Global assessment of groundwater systems in SIDS

Leszek BIALY, UNESCO-IHP

What is TWAP?

2 years project funded by GEF providing global baseline assessment of transboundary water systems

Five components Transboundary Aquifers, and SIDS groundwaterTransboundary River basinsTransboundary Lake Basins and ReservoirsLarge Marine Ecosystems (LME)Open Ocean

SIDS

American SamoaAnguillaAntigua and BarbudaArubaBarbadosBelau/PalauBritish Virgin IslandsCape VerdeComorosCook IslandsC'wealth of the Northern MarianasDominicaFederated State of MicronesiaFiji

French PolynesiaGrenadaGuamJamaicaKiribatiMaldivesMarshall IslandsMauritiusMontserratNauruNetherlands AntillesNew CaledoniaNiuePuerto Rico

Saint Kitts and NevisSaint LuciaSaint Vincent &the GrenadinesSamoaSao Tome & PrincipeSeychellesSingaporeSolomon IslandsThe BahamasTimor-LesteTongaTrinidad & TobagoTuvaluUS Virgin IslandsVanuatu

TBA Assessment Methodology

1. Mean annual groundwater recharge depth2. Annual amount of renewable groundwater

resources per capita3. Natural background groundwater quality4. Human dependency on groundwater5. Groundwater depletion6. Groundwater pollution7. Population density8. Groundwater development stress9. Groundwater management legal frameworks10.Groundwater management institutional

frameworks

10 core indicators

Data collection - Questionnaires

Complementary research by SFU

• Predominant aquifer lithology• Predominant type of voids (pores, fissures, fissured karst, mixed)• Predominant hydraulic condition (confined, semi-confined, unconfined, mixed)• Depth: range(min-max)and average (location of top in meters below surface)• Thickness: range(min-max)and average (meters)• Transmissivity: range and average• Predominant sources of virgin recharge (precipitation, runoff influent streams, lakes, ect.)• Mean annual virgin recharge• Areal extent of recharge area• Predominant sources of natural discharge• Interlinked lakes, river systems and large marine ecosystems• Stored volume of fresh groundwater• Predominant natural groundwater quality

OUTPUT

• Categorization of each SIDS on the basis of its geomorphologic nature

• Categorization of each SIDS, including an inventory of collected data and information

• Conceptual(representative) hydrogeological cross section for each representative SIDS

• Values of groundwater indicators for each SIDS – including current state indicators and projected groundwater stress indicators organized as best as possible

• Summary profile for each SIDS• GIS layers and related MS Access database

summarizing the attributes of each SIDS

Data base and Information Management System

• Documents

• Images

Geo-referenced data:• Core Indicators• Main parameters• Additional

parameters

One aggregated value per TBA or

SIDS• Georeferenced

Images

• Projections

Water GAP

Objectives

It is expected that the assessment will to find answers for following questions:

• What human and ecosystem users of the water resources are currently affected or impaired (use of conflicts, depletion and degradation)

• How will water conditions and users develop during the next decades? Global change is likely to produce increased pressures during the next decades, such as higher water demands for food security/irrigation and domestic use, more intensive use of fertilizers and nitrogen, and increasing seawater intrusion in costal zones.

• Where will all this problems be occurring? Increasing droughts or floods are observed in some areas and have been projected though modelling – these projections will be incorporated and summarized in this assessment

Global Objectives

• The assessment will respond to the need of GEF International Waters and many Official Development Assistance providers, IFIs and governments to prioritize, and to focus scarce resources where they can be more cost-effective in addressing groundwater concerns;

• It will allow to monitor evolving trends, and the impacts of GEF IW programs, and those of other agencies and actors;

• It will bring to the global attention the vulnerability of water systems, and catalyze action.

• Level 1 = baseline assessment: description and indicator-based assessment of TBAs and SIDS

• Level 2 = in-depth assessment, limited number of TBA case studies, extended set of indicators

Level 1 – Level 2 Assessment

Thank you