Based on GEMStat raw data, the ICWRGC performs analyses, evaluations and data products. These results, maps, graphs, etc. can be freely retrieved and utilized by the public for non-commercial use. At present, previous products are being revised and adapted. Keep tuned for new products!

Data availability

GEMStat hosts a large variety of water quality data from countries worldwide. The regional subdivision follows the classification of UNEP-Regions (i.e. where UN Environment has Regional Offices).

In the following you find background information about the geographic and temporal coverage of GEMStat as well as available station types and parameters.

Source: UN Environment

Geographic coverage

At the moment, GEMStat contains more than 3.5 million entries from approximately 3000 stations in 75 participating countries. The greatest coverage of stations is currently in Latin America and the Caribbean. The highest number of sample values is currently available from Asia and the Pacific.

Station types

GEMStat has data from different types of stations: groundwater, lake, reservoir, river, and wetland stations. Currently, the largest number of the data by far comes from rivers stations, followed by data from lakes and groundwater.

Temporal coverage

The Global Environment Monitoring System for Water (GEMS/Water) was founded as a global network for water quality monitoring in 1978. Overall, data is available for the time period from 1965 to 2017, covering a total time frame of 52 years. The longest time series are currently available from Europe, North America and Asia and the Pacific.

Parameter coverage

Parameters in GEMStat are classified following the CUAHSI Hydrosphere Ontology. In total, about 250 parameters are available, which are classified into a hierarchical system of groups and subgroups.

Currently, most GEMStat data falls within the category chemical parameters, followed by physical parameters, while biological parameters represent only a minor proportion. The largest proportion is thereby contributed by inorganic compounds and nutrients.

Metrics on usage

As a global database, GEMStat data is regularly requested by a wide range of users from all over the world. In the following you find background information about data requests and our users.

Which countries and parameters are most requested?

The comparison of data requests (i.e. data provided to users by the GEMStat team) shows that between 2015 and 2017 most data requests referred to data from Latin America and the Caribbean, Asia and the Pacific and Africa. Among the five most-requested countries are currently Brazil, Japan, India, China, Morocco, and Argentina.

With respect to the type of parameters requested, between 2014 and 2017 mostly chemical and physical parameters were provided. Among the most requested parameters were Oxygen Demand, pH, Oxygen, Temperature, and Suspended Solids.

What is the geographical and professional background of our users?

GEMStat data is requested by a wide range of countries and sectors. Currently most data requests come from Europe, Asia and the Pacific, and North America. Most inquiries originate from academia and are made by students (including PhD students) and researchers. At regular intervals, however, we also receive requests from industry and different organisations.

Data explorer

Use our data explorer for locating stations and getting time series plots, annual boxplots, mean monthly boxplots and scatter plots with different parameters. And this is available for one station, or aggregated for a particular country or catchment.