Transboundary aquifers in Africa: Kilimanjaro Aquifer Malte Grossmann
Context Research and consultancy study: cooperation on transboundary groundwater resources Presented at last Seminar Study is availabe online at www.gdi.de or www.tu-berlin.de
Context case studies Characterize transboundary linkages and management issues Describe exisiting transboundary cooperation Implications for development cooperation?
Content Extent of Aquifer, water and land use patterns Hydrogeology Transboundary linkages and management issues Institutional setup (national and cross-boundary) Conclusion: potentials and issues for transboundary cooperation
Aquifer and River Basins Lake Amboseli Basin Chyulu Hills Kilimanjaro
Rainfall
Population centers and water supply High pop. density around Mt. Kilimanjaro / Mt. Meru Urban centres Moshi, Arusha: ground and springwater Mt Meru Kilimanjaro Rural water supply mainly gravity schemes Pipelines supply urban centres in Kenya
Agricultural land use and irrigation Livestock watering Furrow irrigation on upper slopes Plantations (Sugar, Coffee) Smallholder irrigation: gravity schemes from springs and shallow wells
Knowledgebase: hydrogeological studies
Conceptual model Diffuse and concentrated flow (faults) on slopes high yielding alluvial aquifers (500 m³/h), high yielding springs (10 m³/s) and swamps at base, confined by basement rocks Source: Rohr, 2003
Water Balance (Recharge / Discharge) 6000 5000 4000 m above sea level 3000 2000 1000 0 0 1000 2000 3000 4000 5000 mm Source: Rohr, 2003 Precipitation Evapotranspiration Runoff Infiltration Irrigation Discharge
Implications for groundwater management: very strong interrelation ground and surface water resources Kilimanjaro (and other Mountains) are source / recharge areas for water that flows downstream as surface and groundwater Groundwater stabilises river baseflow: Pangani River inflow to Nyumba ya Mungu Reservoir: ca. 20 m³/s spring discharge and 10-15 m³/s surface runoff Closed basins: eg. Pangani Basin: ca. 2-10 m³/s missing at Nyumba ya Mungu, Tsavo Basin: Nolturesh pipeline takes 190 l/s of 200 l/s To what extent can groundwater provide a supplementary water source?
Transboundary issues I: increasing water demand, decreasing catchment forest areas
Change in agricultural land use, irrigation and number groundwater boreholes 60 50 Total number 40 30 20 10 0 1930 1940 1950 1960 1970 1980 1990 Source: Campbell, 2006
Recharge areas and catchment forests Almost all of the recharge occurs in forest belt in Tanzania Reduction in extent of forest belt 1970 s Source: Agrawala, 2003 2000 s
Transboundary issues II: conflicting interests on water abstraction and impacts on groundwater flows
Lake Chala Hotspot Increased groundwater abstraction in Kenya: Plans for abstraction of water from groundwater fed Lake Chala for irrigation development, pipeline to Mombassa, increased groundwater abstraction in Kenya Reduced springwater and river flows in Tanzania?
Summary: conceptual model of co-operation problem Classical upstream downstream constellation, with recharge in one country and mainly subsurface flows to second country Forest Tanzania Kenya Lake Chala Ruvu River Springs Lumi River Lake Jipe Aquifer Impermeable Layer
Similar institutional setup in Tanzania and Kenya based on river basins Transitional institutional setup in Tanzania
Projects to improve water resource management capacity RBM / SIIP river basin and irrigation project (World Bank,1998 2003) IUCN Water and Nature Initiative (WANI) with studies e.g. situation analysis of Pangani basin. Pangani River Basin Management Project (Pangani Basin Office / Pamoja Trust / IUCN / GEF / GoT, 2002 2007) aims to improve water management and reduction of conflicts by research and dialogue.
Transboundary Cooperation No specific transboundary agreement or organisation for water management in Kilimanjaro Aquifer or Pangani / Athi River Basins exists. But: Greater Pangani Cross-border Dialogue. Aims to develop an integrated management plan and forum / dialogue for Lake Jipe, Lake Chala and Umba River. Facilitated by Coast Development Authority (Kenya) and Pangani Basin Water Office (Tanzania) with support of InWent/GTZ. East African Community Treaty provides for the establishment of cross-border natural resource management mechanisms under Protocol on Env. And Nat Res Management. Strategic environmental assessments for shared ecosystems. Record of transboundary cooperation on water issues: Lake Victoria Basin Commision, Nile Basin Initiative, establishment of transboundary water use association for Mara River Basin.
Summary: issues for transboundary cooperation establish cross border resource management mechanism as mandate by EAC Treaty. - continue development of Greater Pangani Basin Dialogue, possibly develop into transboundary WUAs / catchment committees? Continue to build (transboundary) knowledge base and capacity for conjunctive management - continue efforts to build and sustain knowledge base on groundwater resources and their interaction with surface waters - Monitoring of water use and groundwater resources - (geo)- hydrologic study of Lake Jipe / Lake Chala Basin? Explore / establish (cross-border) linkages between water use and catchment forestry (such as PES Schemes,..).
Summary: status of transboundary cooperation in cooperation path Kilimanjaro Aquifer
Summary: general recommendations drawn from all case studies Support existing regional river and lake basin organisations and initiatives to include groundwater management issues Improve the knowledge base and build capacities for groundwater management Assist in development of (flexible) management approaches where problems have been identified strengthen national groundwater governance
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