Specific Objectives of the Project:
The goal of this project was to investigate the implications of measurement error in remotely sensed land-use data for accurately pinning down parameters in economic analyses relevant to California agriculture. Data products that identify land use and crop categories from satellite imagery are commonly used in research and planning models, but they inevitably contain classification errors. To understand the implications of remote-sensing land use products for accurately pinning down economic parameters, I systematically compared different land use data products for California and evaluated the magnitude of the measurement error relative to detailed field surveys.

Summary of Results:
Measurement error in derived data products is known to pose challenges for inference. When the error is non-classical, which is often the case with satellite data, then it can introduce bias in parameters that are otherwise well-identified. Knowledge about the nature of the error becomes important for credible inference. To better understand the implications of remote-sensing land-use products for accurately pinning down economic parameters, this paper first assesses the accuracy of two different remotely sensed land-use data products with California coverage by comparing them against field surveys from an agricultural region on the California coast. I then systematically compare the two across the state, a geography that features a diversity of crops unlike the rest of the United States. I find that overall accuracy varies widely between the two datasets - 4.7% to 5.9% in one and 77.8% to 87.25% in the other, depending on the year. This validation exercise illustrates the nature and magnitude of the measurement error in California, with important implications for policy.

Specific Objectives of the Project:
(a) Construct a database on how the 298 agencies registered at present to manage basins under SGMA are (i) structured legally, (ii) governed, and (iii) planning to implement the SGMA mandates; (b) Study differences in (iii) as a function of (i) and (ii) and other characteristics of the underlying groundwater resources, availability of surface water, agricultural products being produced, demographics, and urban/rural interfaces; and (c) Provide guidance to groundwater agencies, California Department of Water Resources (DWR), and other policy makers regarding SGMA implementation based on results adduced from (a) and (b).

Project Report/Summary of Results:
Regions of California will be facing significant reductions in water use in the coming years. This project provides an update on the progress made thus far towards implementing the Sustainable Groundwater Management Act (SGMA). For all high- and medium-priority basins, we record and discuss the composition of newly formed groundwater agencies and their proposed management actions by coding agency board seats by entity type and groundwater management activities by strategy type. We find that the majority of board seats are held by quasi-public water entities like irrigation districts and local agencies, skewing representation towards existing agricultural interests. The 92 unique GSAs participating in California’s high- and medium-priority basins grouped to form 43 Groundwater Sustainability Plans (GSPs) containing management actions that can be categorized into either supply augmentation or demand management. Of the 27 GSPs imposing demand management through groundwater allocations, 19 plans are also considering creating a market to trade those allocations. Basins not allowing trade are concentrated on the west side of the Central Valley. These actions may have large implications for the economic costs of SGMA.

Specific Objectives of the Project:
The objectives of this project were to explore the empirical linkages among groundwater extraction, groundwater quality, and land use in a groundwater basin that suffers from seawater intrusion. We estimated the probability that a farmer switches crops in response to changes in groundwater salinity. With an estimate of how decisions are impacted by water quality, we can evaluate the economic impacts of changes in water quality on farmer welfare, which has implications for understand the costs of climate change and sea-level rise.

Project Report/Summary of Results:
Many coastal agricultural regions are at risk of sea-level rise and groundwater overdraft, which lead to saltwater intrusion of underlying aquifers. Increased salinity levels in irrigation water can lead to crop yield reductions and degraded land quality. This project considers the value of groundwater quality in agricultural production using micro-level data from California's central coast. We combine panel measurements of groundwater salinity and fine spatial land use data with property ownership boundaries to predict the likelihood that farmers shift crops in response to a change in groundwater salinity. This allows us to estimate marginal damages associated with changing salinity while incorporating the adaptive response of crop switching. Results inform our understanding of the social marginal cost of groundwater extraction and the potential impacts of sea-level rise to coastal agriculture.