A través del estudio de cuatro casos concretos (Canarias, Israel, y los regadíos manchegos y almerienses) este trabajo pretende mostrar la relevancia del marco institucional como condicionante de los comportamientos de gestión de recursos acuíferos, poniendo al mismo tiempo de manifiesto la capacidad de los propios agentes para actuar sobre las reglas del juego

A traves del estudio de cuatro casos concretos (Canarias, Israel, y los regadios manchegos y almerienses) este trabajo pretende mostrar la relevancia del marco institucional como condicionante de los comportamientos de gestion de recursos acuiferos, poniendo al mismo tiempo de manifiesto la capacidad de los propios agentes para actuar sobre las reglas del juego.

Lipids stored subcutaneously serve as the main energy source for long-distance bird migration. The 2 major inputs of such lipids are dietary fats and de novo synthesis of fatty acids from acetyl-CoA derived from non-lipid sources, including ingested carbohydrates. Remarkably, relatively little is known about the specific roles of dietary fats and carbohydrates in fat-deposition processes of migratory passerines. We report the results of a large-scale field experiment complemented by a captivity experiment, aimed at testing the effects of the availability of simple carbohydrates and water on fuel deposition rates of autumn-migrating passerines in the northern Negev of Israel. We found that in the main study site, Ein Rimon, where birds mostly consume fat-rich Atlantic pistachio (Pistacia atlantica) fruits, access to both water and sucrose solution resulted in faster body mass gain. Similar patterns were evident among captive Eurasian Blackcaps (Sylvia atricapilla) subjected to the same nutritional conditions. Furthermore, supplementation with sucrose solution caused a significant reduction in the consumption of fruits by Eurasian Blackcaps, indicating that their preference for the fat-rich Atlantic pistachio fruits decreased when simple carbohydrates were available. Our results show that availability of simple carbohydrates can significantly accelerate fuel deposition rates in autumn-migrating passerines. We suggest that simple carbohydrates, dissolved in a solution (e.g., nectar), can be assimilated and absorbed faster than other food types and are therefore beneficial during the first days of stopover, when digestive capacity is reduced as a result of migration flight.

Many coastal areas around the world suffer severe water stresses due to improper management of water resources. In these areas, groundwater is typically the most important source for drinking water, and its overexploitation may lead to deterioration in water quality. In coastal confined aquifers, the dynamics of saltwater intrusion (SWI) and well salinization are the focus of many recent studies that commonly do not include a geological study of the subsurface structure of the aquifer. The goal of the present work is to study the effect of groundwater extraction on SWI, using the Judea Group Aquifer as a case study representing a coastal confined aquifer that suffers drawdown due to excess pumping. First, the offshore-onshore structure of the aquifer is described, and then a groundwater model is constructed based on the inferred structure. The resulting model shows that under realistic conditions, a water well situated 5 km inland from the shoreline is expected to undergo salinization after ~190 years since level drop. The SWI advances inland faster when the confinement is efficient, suggesting that semi-confined aquifers should be preferred for pumping compared with confined ones. Additionally, the model shows that under certain conditions, deep submarine groundwater discharge (SGD) occurs through the aquifer outcrop, ~15 km offshore and at depths of ~200 m. The SGD comprises brackish and warm water. The insights from this work are important both for studies on freshwater budgets in coastal areas and for the study of SGD and its implications for the ocean.

Sharp-interface (or interface) flow models with Dupuit-Forchheimer approximation are widely used to assess, to first order, an aquifer’s vulnerability to seawater intrusion (SWI) and to evaluate sustainable management options for coastal groundwater resources at the screening level. Recognising that interface flow models overestimate SWI, corrections have been proposed to account for the neglected mixing and also for the outflow through a finite gap. These corrections, however, were introduced in the context of specific studies and may not be generally applicable as proposed. The interface model is revisited, placing its corrections in the context of variable-density flow (VDF) theory, by expressing them in terms of the dimensionless parameters governing VDF in schematised (aspect ratio = thickness/length) homogeneous confined coastal aquifers: the coupling parameter (α), a Péclet number (Pe), and the dispersivities ratio (rα). Interfaces are compared to the 50%-salinity lines of VDF numerical solutions and regression equations are developed for estimating the outflow gap and for correcting the length of the interface (terminating with a blunted edge); the dispersion correction, which modifies the interface curvature, is restated with a variable exponent. The corrections for dispersion and for the interface length appear to be the most effective; an outflow gap is important only at small α values (strong advection relative to vertical flow due to density differences). These concepts are applied successfully to calculate the interface position in the lowermost confined sub-unit of the Coastal Plain aquifer of Israel, as an estimate of SWI.