s Central Valley, USA. Hydrogeology Journal 23: 1205-1216 DOI 10.1007/s10040-015-1283-9. Winner Editor Choice Award 2015.
Mayzelle M, Viers J, Medellín-Azuara J, Harter T (2015) Economic Feasibility of Irrigated Agricultural Land Use Buffers to Reduce Groundwater Nitrate in Rural Drinking Water Sources. Water 7: 12-37.
Medellín-Azuara, J. Howitt, R.E. Hanak, E., Lund, J.R. and Fleenor, W.E. (2014). Agricultural Losses from Salinity in California’s Sacramento-San Joaquin Delta. San Francisco Estuary and Watershed Science Journal. 12(1):1-16.
Null, S. Medellín-Azuara, J., Escriva-Bou, A., Lent, M., Lund, J.R. (2014) Optimizing the dammed: Water supply losses and fish habitat gains from dam removal in California. Journal of Environmental Management, 136:121-131.
Sicke, W.S., Lund, J.R., and Medellín-Azuara, J. (2013). Climate Change Adaptations for California’s San Francisco Bay Area Water Supplies. British Journal of Environment and Climate Change. 3(3):292-315.
Cahill, R., Lund, J.R., DeOreo, B., Medellín-Azuara, J., (2013). Household water use and conservation models using Monte Carlo techniques. Hydrol. Earth Syst. Sci. 10(4):4869-4900.
Medellín-Azuara, J, Rosenstock, T., Howitt, R.E., Harter, T., Jessoe, K., Dzurella, K., Pettygrove, S., Lund, Jay R. (2013) Agro-Economic Analysis of Nitrate Crop Source Reductions. Journal of Water Resources Planning and Management. 139(5):501-511.
Howitt, R.E., Medellín-Azuara, J, MacEwan, D.M, and Jay R. Lund, (2012) Calibrating Disaggregate Economic Models of Agricultural Production and Water management, Environmental Modeling and Software. 38:244-258.
Medellín-Azuara, J., Howitt, R.E. and Harou, J.J. (2012). Predicting farmer responses to water pricing, rationing and subsidies assuming profit maximizing investment in irrigation technology. Agricultural Water Management, 108:73-82
Medellín-Azuara, J. Howitt, R.E., MacEwan, D.M. and Lund, J.R. (2012) Economic Impact of Agricultural Climate Related Yield Changes in California. Climatic Change, 109(1):387-405.
Connell, C.R., Medellín-Azuara, J., Lund, J.R. and Madani, K. (2012). Adapting California’s water system to warm vs. warm-dry climates. Climatic Change, 109(1):103-149.
Tanaka, S.K., C. Connell, K. Madani, J. Medellín-Azuara, J. Lund, E. Hanak, (2011) "Economic Costs and Adaptations for Alternative Regulations of California's Sacramento-San Joaquin Delta," San Francisco Estuary and Watershed Science.
Medellín-Azuara, J., Harou. J.: Howitt, R.E. (2010). Estimating economic value of agricultural water under changing conditions and the effects of spatial aggregation. Science of the Total Environment, 408(23):5639-5648. doi:10.1016/j.scitotenv.2009.08.013.
Harou, J., Medellín-Azuara, J., Zhu, T., Tanaka, S., Lund, J., Stine, S., Olivares, M. and M. Jenkins (2010) Extreme Drought and Water Management in California. Water Resources Research, 46(W05522): 1-12. Winner of the Editor’s Choice Award in Water Resources Research.
Harou, J., Pulido-Velazquez, M.A., Rosenberg, D.E., Medellín-Azuara, J., Lund, J.R., Howitt, R.E. (2009), Hydro-economic Models: Concepts, Design, Applications, and Future Prospects, Journal of Hydrology, 375:334-350.
Waller-Barrera, C., Mendoza-Espinosa, L. G., Medellín-Azuara, J. and J.R. Lund, (2009) Optimización económico-ingenieril del suministro agrícola y urbano: una aplicación de reúso del agua en Ensenada, Baja California, Revista Ingeniería Hidráulica en México, 24(4):87-103.
Medellín-Azuara, J., Mendoza-Espinosa, L.G., Lund, J.R., Harou, J.J., and Howitt, R.E. (2009) Virtues of simple hydro-economic optimization networks: Baja California, México. Journal of Environmental Management, 90(11):3470-3478.
Medellín-Azuara, J., Lund, J.R., Howitt, R.E. (2009). A calibrated agricultural water demand model for three regions in northern Baja California, Agrociencia, 43(2):83-96.
Medellín-Azuara, J., L.G. Mendoza-Espinosa, J.R. Lund, and R.E. Howitt (2008). Hydro-economic analysis of water supply for the binational tranboundary region of Baja California, Mexico, Water Science and Technology: Water Supply8(2):189-196.
Medellín-Azuara, J. Harou, J.J., Olivares, M.A., Madani, K., Lund, J.R., Howitt, R.E., Tanaka, S., Jenkins, M.W., and Zhu, T. (2008) Adaptability and Adaptations of California’s Water Supply System to Dry Climate Warming. Climatic Change, 87 (Suppl 1):S75–S90.
Medellín-Azuara, J., Lund, J.R. and Howitt, R.E. (2007) Water Supply Analysis for Restoring the Colorado River Delta, México. Journal of Water Resources Planning and Management, 133(5):462-471.
Medellín-Azuara, J., Mendoza-Espinosa, L.G., Lund, J.R., Ramirez-Acosta, R.J. (2007). The application of economic-engineering optimization for water management in Ensenada, Baja California, México. Water Science and Technology, 55(1-2):339-347.
Medellín-Azuara, J. and J.R. Lund (2006). Systems Analysis for Restoring the Lower Colorado River Delta. Pacific McGeorge Global Business & Development Law Journal, 19(1) 2006.

