IAEA Programme on Water Resources

2.3.1 (G.1) Sustainable Water Use and Services

Project 2.3.1.1 (G.1.01): Exchange of information, training and cooperation with international organizations in isotope hydrology

Rationale: A multitude of efforts at various levels are required to integrate isotope techniques and benefit from their use in water resource management. These include incorporation of isotope hydrology in appropriate educational programmes and hydrological practices, as well as development of trained human resources from among practising professionals in Member States. Expertise in isotope hydrology in many countries resides in agencies that are not directly responsible for water resources management and insufficient communication between hydro geologists and isotope scientists is a significant impediment to the integration of isotope techniques in the water sector. Through General Conference resolutions, Member States have requested the Agency to continue to help integrate isotope hydrology in their water sectors through national programmes and through collaboration with other international organizations, including UNESCO. Activities implemented in the last progamme cycle have resulted in many initiatives that would produce desired results over the coming years. A joint IAEA/UNESCO International Isotopes in Hydrology Program (JIIHP) was launched in 2002 and is generating substantial interest among Member States to bring together their isotope and hydrology professionals. Similarly, progress is being made in having isotopes included in academic curricula and in building human capacity. Collaboration with international programmes in water cycle research has been established and joint projects are being formulated with UNDP/Global Environment Facility (GEF) and the World Bank. These efforts need to be continued and in some cases strengthened to meet the objectives.

Project 2.3.1.2 (G.1.04): Support to Member States for the management of national and transboundary groundwater resources

Rationale: Management of national and transboundary aquifers is an increasingly important aspect of sustainable water resource management strategies in Member States and an important resource for helping to meet the Millennium Development Goals (MDGs). Isotope techniques are critical for mapping renewable and non-renewable groundwater resources and for facilitating the management of transboundary aquifers, as well as for characterizing the interaction between national and transboundary rivers and aquifers. The World Bank (WB), together with the Global Environment Facility (GEF) is launching a project to increase the awareness of groundwater in the policy and political debates in developing countries. The Agency’s work in facilitating the use of isotopes, and the role of isotopes in building a sound scientific understanding of aquifer hydrogeology are well known and have led to it being an important partner in the WB/GEF project. At the same time, there is a continued need to integrate isotopes into a broader set of member state capability for managing groundwater resources. This requires substantial assistance to Member States for the overall scientific and policy development approaches involving isotope data and methods. Potential impacts of climate change on water availability and use are another concern where isotopes, if used appropriately, can add significant value to strategies for mitigation and adaptation. Member States require assistance in increasing the awareness of the use of isotopes and in integrating their scientific capacity in isotope hydrology within their water sector. Projects with a wide scope, larger than a strict isotope hydrology focus, formulated and funding with external funding to supplement the Agency’s and Member States’ resources are an appropriate vehicle for assisting Member States’ use and benefit from the advantages of isotope hydrology.

2.3.2 (G.2.) Isotope Methods for the Improved Understanding of the Water Cycle

Project 2.3.2.1 (G.2.04): Isotope Methods for the Assessment of Groundwater Sustainability

Rationale: Groundwater is the primary source of drinking water for half of the world’s population and of the irrigation water used for food production. In many parts of the world, groundwater levels are rapidly declining and over wide areas, groundwater withdrawal exceeds natural recharge, particularly in arid and semi-arid areas where fossil or non-renewable waters are being mined. In more humid climates non-renewable waters may be replaced by modern recharge of poorer quality. The concept of aquifer sustainability rests firmly on the development of a sound scientific understanding of the basic hydro geological conditions, but at the same time needs to be integrated and interfaced with a broader and integrated framework for evaluating water resources and social needs. More efficient irrigation practices depend upon the knowledge of the actual use of water by vegetation compared to that lost by evaporation and by infiltration below the root zone. Evaluation of the sustainability of groundwater requires improved understanding of the residence times of water, including origin and age distribution of river baseflow as a major sink in the continental hydrological cycle. Isotope studies in particular have been crucial in defining the occurrence of and in estimating the extent of modern recharge, including that resulting from irrigation. Similarly, they are useful for designing and monitoring artificial recharge and aquifer storage schemes. Delineation of fossil water aquifers is dependent entirely on the availability and synthesis of isotope data.

