This web map was created for use in its respective dashboard, in support of California's Groundwater Live.The web map includes data for current groundwater levels statewide.For inquiries, please email calgw@water.ca.gov.

A comprehensive picture, at European Union scale, of the aquifers and their characteristics is available in digital form. In 1982, a study by the European Commission provided a complete catalogue of national water resources for several Member States of the European Union (Belgium, Federal Republic of Germany, Denmark, France, Ireland, Italy, Luxembourg, Netherlands and United Kingdom).

This catalogue comprised a series of groundwater resources maps of Europe, at scale 1:500,000 ; there were 38 map sheets covering four themes:

-Inventory of aquifers; -Hydrogeology of aquifers; -Groundwater abstraction; -Potential additional groundwater resources.

[Summary provided by the European Union Joint Research Center.]

Groundwater Elevation Change Maps summarize the change in groundwater level measurements over time, collected from wells in the northern Sacramento Valley by the Department of Water Resources (DWR) Northern Region Office (NRO) and monitoring cooperators. Northern Sacramento Valley groundwater levels are measured seasonally, during the annual water year, as part of our ongoing data collection program. Many of the wells have over 30 years of monitoring history, with the longest active monitoring well dating back to 1921. Groundwater level data provides valuable information regarding seasonal fluctuations and long-term changes in groundwater level trends over time. The groundwater level data presented in these figures includes the Sacramento Valley and Redding groundwater basin portions of Shasta, Tehama, Butte, Colusa, Glenn, and Sutter counties and are organized by year, season, well depth, and period of change.

This dataset is available for use for non-commercial purposes only on request as AfA248 dataset Groundwater Vulnerability Maps (2017). For commercial use please contact the British Geological Survey.

The Groundwater Vulnerability Maps show the vulnerability of groundwater to a pollutant discharged at ground level based on the hydrological, geological, hydrogeological and soil properties within a single square kilometre. The 2017 publication has updated the groundwater vulnerability maps to reflect improvements in data mapping, modelling capability and understanding of the factors affecting vulnerability Two map products are available: • The combined groundwater vulnerability map. This product is designed for technical specialists due to the complex nature of the legend which displays groundwater vulnerability (High, Medium, Low), the type of aquifer (bedrock and/or superficial) and aquifer designation status (Principal, Secondary, Unproductive). These maps require that the user is able to understand the vulnerability assessment and interpret the individual components of the legend.

• The simplified groundwater vulnerability map. This was developed for non-specialists who need to know the overall risk to groundwater but do not have extensive hydrogeological knowledge or the time to interpret the underlying data. The map has five risk categories (High, Medium-High, Medium, Medium-Low and Low) based on the likelihood of a pollutant reaching the groundwater (i.e. the vulnerability), the types of aquifer present and the potential impact (i.e. the aquifer designation status). The two maps also identify areas where solution features that enable rapid movement of a pollutant may be present (identified as stippled areas) and areas where additional local information affecting vulnerability is held by the Environment Agency (identified as dashed areas).

This data release contains data used to develop models and maps that estimate the occurrence of lithium in groundwater used as drinking water throughout the conterminous United States. An extreme gradient boosting model was developed to estimate the most probable lithium concentration category (≤4, >4 to ≤10, >10 to ≤30 or >30 µg/L). The model uses lithium concentration data from wells located throughout the conterminous United States and predictor variables that are available as geospatial data. The model is included in this data release in the zipped folder named Model_Archive and was used to produce maps that are also included in this data release. The model input data (predictor variables) that were used to make the maps are within a zipped folder (Map_Input_Data.zip) that contains 20 tif-raster files, one for each model predictor variable. The map probability estimates that are outputs from the model are in a zipped folder (Map_Output_Data.zip) that contains 10 tif-r ...

This digital dataset represents the surface hydrogeology of an approximately 45,000 square-kilometer area of the Death Valley regional ground-water flow system (DVRFS) in southern Nevada and California. Faunt and others (2004) constructed the map by merging mapped lithostratigraphic units into 27 hydrogeologic units (HGUs). The HGUs represent rocks and deposits of considerable lateral extent and distinct hydrologic properties. The hydrogeologic map was fundamental to the development of a hydrogeologic framework model and a transient ground-water flow model of the DVRFS. These models are the most recent in a number of regional-scale models developed by the U.S. Geological Survey (USGS) for the U.S. Department of Energy (DOE) to support investigations at the Nevada Test Site (NTS) and at Yucca Mountain, Nevada (see "Larger Work Citation", Chapter A, page 8).

