Groundwater Data: California’s Missing Metrics
SHARE


Groundwater Data: California’s Missing Metrics

When it comes to groundwater data collection, California lags far behind other western states, most of which have much stricter disclosure requirements for water users. All this despite the fact that California pumps more groundwater annually than any other state in the US.

California’s groundwater resources are significantly depleted in many areas. With the ongoing drought and less surface water available, groundwater resources are under pressure as never before to meet drinking water and irrigation demands. To provide for present and future water needs, careful management of groundwater is essential.

Groundwater data are the critical foundation for water managers to both prevent problems and formulate solutions. In California, where groundwater makes up between 30-60% of the state’s water supply system, everyone benefits from good groundwater management, whether through direct use, or indirectly from the social, economic and environmental contributions associated with groundwater use.

No State Mandate for Groundwater Data Collection

“The lack of data is appalling. Without information, you are working through solutions in mud.”
- James Caruso, Senior Planner, San Luis Obispo County

A new study by Water in the West indicates that basic data is lacking in many of California's groundwater basins. As millions of acre-feet are pumped statewide each year, many heavily used basins have no record of

  • How much groundwater was withdrawn
  • Where it was pumped from
  • How much water remains in the aquifers.

Nor are adequate data available on groundwater quality or aquifer characteristics.

California Trails Other Western States

When it comes to groundwater data, California has little groundwater data compared to other western states, most of which have much stricter information disclosure requirements for water users. For example, a key metric needed for good groundwater management – well log data – is publicly available in every western state except California. All this despite the fact that California pumps more groundwater annually than any other state — nearly one-fifth of all the groundwater pumped in the U.S. annually.

Well Log Availability by State

Source: The Nature Conservancy, unpublished data

Estimated Groundwater Withdrawals, 2005

Source: U.S. Geological Survey

Given the importance of consistent and reliable groundwater data for good management, it is unsurprising that many western states have legislated requirements for agencies to collect it and make it available to the public.

Current Rules Are Not Enough...

California’s lack of data collection is not the result of ignorance about its importance, but the victim of chronic underfunding and politics. In 2009, California legislators passed a bill (SBX7-6) creating the California Statewide Groundwater Elevation Monitoring (CASGEM) program to track seasonal and long-term trends in groundwater elevations in the state’s groundwater basins over time. The law also requires collaboration between local monitoring entities and the Department of Water Resources to collect and disseminate groundwater elevation data in a public database. Despite its potential, CASGEM has not been well used and has had limited success due to the lack of dedicated program funding.

...While Antiquated Laws Actually Enforce Secrecy

Furthermore, while the drought and related cutbacks on surface water supplies are motivating groundwater users to drill new or deeper wells in increasing numbers, California law actually prohibits public access to well logs compiled by drilling companies, even though drillers are required by law to submit the logs to the California Department of Water Resources. Previous efforts to change this have fallen short. California is the only western state to restrict access to well logs.

Conflicts over Groundwater Use Are on the Rise, Exacerbated by Data Shortages

While California still lacks a comprehensive groundwater management regime, the obstacles may be shifting because:

  • Heavy pumping is bringing water users into conflict with one another more frequently – pumping by large users is causing neighboring farms and rural residential wells to run dry. Without data and appropriate interpretation, well owners don’t know how their aquifer is doing and can’t anticipate changes. And some want to pump large amounts of groundwater – not for their own use – but to sell somewhere else, upsetting their neighbors whose well water levels continue to decline.
     
  • River flows and groundwater-dependent ecosystems are being disrupted by the drawing down of groundwater levels, highlighting the connection between surface water and groundwater. (See article on groundwater-surface water conflicts.)
     
  • Timely and accurate data is vital for aquifer recharge and storage - replenishing depleted groundwater aquifers requires knowing how much water is going into and coming out of the aquifers. (See article on groundwater recharge.)

Calls for Groundwater Data Reform

In a dramatic shift, the Association of California Water Agencies (ACWA) has recently come out in favor of broader groundwater data collection and sharing, including levying fees on groundwater pumping (which requires metering to know how much water is extracted).

If California begins moving toward more comprehensive data collection and sharing, what are the pieces of information that are vital to effective management?

