National groundwater monitoring programmes

A global overview of quantitative groundwater monitoring networks

National groundwater monitoring programmes - A global overview of quantitative groundwater monitoring networks
National groundwater monitoring programmes - A global overview of quantitative groundwater monitoring networks

Groundwater is a vital natural resource, being increasingly under pressure of climate change and human activities. We need to monitor the invisible groundwater in order to use and protect it properly. Therefore, IGRAC has published 'National groundwater monitoring programmes: A global overview of quantitative groundwater monitoring networks'. This document provides an overview of quantitative groundwater monitoring networks at national scale. It is prepared to encourage sharing of monitoring experience, assist in improvement of monitoring and data processing and increase awareness of a general lack of groundwater monitoring. The full report, as well as four regional overviews and all 81 country profiles, is now available for download.


Groundwater is the most abundant freshwater resource on the planet: it provides almost half of all drinking water worldwide, about 40% of water for irrigated agriculture and about one third of water required for industry. It sustains ecosystem and maintains the baseflow of rivers. Groundwater is a critical storage element for climate-change adaptation, it prevents land subsidence and seawater intrusion. Yet,  aquifers  (being invisible) are often insufficiently understood and poorly managed. 

Groundwater meter, source: Wikipedia
Groundwater meter nearby Oranjewoud

State of aquifers (both quality and quantity of groundwater) is changing in time due to change of various environmental processes (e.g. change of precipitation pattern) and human impacts (i.e. change of land cover, groundwater abstraction). Ground­water assessment is not complete- and no predictions can be made without an analysis of historical measurements (change in time). In short: we can’t manage, what we don’t measure.

Groundwater is monitored around the world by measuring groundwater levels, groundwater abstraction rates, spring discharge and groundwater quality. Globally, there is no suffi­cient knowledge about the state and trends of groundwater resources, primarily due to:

  • insufficient monitoring
  • limited accessibility to monitoring data/outcomes 

Monitoring of groundwater is more challenging than monitoring of surface water (river and lakes): initial  investments (e.g. drilling a borehole) are larger, spatial representativeness of monitoring points (due to hydrogeological heterogeneity) is smaller and assistance of remote sensing (so helpful to surface water observations) is limited.  

Groundwater monitoring data is also less accessible than those of rivers and lakes, again partly due to less visible nature of aquifers. Surface water monitoring data are often available per catchment, even for those internationally shared, thanks to numerous international cooperation agreements. Groundwater monitoring data are usually available at the national level, less often per aquifer and in very few cases per internationally shared aquifer (as a part of an international agreement). Fortunately, there is a clear positive trend: more and more countries are making groundwater monitoring data available online or on request.    

The report contains a global overview of national quantitative groundwater monitoring networks. The purpose of the overview is to:

  • provide an integrated and structured information on groundwater monitoring programmes worldwide;
  • serve as the best entry point to information on state and trends of groundwater resources per country, globally; 
  • assist in improvement of national monitoring programmes, especially of data processing and usage by learning from other programmes;
  • encourage sharing of groundwater data and information by countries and their cooperation on transboundary groundwater resources; and
  • increase visibility of groundwater monitoring and increase attention to state of groundwater resources.

The overview includes only a quantitative aspect of groundwater monitoring. IGRAC is working on an overview of groundwater quality monitoring networks as well.

Groundwater monitoring from a global perspective 

Groundwater is a local resource but one with a global impact. Accordingly, groundwater monitoring is one of IGRAC's core activities. IGRAC works under auspices of World Meteorological Organisation (WMO) and looks after groundwater change and monitoring in most of WMO programmes and networks. Already in 2004, IGRAC produced the 'World-wide Inventory on Groundwater Monitoring' with the objective of revealing the state of groundwater monitoring worldwide and identifying needs for monitoring information and related guidelines. Subsequently, a guideline on groundwater monitoring for general references purposes was produced in 2008, focusing on the early stages of groundwater monitoring, often characterised by limited hydrogeological information, financial resources and/or institution capacity. In 2012, the Global Groundwater Monitoring Network (GGMN) programme was launched, with the objective of improving quality and accessibility of groundwater information and subsequently the knowledge on the state of groundwater resources. The GGMN Programme  consists of two components: 

  • The GGMN people network
  • The GGMN portal  

New GGMN Portal

In meantime, the programme involved groundwater specialists (people network) from more than 50 countries, whereas the GGMN Portal is used for storage, processing and dissemination of groundwater data worldwide. 

In the constant process of populating the GGMN with new monitoring stations and updated measurements, valuable information was collected on national groundwater monitoring programmes around the world. At some point it became obvious that this informations needs to be augmented, structured and made available as an overview to everyone interested in groundwater. 

The content of the overview 

The core of this overview are the “country profiles”: each national monitoring network is presented separately in an uniformly structured manner to allow easy browsing, comparison and further analyses. Information collected per country is organised in four sections dedicated to:

  • Institutional settings and purpose: Institution/s in charge of groundwater quantity monitoring and purpose of the network/s; 
  • Characteristics of the network: number of monitoring stations, density of the network, frequency of monitoring, manual or automatic measurement, telemetry; 
  • Processing: methods used to analyse data collected to create meaningful information (e.g. statistical methods to produce monthly groundwater level maps); and
  • Dissemination: how data and information are communicated to the public (e.g. website, reports, free downloading of data).

When any of these sections is not presented, it means the related information is not available and/or not publicly accessible online.

Analysis of results

I. Type of networks

Groundwater monitoring networks found can be divided into three categories:

  1. National - the network is a country-wide and generally, one organisation is responsible for its management;
  2. Regional/local - a country has several networks with different coverages and organizations managing them; and
  3. Project-based - the network was established as a result of a funded project (usually has a local coverage).