The aquifer risk map is being developed to fulfill requirements of SB-200 and is intended to help prioritize areas where domestic wells and state small water systems may be accessing groundwater that does not meet primary drinking water standards (maximum contaminant level or MCL). In accordance with SB-200, the risk map is to be made available to the public and is to be updated annually starting January 1, 2021. The Fund Expenditure Plan states the risk map will be used by Water Boards staff to help prioritize areas for available SAFER funding.

This layer contains summarized water quality risk per census block group, square mile section, and well point. The overall census block group water quality risk is based on five risk factors (1. the count of chemicals with a long-term average (20 year) or recent result (within 2 years) above the MCL, 2. the count of chemicals with a long-term average (20 year) or recent result (within 2 years) within 80% of the MCL, 3. the average magnitude or results above the MCL, 4. the percent area with chemicals above the MCL, and 5. the percent area with chemicals within 80% of the MCL). The specific chemicals that contribute to these risk factors are listed as well. Higher values for each individual risk factor contribute to a higher overall score. The scores are converted to percentiles to normalize the results. Higher percentiles indicate higher water quality risk. The water quality data is based on depth-filtered, de-clustered water quality results from public and domestic supply wells, collected following a similar methodology as the Domestic Well Needs Assessment White Paper. The methodology used to calculate the risk percentiles is outlined in the Aquifer Risk Map Methodology. To provide comments or feedback on this map, please email SAFER@waterboards.ca.gov or Emily.Houlihan@Waterboards.ca.gov.Methodology for the draft aquifer risk map available for download.

Map Direct focus to show Groundwater Contamination. Please refer to https://floridadep.gov/water for more information. Originally created 03/01/2007, and moved to Map Direct Lite on 06/24/2015. Please contact GIS.Librarian@floridadep.gov for more information.

It is a vector dataset. Vector data portray the world using points, lines, and polygons (areas). The recharge data is shown as polygons. Each polygon holds information on: Average Recharge (mm/yr) - average annual recharge to the groundwater aquifer across that polygon Recharge Coefficient (%) – the proportion of effective rainfall that becomes groundwater Effective Rainfall (mm/yr) – the rainwater remaining after plants have taken up some of the rainfall Recharge Pre Cap (mm/yr) - effective rainfall x recharge coefficient, not limited by maximum recharge capacities Recharge Cap Apply – is there a maximum amount of recharge that the aquifer can accept? (Yes/ No) Recharge Maximum Capacity (mm/yr) – the maximum amount of recharge the aquifer can accept. Only applies to bedrock aquifers of category Ll, Pl, or Pu. Average Recharge Range (mm/yr) - Annual Recharge (mm) categorised into a range of values used to style the map. Hydrogeological Setting Code - determined by the combinations of different geological layers Hydrogeological Setting Description – the description of the main geological layers that combine to let different amounts of rainfall through to become groundwater Vulnerability Category – the code for the groundwater vulnerability Vulnerability Description – the groundwater vulnerability description Soil Drainage – whether the soil is well drained or poorly drained Subsoil Type (Quaternary Sediment Code) – the code for the subsoil type Subsoil Description (Quaternary Sediment Description) – description of the subsoil type Sand/Gravel Subsoil – whether the subsoil is sand/gravel or not Subsoil Permeability Code - the code for the permeability of the subsoil Subsoil Permeability Description – description of the subsoil permeability Sinking Stream – indicates the presence of a stream that sinks fully or partially into the ground. Derived from the Groundwater Vulnerability 40K mapping. Sand and Gravel Aquifer Category –Sand and Gravel Aquifer Category from Groundwater Resources (Aquifers) 40K mapping Sand and Gravel Aquifer Description –Sand and Gravel Aquifer Description from Groundwater Resources (Aquifers) 40K mapping Bedrock Aquifer Category –Bedrock Aquifer Category from Groundwater Resources (Aquifers) 100K mapping Bedrock Aquifer Description –Bedrock Aquifer Description from Groundwater Resources (Aquifers) 100K mapping Hydrostratigraphic Rock Unit Group Name– Rock Unit Groups that have hydrogeological significance County – Irish County

Data supporting the publication:Cuthbert et al (2019). Global patterns and dynamics of climate–groundwater interactions. Nature Climate Change, 9, 137–141. DOI:10.1038/s41558-018-0386-4https://www.nature.com/articles/s41558-018-0386-4See the ReadMe file uploaded with the data and the Methods section of the paper for details of the derivation of each dataset.

