Performing Department
School of Public Policy
Non Technical Summary
Marginal water sources such as wastewater become more important as water becomes scarcer in many places such assouthern California. Use of recycled wastewater for various purposes (irrigation, aquifer replenishment, and wetland support)could, if done properly be very valuable and less damaging. This project proposes to combine scientific, behavioral, and policy dataofwastewater reuse by developing a framework that will include both a formal model of wastewater treatment cost, wastewaterapplication in conjunction with surface water and ground water, likely agricultural crop damages from use of wastewater, effectson groundwater quality deterioration, and effects on soil quality. Once these relationships are estimated policies will be identified,quantified and modeled for their effectiveness in preventing negative impacts of use of wastewater. Because different agents(ag, urban, env) are affected differently by different policy interventions, they may object certain policy interventions. The finalstage of the proposed framework will apply tools from the field of cooperative game theory to assess how net gains in theregional context are distributed among the different agents in the region and how could the different policy interventions beranked vis a vis their fairness and stability. The project is characterized by a very active set of participation activities with policymakers, water users, and technical associations. There are two types of outcomes that are expected. First, an interaction withwater users, policy makers, and technical associations, will allow immediate feedback and dissemination, and second, resultsand conclusions from the study will be published in technical journals and in policy journals.
Animal Health Component
0%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Goals / Objectives
With continued population growth, drought worseningand increased demand for water, mainly by the domestic sector and environmental sectorson the one hand, and deteriorating quality of water and variability of water supply, fresh waterresources become a real constraint to economic development, and in many cases also lead to environmental pollution andloss of ecosystem services. Experts identified desalinization as being the next available technology to produce necessarywater supplies, but so far the cost of such water is still high and restricts their use. In the process of discussing futuredevelopment of new water resources, one resource has been overlooked, especially in California, namely wastewater. Reuse of treated wastewater in irrigated agriculturemay serve several purposes. Reuse of wastewater for Irrigation may reduce theneed for development of new, expensive fresh water resources (e.g., new dams, transfer of water from remote locations, andover-pumping of ground water aquifers). In addition, by treating and reusing wastewater in irrigated agriculture environmentalpollution may be controlled (reduced or eliminated), making irrigated agriculture an environmental guard in this respect. Therange of wastewater reuse options in agriculture is very broad and the quality requirements of the treated effluent may differwidely depending on the target use. e.g., as irrigation water for inedible or for edible crops, as industrial cooling water or asdrinking water. An economic analysis of the costs of municipal wastewater, treatment for policy and planning purposesrequires a flexible tool, which can be modified to the problem under consideration. Urban centers produce sewage that has to be treated and disposed off at any cost to the citizens. A common practice is that the urban centers follow the state regulations for treatment level and transport the wastewater for disposal in a river, or in the ocean--a costly operation from energy, infrastructure, and environmental point of view. There could be several alternatives that will attract society, such as use of the treated wastewater locally for irrigation. While use of the wastewater for irrigation might be cost effective in terms of energy and infrastructure savings, it could be more expensive in terms of treatment cost (to remove more polluting constituents, and the political economy of the stakeholders involved.The goal of this project is to demonstrate the joint benefits from use of treated wastewater in irrigated agriculture, useing existing experimental data fromsouthern California (Escondido), where treated water is used for irrigation of avocado--a sensitive crop to the salinity in the wastewater. The experimental data will provide a building block for estimation of a production function of avocado with damage component. The project will also incorporate interests of the city and the farmers regarding the quality of the wastewater to be supplied by the city to the farmers and the cost to be paid by the farmers to the city for the water. In addition the project will estimate the damage and water quality deterioration in the groundwater that might be polluted by the return flows fromthe irrigation. Using economic and regulatory principles the project will provide a range of water qualities and prices that will be acceptable to the city and the farmers and will maximize the regional welfare in the region.To reach these gowls the involvement of farmers and staff from the treatment facility in Escondido will be sought. Additional goal is to analyze data from an on-going experiment in Escondido, which uses various types of water for irrigation of avocado over a period of (by now) 4 years.
Project Methods
This project proposesto combinescientific and policy aspectsofwastewaterreuse by using actual data on wastewater treatment production; actual data on avocado performance under a veriety of water quality and quantity levels;data elicited from the interest groups in the region through structured interviews; and data about the salt level built up in the groundwater aquifer. These data will allow to estimate the cost function of wastewater treatment to various levels of quality required by irrigators;a production function of avocado irrigated with various water qualities, (fresh, saline,and wastewater); deterioration of water quality in the aquifer,and a strategic model of interest groups such as the city, the irrigators, and the regulator in charge oftheenvironment.The regional model will consist ofaframeworkthatwillincludebothaformal model ofwastewatertreatment cost,wastewaterapplication in conjunction with surface waterandground water,likelyagriculturalcrop damages fromuseofwastewater,effectson wetland, andeffectsonsoilquality. Oncethese relationshipsare estimated, policies will be identified,quantified and modeledfortheir effectiveness in preventingnegativeimpacts of useofwastewater. Policies will include taxes on pollution of the aquifer, quotas on the emissions, subsidies for irrigation technology improvements, and trade in pollution permits. Since theagents involved (ag,urban,env)areaffected differently by different policy interventions, we willapplytools from the field of cooperative game theorytoassesshownet gainsintheregional contextcould bedistributedamongthe different agents inthe regionand howcouldthe different policyinterventionsberanked vis a vis theirfairness andstability.