Projects Funded for Ariel Dinar


Impact of UC Cooperative Extension on California's Irrigation Water Use Efficiency


Impact of and Adaptation to Climate Change Induced Water Scarcity in Southern California/Desert Agricultural Production Regions


Specific Objectives of the Project
(1) Estimate impact of climate change induced water scarcity on agriculture in southern/desert regions of California;
(2) Model (in a normative framework) possible adaptation responses of agricultural growers across various farm types to water scarcity scenarios predicted to affect the region, and estimate the economic value of such adaptation practices;
(3) Infer the normative results by positively observing decisions of agricultural growers in a subset of the regions.

Project Report/Summary of Results
A preliminary review of the literature was conducted and a review paper was written and submitted to a technical journal; A Ricardian model to allow estimation of impact of climate change on agriculture in Imperial, San Diego, and Riverside counties was developed; Data files from the agricultural commissioner reports were identified for all individual farms in these counties; A questionnaire was developed and being cleared by HRB for phone interview with growers (300, 400, 400 in Imperial, San Diego, and Riverside Counties).
(1) A choice model at the county level was developed; a set of adaptation technologies and practices was identified as bundles of technologies and practices for each county; Using the same data sources as in (1), the data collection is about to culminate in July;
(2) The comparison between the Ricardian model with County fixed effects and the choice model will be conducted once preliminary results are available.


Adoption of Technologies and Management Practices by California Avocado Growers in Response to Water Scarcity and Quality Problems


Specific Objectives of the Project

  1. Understanding the socio-economic and physical determinants of adoption of technologies and management practices by California Avocado growers.
  2. Estimating economic impact of adoption of technologies and management practices on the ability of avocado growers to withstand drought and water quality deterioration.

Summary of Results

Avocado growers use a variety of management practices for crop irrigation and control of soil salinity. When faced with changes in water availability, reliability, and quality, growers must consider not only the effects of these changes on yields, but also the economic implications of their decisions. As new information becomes available on best irrigation practices that conserve water while avoiding salinization, growers must access this information and apply it to their own situation. Avocado is an important crop in the economy of California, which is sensitive to water availability and quality. This study determines how growers make decisions about water management and irrigation technology implemented at their avocado orchards. This study considers how farm traits, socio-economic and regional factors affects how growers adopt strategies and technologies in response to water quantity and quality changes. The results of this study are based on primary information collected from avocado growers in California. The final results will determine which irrigation management strategies are most cost-effective for responding to drought or a shift to low quality groundwater resources, and what are the behavioral aspects of grower decisions with respect to water management and adoption of new technologies. Ultimately, these research findings can both be applied to avocado production globally and extended to other crops that require precision water management.


Adoption of Outdoor Water Conservation Technologies


The objectives of this research were to evaluate the impact of a water conservation program being promoted by many of the water districts in southern California—the high efficiency sprinkler nozzle program—on water use. In particular, we intended to investigate the impact of these sprinkler heads on water use at the household level and the subsequent potential impact at the district level. Furthermore, we attempted to estimate an adoption model that identified factors which influence a household's decision to adopt the technology.

In this program, households can receive vouchers for up to 25 free high efficiency sprinkler nozzle heads. The data consists of monthly water use and household characteristics over ten years on approximately 120,000 residential meters. Our analysis consists of two approaches to evaluating these potential effects. First, we compared different subpopulations average use before and after adoption; second, we estimate a discrete continuous choice (DCC) model. Preliminary results suggest that residential customers who redeemed vouchers for 25 high efficiency sprinkler nozzles typically experienced a subsequent reduction in overall water use of around 1.2%. As a fraction of total outdoor water use, the reduction is around 2.7%. This is markedly lower than the technically achievable reduction of 30% that has been estimated by the manufacturer.

In terms of what factors seem to influence adoption, we find that adoption rates were positively related to house value, income levels, average water prices, ET, household size, and landscape area (although nonlinearly); adoption rates were negatively related to distance to the nearest nozzle head distributor (which suggests travel and time costs are important factors influencing whether households redeem their vouchers). Adoption rates for those in the top, middle, and bottom terciles of water use were approximately 2.3%, 2.0%, and 0.78%. Ongoing research is currently focusing on gathering more complete information on those households that redeemed the vouchers in terms of the number of nozzles they actually installed and the degree to which they were installed correctly.