TRANSBOUNDARY AQUIFERS

TRANSBOUNDARY GROUNDWATER MANAGEMENT IN THE RIVER BASIN ORGANISATIONS OF SADC WITH SPECIAL REFERENCE TO THE NAMIBIAN CASE

Greg Christelis, Piet Heyns, Jürgen Kirchner, Alexandros Makarigakis, Armin Margane

Department of Water Affairs and Forestry, Ministry of Agriculture, Water and Forestry, Republic of

INTRODUCTION

• Background • Transboundary Aquifers in SADC • Major Transboundary Aquifers in Namibia • The Way Ahead for future cooperation • Conclusions

Department of Water Affairs and Forestry, Ministry of Agriculture, Water and Forestry, Republic of Namibia

1 SADC LEGAL AND INSTITUTIONAL FRAMEWORK AND MANAGEMENT OF TRANSBOUNDARY WATERS • SADC Treaty established in 1992 • Article 22(1) of the SADC Treaty makes provision for the conclusion of protocols – Member States drafted a Protocol on shared watercourse systems – revised in line with the United Nations Convention on the Non-Navigational Uses of International Watercourses, adopted in 1997 by the General Assembly of the UN – Groundwater is not excluded (in Article 1 a watercourse is defined as “a system of surface and groundwaters consisting by virtue of their physical relationship as a unitary whole normally flowing into a common terminus such as a sea, lake or aquifer”) • Necessity to manage Aquifers of common interest under existing agreements in a Shared RBO

Department of Water Affairs and Forestry, Ministry of Agriculture, Water and Forestry, Republic of Namibia

20 identified TBAs in SADC

No. Aquifer name Countries 1 Kagera Aquifer Tanzania, Uganda 2 Kilimanjaro Aquifer Tanzania, Kenya 3 Coastal Sedimentary Basin I Tanzania, Kenya 4 Coastal Sedimentary Basin II DR of Congo, Angola 5 Congo Intra-cratonic Basin DR of Congo, Angola 6 Karoo Sandstone Aquifer Mozambique, Tanzania 7 Coastal Sedimentary Basin III Mozambique, Tanzania 8 Coastal Sedimentary Basin IV Angola, Namibia 9 Northern Kalahari/Karoo Basin Namibia, Botswana 10 Nata Karoo Sub-basin Angola, Namibia, Zambia, Botswana 11 Medium Zambezi Aquifer Zambia, Zimbabwe, Mozambique 12 Shire Valley Alluvial Aquifer Malawi, Mozambique 13 SE Kalahari/Karoo Basin Namibia, Botswana, South Africa 14 Ramotswa Dolomite Basin Botswana, South Africa 15 Tuli Karoo Sub-basin Botswana, South Africa, Zimbabwe 16 Limpopo Basin Zimbabwe,South Africa, Mozambique 17 Coastal Sedimentary Basin V Namibia, South Africa 18 Karoo Sedimentary Aquifer Lesotho, South Africa 19 Rhyolite-Breccia Aquifer Mozambique, Swaziland 20 Cuvelai and Etosha Basin Angola, Namibia

Department of Water Affairs and Forestry, Ministry of Agriculture, Water and Forestry, Republic of Namibia

2 ISARM SADC

An ISARM SADC initiative supported by UNESCO commenced in March 2007 in Pretoria RSA. The initiative intends to • Establish a network • Provide a Mechanism for Coordination • Provide a TBA Inventory including: – Name of TBA, country and location (include hydrogeological and location map) – Hydrogeological overview – Provide Technical sources of information (water resource plans from counties) – Water demand and social requirements – Key development and management aspects (monitoring wells, etc.) – A cross-section showing the conceptual hydrogeological conditions

Department of Water Affairs and Forestry, Ministry of Agriculture, Water and Forestry, Republic of Namibia

NAMIBIAN TBAs

At least six transboundary aquifers are shared with its neighbours

1.Caprivi Kalahari Basin Nata / Karoo Sub-basin (10) 2.Northern Kalahari / Karoo Basin (9) 3.Southeast Kalahari / Karoo Basin (13) 4.Cuvelai-Etosha Basin (20) 5.Orange River Coastal Aquifer (17) 6.Cunene River Coastal Aquifer (8)

Department of Water Affairs and Forestry, Ministry of Agriculture, Water and Forestry, Republic of Namibia

3 RECENT DWAF / BGR STUDIES

14° 16° 18° 20°22° 24° C C Z A M B I A u u ba it Z A N G O L A n o a Kunen g m e o b /K C e Calueque Dam a ua z va nd i n o Katima Mulilo Oshakati go Kongola o be 18° Ondangwa Rundu B h ti C an ko ny Oshivelo a Li ETOSHA PAN Tsintsabis at A Om Tsumeb Otavi Tsumkwe Grootfontein