Project 2.3.2.2 (G.2.05): Development of isotope methodologies for water quality assessment and Management

Rationale: Degradation of water quality from agricultural and other anthropogenic activities is partly responsible for the looming scarcity of freshwater. Irrigated agriculture contributes a majority of the nutrient load (nitrogen, phosphorous, etc.) to rivers, lakes and shallow aquifers. Urban and industrial activities similarly contribute a variety of contaminants to surface and groundwater. Wetlands, on the other hand, help to improve water quality by filtering out and transforming nutrients and other pollutants. Crucial knowledge gaps exist in understanding the processes related to nutrient cycling, water balance estimations, and cause-and-effect relationships. Tracing and partitioning of pollution sources is a key challenge in the development of drinking water supply strategies, as well as wastewater treatment and remediation practices. Water resource managers need this detailed information to develop appropriate decision support tools. Recent technological advances have enabled the use of N-15, C-13, S-34 and oxygen isotopes in nitrate and sulphate as indicators of point and non-point anthropogenic loadings to natural waters. Most recent analytical techniques include the measurement of isotopes in dissolved species, such as dissolved organic and inorganic carbon and nitrogen.

Project 2.3.2.3 (G.2.06): Isotope Methods for the Study of Water and Carbon Cycle Dynamics in the Atmosphere and Biosphere

Rationale: An improved scientific understanding of the water cycle to better manage water resources under the current and future climatic conditions is an internationally recognized goal, as stated in the Johannesburg Plan of Implementation that resulted from the World Summit on Sustainable Development. Vegetation plays a critical role in modulating atmospheric water cycle and climate processes over the continents, and has a major influence on seasonal and inter-annual climate variability. Ecosystem exchanges are critical for tracing direct climate change impacts of anthropogenic greenhouse gas emissions on the water cycle. The existing IAEA/WMO Global Network for Isotopes in Precipitation is a valuable resource for a quantitative understanding of precipitation inputs to the hydrological system. The reverse process of feedback to the atmosphere is difficult to measure and isotopes offer a unique means for this purpose. Wider application of quantitative water balance of lakes, reservoirs, watersheds, and irrigation efficiency using isotope techniques require better characterization of atmospheric moisture isotope signatures and variability, and improved understanding of boundary layer mechanisms which control kinetic fractionation during evaporation. Scientific investigations have established the high potential of isotopes for evaluating water and carbon exchange in the boundary layer, although the potential has been limited by a lack of interaction global information exchange and coordination between Member States.

2.3.3 (G.3.) Analytical Services for Isotope Hydrology

Recurrent Project 2.3.3.1 (G.3.01): Development of Member State capacity for isotope analysis of hydrological samples

Rationale: The Agency has supported Member States in their efforts to increase their ability to obtain isotope analysis through upgrading or establishing their isotope laboratories. This requires assistance in terms of equipment as well as supplementary support, training and advice for proper operation of the established laboratories. Support is provided to established laboratories in performing high quality data by bilateral activities to improve measurement schemes. A network of laboratories provides measurements for TC projects under rigid quality assurance requirements as continuously monitored by the Agency. Further assurance of the quality of measurements being made in Member State laboratories is provided through international laboratory comparison exercises, proficiency tests and advice on quality control schemes to be applied. The Agency as an impartial body is well suited and acknowledged to organize such performance tests. The Agency also is the only source of reference materials necessary for calibrating stable isotope mass spectrometers. New approaches to improve the measurement of isotope data are supported by fostering research on and testing/improving methodologies.

Project 2.3.3.2 (G.3.02): Development of helium isotope applications for water resources management

Rationale: The availability of information on groundwater ages and travel times in shallow aquifers world wide can significantly improve groundwater management and protection practices and facilitate the integration of isotopes in hydrology. Until recently, high tritium concentrations in precipitation resulting from atmospheric nuclear testing of the 1950s and 1960s provided an easy means for determining the presence of post 1950s recharge and for estimating travel times to water table. However, atmospheric tritium concentrations have been decreasing over the last 30 years and are currently almost at their low, natural levels, making tritium less useful as a hydrological tracer. To overcome this limitation, a new method has been developed over the last about 15 years using helium-3 which is a daughter product of tritium decay. Tritium-helium dating has been shown to be an effective and powerful tool for obtaining groundwater ages on the order of one to fifty years. In spite of their potential, the hydrological and marine applications of helium isotopes have been relatively limited to date, primarily because of the limited availability of measurement facilities and cost. There are less than ten laboratories world-wide where helium isotopes are measured for hydrological or marine applications. The capacity of these laboratories is limited and, when available, the costs of measurement are extremely high. The availability of an operational helium isotope facility at the Agency would result in advancing the use of isotopes for water resource management and would allow introduction of the helium isotope tool in both the regular budget and TC projects. Outcomes of other projects in Programme 2.3 will be enhanced by the incorporation of helium isotope measurements. In addition, an Agency laboratory can be used for training Member State scientists in sampling and analysis for helium isotope measurements. Without this analytical service and training, which is very difficult to obtain at existing non-Agency laboratories, the use of helium isotopes is unlikely to be successfully transferred over the long run.