Global Change and its Impact on Water Resources: the Role of UNESCO’s International Hydrological Programme - Weller and Liska page 3


IFI: International Flood Initiative

The International Flood Initiative (IFI) promotes a holistic approach to flood management under the global change threat, and is a collaborative effort of different agencies and science bodies such as World Meteorological Organization (WMO), United Nations Educational, Scientific and Cultural Organization (UNESCO), International Association of Hydrological Sciences (IAHS), United Nations University (UNU), International Strategy for Disaster Reduction (ISDR), The International Centre for Water Hazard (ICHARM). Recently, UNESCO has launched a new book series entitled “Flood Management in a Changing Climate” as a contribution to the International Flood Initiative (IFI). The books will focus on various aspects like extreme precipitation and climate change, hydrologic modelling of floods, flood inundation modelling and flood risk management. They will provide sound knowledge to the theory of flood disaster management and practice under the current climate change conditions. Best practices around the world and state of the art knowledge will be presented together with a set of computational tools for practical applications. In cooperation with IAHS IHP has compiled a list of major floods from around the world from 1860-2008 with a focus on their magnitude, meteorological causes and socio-economic impacts. A summary is published in the third World Water Development Report (WWDR 3).

G-WADI – A Global network on Water And Development Information in arid lands

The G-WADI Programme aims to strengthen the global capacity needed to manage the water resources of arid and semi-arid areas and to build an effective global community through a network of international and regional cooperation. It has identified key research topics related to climate change impacts, risk assessment and management of water resources of arid and semi-arid regions. Since its inception the Center for Hydrometeorology and Remote Sensing (CHRS), University of California, Irvine has been collaborating with IHP on the development of tools to provide access to global satellite estimates of precipitation at high spatial and temporal resolutions that are relevant to the monitoring of precipitation input, especially important in transboundary basins and aquifers in areas where ground observation networks are lacking. The website contains applications and tools for water resource managers that can improve flood forecasting and warning, as well as drought monitoring. CHRS recently launched a real-time Google Earth precipitation mapper. This application is gaining in popularity, particularly in the developing world. It will strengthen the capacity to manage water resources around the globe by allowing operational hydrologists and water resources managers’ access to satellite-based global precipitation estimates within one to two hours of the actual acquisition of the global infrared imagery (

Water Quality

The impact of climate change on water quality is likely to be considerable. The projected reductions in precipitation and runoff will lead to a decrease in both the quantity and quality of water supply. Droughts deteriorate water quality since less water is available for the dilution of wastewater. Higher water temperatures, increased precipitation intensity, and longer periods of low flows are projected to exacerbate many forms of water pollution, including sediments, nutrients, dissolved organic carbon, pathogens, pesticides, salt and thermal pollution (IPCC, 2008). This promotes algal blooms and increases bacterial and fungal content, and, in turn, impacts ecosystems, human health, and the reliability and operating costs of water systems. Rising temperatures are likely to lower water quality in lakes through increased thermal stability and altered mixing patterns, resulting in reduced oxygen concentrations and an increased release of phosphorus from the sediments. More intense rainfall is expected to lead to a deterioration of water quality since it enhances the transport of pathogens and other dissolved pollutants (such as pesticides) to surface water and groundwater. It also results in increased erosion, which in turn leads to the mobilization of adsorbed pollutants such as phosphorus and heavy metals. More frequent heavy rainfall will overload the capacity of sewer systems, and water and wastewater treatment plants more often. In areas with overall decreased runoff such as in semi-arid areas, water quality deterioration will be even worse.
UNESCO’s IHP is addressing water quality issues through a research progamme aimed at protecting water quality. The impact of climate change on water quality is one of the key areas where specific activities, projects and case studies on related topics are being developed. In addition, IHP works on policy recommendations for mitigation and adaptation measures. The activities focus on the following strategies:
  • Minimizing pollution load in rivers and surface water bodies during extreme weather events such as floods and droughts;
  • Developing sustainable approaches to sanitation and wastewater management in order to prevent the increased sewage contamination of surface and groundwater and transmission of water- and vector-borne diseases during flood events;
  • Developing strategies for augmenting and maintaining the resilience capacity of the natural aquatic environment to cope with pollution.