Presentation given during the USGS/IAEA/IW:LEARN groundwater learning exchange in the US April 14-26, 2007.

1. CONSULTED MANAGEMENT
OF A SHARED RESOURCE
CASE OF NORTH WESTERN
SAHARA AQUIFER SYSTEM
USGS / IAEA GEF-IW:LEARN
Groundwater Study

2. GREAT SHARED CIRCUM SAHARA BASINS

3. BASINS CHARACTERISTICS
Basin Countries sharing the
basin
Area in
km2
Reserves in billion of
m3
Northern
Sahara
Nubian
sandstone
Libya, Egypt, Sudan,
Tchad
2.000.000 150.000 6.000
Septentrional
Sahara
Algeria, Tunisia, Libya 1.000.000 60.000 8 à 10
Southern
Sahara
LakeTchad
Tchad, Niger,
Cameroun, Nigeria
350.000 20
Iullemenden
Niger, Mali, Algeria 200.000 40.000 200
Taoudéni
Mali, Mauritania, Algeria 500.000 2.000 25
Senegalo-
Mauritanian
Mauritania, Senegal,
Guinea-Bissau, Gambia
30.000 500 20

4. CHALLENGE AND OPPORTUNITIES
•SIGNIFICANT RESERVES BUT
SLIGHTLY RENEWABLE
•VOLUMES LIMITS ECONOMICALLY
EXPLOITABLE FOR AGRICULTURE
•GROWTH NEEDS
•NON CONSULTED MANAGEMENT

5. SUSTAINABLE MANAGEMENT
BASIN AWARENESS
KNOWLEDGE CONTROL
COOPERATION AND TECHNICAL
EXCHANGE
PERMANENT CONSULTATION
NWSAS BASIN

6. 1ST PHASE OF NWSAS PROJECT / 1999 - 2002

7. •INFORMATION SYSTEM :
•Common data base
•Common GIS
•MATHEMATICAL MODEL
•Integration of the whole basin (for the first
time)
•Realization of the Simulations
•CONSULTATION MECHANISM
•Shared vision
•Sustainable management of the basin
NWSAS PROJECT COMPONENT

8. NWSAS LIMITS
CI
CT

9. AREA 1.000.000 km2
THEORETICAL RESERVES 60.000 Billion of m3
THEORETICAL RECHARGE 1 Milliard de m3
/an
TERMINAL COMPLEX
AREA : 600 000 km²
RECHARGE : 600 Mm3
/an
INTERCALARY CONTINENTAL
AREA : 1 000 000 km²
RECHARGE : 300 Mm3
/an
TWOAQUIFERSYSTEM
GENERAL DATA

10. ERGS
CHOTTS
SEBKHAS
REDUCTION OF AVAILABLE
AREAS
WATER QUALITY
• SALINISATION
• TEMPERATURE
SOILS
- DISPONIBILITY
- QUALITY
- HEAVY INVESTMENT
WELLS
DEPTH (50 – 2500 m)
PRODUCTIVITY (10 l/s – 200
l/s)
PUMPING COST
OBSTACLES TO SOIL OCCUPATION

11. NWSAS GEOLOGICAL MAP

12. WEST –EAST SECTION

13. • QUALITY PROTECTION
• PUMPING DEPTH
• SAVING OF THE EXISTENT
LOW EXPLOITABLE VOLUMES / SIGNIFICANT RESERVES
MOBILISATION CONDITIONS

14. NEEDS (m3/y)
1970 2000 2030
600 Millions 2.5 Billions 8 Billions
POPULATION
(Millions)
1.0 4.0 8
IRRIGATED
AREAS
50.000 ha 170.000 ha 400.000 ha
COUNTRIES ALGERIA + LIBYEA + TUNISIA
PROJECTED ABSTRACTION

15. 0
0,3
0,6
0,9
1,2
1,5
1,8
2,1
2,4
2,7
1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000
TOTAL ABSTRACTION IN NWSAS
Billions m3/y
LYBIA
TUNISIA
ALGERIA
Abstraction > Recharge
ABSTRACTION EVOLUTION

16. 0
100
200
300
400
500
600
700
800
900
1000
1100
1200
1300
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
Année
Nombredepointsd'eau
Alg
Tun
Lib
WATER POINTS EVOLUTION
0
200
400
600
800
1000
1200
1400
1600
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
Année
Nombredepointsd'eau
Alg
Lib
Tun
CI
CT

17. WATER POINTS EVOLUTION : 1960

18. 1970
WATER POINTS EVOLUTION : 1970

19. 1980
WATER POINTS EVOLUTION : 1980

20. 1990
WATER POINTS EVOLUTION : 1990

21. 2000
WATER POINTS EVOLUTION : 2000

22. ABSTRACTION CONSEQUENCES
- Salted water- Salted water
- Artésianisme disappearance- Artésianisme disappearance
- Excessive pumping height- Excessive pumping height
- Tunisian outlet depletion- Tunisian outlet depletion
- Foggaras depletion in Algeria- Foggaras depletion in Algeria
- Interferences : drawdown between countries- Interferences : drawdown between countries
- Saline intrusion in the golf of Syrte in Libya- Saline intrusion in the golf of Syrte in Libya

23. Chott
Aquifer
Chott
Flow inversion
Rising flow
Fresh water
salted water
wells
wells
Piezometric level
piezometric level
Aquifer
Risky situation
Natural state
RISKS AT THE CHOTTS LEVEL