Countries with a centralised monitoring system, per region (in %)
Countries with a centralised monitoring system, per region (in %)

In several cases a regional/local network was established as a part of a funded project supported by an external party (intergovernmental organization, international development bank, etc.), as it is the case of Afghanistan and El Salvador. However, in some cases, the monitoring stops after a project ends, as it is the case of Mali’s groundwater monitoring network.

Groundwater monitoring is centralised in most of the countries. Otherwise, federal states, regions or counties often have their own programmes. If so, data collected is not necessarily reported to the central government for vari­ous reasons. For example, in Germany, each federal state is responsible for collection, processing and dissemination of data, while in Bolivia there is no national groundwater monitoring programme, only a several local networks are in place.

II. Purpose of the network

The most frequent purpose of a national network is the reference monitoring i.e. to assess temporal and spatial variations of groundwater with respect to other environmental processes and human activities. Also occasionally mentioned objectives of national networks include the contribution of scientific information and the monitoring compliance with regulation or standards. An example of a specific purpose at a national level is the Climate Response Network managed by the US Geological Survey: to monitor the effects of droughts and other climate variability

III. Frequency and method of monitoring

Monitoring frequency
Monitoring frequency

Frequency of monitoring varies greatly. Countries reported frequencies of: 15 min, hourly, daily, weekly, monthly, and several times per year, including combinations of them. More frequent monitoring (daily or more) are associated with the use of automatic networks. 

Automatic monitoring is used in at least 42 countries, from which in 28 in combination with manual monitoring. The monitoring method was not reported for in 30 countries. However, in some cases it can be assumed from information about frequency of observation: for instance, if monitoring is done less than every 3 months to yearly, it is likely that it is done manually (e.g. Algeria, Colombia, Malaysia, Tunisia, Uruguay) while if measurements are taken hourly, it is clear that an automatic network is in place (e.g. New Zealand).

Methods of data collection
Methods of data collection

In every case when (only) manual data collection was reported, the frequency of observation was given as well, ranging from less than daily to yearly. In several cases the frequency of observation was not provided, but it can be derived from the method used to collect data. When there is a water level logger installed in the well, it can be expected that data are taken several times a day, or daily (e.g. Australia, Myanmar, Paraguay, Somalia, Switzerland). 

In some cases where a wide range of frequencies is reported it can be assumed that both manual and automatic methods are used (e.g. Chile, France, Serbia).

Information on the monitoring method and frequency of observation was not found for 8 countries from which no feedback was received either. Although feedback was received from Eswatini, Ghana, Greece and Hungary, this piece of information was not included. Hopefully, it will be added in a second edition of this overview. 

IV. Processing 

At least 33 countries provide reports on outcomes of groundwater monitoring, and 41 produce groundwater maps (groundwater level interpolation maps, trend maps, etc. In many cases, maps are included in the reports, as it is the case with the Hydrographic Yearbook of Austria. 

Number of countries that proccess monitoring data per region
Number of countries that proccess monitoring data per region

Although several countries reported producing maps and/or reports, it is not clear how to access them. In total, 25 countries (31%) reported processing of groundwater level data (countries which reported “time series analysis” but without describing methods used and results obtained were not considered in this statistics).

The majority of the countries that process groundwater levels (16) is producing maps categorising groundwater level such as “above/below normal”, “above/below average”, “high/low groundwater level”, etc. These countries are: Australia, Austria, Belgium, Czech Republic, Finland, France, Germany, Italy, Ireland, Lithuania, Norway, Portugal, Sweden, Switzerland, United Kingdom and United States.

This type of maps is a simple and effective way to inform policy makers and the public about the status of groundwater resources. Long groundwater level records (time series) are usually needed to produce such map. The map can include other information as well (e.g. homogenious areas within an aquifer) in order to make further assumptions about spatial distibution of groundwater levels.

A map is not the only way of representing categories of ground­water levels: a good example of this is the Indicator of ground­water levels and spring discharges found in Switzerland, which is presented in graph form. Another example are the National Aquifer Composite Hydrographs produced in the Unit­ed States

V. Availability of information 

Map portal
Countries with a map portal with groundwater information, per region (in %)

It was found that 51% of the countries (41) have a web-based GIS data portal (a map portal) to disseminate groundwater information. From these countries, four did not provide a portal address (Estonia, Greece, Korea, Pakistan). Czech Republic and Finland disseminate maps not in a map portal but as static images. Nevertheless, they are included in this analysis due to their quality and updating frequency (monthly and daily, respectively). 

Concluding remarks

The first overview (or rather an inventory) was made more than 15 years ago and information collected then was quite limited. If is therefore difficult to say whether the groundwater monitoring networks in meantime expanded worldwide or perhaps reduced in their density. Nevertheless, the frequency of observations increased, primarily due to development of technically advanced and affordable loggers. Further, accessibility to information substantially increased also thanks to expansion of web-based portals and eagerness of responsible organisations to provide monitoring services and justify (usually public) investments in groundwater monitoring. 

This overview is a first edition, to be updated by countries as they progress in monitoring, processing and dissemination of information on state of groundwater resources. Larger involvement of regional organisations would be certainly beneficial for the further development of this overview. The analysis shown in this introduction is very preliminary: hopefully this overview will encourage a discussion on various aspects of monitoring and in particular on (spatial and temporal) processing and interpretation of monitoring data. IGRAC will be happy to facilitate a discussion and promote the outcomes.

Do you have any questions, comments or would you like to add a monitoring network to a second edition of this overview, please contact us!






Full report, regional overviews and country profiles: Now available for download!
Full report, regional overviews and country profiles: Now available for download!