Meet the Five Missing Metrics Essential to Groundwater Management

A study by Water in the West has determined that the collection and sharing of five metrics are key – at a minimum – to effective management of groundwater resources. Each is important on its own, but they are all intertwined.

Well Drilling Logs

Information on location, depth and subsurface geology, collected at the time a well is dug or deepened

Groundwater Elevations

Information on changes over time in the aquifer level. In some areas, this may include monitoring of land subsidence

Production Metering

Information on how much water is pumped from a basin

Water Quality

Information that captures fluctuations in temperature, salinity and contaminants

Groundwater Models

A representation of geology and geography, water supply and demand, and climate for groundwater planning and forecasting

data some data no data data some data no data data some data no data data some data no data data some data no data
Missing Metric #1

Well Drilling Logs

Where Wells Were Drilled, How Deep and What Lies Underneath
A well log is a report produced by the driller that contains basic information about the well, including location, date and time drilled, well diameter and casing material, screen depth, water level, intended use, and geology. The geologic profiles derived from all wells drilled in a basin, taken together, can help inform how water is flowing underground and the nature of the water.
 
 
 
 
Drilling Log Data
How Drilling Log availability affects different groups...
Data
Some Data
No Data
Scroll or click the dial labels to change scenarios

Well Owners  

Water Managers

The Public


Well logs have been required in California since 1949, but they are provided to DWR in hard copy, making data access and analysis difficult. Additionally, California law prohibits nearly everyone, besides government agencies, from accessing the data without the owner’s consent. The lack of access to well log data negatively affects groundwater management in California, as these data are critical to understanding the size and geographic distribution of aquifers — or water-bearing formations — within a groundwater basin. Well logs can provide insight into where water best infiltrates into groundwater aquifers. With this data, managers can better manage groundwater through an improved understanding of the aquifer system – by protecting groundwater recharge areas from development, or enhancing recharge by targeting their managed aquifer recharge projects to these areas. In addition, the well construction information from well logs is essential in understanding the depths from which groundwater is produced in an aquifer.

Missing Metric #2

Groundwater Elevations

How Much Water is Left, and Where
Groundwater elevations are influenced by groundwater pumping, geology, subsurface flows, and basin hydrology. Knowing whether aquifer elevations are increasing, decreasing, or stable, as well as the location of these changes, alerts managers to the potential for a variety of problems and where management efforts need to be concentrated. To capture fluctuations and long term basin-wide trends – as well as reflect often significant differences in geology, land cover types and water demand across an aquifer – it is generally necessary to monitor groundwater elevations in a number of wells at least quarterly, if not monthly, to capture seasonal variations.
 
 
 
 
Groundwater Elevations
How groundwater elevations availability affects different groups...
Data
Some Data
No Data
Scroll or click the dial labels to change scenarios

Well Owners

Water Managers

The Public


Groundwater elevation data, collected over the long term and analyzed for trends, can alert managers to the potential for a variety of problems. How many local wells will dry up if groundwater elevation declines? What rivers and ecosystems depend on groundwater to maintain instream flows, and how will increasing pumping or decreasing quality affect them? At their simplest, groundwater elevation data can warn of aquifer depletion and point to changing energy costs. Combining groundwater elevation data with groundwater quality and geologic information signals to water managers the potential for saltwater intrusion, land subsidence, and the spread of contaminants — critical to protecting public water supplies and infrastructure from potentially irreversible harm. Understanding groundwater elevation trends can also help determine how much water needs to be recharged into the basin. Different well locations throughout the basin can provide information on where management efforts are needed. The more wells there are, the finer the resolution.

Missing Metric #3

Production Metering

How Much Water Is Being Pumped Out?
Production metering is a means of tracking how much water has been pumped from a specific well. When combined for all wells in a basin, production metering can be used to determine how much water is pumped from the basin. At a minimum, production should be reported monthly to capture seasonal variability in demand. With the support of other information, the collection and sharing of production data enable management agencies to more effectively identify problem areas within a basin and take management actions – such as recharge – to address them.
 
