Global Network of Isotopes in Rivers (GNIR)

Welcome to the web site of the Global Network of Isotopes in Rivers (GNIR), a global environmental observation programme dedicated to the compilation of isotopic assays of water, nutrients, particulate and dissolved constituents in our global river systems. GNIR serves as an essential world-wide repository for riverine isotope data, and facilitates public dissemination of contributed riverine isotopic data through a cost-free user-friendly web portal. GNIR is a complimentary programme to the IAEA's well-established Global Network of Isotopes in Precipitation (GNIP).

A Short History of GNIR

GNIR functions in a similar way to GNIP, relying on voluntary international partnerships between the IAEA and organisations, institutions, as well as researchers for sample collections, isotopic analyses, and contribution of published or unpublished data for global rivers and streams.

An IAEA Coordinated Research Project (CRP) entitled "Design criteria for a network to monitor isotope compositions of runoff in large rivers" from 2002-2006 served as the pilot project for a global river isotope observation network. Isotope data (18O, 2H, tritium) were collected from 20 large rivers from headwater to outlet, providing the scientific basis for longitudinal isotopic observation of various river systems. The findings of the pilot study are summarised in an IAEA TECDOC. A related CRP entitled "Isotopic age and composition of streamflow as indicators of groundwater sustainability" was conducted between 2004-2009, and added considerable riverine isotopic data. Results can be found in an IAEA Working Material. Further progress and data collections derived from an expert meeting in 2007, "Application of isotope techniques for assessing nutrient dynamics in river basins", which focused on the use of isotope techniques to evaluate the fate of nutrients in river systems. Proceedings and studies were summarised and published in 2013 in an IAEA TECDOC. The isotopic data generated in CRPs are housed in the GNIR database for public access.

Presently, the GNIR database contains around 21,000 stable water isotope records from 750 sites in 35 countries. In addition, 12,200 tritium records were collected from 170 stations in 28 countries.

A new CRP "Application and development of isotope techniques to evaluate human impacts on water balance and nutrient dynamics of large river basins" is implemented by the IAEA 2014-2017 in order to enhance and improve the GNIR. Strenuous efforts are being made to collaborate with as many international research groups as possible to strengthen GNIR through this CRP.

The Objectives of GNIR:

Long-term, synoptic observation of the isotopic components of river water, particulate and dissolved constituents facilitates a better understanding of the resilience of our major global river systems to environmental and human perturbations. The main objectives of GNIR are to:

• Encourage systematic collections of riverine isotope data from the world's rivers. This includes primarily the water stable isotopes (18O, 2H).

• Encourage the inclusion of other important assays that can also inform water management decision. These may include radiogenic tracers like tritium, isotopes of dissolved solutes and nutrients, particulate organic matter, as well as isotopes of suspended matter.

• Facilitate dissemination and publication of contributed riverine isotopic data.

The Main Application of GNIR

GNIR provides important scientific data for water research and management studies, including:

(i) Assessing sources of river water, connectivity of inter-related hydrological processes, basin scale evaporation, and water cycle modelling.

(ii) Evaluating environmental impacts on rivers, such as changes in recharge sources, basin scale water balance, or the impacts of impoundments and irrigation.

(iii) Providing a more complete understanding of water quality issues, in-stream biogeochemistry, and nutrient cycling of global rivers.

(iv) Assessing human impacts on water quality, like intense agriculture and the discharge of municipal or industrial water and irrigation returns.

(v) Quantifying the interaction of river biogeochemistry and hydrological processes.

(vi) Quantifying global riverine fluxes from river basins to our oceans.

Become Involved in GNIR

There are several ways to get involved and contribute to GNIR

1. The IAEA welcomes your published or unpublished isotope data, and can integrate it into the GNIR data repository to make your results available to the isotope community. Your work will be appropriately attributed.

2. In addition to that, the IAEA welcomes proposals for new GNIR network stations. Stations are ideally located at a flow-gauged sites, or wherever you perform regular river water sampling. A time commitment of 2-3 years of monthly (or hydrograph representative) sample collections are appreciated. Longer-term stations and networks are especially valuable. We encourage sufficient spatial network coverage and are happy to receive and to provide technical advice for new station proposals.

3. For GNIR participants, who cannot conduct stable isotope analyses of water (18O, 2H), the IAEA and partner laboratories may be able to provide analytical support. Additional support for other isotopic measurements may be also available through the network.

Contact Us

If you wish to receive more information, to provide general feedback, to propose a new GNIR station(s), or to contribute published or unpublished isotope data from rivers, please contact us through our GNIR contact point at:

Responsible/Contact: Isotope Hydrology Section | Last update: 12 November 2014