Large rivers are a significant resource for drinking water, agricultural and industrial water supplies, fisheries, transportation and energy production. Human impact on large watersheds, such as intensive agriculture, discharge of urban wastewater, impoundments, irrigation and damming, have profound effects on river biogeochemistry, sediment transport and water balance. Understanding the hydrology of large river basins using geochemical and isotope parameters as means to constrain and model nutrient and sediment dynamics in large river basins was the focus of the coordinated research project (CRP) “Application and development of isotope techniques to evaluate human impacts on water balance and nutrient dynamics of large river basins”.
CRP Overall Objective
The CRP’s main objective was to improve the use of environmental isotopes to better understand the relationship between hydrological and biogeochemical processes in large river basins as well as to contribute to the IAEA’s Global Network of Isotopes in Rivers (GNIR).
Specific Research Objectives
- Review and assess the use of water isotopes to evaluate the sources of water, hydrological processes and water balance of large rivers;
- Review and assess the application of existing as well as new sampling and analytical methods of geochemical and isotope parameters in order to evaluate nutrient and sediment dynamics in large river basins;
- Improve the understanding and assessment of human and environmental impacts on water balance, nutrient cycling and sediment transport in large river basins;
- Improve the interpretation of the relationship between hydrological and biogeochemical processes in large river basins.
Impact on Member States
This CRP contributed to strengthening the GNIR programme through better understanding of the relationship between hydrological and biogeochemical processes in large river basins that contribute to SDG6 target 6 to “restore water related ecosystems, including mountains, forests, wetland, rivers, aquifers and lakes.”
Two international joint projects were initiated as part of the CRP:
1) National Natural Science Foundation of China (NSFC) - Agence Nationale de Recherche (ANR), the French National Research Agency, joint project titled “Sediments in the largest rivers of China: Messengers from geological processes and Environmental Changes (2016-2018)” was initiated by Prof Jérôme Gaillardet, France, and Dr Hu Ding, China, who were both involved in this CRP.
2) NSFC - International Centre for Integrated Mountain Development (ICIMOD) coordinated project “Study On The Water Quality and its Controlling Mechanism in Yarlung Tsangpo-Brahmaputra River Basin: A Multi Isotope Approach (2017-2019)” was initiated by Dr Ananta Gajurel, Nepal, and Dr Hu Ding, China.
Relevance
The CRP outcomes revealed the importance of isotope methods for river studies at both regional and large watershed scales. Common approaches and isotopic tools were identified and effectively applied, including stable isotopes to evaluate water sources and quantify hydrologic processes like evaporation and transpiration at large basin scales. Over 20 publications in the peer review literature were produced by CRP participants. Several publications were among the first to look at nutrient isotopes in rivers related to water pollution in Africa and South America. Based on the recommendations of this CRP, a new CRP focusing primarily on river nutrient N isotopes and water pollution is currently in progress.
Institutions from 17 countries (Argentina, Belgium, Canada, China, Congo, France, Germany, Hungary, India, Kenya, Malaysia, Nepal, Romania, the Russian Federation, Ukraine, USA and Vietnam) participated in this CRP.
For further information related to this CRP, please see the CRP webpage.