20° Okorusu / Platveld C CAWMP Waterberg OKAVANGO DELTA Gam GO Okakarara C B O T S W A N A Otjinene Omatako Dam

Karibib Okahandja

OMDEL Dam 22° Henties Bay Swakoppoort Dam Swakopmund Arandis Areas Related to New Project Ideas (1999) Walvis Bay CAWMP A Oshikoto Region: Oshivelo Aquifer B Eastern Caprivi Area 24° C Omaheke Region: Eastern parts of the Tsumkwe and Otjinene districts

GOC Grootfontein - Omatako Canal Canal, pipeline Pipeline, planned

CAWMP Boundary of Central Area Water Master Plan 26° Koichab Pan

Lüderitz

28°S

Ora 050 150 250 350 km nge R. S. A. 12°E

D:\ Gersdorf \ Plöthner 52.dsf

Location of project areas in Nibi Department of Water Affairs and Forestry, Ministry of Agriculture, Water and Forestry, Republic of Namibia

Schematic Profile of Upper and (shared?) Lower Kalahari Aquifer

NW SE Kwando Linyanti

~ 24 MCM/a recharge from Kwando River by river bed infiltration upward leakage along major fault ? 14 m hydraulic head difference

Upper Aquifer Aquitard Lower Aquifer

Reduced water

basalt no basalt ? Karoo Sandstone ?

Department of Water Affairs and Forestry, Ministry of Agriculture, Water and Forestry, Republic of Namibia

4 Groundwater Flow in the (shared) Lower Kalahari Aquifer (LKA)

Department of Water Affairs and Forestry, Ministry of Agriculture, Water and Forestry, Republic of Namibia

AREA OF HIGH GROUNDWATER POTENTIAL

Total number of population: ~ 100,000

surface water supply

Lower Aquifer could be the basis for water supply in large parts of the western-central part of the E-Caprivi

Department of Water Affairs and Forestry, Ministry of Agriculture, Water and Forestry, Republic of Namibia

5 Northern Kalahari / Karoo Basin

Eiseb Area

Eiseb Area

Department of Water Affairs and Forestry, Ministry of Agriculture, Water and Forestry, Republic of Namibia

HIGH POTENTIAL - EISEB AREA

assumed freshwater aquifer

en ab Gr b se Ei

Department of Water Affairs and Forestry, Ministry of Agriculture, Water and Forestry, Republic of Namibia

6 SOUTHEAST KALAHARI / KAROO BASIN

Department of Water Affairs and Forestry, Ministry of Agriculture, Water and Forestry, Republic of Namibia

Part of the Orange-Senqu Basin

Department of Water Affairs and Forestry, Ministry of Agriculture, Water and Forestry, Republic of Namibia

7 GEOLOGICAL CROSS SECTION

NW SE (m ASL) Section-1 Sec t i o n - 2

769 23 18 1400 264 Hoachanas

6 39 6 Sec t i o n - 3 Section-4 64 ) St am p r i et 6 der 4 od 8 51 M 128 Goch as art Sw 1300 K -9( la) J 2 ivil Auob R. 27 rtz 32 Ma 58 5 2 Tweeriver 0 -5( 6 10 A- 11 J W 8 as D 32 ch 10 2 oa Auob R. 13 39 2 )G 45 95 (79 B 5-N 1200 K JO B 29 8 P- 52 AC 0 R 5 P-3 55 AC R-1 G r) P.E. A ve 31 1100 eri 29 e 756 A (Tw 12 J-8 R K

1000 N R P.E. R M K A R A 900 Do R K Kalahari Beds M B Kalkland Basalt A 800 Do Karoo Dolerite R Rietmond Member A Auob Member N M Mukorob Member P.E. N Nossob Member M 700 P.E. Pre-Ecca Group N P.E.

