No abstract

The khettaras constitute a hydraulic system for mobilising water by gravity from the water table to the surface to irrigate fields in oases. This system, which has been fairly widespread in North Africa, in particular in Algeria (foggara) and Morocco (khettaras), was introduced several centuries ago in the oases of southeastern Morocco and has continued to operate despite various natural and anthropic constraints. Based on these ingenious and millennial hydraulic systems, successive civilisations living in these environments have been able to establish laws and regulations for the management and mobilisation of natural resources, especially water. Indeed, to get the most out of these systems, users have had to abide by rules (Al Orf/Azref) designed to protect, promote, and care for the systems to enhance their sustainability. These hydraulic systems have declined in recent years, notably due to extensive groundwater pumping, climate variability (severe droughts), and the local population’s disinterest for this type of development. Therefore, we have unfortunately witnessed the loss of a thousand-year-old local ancestral know-how that had been developed by different succeeding civilisations in the area. Recent initiatives (2008–2011) have been undertaken by the Moroccan government for the restoration and development of some abandoned khettaras in the Tafilalet Oasis so that they could be utilised in the development of an oasis-based cultural tourism and integrated in a tourist circuit known as Majhoul. This initiative, still in its infancy, has constituted an alternative and a fairly encouraging development for this national and world heritage.

Karstic aquifers play an important role for drinking and irrigation supply in Morocco. However, in some areas, a deeper understanding is needed in order to improve their sustainable management under global changes. Our study, based on chemical and isotopic investigation of 67 groundwater samples from the karst aquifer in the Rif Mountains, provides crucial information about the principal factors and processes influencing groundwater recharge and residence time. The δ18O and δ2H isotopic values indicate that the recharge is derived from meteoric water at high, intermediate, and low elevations for Lakraa Mountain, North of Lao River, and Haouz and Dersa Mountain aquifers, respectively. All samples show an isotopic signature from Atlantic Ocean except for those from the Lakraa Mountain aquifer, which shows Mediterranean Sea influence. Groundwater age determined by radiocarbon dating using the IAEA model indicates that the ages range from modern to 1460 years. This short residence time is consistent with the detectable tritium values (>2.7 TU) measured in groundwater. These values are similar to those of precipitation at the nearest GNIP stations of Gibraltar and Fez-Saiss, situated around 100 km north and 250 km south of the study area, respectively. This evidence indicates that groundwater in the Rif Mountains contains modern recharge (<60 years), testifying to significant renewability and the vulnerability of the hydrological system to climate variability and human activities. The results also indicate the efficiency of isotopic tracing in mountainous springs and would be helpful to decision makers for water in this karstic zone.

No abstract

No abstract