Groundwater Data in California: Insights from Professionals and Stakeholders

December 05, 2016 | Water in the West | Insights

Ilana Crankshaw and Tara Moran,  Visualizations: Geoff McGhee

California is currently entering its sixth year of drought. The length and intensity of this recent drought has caused declining groundwater levels,1 loss of groundwater dependent ecosystems,2 drying of domestic wells,3 and numerous other impacts. This drought has highlighted the need for better management of our water systems.

* Some basins have been regulated through groundwater adjudications and as special act districts but there has been no statewide system for managing or regulating groundwater withdrawals.

Groundwater provides up to 60 percent of the state’s water supply 4 during drought. Despite its importance, the resource has remained largely unregulated.* That is changing. In 2014, California passed the Sustainable Groundwater Management Act (SGMA).5 The Act represents the most significant piece of water legislation that the state has passed in 100 years.

As a first step, SGMA requires the formation of new agencies to manage groundwater. These local agencies are next required to develop or expand technical information about the groundwater basins they are managing. This includes estimating groundwater production using meters or other technologies and developing groundwater-monitoring networks.

Given that only 12 percent of local agencies with groundwater monitoring networks currently have a dedicated groundwater monitoring well, this will be a major task in many groundwater basins across the state.


Groundwater Data Survey Results

To better understand the most pressing data needs for groundwater management in California, Water in the West and the Gould Center for Conflict Resolution surveyed individuals involved in groundwater management at the local, state, and federal level. Survey respondents included people working for water management agencies, government staff, consultants, farmers, tribes, and non-governmental organizations (NGOs).

This post highlights a few key findings from the survey that shed light on what will be needed to implement SGMA.


I. Hopes for Improved Groundwater Data

Survey respondents were asked:

“What one improvement related to data collection and/or monitoring would make the biggest difference to groundwater management?”

The following quotes provide examples of the responses received to the open-ended question posed above. These free-form responses were grouped into four general categories, and then tabulated as seen in the graph below.

“Accurate extraction and groundwater level monitoring.”
Response categorized as:
Additional Data
“A comprehensive data management system that can be used by all users”
Response categorized as:
Data Sharing and Standardization
“Enough monitoring to establish sustainable yield of a basin.”
Response categorized as:
Additional Data


Access to Better Data Was an Overwhelming Priority for Respondents

What data or monitoring change would most improve groundwater management?
Frequency of Respondents

Key Findings

Based on these results, respondents overwhelmingly indicated 1) a need for additional data, and 2) a need for data sharing and standardization. These responses were consistent among the different user groups that were surveyed.

Who Responded?

Distribution of survey respondents. "Other" category includes NGO employees, farmers, and tribes.

These responses indicate:

  1. Water managers need more data to manage groundwater effectively.
    Survey respondents identified several types of additional data needed to support groundwater management, including information on groundwater levels, groundwater extraction, water quality, surface water, and well data, including well location and well log information. These results indicate that improvement to basic groundwater data collection practices could substantially improve groundwater management under SGMA.
  2. Data need to be collected in a consistent, transparent format — with supporting metadata — to enable sharing among water management entities.
    Data collection is important. However, the need to share data with other resource managers and interested parties is equally important. In fact, SGMA requires it. In groundwater basins where there is more than one agency managing groundwater, the law requires that these agencies develop groundwater sustainability plans using the “same data and methodologies” and integrate these data at the basin-scale using “a shared data platform.”
    Recognizing the need to integrate datasets for improved water management, the governor recently signed the Open and Transparent Water Data Act (AB 1755), which requires the Department of Water Resources, in consultation with the California Water Quality Monitoring Council, the State Water Resource Control Board and the Department of Fish and Wildlife to create and operate a statewide water data platform that integrates water and ecological datasets for improved resource management. It also requires these agencies to jointly develop data sharing and documentation protocols.


II. Concerns About Missing or Incomplete Information

Groundwater data collection has not been required in the past, which has resulted in many data gaps. Additionally, some data collection techniques need to be improved and updated in order to be useful for effective management.

Survey respondents were asked:

“Are there data that are missing or highly uncertain in your jurisdictional area that interferes with the ability to manage groundwater effectively?”

The responses to this multiple-choice question were largely consistent across respondents. They showed a strong preference towards two data priorities for effective groundwater management: groundwater extraction information and recharge information. These results suggest that improving data collection in these targeted areas would substantially improve effective groundwater management in the state.


Respondents Were Missing Information on Groundwater Extractions and Groundwater Recharge

What data are missing or highly uncertain?

Key Findings

  1. Respondents felt that groundwater recharge data would improve water management.
    Groundwater recharge will be an important tool used to offset reductions in groundwater pumping during SGMA implementation. Information on the areas best suited for groundwater recharge will be critically important in ensuring that recharge projects are successful.
  2. Collecting groundwater extraction data would improve water management.
    While groundwater extraction data are a basic and foundational data type, they are not commonly collected. These data can be used to determine total groundwater use within a region or for the basin as a whole and will be critical for sustainable groundwater management under SGMA. While collecting groundwater extraction data has traditionally been viewed as politically infeasible, the Fox Canyon Groundwater Management Agency provides an example of an agency that has been collecting this information for many years (see below).
  3. Land use data are prioritized over population forecasts.
    Survey respondents prioritized information about land use changes over population forecasts. Given that agricultural water use accounts for nearly 80 percent of the state’s total water use, it is likely that land use changes are seen as a better indicator of water use projections than population forecasts.

Case Study: Fox Canyon Groundwater Management Agency

Despite the importance of groundwater extraction data for effective groundwater management, few agencies in California require groundwater metering – often citing local opposition as the main barrier.

One agency with a history of effectively collecting groundwater extraction data is the Fox Canyon Groundwater Management Agency (FCGMA).

Facing issues of groundwater overdraft and seawater intrusion, FCGMA was formed in 1982 as a special act district. The district soon realized that they would not be able to manage effectively without information on well location and pumping volumes.

The FCGMA first took action in 1983 by passing Ordinance No. 1, which required all well owners with extraction facilities to register their wells and report annual extractions. In 1987, Ordinance No. 3 was passed requiring the installation of flow meters on wells extracting more than 50 acre-feet per year. In 1990, FCGMA first implemented groundwater reduction requirements through Ordinance No. 5. The fact that a system was already in place to track groundwater extractions meant that they were able to base reductions on historical water use. Ordinance No. 5 set a groundwater use reduction goal of 25% by 2010, which FCGMA was able to successfully meet due in part to groundwater extraction reporting in the basin.