EVOLUTION OF IRRIGATION AND IMPACT ON THE COMMUNITIES OF TAFILALET OASIS (ERRACHIDIA, SOUTH EASTERN MOROCCO) International Conference WASAMED BARI, ITALIE, FEV L.KABIRI*, P. MINOIA**, M. CAMUFFO**ET R. BORGHI**
LOCALISATION OF THE CASE STUDY
Domaine anti Atlasique et.. Domaine atlasique et mesetien Domaine rifain Study area Structural frame of Morocco and localisation of the case study
Detail of the regional geological features
Localisation of the water basins
SITUATION AND DELIMITATION OF THE BASINS Km ² (9 % of national space ) 0.81 millions inhabitants (2.7% of Maroc) Overlapping 3 economical regions 4 provinces 70 rural communes 9 municipalities 22 ONEP centres 1395 localities
CLIMATE Climate: arid becoming Saharian towards South caracterised by inter and intra-annual irregularity. The extreme temperatures vary between winter freezing within the basins upstreams and a maximal average in july of 41 °C. The yearly average temperature is 20 °C with variations between 16 ° ande 23°C. Average evaporation varies between 2678 mm upstream (Rheris) and 5342 mm to the South (Taouz, Ziz) with an average over the totality of the watersheds of 3460 mm. Average pluviometry in the basin : 200 mm in the High Atlas reaching 50 mm in the Southern zone (Anti-Atlas and Tafilalet)
Freshwater resources Water amounts are in average 581 millions Mm3 (3.4% of the national amounts). Great inter-annual variability caracterised by considerable differences between the law and the aluvional water periods. The natural perennial flow are weak sometimes non-existing.
Section along the oued Ziz Section along the Tarda oued Section along the oued Ferkla Groundwater (Ziz, Tarda et Ferkla)
Haut Guir(Jurassique and quaternaire) extracted : 11 Mm3 Haut Ziz-Rheris(Jurassique and quaternaire) extracted: 63.1 Mm3 Moyen et Bas Guir (Crétacé et Quaternaire) Extracted : 16.8 Mm3 Moyen Rheris (Infrac and quaternaire) extracted : 13.5 Mm3 Moyen Ziz (Crétacé and quaternaire) extracted : 48.4 Mm3 Bas Ziz (Quaternaire and Primaire) extracted: 23.4 Mm3 Bas Rheris (Quaternaire and Primaire) extracted : 21.5 Mm3 Maider (Quaternaire and Primaire) extracted : 22.6 Mm3 -Number of water tables: 16 -Exploitable resources: 313 Mm3/per year, 8 % of national resources -current exploited volumes estimated at 220 Mm3/year Resources and extractions
The whole urban pollution contaminates the water corses downstream the centres 22 % of measured points overpass the rules required for NH4 + State of freshwater quality
14Mm3 0 Mm3 14 Mm3 558Mm3 206 Mm3 352 Mm3 Water consumptions
AEP: * rendement : 60% * perte d’eau = 5.6 Mm3/an Retard d’équipement des périmètres dominés par les barrages : 2639 ha Efficience relativement faible du réseau et du système d’irrigattion (75 %) : manque à gagner :51 Mm3/an Efficience des adducteurs :70 % à 80 %, soit une perte de Mm3/an(moyenne) Soit une perte totale de 179 Mm3/an sur 558 Mm3/an régularisé pour l’irrigation (32 %) Main issues: weak efficiency
Traditional systems for water management in oasis Some examples
Tanast (water watch)
Oughrour
Khettarats Khettarat
Collective pumping stations at Ferkla ( )
Extension of irrigation areas in Ferkla oasis in the decade 1988/ /99
Regression of date palm numbers at Ferkla
Main issue: decreasing and overexploited water resources TINEJDAD water table DAYET MAIDER water table Conséquences Intrusion of saline waters in groundwater tables Degradation of sources Difficult relations between AEP-rural and irrigation services (PMH) Increase of pumping costs
Water amounts at the Hassan Addakhil dam : 199 Mm : 146 Mm3 (-24%) : 103 Mm3 (-87%) Meski
State of date Palms
State of olive trees
Civil society reaction: active associations Recently introduced solutions in Jorf geo-membrane basins from khettarat to collect waters for oasis agriculture (cooperation IFAD-ORMVAT-local NGO)
Jorf: Drip irrigation
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