Groundwater potentiometric-surface contours for spring 2022 (April 4 to 8, 2022) and autumn 2022 (October 30 to November 4, 2022) were created for the alluvial aquifer in Big Lost River Valley. The well numbers and station names used to create the potentiometric-surface contours and groundwater-level change maps are provided in this data release. The location, depth to water, and potentiometric-surface altitude for these wells can be accessed on USGS National Water Information System (NWIS) or Idaho Department of Water Resources (IDWR) groundwater portal. The interpreted 20-foot contours of the potentiometric-surface are also provided in this data release. The contours are referenced to the North American Vertical Datum of 1988 (NAVD 88). The potentiometric-surface contours are divided into three water-bearing units - shallow, intermediate, and deep - based on well depth, potentiometric-surface altitude, and hydrogeologic unit. The intermediate and deep units were only identified in the southern portion of the valley near Arco, Idaho. The potentiometric-surface contours ranged from 4,900 to 6,660 feet above NAVD 88. The groundwater-level change at well sites from spring to autumn 2022, spring to autumn 1968, spring 1968 to spring 2022, spring 1991 to spring 2022, and spring 1968 to spring 1991 were calculated and are provided in a shapefile.

This project consists of 11 files: 1) a zipped folder with a geodatabase containing seven raster files and two shapefiles, 2) a zipped folder containing the same layers found in the geodatabase, but as standalone files, 3) 9 .xml files containing the metadata for the spatial datasets in the zipped folders. These datasets were generated in ArcPro 3.0.3. (ESRI). Six raster files (drainaged, geology, nlcd, precipitation, slope, solitexture) present spatially distributed information, ranked according to the relative importance of each class for groundwater recharge. The scale used for these datasets is 1-9, where low scale values are assigned to datasets with low relative importance for groundwater recharge, while high scale values are assigned to datasets with high relative importance for groundwater recharge. The seventh raster file contains the groundwater recharge potential map for the Anchor River Watershed. This map was calculated using the six raster datasets mentioned previously. Here, the values assigned represent Very Low to Very High groundwater recharge potential (scale 1 - 5, 1 being Very Low and 5 being Very High). Finally, the two shapefiles represent the groundwater wells and the polygons used for model validation. This data is part of the manuscript titled: Mapping Groundwater Recharge Potential in High Latitude Landscapes using Public Data, Remote Sensing, and Analytic Hierarchy Process, published in the journal remote sensing.

Groundwater flow is the movement of water in an aquifer or hydrogeological unit. The dataset shows groundwater flow rate and direction in the hydrogeological unit. Groundwater flow is establish from piezometric surface map. The method used to create the dataset is described in the metadata associated with the dataset. The dataset represents a description of the flow, including rate in m/d, direction, date and source. Typically, the data provided will not be in the form of a shapefile with linked properties but in the form of an image that sketches the groundwater flow. The image could also represent a cross section of the hydrogeologic units showing the regional trends of the groundwater flow.

The map graphic image at https://www.sciencebase.gov/catalog/file/get/63140561d34e36012efa2b7f?name=arsenic_map.png illustrates arsenic values, in micrograms per liter, for groundwater samples from about 31,000 wells and springs in 49 states compiled by the United States Geological Survey (USGS). The map graphic illustrates an updated version of figure 1 from Ryker (2001). Cited Reference: Ryker, S.J., Nov. 2001, Mapping arsenic in groundwater-- A real need, but a hard problem: Geotimes Newsmagazine of the Earth Sciences, v. 46 no. 11, p. 34-36 at http://www.agiweb.org/geotimes/nov01/feature_Asmap.html. An excel tabular data file, a txt file, along with a GIS shape file of arsenic concentrations (20,043 samples collected by the USGS) for a subset of the sites shown on the map. Samples were collected between 1973 and 2001 and are provided for download.

A potentiometric surface map for spring 2016 was created for the Mississippi River Valley alluvial (MRVA) aquifer, which was referenced to the North American Vertical Datum of 1988 (NAVD 88), using most of the available groundwater-altitude data from wells and surface-water-altitude data from streamgages. Most of the wells were measured annually or one time, after installation, but some wells were measured more than one time in a year and a small number of wells were measured continually. Streamgages were typically operated continuously. The potentiometric surface map for 2016 was created as part of the U.S. Geological Survey (USGS) Water Availability and Use Science Program to support investigations that characterize the MRVA aquifer. The potentiometric contours ranged from 10 feet to 340 feet above NAVD 88. The regional direction of groundwater flow was generally towards the south-southwest, except in areas of groundwater-altitude depressions, where groundwater flows into the depressions, and near rivers, where groundwater flow generally parallels the flow in the rivers. There are large depressions in the potentiometric surface in the lower half of the Cache region and in most of the Grand Prairie and Delta regions.

