Background

Vulnerability to water shortages is already acute in many regions of California during drought events. Climate change including higher temperatures and more extreme droughts, land use change, and claims to water by more diverse interests, will exacerbate this vulnerability. Our projects focus on three approaches to achieving water supply security and sustainability for the state's communities.

1) Groundwater Drought and Climate Change

2) Institutions to Govern the Groundwater Commons

3) Relationships Between Land Use Change and Water Supply Sustainability Under Climate Change

1. GROUNDWATER, DROUGHT AND CLIMATE CHANGE:

Groundwater is a critical resource in California, providing approximately forty percent of the state’s water supply and significantly more during dry years. 

Linkages Between Groundwater, Drought and Climate Change

This project is documenting and assessing the critical issues and relationships between groundwater and drought under climate change (Langridge and Van Schmidt 2020; Langridge and Fencl 2020).

Local Drought Reserves

Traditional drought adaptation strategies typically focus on monitoring weather conditions, generating surface and groundwater data, and implementing water shortage contingency plans after a drought occurs. Desalination, recycled water, new surface storage facilities, and increased water use efficiency are commonly proposed approaches for balancing supply and demand during a drought. While these strategies can be effective, they may also lead to pernicious unintended consequences. An increase in groundwater supply during a dry period can prompt growth during subsequent normal periods that increases future water requirements. Moreover, long-term demand reduction can result in a hardening of demand-side conservation capabilities during a future drought. This results in an increase of a region’s vulnerability to future water shortages. We are exploring a proactive approach to increase a community’s resilience to future prolonged droughts - the establishment and maintenance of local strategic groundwater reserves. This includes case studies of individual management approaches to develop and sustain such reserves (Langridge et. al. 2018; Langridge and Daniels 2017; Langridge et. al. 2012; Langridge 2012).

2. INSTITUTIONS TO GOVERN THE GROUNDWATER COMMONS:

A Comparative Study of Adjudicated Groundwater Basins and Special Act Districts.

In 2016, our research team completed a detailed evaluation for the State Water Resources Control Board (SWRCB) of all the current adjudicated basins and all special act districts, two major institutional arrangements to manage groundwater in California. Court-adjudicated basins are where water users turn to the court to define and assign private property rights over groundwater and to oversee the rules governing basin management. Legislatively created special act districts allow for enhanced local regulation of groundwater. The adjudicated basins and special act districts encompass major municipal and agricultural areas in the state. Initial work provided a comparison of the legal and administrative foundations for these institutional arrangements and examined their implications for the polycentric regulation of groundwater use (Langridge and Ansell 2018)

Polycentric Systems and Groundwater Governance

Institutional structures and behaviors influence decisions regarding the management of common pool resources (CPRs) such as groundwater. A major area of interest is the specific role of polycentric systems in supporting sustainable governance of CPRs. Polycentric systems are defined as multiple, overlapping decisionmaking centers with some degree of autonomy that interact with others through processes of cooperation and conflict. Most studies focus largely on the nature of the interactions among different decision‐making centers but we have a limited understanding of how particular polycentric systems have evolved over time and the implications of these developmental processes on sustaining the CPR. An evolutionary view will shed light on where there are opportunities and constraints for cooperation on CPR management decisions throughout the evolutionary process. We use a modified backcasting approach, which is unique for polycentric systems research, to enable us to better recognize where variations develop in polycentric systems and provide an increased understanding of how to support relationships between decision-making institutions that can enable increased learning and enhance resource sustainability. We are currently elaborating on a general framework for how polycentric systems for CPR governance evolve, and are illustrating the framework with a case study of groundwater institutions in the San Gabriel River Watershed in Southern California.

Linkages Between Groundwater Resource Structures-Processes and Groundwater Resource Outcomes for SGMA and adjudicated groundwater basins:

This new project is designing a Large-N study to compare how different physical and social variables, derived from Ostrom's Social-Ecological (SES) framework  affect groundwater resource outcomes for adjudicated basins and special act districts over time. It will then apply the findings to newly formed GSAs under SGMA. SGMA exempted all adjudicated basins. It also provided all special act districts (SADs) with the right to be the exclusive local agencies within their statutory boundaries, and the option to be the sole GSA in their service area, and most have become GSAs. Previous work for the state examined many variables for all the adjudicated basins and SADs and this work will be updated for this project.

3) Relationships Between Land Use Change and Water Supply Sustainability Under Climate Change

The Impacts of land use (LULC) Trends on the Vulnerability of Human and Natural Communities to Water Shortages on California’s Central Coast

Global scale projections of land use change have been an important component of climate change research, however, their utility at local to regional scales is often limited. Climate change data at local scales relevant to land use decisionmaking is also incomplete. These are significant research gaps, as local decisions about land-use activities and land-cover (LULC), including agricultural and municipal development, are localized in nature and require accurate climate and land use data if land and resource managers are to effectively adapt to impending climate change and plan for alleviating community vulnerability. This project examined how climate and LULC trends will impact the vulnerability of human and natural communities to water shortages in the understudied Central Coast region of the state, including disadvantaged communities in the Salinas Valley (Wilson et. al. 2020; Van Schmidt et. al. 2022 pending).

The Relationships Between Urban Development – Housing and Water Sustainability in Five Central Coast Counties

This new project is providing a collaborative evaluation of relationships between water sustainability and affordable housing for communities in California’s Central Coast under two climate scenarios. It joins high-resolution locally tailored development models with interdisciplinary assessments of their impacts on social and ecological communities. Working with local stakeholders, we are developing an updated business-as-usual (BAU) model that integrates data from the UPlan and LUCAS models. It will be run under two climate scenarios to project current trends into the future. This will form the basis for establishing policy scenarios to illuminate relationships between  (1) water shortage vulnerabilities (post SGMA), (2) urban development and affordable housing requirements (post RHNA) – with an assessment on impacts for disadvantaged communities, (3) preservation of both agricultural and undeveloped lands, and (4) carbon ecosystem balances.