The oases of the pre-Saharan basin of Wadi Ferkla in southeastern Morocco receives low and erratic rainfall (annual average of 141 mm and inter-annual standard deviation of 70 mm). From the 1980s, surface water and groundwater are increasingly used due to the expansion of irrigation, mainly along two wadis, namely Wadis Ferkla and Satt originating in the High-Atlas and the Anti-Atlas Mountains, respectively. Their flows reach the Ferkla's irrigated perimeters only when the volume of the flood events exceed upstream evaporation, withdrawals and riverbed's infiltration. Nowadays, these irrigated perimeters exert significant pressure on groundwater resources, through numerous drillings equipped with pumping systems, most of them being powered by solar energy. This increasing water demand situation incentivizes individual farmers to design and implement innovative techniques to increase water access for their farms. For instance, the spreading of floodwaters – an ancestral and collective irrigation practice in traditional oases – is currently being modernized by individual farmers. The new technique consists in partially diverting flood flows into earthen basins. The stored water either infiltrates to recharge local aquifers, or is pumped for flood irrigation of date palms. An experimental protocol was set up to characterize groundwater recharge below one of these on-farm basins equipped with a recharge well. Barometric probes were installed in the basin, in the recharge well and in neighboring boreholes to automatically monitor water levels. A topographic survey of the monitoring points and of the basin aimed at deriving piezometric levels from water levels measurements and estimating the height-surface-volume curves of the basin. After 7 months of continuous monitoring, 3 flood events were recorded. The establishment of the basin water balance at a fine time-resolution allowed estimating its different components including the infiltration rate influencing groundwater recharge. An analytical modeling of this process was developed to assess its effect on groundwater level variations. This approach aims to contribute to a broader reflection on securing water management in this fragile oasis ecosystem.

The Gharb plain in Morocco suffers from water excess in winter and from water deficit during the spring and summer. This explains the low profitability of the investments in irrigation agreed by the Moroccan state and low yields of winter crops. Furrow irrigation systems may be a way to increase water productivity by improving the surface drainage in winter, and by irrigating the crops efficiently in spring and summer. The aim of this study was to assess the hydraulic performance of furrow systems and its agronomic impacts based on an experimental and a modelling approach. Yields were simulated for a series of 11 climatic years (1995–2006). Results clearly showed the advantage of the furrow system whatever the sowing dates. These results confirmed that to improve the water productivity of winter crops in the context of the Gharb scheme, attention has to be paid to surface drainage. Copyright © 2009 John Wiley & Sons, Ltd.

Water excess during winter limits crop development on heavy clay soil conditions of the Gharb valley (Morocco). The furrow system to eliminate these negative effects is the adopted solution. This article focuses on the development of a water transfer model through a furrow system during unsteady rainfall event to evaluate the runoff volume resulting from a reference rainy event. This model contains a production function associated to a transfer function. The production function is based on the Green-Ampt infiltration equation. The latter has been adapted to account for unsteady rain conditions and rainfall intermittence. The transfer function is based on the kinematic wave model, the explicit solution of which is coupled with the water excess generated by the production function. Simulated runoff in the furrows is collected by a drainage ditch evacuating the flow outside a plot of 1.3 ha. The similarity between parameters of a furrow irrigation model and those of the production function is advantageously used for model calibration.The proposed modelling approach shows capabilities to predict water amount and peak discharges evacuated from a plot of around I ha by a furrow system under unsteady rainfall events. As an application, it is used to evaluate the ability of the surface drainage system to evacuate the excessive volumes of water under typical rainfalls. (C) 2009 Elsevier B.V. All rights reserved.

The Gharb plain in Morocco faces both problems of excesswinter rainfall and salinity hazards due to a shallow,permanent and saline groundwater. A large area of 80.000 hahas been equipped with subsurface drains out of a totalplanned area of 200.000 ha. This system has been designedwithout any local references and has encountered severalmaintenance problems mainly caused by high drain depths.