Statistical analyses and maps representing mean, high, and low water-level conditions in the surface water and groundwater of Miami-Dade County were made by the U.S. Geological Survey, in cooperation with the Miami-Dade County Department of Regulatory and Economic Resources, to help inform decisions necessary for urban planning and development. Sixteen maps were created that show contours of (1) the mean of daily water levels at each site during October and May for the 2000-2009 water years; (2) the 25th, 50th, and 75th percentiles of the daily water levels at each site during October and May and for all months during 2000-2009; and (3) the differences between mean October and May water levels, as well as the differences in the percentiles of water levels for all months, between 1990-1999 and 2000-2009. The 80th, 90th, and 96th percentiles of the annual maximums of daily groundwater levels during 1974-2009 (a 35-year period) were computed to provide an indication of unusually high groundwater-level conditions. These maps and statistics provide a generalized understanding of the variations of water levels in the aquifer, rather than a survey of concurrent water levels. Water-level measurements from 473 sites in Miami-Dade County and surrounding counties were analyzed to generate statistical analyses. The monitored water levels included surface-water levels in canals and wetland areas and groundwater levels in the Biscayne aquifer. Maps were created by importing site coordinates, summary water-level statistics, and completeness of record statistics into a geographic information system, and by interpolating between water levels at monitoring sites in the canals and water levels along the coastline. Raster surfaces were created from these data by using the triangular irregular network interpolation method. The raster surfaces were contoured by using geographic information system software. These contours were imprecise in some areas because the software could not fully evaluate the hydrology given available information; therefore, contours were manually modified where necessary. The ability to evaluate differences in water levels between 1990-1999 and 2000-2009 is limited in some areas because most of the monitoring sites did not have 80 percent complete records for one or both of these periods. The quality of the analyses was limited by (1) deficiencies in spatial coverage; (2) the combination of pre- and post-construction water levels in areas where canals, levees, retention basins, detention basins, or water-control structures were installed or removed; (3) an inability to address the potential effects of the vertical hydraulic head gradient on water levels in wells of different depths; and (4) an inability to correct for the differences between daily water-level statistics. Contours are dashed in areas where the locations of contours have been approximated because of the uncertainty caused by these limitations. Although the ability of the maps to depict differences in water levels between 1990-1999 and 2000-2009 was limited by missing data, results indicate that near the coast water levels were generally higher in May during 2000-2009 than during 1990-1999; and that inland water levels were generally lower during 2000-2009 than during 1990-1999. Generally, the 25th, 50th, and 75th percentiles of water levels from all months were also higher near the coast and lower inland during 2000–2009 than during 1990-1999. Mean October water levels during 2000-2009 were generally higher than during 1990-1999 in much of western Miami-Dade County, but were lower in a large part of eastern Miami-Dade County.