0 50 100 150 200 250 300 (Km)

< Fig.2-1 Geological Cross Section of Study Area >

Department of Water Affairs and Forestry, Ministry of Agriculture, Water and Forestry, Republic of Namibia

TOTAL DISSOVED SOLIDS IN THE MAJOR AQUIFERS KALAHARI AUOB NOSSOB

N N N %[ %[ %[ Windhoek Gobabis W E Windhoek Gobabis W E Windhoek Gobabis W E %[ %[ %[ S S S

Men t z Men t z Men t z % % %

Rehoboth J- 10# Rehoboth J- 10# Rehoboth J- 10# %[ %[ %[ J- 4 J- 4 J- 4 Leonardville 0# Leonardville 0# Leonardville 0# Corridor Corridor Corridor %[ % %[ % %[ % Uhl enhorst J-2 Aminius Uhl enhorst J-2 Aminius Uhl enhorst J-2 Aminius 0# % 0# % 0# % % % % Tsumis Tsumis Tsumis % % % Hoachanas Hoachanas Hoachanas Duineveld Duineveld Duineveld % % % % % % J-9 J-9 J-9 Schlip Kalkrand 0# J-3 Schlip Kalkrand 0# J-3 Schlip Kalkrand 0# J-3 % 0# % 0# % 0# %[ Aranos %[ Aranos %[ Aranos % % % Dobbin Dobbin Dobbin % % % J-5 J-5 J-5 0#% 0#% 0#% Stampriet Stampriet Stampriet Gene si s Gene si s Gene si s Mari en tal % Mari en tal % Mari en tal % Study Area %[ % Study Area %[ % Study Area %[ % 0# JICA Test Well Wandervogel 0# JICA Test Well Wandervogel 0# JICA Test Well Wandervogel J-6 J-6 J-6 %[ Mai n Town 0# %[ Mai n Town 0# %[ Mai n Town 0# % Town Go c has % Town Go c has % Town Go c has Main Road % Main Road % Main Road % Road Road Road TDS of Kalahari Gibeon TDS of Auob Gibeon TDS of Nossob Gibeon 300 - 500 % 300 - 500 % 300 - 500 % 500 - 1000 500 - 1000 500 - 1000 1000 - 2000 J-7 1000 - 2000 J-7 1000 - 2000 J-7 # # # 2000 - 3000 0 2000 - 3000 0 2000 - 3000 0 3000 - 5000 J-8 3000 - 5000 J-8 3000 - 5000 J-8 5000 - 10000 0# 5000 - 10000 0# 5000 - 10000 0# 10000 - 20000 10000 - 20000 10000 - 20000 20000 - 30000 20000 - 30000 20000 - 30000 30000 - 40000 30000 - 40000 30000 - 40000

% % % Tses Mat a- Ma t a Tses Mat a- Ma t a Tses Mat a- Ma t a % % % 02040(Km) Ko es 02040(Km) Ko es 02040(Km) Ko es Ko mnar ib % Ko mnar ib % Ko mnar ib % % % % Klei n Vaalgras % Klei n Vaalgras % Klei n Vaalgras %

Department of Water Affairs and Forestry, Ministry of Agriculture, Water and Forestry, Republic of Namibia

8 GROUNDWATER RECHARGE

[% N W E [% S 20

%U Local Meteoric Water Line (LMWL) Y J-1 0 δ2H = 7.10δ18O + 8.01 [% J-4 Y ille [% %U

%U %U Y J-2 %U -20

%U %U Y J-3 %U Y [% Y Evaporation line H ‰ H ‰

%U 2 δ %U J-5 Y %U -40

Study Area Estimated recharge = 2mm/year %U Rainfall Station [% (a) %U

Y JICA Test BH J [% Main Town Y Groundwater (Kalahari) Aminuis %U δ2H = 5.18δ18O -13.2 %U Town -60 Main Road %U Road Estimated recharge = 7mm/year Recharge-K 0-1 Y 1-2 YY 2-5 -80 5-10 -12 -8 -4 0 4 %U δ18O ‰ 0 20406080100Km%U %U %U %U Klein Vaalgras

Department of Water Affairs and Forestry, Ministry of Agriculture, Water and Forestry, Republic of Namibia

Cuvelai - Etosha Basin

Department of Water Affairs and Forestry, Ministry of Agriculture, Water and Forestry, Republic of Namibia

9 CUVELAI - ETOSHA BASIN

Department of Water Affairs and Forestry, Ministry of Agriculture, Water and Forestry, Republic of Namibia

GROUNDWATER INVESTIGATION TARGET AREAS

Department of Water Affairs and Forestry, Ministry of Agriculture, Water and Forestry, Republic of Namibia

10 THE WAY FOREWARD

• Relatively inexperienced in dealing with transboundary aquifer systems. • A pilot project needs to be undertaken ASAP. • Moving towards multi-facets of transboundary groundwater issues • Integrated groundwater into R/LBOs Management.

Department of Water Affairs and Forestry, Ministry of Agriculture, Water and Forestry, Republic of Namibia

THANK YOU

Department of Water Affairs and Forestry, Ministry of Agriculture, Water and Forestry, Republic of Namibia

11