• Energy Research

The structural water deficit suffered by the Segura basin in southern Spain trend toward unsustainability. The imbalance between the resources and the demand has been caused by the expansion of irrigated areas, the emergence of illegal new irrigated lands and pumping wells, the increase in energy cost and the bad management of water use rights by the public water administration. In addition, climate change and frequent drought in this semi-arid region aggravate the situation. As a consequence, many aquifers are overexploited. The region of Murcia has well-developed agri-food sector, which is a key factor in the regional economy. This sector accounts for 21.4% of the regional GDP, and Murcia also has an important tourism sector, so the overexploitation of the aquifers would concern production, exportation and agricultural development as well as the decline in the water level, environmental damage and water quality impairment. On the other hand, the fulfilment of the “good ecological status” objectives set by the Water Framework Directive, with a deadline of 2027, will be a difficult task for water managers. This study proposed a hydroeconomic model to obtain the cost of the overexploited aquifers in the Segura basin in order to decide on the feasibility of using groundwater for agriculture in situations of overexploitation. The results showed that the price paid by farmers for irrigation water in the year 2027 would be 0.53 €/m3 (i.e., annual spending of 180M€), which will involve 10% of the final agricultural crop production in the Region of Murcia. Alternative water sources are proposed to increase water supply security for farmers and to ensure the socio-economic and environmental sustainability of the basin. Finally, the methodology proposed would help to manage water use in other European Mediterranean basins under similar climatic, hydrological and agricultural conditions. Departamento de Ciencias Politécnicas, Universidad Católica de Murcia, España Fundación Instituto Euromediterráneo del Agua, Universidad de Murcia, España Instituto Universitario del Agua y del Medio Ambiente, Universidad de Murcia, España Unidad de Murcia, Instituto Geológico y Minero de España, España Departamento de Ecología e Hidrología, Universidad de Murcia, España

Droughts and climate change in regions with profitable irrigated agriculture will impact groundwater resources with associated direct and indirect impacts. In the integrated water resource management (IWRM), managed aquifer recharge (MAR) offers efficient solutions to protect, conserve, and ensure survival of aquifers and associated ecosystems, as the Water Framework Directive requires. The purpose of this paper is to analyse the socio-economic feasibility of the MAR system in the overexploited Boquerón aquifer in Hellín (Albacete, Spain) under climate change and varying irrigation demand conditions. To assess, in monetary terms, the profitability of the MAR system, a cost-benefit analysis (CBA) has been carried out. The results for the period 2020–2050 showed that the most favourable situations would be scenarios involving artificial recharge, in which future irrigation demand remains at the present level or falls below 10% of the current irrigation surface, as these scenarios generated an internal rate of return of between 53% and 57%. Additionally, the regeneration of the habitat will take between 5 and 9 years. Thus, the IWRM with artificial recharge will guarantee the sustainability of irrigation of the agricultural lands of Hellín and will achieve water balance even in severe climate change conditions.

Wildfires in Mediterranean regions have become a serious problem, and it is currently the main cause of forest loss. Numerous prediction methods have been applied worldwide to estimate future fire activity and area burned in order to provide a stable basis for future allocation of fire-fighting resources. The present study investigated the performance of an artificial neural network (ANN) in burned area size prediction and to assess the evolution of future wildfires and the area concerned under climate change in southern Spain. The study area comprised 39.41 km2 of land burned from 2000 to 2014. ANNs were used in two subsequential phases: classifying the size of the wildfires and predicting the burned surface for fires larger than 30,000 m2. Matrix of confusion and 10-fold cross-validations were used to evaluate ANN classification and mean absolute deviation, root mean square error, mean absolute percent error and bias, which were the metrics used for burned area prediction. The success rate achieved was above 60–70% depending on the zone. An average temperature increase of 3 °C and a 20% increase in wind speed during 2071–2100 results in a significant increase of the number of fires, up to triple the current figure, resulting in seven times the average yearly burned surface depending on the zone and the climate change scenario.