Groundwater is the water that soaks into the ground from rain and can be stored beneath the ground. An aquifer is a body of rock and/or sediment that holds groundwater. There are two main types of aquifer in Ireland – bedrock aquifers, and sand and gravel aquifers. Bedrock is the solid rock at or below the land surface. Over much of Ireland, the bedrock is covered by materials such as sands and gravel. The sands and gravels occur naturally on top of the bedrock. They were laid down by meltwater from melting ice sheets, by rivers, or by wind. There are two main types of bedrock aquifer. In most of them, groundwater flows through fractures and fissures. In about half of the limestone rocks, groundwater flows through cavities and caves. This type of limestone is called karst. Not all sand and gravel layers are aquifers. This is because some of them are very thin or are dry. If the sands and gravels are saturated with water, they have the potential to supply large volumes of water through wells or springs. The aquifer maps show the potential of areas in Ireland to provide water supplies. There are three main groups based on their resource potential: Regionally important – the aquifers are capable of supporting large public water supplies sufficient to support a large town; Locally important – the aquifers are capable of supporting smaller public water supplies or group schemes; Poor – the aquifers are only capable of supporting small supplies, such as houses or farms, or small group schemes. The three main groups are broken down into nine aquifer categories in total. Please read the lineage for further details. Information used to assign bedrock aquifer categories include: rock type (Hydrostratigraphic Rock Unit Groups - simplified bedrock geology with similar hydrogeological properties), yield (existing wells and springs), permeability and structural characteristics. All of the information is interpreted by a hydrogeologist and areas are drawn on a map to show the aquifers. The Sand and Gravel Aquifer map is to the scale 1:40,000 (1 cm on the map relates to a distance of 400 m). It is a vector dataset. The sand and gravel aquifer data is shown as polygons. Each polygon holds information on the aquifer code, description, name, comments and confidence level associated with the delineation of the area as an aquifer. The Aquifer Geological Lines shows the details of the structural geology; faults and thrusts. Faults are the result of great pressure being applied to rock across a whole continent or more. These rocks break under the pressure, forming faults. Faults are recorded as lines where the break in the rock meets the surface. A thrust fault is a break in the Earth's crust, across which older rocks are pushed above younger rocks. Geologists map and record information on the composition and structure of rock outcrops (rock which can be seen on the land surface) and boreholes (a deep narrow round hole drilled in the ground). Lines are drawn on a map to show the structure. To produce this dataset, the twenty one 1:100,000 paper maps covering Ireland were digitised and any inconsistencies between map sheets were fixed. We collect new data to update our map and also use data made available from other sources. This map is to the scale 1:100,000 (1cm on the map relates to a distance of 1km). It is a vector dataset. The Geological Lines data is shown as lines. Each line holds information on: description of the line, bedrock 100k map sheet number, line code and name (if it has one).

The map of the vulnerability of the groundwater of the Flemish Region can be defined as a map of the degree of risk of contamination of the groundwater in the upper water layer by substances that penetrate into the ground from the bottom, taking only static parameters into account. This map can later serve as a basis for a more detailed map, which can also include dynamic and hydrochemical factors. However, where the upper recoverable aquifer is naturally salinized (< 1500 ppm), this is indicated. An aquifer is considered to be the saturated zone of a formation which has a thickness and extension sufficient to extract water from it in an economically viable manner. A flow rate of at least 4 m³ per hour has been assumed for the card. In practice, this sometimes leads to misunderstandings: the map gives an idea of ​​the first economically interesting water layer, which in many cases does not correspond to the layer that is first approached during excavation work, for example. The second important point is that the maps are made for contaminants that penetrate into the soil from the bottom, taking into account only static factors. i.e. they mainly reflect the danger of the flow-through, especially in a vertical direction, of pollutants carried by seeping water, or of polluting liquids from the surface into the saturated zone through the soil and the unsaturated zone. Factors such as the nature and extent of the contamination, its spread by the flow of the contaminated water under the prevailing hydrogeological conditions, as well as the interaction between the pollutant and the formation are thus not taken into account. In practical terms, the extent and nature of the aquifers and overburdens, together with their hydraulic parameters, in particular the nature and value of the permeability, are taken as starting points. The map is based on three factors. the aquifer, the overburden and the unsaturated zone. These are divided into a number of classes, each with a specific index, after which the final vulnerability scale is drawn up on the basis of combinations of the various indices. A map of the three factors is also available separately: >>>The naturally salinized zones This layer shows the zones where the groundwater in the first aquifer is naturally salinized.

This map provides data and information about the major groundwater resources of the world. About 35% of the area of the continents (excluding the Antarctic) is underlain by relatively homogeneous aquifers, 18% is endowed with groundwater, some of which are extensive, in geologically complex regions. Nearly half of the continental areas contain generally minor occurrences of groundwater that are restricted to the near-surface unconsolidated rocks, where groundwater resources are usually sufficient for small to medium-sized population centres.For more information, visit: www.whymap.org

The Global Groundwater Information System (GGIS) is an interactive, web-based portal to groundwater-related information and knowledge. The GGIS consists of several modules structured around various themes. Each module has its own map-based viewer with underlying database to allow storing and visualizing geospatial data in a systematic way. Data sets include global data on transboundary aquifers, global groundwater data by aquifer, and country disaggregation, global groundwater stress (based on GRACE data), global groundwater quality data. There is also specific regional/national data focusing on the following aquifers: Dinaric Karst (Balkans), Ramotswa and Stampriet aquifers (Southern Africa), Esquipulas-Ocotepeque-Citala (Central Amerca), Pretashkent Aquifer (Central Asia). It also provides access to SADC Groundwater Information Portal, and groundwater on Small Island States