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OPTIMA PROJECT

Tunisia case study

Fourth Management Board MeetingDecember 19-20, 2006 Milano

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CASE STUDY

Water useDomesticIndustryAgriculture

Incre

as

e

Melian basin

Area = 553Km²Population = 390 000 inhabitants 4 subcatchments Dense Drainage network

Aquifer

Lithology = Plio-quaternary Groundwater storage = 27.31 MCM/ year Exploitation = 28.1 MCM / year Nbre of Bore holes = 494State = overexploited

Nodes

2 reservoirs26 mountain lakes 2500 wells

Case study: Melian basin, TUNISIA

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RIVER BASIN DATABASE

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ECONOMICS

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DEMOGRAPHY

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INSTITUTIONS

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DEMAND

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RAINFALL- RUNOFF MODEL

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WATER RESSOURCE MANAGEMENT MODEL(WRM)

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Irrigation districts

Area(ha)

Water demand

(m3/ha/an)

Crops Water technolog

y

Ben Mahmoud 465 5 316 fruits Drip irrigation

Ksibi 316 3 618 fruits + vegetables

Drip irrigation

Vallée El Hma 207 2 000 fruits Drip irrigation

DATA COLLECTED

Irrigation Districts

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District

Domestic connecte

d

Domestic non

connected

Commer.use

Administ.use

Municipal use

Total

Industry Tourism

Other uses

total

BenArous

9909 14 468 590 256 1317

2817 9 123 14189

Water consumption volume per use (1000 m3 )- year 2000

DATA COLLECTED

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G.WRenewable ressource

(Mm3)Exploitable ressource

(Mm3)Water Earning / Deficit

Mornag 17.4 26.7 9.3-

Oligocène 7.3 11.9 4.6-

Miocene 4.3 1.0 +3.3

Geology stratum

TypeArea(km2)

Depth(m)

Precipitation(mm)

Infiltration coef

PorosityRenewable ressource

(m3)Storing coef

Geologic storing

(m3)

quaternary Sandy 183.6 150 464 20 120 17.04 8 1763

miocène Sandy 5 100 465 15 80 0.35 12 48

oligocène

Khlidia 58 120 400 13.3 70 3.09 10 406

Becbeka 96.5 200 467 8.8 100 3.97 10 965

Jbel Tella

4.5 120 360 12.8 70 0.21 10 31

DATA COLLECTED

Aquifer parameters

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Dams: name, coordinates , sector, year of construction, storage capacity, irrigated area,inflow water, name of catchment…

Collection of historic data related to the wells’ observation in the groundwater

Mountains Lakes: name, coordinates, realization year, name of catchment, area of the catchment, storage capacity, delegation…

Observation well: name, coordinates, year, dry residue , standing water level…

Collection of 2500 wells built in the case study: complete information is available concerning: wells depth, diameter, usage, exploitation, equipment, standing water level, dry residue…

Collection of hydrologic, hydrogeologic and economic data

DATA COLLECTED

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WATERWARE NODES CHART

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NEW TOPOLOGIC MODEL

M’chergua reservoir

Sea

Melian basin Melah basin

Rmel basin

Hma basin

Hma reservoir

Irrigation

TP

Domestic

Industry

Medjerda canal

GW

GW-SONEDEl Gola-SONED

Demand node

Start node

End node

TPReservoir node

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Implementation of WRM model

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DOMESTIC NODE

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IRRIGATION NODE

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BIR M’CHARGUA RESERVOIR

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EL HMA RESERVOIR

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GROUNDWATER

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MIOCENOUS GW

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OLIGOCENOUS GW

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PLIO-QUATERNARY GW

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WRM RESULTS

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WRM RESULTS (2)

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WRM ECONOMIC RESULTS

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Water supply is very dependent on the external importations of water

Water management in the basin is very complex because of the multitude of stakeholders involved in water issues

Drainage of used water (from sabkhat sijoumi) into the Melian basin is causing pollution into marine environment

The runoff in the Melian basin is very low

The groundwater is overexploited (150%), this situation leads tothe deterioration of the groundwater quality

PROBLEMS RELATED TO OUR CASE STUDY

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Reduce the water exploitation of the groundwater

Creation of a new treatment plant in the area to exploit the treated water for irrigation

Restoration and rehabilitation of Sabkhat Sijoumi by ONAS (The National Sanitation Board The National Sanitation Board )

Increase of the groundwater quantity by artificial recharge coming from surface water that is not exploited at present

WATER RESOURCES OPTIMIZATION

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THANK YOU FOR YOUR ATTENTION