Decadal survey and SWOT hydrologic science and applications questions SWOT Hydrology Ohio State University September15, 2008 Dennis P. Lettenmaier Department of Civil and Environmental Engineering University of Washington

SWOT science and applications questions Water Cycle: What is the spatial and temporal variability in the world's terrestrial surface water storage and discharge. How can we predict these variations more accurately? Floodplains & Wetlands: How much water is stored on a floodplain and subsequently exchanged with its main channel? How much carbon is potentially released from inundated areas? Society: What are the policy implications that freely available water storage data would have for water management? Can health issues related to waterborne diseases be predicted through better mappings?

Outline 1) Some thoughts on the Decadal Review, and selection criteria 2) UN Millennium development goals, and the World Water Assessment process 3) GEO and GEOSS 4) The state of global in situ hydrologic networks, and prospects for global hydrologic observations 5) Implications of SWOT for global water problems – transboundary rivers as an example

Decadal Review Evaluation of RFIs on the basis of both scientific and societal benefits (with equal weightings) Water-related missions (SMAP, SWOT, SCLP) all score well in both categories Societal benefits (not entirely interchangeable with “applications”) generally not developed as well as science

UN Millennium Development Goals (2000) Goal 1: Eradicate extreme poverty and hunger Goal 2: Achieve universal primary education Goal 3: Promote gender equality and empower women Goal 4: Reduce child mortality Goal 5: Improve maternal health Goal 6: Combat HIV/AIDS, malaria and other diseases Goal 7: Ensure environmental sustainability Goal 8: Develop a global partnership for development

World Water Assessment Program (WWAP) provides the link between water and the Millennium Development Goals Mission: “… develop the tools and skills needed to achieve a better understanding of those basic processes, management practices and policies that will help improve the supply and quality of global freshwater resources.” Goals: assess the state of the world's freshwater resources and ecosystems; identify critical issues and problems; develop indicators and measure progress towards achieving sustainable use of water resources; help countries develop their own assessment capacity; document lessons learned and publish a World Water Development Report (WWDR) at regular intervals.World Water Development Report

Group on Earth Observations (GEO) GEO derives from the 2002 World Summit on Sustainable Development and by the G8 (Group of Eight) leading industrialized countries. Voluntary partnership of governments and international organizations -- as of July 2008, GEO’s Members include 74 Governments and the European Commission, in addition to 51 intergovernmental, international, and regional organizations that are recognized as “Participating Organizations” GEOSS (Global Earth Observing System of Systems) has a 10-Year Implementation Plan for 2005 to Vision statement for GEOSS, includes nine “Societal Benefit Areas”: disasters, health, energy, climate, water, weather, ecosystems, agriculture and biodiversity. (Note similarity to Decadal Review panels)10-Year Implementation Plandisastershealthenergyclimatewater weatherecosystemsagriculturebiodiversity

GEOSS Implementation Plan (2005) Water-related issues addressed by GEOSS will include: precipitation; soil moisture; streamflow; lake and reservoir levels; snow cover; glaciers and ice; evaporation and transpiration; groundwater; and water quality and water use. GEOSS implementation will improve integrated water resource management by bringing together observations, prediction, and decision support systems and by creating better linkages to climate and other data.

2200 flow stations closed in many had 30+ years of record USA Mike Norris, USGS UK and SADC SADC UK Australia Bureau of Meteorology Data sharing Global hydrologic networks – in decline? Data sharing remains a critical issue Visual courtesy Vladimir Smakhtin, WRMI

Global river discharge errors Discharge fractional error σ Q /Q

Comments on the tractability of the hydrologic data problem It may well not be resolvable with in situ observations – too many countries, interests, economic and other motivations Lack of a global hydrologic prediction strategy (contrast with weather!) is a key determining factor The DR, and other, missions can represent a first step towards a global strategy, which cannot be accomplished with in situ obs alone Articulating the role of in situ obs (more specific (and accurate) local information; calibration of satellite – derived variables, etc)

The role of SWOT in trans-boundary water management Networks are especially sparse in developing countries Knowledge of reservoir storage in trans- boundary rivers is often restricted, and has critical implications for water management in downstream countries Free and open (and timely) exchange of SWOT data will be a critical need

Basins at Risk A basin is at risk if changes in the physical setting (e.g. large infrastructure project, prolonged drought) are outside of the bounds of current agreements. The following basins do not have agreements and are not forming them: Africa  Incomati, Kunene, Lake Chad, Limpopo, Okavango, Orange, Senegal, Zambezi Asia  Ganges-Brahmaputra, Han, Kura-Araks, Mekong, Ob, Salween, Tumen, Central America  Lempa South America  La Plata Basins at risk that are talking: Aral Sea, Jordan, Nile, Tigris-Euphrates

Basins at Risk Potential for conflict but no negotiation Potential for conflict but some negotiation No/low potential for conflict

Ganges-Brahmaputra-Meghna Major Issues Need to improve flood data communication across borders Problems of sharing dry season flow between India and Bangladesh Need to involve China in discussions before China builds large diversions and dams on the Tsangpo (Brahmaputra) General lack of knowledge about the GBM system % of basin-wide reservoir inflows % of basin-wide reservoir volume India100

Aral Sea % of basin-wide reservoir inflows % of basin-wide reservoir volume Turkmenistan138 Kyrgyzstan1439 Kazakhstan1613 Uzbekistan1711 Tajikistan4029 Major Issues No functioning basin management agreements Need to coordinate winter and summer water uses Monitoring of remote mountain lakes Large dams planned, so need for basin cooperation is urgent Total basin outflow: cms

Zambezi % of basin-wide reservoir inflows % of basin-wide reservoir volume Zimbabwe2867 Mozambique5023 Zambia2110 Major Issues Political instability (esp, in Zimbabwe) prevents action on transboundary water issues Flooding downstream in Mozambique due to poor data lead time Large inter-basin water transfers envisioned – need proper data and strong water agreements for that to not to be contentious But…Southern Africa Development Community (SADC) provides a good starting point

Summary Key role of societal benefits in DR selection criteria – area needs better development by SWOT (and other hydrology missions) SWOT potentially plays a key role in WWAP and GEO; need stronger links Global hydrologic observation problem is fundamentally intractable without satellite observations – need for a global hydrologic prediction strategy Better understanding potential role of SWOT in transboundary rivers is a starting point