 
 
 
Production Metering
How production data availability affects different groups...
Data
Some Data
No Data
Scroll or click the dial labels to change scenarios

Well Owners  

Water Managers

The Public


Because groundwater pumping is the largest form of withdrawal from aquifers, production metering is critical to answering many questions about the health of a groundwater basin, such as: How does pumping cause changes in groundwater elevations? Are we using more water than is currently being recharged? How can we design effective measures to influence pumping or increase recharge?

Knowing the amount of water being pumped and recharged into an aquifer can give water managers the information they need to make decisions and take action to sustainably manage groundwater through seasonal changes and through wet years and drought. Production metering data also can help in the development and administration of flexible tools that help groundwater users deal with scarcity, like water marketing and incentive programs, to increase water use efficiency. Finally, in a court context, a record of water usage over time is necessary for groundwater users to prove their legal rights.

Missing Metric #4

Groundwater Quality

Groundwater quality monitoring requires taking water samples from a well to test for chemicals that could affect groundwater users. At a minimum, sampling should be done twice a year, but quarterly or monthly monitoring enables water managers to identify trends and mitigate contamination. Water quality trends should be examined in conjunction with information on land use, groundwater elevations, and subsurface hydrogeology to ensure more comprehensive management policies and actions.
 
 
 
 
Groundwater Quality
How groundwater quality availability affects different groups...
Data
Some Data
No Data
Scroll or click the dial labels to change scenarios

Well Owners  

Water Managers

The Public


Understanding groundwater quality and how it is changing over time is important to protect public health, as well as the long-term health of aquifers. In addition to the natural variability in groundwater quality that can exist across and within an aquifer system, a variety of man-made pollutants including fertilizers, pesticides, and petrochemicals can infiltrate into the ground and contaminate aquifers. It is vital to take all steps necessary to prevent contamination and to address it early if it happens. Understanding water quality also can help in protecting agricultural lands. For instance, using groundwater high in salts can damage crops and soils. Saltwater intrusion into freshwater aquifers along the coast can become a problem as groundwater pumping increases. As groundwater elevations decline, both man-made and naturally occurring contaminants in an aquifer can become concentrated, requiring more costly treatment or well abandonment.

Missing Metric #5

Groundwater Models

For planning and forecasting
Groundwater models are used to understand how groundwater flows through aquifers in a groundwater basin and how they are affected by recharge (surface water, precipitation, etc.) and discharges (what comes out – pumping, springs and seeps, rivers, etc.). Well logs, production metering, groundwater elevations, and groundwater quality data provide the basis for many of these inputs. Groundwater models integrate a variety of data (and estimates) regarding subsurface geology, land uses, hydrology, climate, water supply and demand. .
 
 
 
 
Groundwater models
How groundwater models availability affects different groups...
Data
Some Data
No Data

Scroll or click the dial labels to change scenarios

Water Managers

The Public


Groundwater modeling helps water managers understand what’s happening in the aquifer and make predictions about trends and changes given different scenarios (pumping, climate, land use, etc.). Water managers, in turn, can use these scenarios to communicate with land use planners, policy makers, other agencies, and the public to make more informed decisions around groundwater, addressing questions such as: How does pumping groundwater at different locations influence groundwater elevations and quality? How will land use changes in this region affect groundwater recharge to the basin? Can we supply current groundwater users without adverse impacts? Can we supply additional groundwater users without adverse impacts? What happens if we continue pumping the way we have been?

Groundwater Data Collection in California

New Research

To get an understanding of whether basic groundwater data is collected and shared for different basins in California, Stanford graduate student Justin Maynard collected and analyzed publicly available information – management plans, reports, regulations, and judgments (in the case of adjudicated basins) – for approximately 150 basins in California. These include the the 130 or so high and medium priority basins and subbasins identified by the Department of Water Resources’ basin prioritization process. A simple scoring system was applied to each basin, with points given for how well they collected and shared key groundwater data - well logs, groundwater elevations, production metering, and groundwater models (the Missing Metrics described above). Scores from each basin were collected and analyzed based on California’s 10 hydrologic regions.