Climate change and the land-use and land-cover changes (LULC) resulting from anthropic activity are important factors in the degradation of an ecosystem and in the availability of a basin’s water resources. To know how these activities affect the quantity of the water resources of basins, such as the Segura River Basin, is of vital importance. In this work, the Soil and Water Assessment Tool (SWAT) was used for the study of the abovementioned impacts. The model was validated by obtaining a Nash–Sutcliffe efficiency (NSE) of 0.88 and a percent bias (PBIAS) of 17.23%, indicating that SWAT accurately replicated monthly streamflow. Next, land-use maps for the years of 1956 and 2007 were used to establish a series of scenarios that allowed us to evaluate the effects of these activities on both joint and individual water resources. A reforestation plan applied in the basin during the 1970s caused that the forest area had almost doubled, whereas the agricultural areas and shrubland had been reduced by one-third. These modifications, together with the effect of climate change, have led to a decrease of 26.3% in the quantity of generated water resources, not only due to climate change but also due to the increase in forest area.

Water availability is essential for the appropriate analysis of its sustainable management. We performed a comparative study of six hydrological balance models (Témez, ABCD, GR2M, AWBM, GUO-5p, and Thornthwaite-Mather) in several basins with different climatic conditions within Spain in the 1977–2010 period. We applied six statistical indices to compare the results of the models: the Akaike information criterion (AIC), the Bayesian information criterion (BIC), Nash–Sutcliffe model efficiency coefficient (NSE), coefficient of determination (R2), percent bias (PBIAS), and the relative error between observed and simulated run-off volumes (REV). Furthermore, we applied the FITEVAL software to determine the uncertainty of the model. The results show that when the catchments are more humid the obtained results are better. The GR2M model gave the best fit in peninsular Spain in a UNEP aridity index framework above 1, and NSE values above 0.75 in a 95% confidence interval classify GR2M as very good for humid watersheds. The use of REV is also a key index in the assessment of the margin of error. Flow duration curves show good performance in the probabilities of exceedance lower than 80% in wet watersheds and deviations in low streamflows account for less than 5% of the total streamflow.

Magnitude and temporal variability of streamflow is essential for natural biodiversity and the stability of aquatic environments. In this study, a comparative analysis between historical data (1971–2013) and future climate change scenarios (2010–2039, 2040–2069 and 2070–2099) of the hydrological regime in the Eo river, in the north of Spain, is carried out in order to assess the ecological and hydro-geomorphological risks over the short-, medium- and long-term. The Soil and Water Assessment Tool (SWAT) model was applied on a daily basis to assess climate-induced hydrological changes in the river under five general circulation models and two representative concentration pathways. Statistical results, both in calibration (Nash-Sutcliffe efficiency coefficient (NSE): 0.73, percent bias (PBIAS): 3.52, R2: 0.74) and validation (NSE: 0.62, PBIAS: 6.62, R2: 0.65), are indicative of the SWAT model’s good performance. The ten climate scenarios pointed out a reduction in rainfall (up to −22%) and an increase in temperatures, both maximum (from +1 to +7 °C) and minimum ones (from +1 to +4 °C). Predicted flow rates resulted in an incrementally greater decrease the longer the term is, varying between −5% (in short-term) and −53% (in long-term). The free software IAHRIS (Indicators of Hydrologic Alteration in Rivers) determined that alteration for usual values remains between excellent and good status and from good to moderate in drought values, but flood values showed a deficient regime in most scenarios, which implies an instability of river morphology, a progressive reduction in the section of the river and an advance of aging of riparian habitat, endangering the renewal of the species.

This study assessed how changes in terms of temperature and precipitation might translate into changes in water availability and droughts in an area in a developing country with environmental interest. The hydrological model Soil and Water Assessment Tool (SWAT) was applied to analyze the impacts of climate change on water resources of the Guajoyo River Basin in El Salvador. El Salvador is in one of the most vulnerable regions in Latin America to the effects of climate change. The predicted future climate change by two climate change scenarios (RCP 4.5 and RCP 8.5) and five general circulation models (GCMs) were considered. A statistical analysis was performed to identify which GCM was better in terms of goodness of fit to variation in means and standard deviations of the historical series. A significant decreasing trend in precipitation and a significant increase in annual average temperatures were projected by the middle and the end of the twenty–first century. The results indicated a decreasing trend of the amount of water available and more severe droughts for future climate scenarios with respect to the base period (1975–2004). These findings will provide local water management authorities useful information in the face of climate change to help decision making.