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International audience; If the success of agricultural intensification continues to rely on the depletion of aquifers and exploitation of (female) labour, transformations to groundwater sustainability will be impossible to achieve. Hence, the development of new groundwater imaginaries, based on alternative ways of organizing society-water relations is highly important. This paper argues that a comparative documentation of grass-roots initiatives to care for, share or recharge aquifers in places with acute resource pressures provides an important source of inspiration. Using a grounded anti-colonial and feminist approach, we combine an ethnographic documentation of groundwater practices with hydrogeological and engineering insights to enunciate, normatively assess and jointly learn from the knowledges, technologies and institutions that characterize such initiatives. Doing this usefully shifts the focus of planned efforts to regulate and govern groundwater away from government efforts to control individual pumping behaviours, to the identification of possibilities to anchor transformations to sustainability in collective action.

International audience; Modeling is one of the available tools to manage irrigation and to forecast crop yields. The purpose of this study was to adapt, calibrate, and validate the PILOTE model on globe artichokes (Cynara cardunculus var. scolymus L.) under drip irrigation in the Lower Cheliff Plain (Algeria) in two seasons (2011/2012 and 2012/2013) and to use it to predict soil water reserves and total biomass in other seasons (2006/2007, 2009/2010, and 2010/2011). The model uses daily climate data, soil characteristics, and plant data to simulate the leaf area index, total biomass, and soil water reserves during the crop growth cycle. Our results revealed a strong correlation between model outputs and observed data (leaf area index, soil water reserves, and plant biomass) in the calibration and validation years (coefficient of efficiency >0.90 and root mean square error

International audience; Semianalytical transient equations for shallow subsurface transverse drainage systems installed in sloping lands are developed. They provide a general relationship between drain flow rates, water table elevations, and recharge rates. This relationship demonstrates that, depending on the recharge intensity, several drain flow rates can be observed at a given water table elevation. The recharge contribution is shown to depend on a water table shape factor and to decrease when the water table is low or the slope is steep. For very steep slopes, the recharge intensity no longer influences the drain flow rate. These equations can be used to confirm previous results obtained in steady-state conditions and to determine precisely under which conditions slope needs to be considered in drainage design. They have been incorporated into the field drainage model SIDRA, which simulates hourly values of water table elevations and drain flow rates. The model predictions are compared with the predictions of a steady-state equation and a numerical model, which solves Boussinesq equation (SLOP model).

International audience; Club goods (also called toll goods) are collective goods with the possibility of excluding individuals who fail to contribute.The possibility of exclusion from the consumption of the public good has conflicting effects on welfare : on one hand it reduces the incentives to free ride, on the other hand it reduces the number of beneficiaries of the public good. Many clubs require a minimum number of members to be able to provide their activity (e.g., a farmer association, etc.). This step-level component can either be considered as a threshold for the provision of the club good itself, or as a threshold for maintaining some activity within an existing club. While previous experimental research focused on fundraising to provide non-existing public goods, we adopt in this work the second interpretation: the club good already exists and there is a step level for it's maintenance. Aggregate contributions above the threshold constitute an improvement of the club services that benefit only to the club members. The game admits two Nash equilibria: to contribute the provision point and to contribute nothing. The first equilibrium involves a coordination problem. Furthermore, the game involves a social dilemma, since the social optimum is attained if all agents contribute their endowment. Our baseline treatment is a step level public good game with linear payoff above the threshold without money back guarantee. We compare three levels of provision point. Non-contributors are excluded but are informed about the amount of good produced within the club. Our data shows that contributions are significantly higher when exclusion is feasible and when the provision point is low. For the low provision point with exclusion, subjects overcontribute significantly with respect to the threshold and welfare improves. For the high provision point, exclusion lowers contributions and welfare (compared to no-exclusion). Furthermore, we found that exclusion stabilizes contribution over time. The unravelling of contributions in the baseline treatments does not show up in treatments with exclusion.Club goods (also called toll goods) are collective goods with the possibility of excluding individuals who fail to contribute.The possibility of exclusion from the consumption of the public good has conflicting effects on welfare: on one hand it reduces the incentives to free ride, on the other hand it reduces the number of beneficiaries of the public good. Many clubs require a minimum number of members to be able to provide their activity (e.g., a farmer association, etc.). This step-level component can either be considered as a threshold for the provision of the club good itself, or as a threshold for maintaining some activity within an existing club. While previous experimental research focused on fundraising to provide non-existing public goods, we adopt in this work the second interpretation: the club good already exists and there is a step level for it's maintenance. Aggregate contributions above the threshold constitute an improvement of the club services that benefit only to the club members. The game admits two Nash equilibria: to contribute the provision point and to contribute nothing. The first equilibrium involves a coordination problem. Furthermore, the game involves a social dilemma, since the social optimum is attained if all agents contribute their endowment. Our baseline treatment is a step level public good game with linear payoff above the threshold without money back guarantee. We compare three levels of provision point. Non-contributors are excluded but are informed about the amount of good produced within the club. Our data shows that contributions are significantly higher when exclusion is feasible and when the provision point is low. For the low provision point with exclusion, subjects overcontribute significantly with respect to the threshold and welfare improves. For the high provision point, exclusion lowers contributions and welfare (compared to no-exclusion). Furthermore, we found that exclusion stabilizes contribution over time. The unravelling of contributions in the baseline treatments does not show up in treatments with exclusion.

International audience; Accurate estimation of water demand at the irrigation scheme scale is a key requirement for water management, which is made difficult by the large diversity of crops and production systems. The main objective of this study was to estimate irrigation water demand at the farm scale, taking different types of knowledge into account: (i) database study, where water demand is supposed to be the supply (L0); (ii) actual cropping pattern (L1),; (iii) actual irrigation techniques and cropping pattern (L2); and (iv) actual irrigation practices, actual irrigation techniques, and cropping pattern (L3). Farm typology makes easy this estimation as it takes into account various farm characteristics. Firstly, a farm typology was established based on 115 farms surveyed in the irrigation scheme of Borj Toumi Toungar (Tunisia), selected for the study. Secondly, climatic crop water irrigation requirements were estimated using the agro-meteorological water balance model Pilote. Typology results were used to estimate water demand at the scale of family farms taking into account different levels of knowledge Six classes of farming areas were identified based on irrigation subsystems, cropping pattern (fruit tree area, cropping vegetable area and field crop area), intensification crop level and cropped surface. Results showed that supply could not entirely cover the climatic water demand. However, it could nearly meet actual water demand at the farm scale. According to the water demand estimation at different levels, results showed that there were few changes in water demand at farm scale when moving from L1 to L2. At the opposite, actual water demand (L3) represented about half the climatic water demand (L2). Calculations based on farm classes highlighted the importance of actual farm practices. Within the same class, the difference between water demand estimation at different levels of knowledge was remarkable. Network rehabilitation is thus necessary to enable farmers to increase water delivered to crops and limit water stress; the collective network was conceived to deliver a flow of 0.34 l/s/ha in this sector. Given changes in farming and varietal choices, this flow proved insufficient to face the climatic water demand.