Groundwater Data Collection and Sharing Scores by Hydrologic Region

Drilling Logs
Production Metering
Groundwater Elevation
Model
 
Total
Score


Hydrological Region Collect
1
Share
1
Digital
1
  Collect
1
Share
1
Digital
1
Collect
1
Share
1
Digital
1
  Develop
1
  Overall
Max: 10
South Lahontan 89% 0% 0%   89% 89% 0%   89% 83% 78%   89%   6.0
Colorado River 83% 0% 0%   83% 83% 0%   100% 58% 0%   50%   4.6
South Coast 84% 0% 0%   62% 57% 1%   84% 54% 34%   50%   4.3
San Francisco Bay 71% 0% 0%   29% 29% 0%   71% 64% 29%   71%   3.6
Tulare Lake 88% 0% 0%   13% 25% 0%   88% 56% 31%   50%   3.5
Sacramento River 97% 0% 0%   6% 3% 0%   94% 70% 39%   24%   3.3
Central Coast 74% 0% 0%   15% 22% 0%   74% 54% 20%   33%   2.9
North Lahontan 100% 0% 0%   0% 0% 0%   100% 57% 0%   14%   2.7
San Joaquin River 78% 0% 0%   6% 0% 0%   78% 17% 22%   33%   2.4
North Coast 33% 6% 0%   0% 11% 0%   33% 28% 17%   33%   1.6

Findings

Our research found that groundwater basins are most commonly managed using at least one of the following four approaches: management plans, ordinances, special act districts, or adjudication. The majority of groundwater management in California is done using management plans, which allow only for the collection of groundwater elevations, quality, and production data only from public supply wells, at their discretion. Data is not included from private wells, which in many areas of the state constitute the largest withdrawals. According to our research, basins with groundwater models tend to be those with one of these four active management types.

Many basins collect data, particularly on well logs, groundwater elevations and water quality. However, the sharing of these data is much less common, due in part to antiquated laws that prohibit sharing information and the common use of file formats that do not allow for easy data sharing and use in analysis (such as PDFs). South Lahontan is the only hydrologic region in California that makes its data more readily available in digital form. Production metering data collection and sharing is generally very low across all hydrologic regions. The South Lahontan, Colorado River, and South Coast regions do a better job of collecting and sharing production data than other regions, but even they do not make these data available in a publicly accessible digital format.

Total scores on groundwater data collection and sharing across the state as a whole were low, with 9 of the 10 hydrologic regions scoring less than 5 out of a possible 10 points. The South Lahontan hydrologic region scored the highest, with 6 points.

Despite the fact that as a state California lags behind, there are quite a few groundwater basins that maintain detailed data collection and sharing of some key metrics, illustrating that there is nothing inherent about California’s legal and institutional framework that prevents good data programs. Examples of innovative approaches to groundwater management in California, including data collection and sharing, are highlighted here.

To Be Relevant, Data Must Be Translated into Information for the Public

Collecting technically adequate groundwater data is not enough. The inherently public nature of groundwater management requires groundwater managers to disseminate information that will garner public support for effective groundwater policies and management.

In contrast to data – which are often numbers given without context – information communicates the actual and potential severity of the larger consequences of groundwater conditions and management decisions in light of local circumstances and future management plans. Where possible, information should answer questions that are important for the public to understand, such as: Is the groundwater safe to drink? Is my well going to continue to supply me with the water I need? How many local wells will dry up if groundwater elevations continue to decline?

Information is only good when it is put to use. It has to be tied to an implementation plan and an ability and willingness to regulate where necessary. There need to be consistent yet flexible standards for data and information across local districts, regions, and the state in order to be transferable and comparable. There must also be sufficient investment in monitoring and dissemination.

Conclusion

California currently encourages collection of data but does not require it. The state also provides little in the way of uniformity and clarity around data collection, methodology, evaluation, and reporting. Adequate groundwater data and modeling are critical to enable and empower groundwater managers to prevent problems and formulate solutions. Just as it would be impossible to manage one’s finances without a clear understanding of the sources and amounts of revenues and expenses, managing groundwater without the five basic metrics (at a minimum) just doesn’t add up in the long term.

While some may see greater data collection, monitoring and reporting as a threat to local control of resources, the contrary is actually true. Better information improves the ability of local agencies to sustainably manage their own groundwater basin, making it is less likely that the state will need to be involved under the auspices of an emergency.