Books and Book Chapters

Medellín-Azuara, J., Howitt, R.E. and J.R. Lund. Modeling Economic-Engineering Responses to Drought- The California Case (2013). In Schwabe et al. Eds. (2013) Drought in Arid and Semi-Arid Environments: A Multi-Disciplinary and Cross-Country Perspective. Springer Publishing, Dordrecht: 341-356.
Medellín-Azuara, Josué, Howitt, R.E. and Lund, J.R. (2011). Hydro-economic modeling to assess climate impact and adaptation for agriculture in California in Dinar and Mendelsohn (eds). Handbook of Climate Change and Agriculture. Northampton, MA: Edward Elgar Publishing.
Medellín-Azuara J, Mirchi A, Madani K (2011) Water supply for agricultural, environmental and urban uses in California’s borderlands:201-212.
Guerrero, H., Yunez-Naude A. and Medellín-Azuara, J., (2008). El Agua en México: Consecuencias de las políticas de intervención en el sector. Lecturas El Trimestre Económico 100. México, D.F.: Fondo de Cultura Económica.
Howitt, R.E. and Medellín-Azuara, J. (2008) Un Modelo Regional Agrícola de Equilibrio Parcial: El Caso de la Cuenca del Río Bravo in Guerrero, H., Yunez-Naude, A. and Medellín-Azuara, J. ed. El Agua en México: Consecuencias de las políticas de intervención en el sector. Lecturas El Trimestre Económico 100. México, D.F.: Fondo de Cultura Económica.
Ramírez-Acosta, R.J., Mendoza-Espinosa, L.G., Medellín-Azuara, J. y Lund, J.R. (2006). Economía, población y eficiencia para el abastecimiento futuro de agua potable en Baja California, en Mungaray-Lagarda, A. y Ocegueda-Hernández, J.M. (Ed.), Estudios Económicos sobre Baja California. (p. 199), México, D.F.: Miguel Angel Porrúa.

SWAP Model

This website provides and overview and resources on the Statewide Agricultural Production Model (SWAP).

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

A Brief Overview of the SWAP Model

This is an introduction to the SWAP Model, the full documentation of the model has been published in The Journal of Environmental Modeling and Software.

The SWAP model is a regional economic model of irrigated agricultural production that simulates the decisions of agricultural producers (farmers) in California. Its data coverage is most detailed in the Central Valley, but it also includes production regions in the Central Coast, South Coast, and desert areas. The model assumes that farmers maximize profit subject to resource, technical, and market constraints. Farmers sell and buy in competitive markets, and no one farmer can affect or control the price of any commodity. The model selects those crops, water supplies, and other inputs that maximize profit subject to constraints on water and land, and subject to economic conditions regarding prices, yields, and costs.

SWAP incorporates project water supplies (SWP and CVP), other local water supplies, and groundwater. As conditions change within a SWAP region (e.g., the quantity of available project water supply increases or the cost of groundwater pumping increases), the model optimizes production by adjusting the crop mix, water sources and quantities used, and other inputs. It also fallows land when that appears to be the most cost-effective response to resource conditions.

When compared to previous PMP based models of irrigated agriculture, SWAP offers three key improvements. First, SWAP includes regional exponential PMP land cost functions, which corrects the inability of previous models, with a quadratic PMP cost function, to handle large policy shocks. Second, SWAP includes regional Constant Elasticity of Substitution (CES) crop production functions which allow for limited substitution between inputs. Leontief production functions were common in many previous models. Finally, regional crop prices are endogenously determined based on a statewide demand function.

Model calibration uses Positive Mathematical Programming (PMP) which has been used in models since the 1980s and was formalized by Howitt (1995). PMP allows the modeler to infer the marginal decisions of farmers while only being able to observe limited average production data through a non-linear cost or revenue function introduced to the model. PMP is fundamentally a three-step procedure for model calibration that assumes farmers optimize input use for maximization of profits. The first step solves a linear profit-maximization program. In addition to basic resource availability and non-negativity constraints, the LP includes a set of calibration constraints to restrict land use to observed values. In the second step, the dual (shadow) values from the calibration and resource constraints are used to derive the parameters for an exponential "PMP" cost function and CES production function. The third step combines the calibrated CES and PMP cost function into a full profit maximization program. The exponential PMP cost function captures the marginal decisions of farmers through the increasing cost of bringing additional land into production (e.g. through decreasing quality). Other input costs, (supplies, land, and labor) enter linearly into the objective function in both the first and third step.

As shown in the image below, the SWAP model has 27 base regions in the Central Valley in addition to agriculture in the Central Coast, South Coast, South Lahontan, and Colorado River regions. There are a total of 37 regions in the current model.


Sequential Calibration and Validation in SWAP

The SWAP model includes a sequential calibration routine and series of validation checks. The calibration phase of the SWAP model uses a sequential six-step process. The six steps are: 

  1. Assemble input, output and elasticity data
  2. Solve a linear program subject to fixed resource and calibration constraints
  3. Derive the CES production function parameters using input opportunity costs from step two
  4. Estimate the crop and region-specific PMP cost functions using a least squares method
  5. Calibrate the aggregate demand functions and regional adjustment costs using prior demand elasticity estimates, and
  6. Optimize and simulate the calibrated SWAP model which includes tests for adequate calibration in terms of input and output prices and quantities.