MENA Seminar, World Water Week, Stockholm 17-23 August 2008 Climate change and human activities impact on the groundwater of the Eastern Morocco: case of Triffa plain and shallow coastal Mediterranean aquifer at Saïdia Y. Zarhloule, A.Fekkoul, M. Boughriba, University Mohamed I, Faculty of Sciences, Oujda, Morocco J.Carneiro, A. Correia Geophysical Centre of Évora, Évora, Portugal A.Kabbabi CERPHOS, Water&Environment laboratory, Casablanca, Morocco م A. Rimi Scientific Institute, Rabat, Morocco B.El Houadi Hydraulic Basin Agency of Moulouya, Oujda, Morocco
NTRODUCTION PROBLEMATIC OF WATER IN MOROCCO e water resources potentialities are: Limited: nowadays 1000m3/per/year 2020 750m 3/per/year Untidily distributed Greatly solicited Under estimated Potentially threatened (nitrates, salinity,etc..) GROUNDWATER RESOURCES IN ESTEARN OF MOROCCO: MOULOUYA HYDROLOGICAL BASIN Shallow aquifer Deep aquifer Potential exploitable water:779mm3/year Present withdrawls: 270Mm /year Remaining possibilities of exploitation: 509Mm3/ye The chemical quality of water is bad, with higher salinity :Aquifers located in the North of the basin MENA Seminar, World Water Week, Stockholm 17-23 August 2008
BJECTIVES & METHODOLOGY Triffa plain aquifer s OBJECTIVES The influence of the anthropic activity on the groundwater resources (overexploitation, nitrates, pesticides, salinity) due to: 1. Intense agricultural activity 2. No controlled use of chemicals product (pesticides, fertilizer) METHODOLOGY 1. Inventory and selection of boreholes (250 wells selected) 2. Acquirement of data (measurement and sampling: Water table, T, Ph, TDS, majors element, pesticides, Heavy metals ) 3. Treatment of data (SIG) : Saidia coastal aquifer s OBJECTIVES Saidia coastal aquifer: The influence of climate changes in the goundwater level and in salinity due to: 1. Sea level rise 2. Changes in precipitation and temperature METHODOLOGY 1. Build a density-dependent numerical model that matches hydraulic head and concentration distributions in the aquifer; 2. Use changes in sea level, temperatures and precipitation fom IPCC scenarios. 3. Estimate changes in recharge. 4. Sea level rise and changes in recharge applied in the groundwater numerical model to
OCATION OF THE STUDY AREA & AQUIFERS STRUCTURES Two aquifers: confined and unconfined layers The unconfined one occupies ¾ of the plain. It s the most important and more exploited In the south of the flexure: the reservoir is formed by the superposition of limestone and silt-limestone In the North the reservoir is formed by limestone The thickness from 20m to 250m Flexure A B 2: Saidia Coastal plain S B Southern mudhole Substratum: Marls Southern dune cord Water table Northern mudhole Compact Clay Northern dune cord Aquifer: Sands Se Schematic Cross Section: Saidia Coastal plain : Triffa plain A Single unconfined layer; Sequence of alluvial and beach deposits Thickness from 10 m to 25 m, with maximums at the two sand dunes; Between those dunes, the sand layers are covered by a mud layer up to 4 m thick.
UMAN ACTIVIES IMPACT: CASE OF TRIFFA AQUIFER S Piezometrical Evolution from 1969 to 2007 1969 1975 1985 2007 roundwater is recharged by - vertically infiltration meteoric water - laterally penetrating fracture water along the BeniSnassen Mountain eneral groundwater flow directed SE NW
S and Nitrates maps High Concentration of TDS in the North and the central part of the aquifer High concentration of nitrates in Western and central part of the aquifer (65% of the samples exceed 50mg/l) There is no correlation between hydrodynamics of the aquifer and anomalies concentration The nitrate contamination occurs mainly in areas of shallow water depths or in areas where the soil is permeable It s due to the intensive irrigated agricuture: application excessive and repeated of mineral and organic
Pesticides data 0,03 0,02 0,01 0 aldrine endos, sulfat lindane dieldrine endrine heptachlore DDT DDD DDE endosu, I endosu, II endrine, aldh hepta,epoxy X-HCH B-HCH S-HCH 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 0,035 0,03 0,025 0,02 0,015 0,01 0,005 aldrine endos, sulfat lindane dieldrine heptachlore DDT 15 wells have been selected for sampling 16 elements have been analyzed 4 wells that show the existence of pesticides independently of the water depth 6 elements have been detected It s due to the type of agriculture (cultivation of herbaceous plants) No controlled use of the pesticides in those area Dismissal of waste waters 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
PACT OF CLIMAT CHANGE: CASE OF SAIDIA OASTAL AQUIFER S otivation for the study Oued Moulouya The area is undergoing fast changes in land-use Planning did not take into account sea-level rising and likely salinity increase Several golf courses planned. Irrigated areas will increase considerably Mediterranean Oulad Mansour hills Saïdia
IPPC(2007) scenarios It was decided to study the climate change impact in the Saïdia aquifer for three IPCC (IPCC 2007) emission scenarios: a) A1B scenario (the IPCC reference one); b) B1 scenario, which shows the smallest variations in temperature and sea level rise c) A1FI scenario, which is the worst case scenario Stresses imposed by Climate Change a) sea level rise the effect of which is incorporated by changing the constant head value in the Mediterranean boundary; b) advance of the seashore line the new location of which is found from a digital terrain model; c) variation of recharge input as linear decreases with time; Table 1. Stresses imposed by climate change IPPC Temperature Sea level Precipitation Recharge Observations scenario change (ºC) rise (m) decrease decrease B1 1.1 0.18 6% 9% B1 lower values A1B 2.8 0.35 12% 19% A1B mean values A1FI 6.4 0.59 38% 47% A1FI higher values
The simulations were conducted for a period of approximately 100 years Decrease in hydraulic head near the Moulouya (m) Increase in salinity at piezometer (mg/l CONCLUSION In the Triffa plain, the higher concentration of nitrate are present in several wells. It s gent to change the Strategy in order to reduce the pressure of irrigated agriculture on oundwater quality ( information and formation of the farmers about fertilizer and pesticides. The Saidia Coastal plain is strongly vulnerable. All parameters intervene in the increasing the lnerability. The climatic changes accentuate the deterioration of the quantity and the quality of the groundwate sources in the area.