24. TERMINAL COMPLEX
1950  2050
SCENARIO ZERO
CURRENT SITUATION
ABSTRACTION SIMULATIONS

25. RISKS IN CHOTTS AREAS : ARTESIANISM DISAPPEARANCE AND WATER SALINISATION

26. RISKS IN THE CHOTTS AREA : ARTESIANISM DISAPPEARANCE AND WATER SALINISATION

27. RISKS IN CHOTTS AREA : ARTESIANISM DISAPPEARANCE AND WATER SALINISATION

28. ARTESIANISM

29. INTERCALARY CONTINENTAL
1950  2050
SCENARIO ZERO
Current situation
ARTESIANISM EVOLUTION

30. 1950
mètres
ARTESIANISM

31. 1970
mètres
ARTESIANISM

32. 1990
mètres
ARTESIANISM

33. 2010
mètres
ARTESIANISM

34. 2030
mètres
ARTESIANISM

35. 2050
mètres
ARTESIANISM

36. INTER COUNTRIES INTERFERENCES

37. Previsional water demand (2050)Previsional water demand (2050)
COUNTRY Abstraction 2000
in billion m3
/year
Water demand frame
2050 in billion m3/year
ALGERIA 1,30 Scenario I : 2,00
Scenario II : 3,00
LIBYA 0,40 0,84
TUNISIA 0,51 Current situation
SCENARIOS OF THE THREE COUNTRIES

38. Six exploratory simulations :
 Algeria : Low Hypothesis
 Algeria : High Hypothesis
 Libya : deficit resorption 2030
 Libya : Ghadames field
 Libya : Abstractions Impacts of Djebel
Hassaouna
 Tunisia : maintaining abstraction 2000
EXPLORATORY SIMULATIONS

39. CONSEQUENCES TO CI : WITHDRAWALS 2050

40. Study and results validation by the countries
Recommendations : localisation of water
potentialities respecting the following constraints:
Maintaining of artesianism
Protection of foggaras
Protection of tunisian outlet
Protection of water quality
Acceptable pumping heigh
SCENARIOS REVISION AND STRATEGY

41. POTENTIAL ABSTRACTION ZONES IN CT
Algeria Tunisia Lybia

42. Algeria Tunisia Lybia
POTENTIAL ABSTRACTION ZONES IN CI

43. MICRO MODEL

44. ALGERIA TUNISIA LIBYA
ABSTRACTION IN
BILLION m3/y
Present 2000 1.5 0.5 0.5
Additional 2050 2.5 0.0 0.8
NWSAS Results 6.0 0.7 1.0
WATER POINTS 6500 1200 1100
RISKS
NATIONAL
SHARED
NEW SIMULATIONS RESULTS

45. NWSAS MAP OF RISKS
Jufrah
Western
Basin
Oued
Mya
Artesian
Basin
Syrte
Tunsian
outlet
Chott
s

46. Consultation Mechanism in its first phase
Development of a permanen tripartie mechanism for the NWSAS common management
and of which attributions are :
-monitoring indicator production,
- development of data base and models,
- promotion of studies, research and training
- réflexion sur l’évolution future du mécanisme
Steering
Committee
Coordination
Unit
NWSAS/OSS
Focal Point
(ANRH)
Focal Point
(DGRE)
Focal Point
(GWA)
Research
Institutions-
centers.
Institutions-
Research

47. -After this phase of investigation, what does the future hold for NWSAS?
The technical problems which the NWSAS countries have encountered are
prompting them to work together: : -partnership relations throughout the
NWSAS project, forged mutual confidence among the technical teams and
conviction that joint actions increase the effectiveness of solutions. .
ROME workshop, December 20th 2002
Photo
M.BESBES

48. TRANSPARENCY AND CAPITALISATION
OF THE INFORMATION
DYNAMIC OF EXCHANGE WITH
SOLIDARITY TOWARDS THE RISK
NWSAS PROJECT RESULTS
CONSULTATION MECHANISM

49. • MIXED COMMISSION
•DECISION MAKERS WILL FOR CONSULTATION
NWSAS PROJECT RESULTS
• LACK OF HARMONIZED TECHNICAL DATA
PRESENT SITUATION
PRECEDENT SITUATION
•AVAILABLE HARMONISED TECHNICAL DATA
•CONSULTATION TOOLS
AVAILABLE FOR DECISION MAKERS
•LACK OF GLOBAL VISION
•SHARED MANAGEMENT OF RIKS
•DATA EXCHANGE

50. THE PROJECT SECOND PHASE 2003 – 2005

51. Sub-regional model
Specific Studies
impacts socio-economic Analysis
Environmental impacts Analysis
Operationnality of Consultation Mechanism
SECOND PHASE COMPONENT

52. SUB-REGIONAL MODEL

53. - SETTING UP OF COMMON SURVEY AND
MONITORING NETWORK
-CHOTTS BASIN
-GHADAMES BASIN
- DATA BANK
SPECIFIC STUDIES

54. • SOCIO-ECONOMIC OF MODELLED REGIONS
• IRRIGATION METHODES AT THE SCALE OF
ALL NWSAS BASIN
• TYPE OF CROPS AND IMPACTS
• SUSTAINABLE DEVELOPMENT
SOCIO-ECONOMIC ANALYSIS

55. water quality
Soils Salinisation
Analyse of environmental risks
Risks linked to phreatic aquifer
Recharge Zones
Wet Lands
ENVIRONMENTAL
ANALYSIS

56. - AGRICULTURE
- ENVIRONMENT
- USERS
- LOCAL DECISION MAKERS
- ONG
- Etc …
FOR : CONTRIBUTION
SENSIBILISATION
ADHERENCE
EXTENSION TO THE OTHER PARNERS

57. Terms of reference:
- operating of the structure
- legal and institutional aspect
- data base administration
- modes of exchange and network monitoring
- periodical updating related to abstractions,
piezometry and quality
- updating of models simulations
- establishment of permanent structure
- Financing modalities, periodical productions …
CONSULTATION MECHANISM

58. END