Artificial groundwater recharge in the MASub Boquerón and integrated management of water resources with Optiges

Artificial groundwater recharge is the technique in which water is usually introduced into the subsoil in order to alleviate water deficits of certain hydrogeological formations. In the study the appropriateness of incorporating the technique into a real system of water resources management is valued choosing the Boquerón groundwater body, and in particular the aquifer with the same name, located in the municipality of Hellín (Segura basin, Spain). The modeling indicates that the technique would reduce water deficits and increase guarantee of supply in the system elements, although the recharged volume is not sufficient to reduce the overexploitation of the Boquerón aquiferLa recarga artificial de acuíferos es la técnica con la que se introduce agua en el subsuelo generalmente para paliar los déficits hídricos de determinadas formaciones hidrogeológicas. En el estudio se valora la idoneidad de incorporar la técnica en un sistema de gestión de recursos hídricos real seleccionando la Masa de Agua Subterránea Boquerón, y en concreto el acuífero del mismo nombre, localizado en el municipio de Hellín (cuenca del Segura, España). La modelización indica que la técnica permitiría reducir los déficits hídricos e incrementar la garantía del suministro en los elementos del sistema, aunque el volumen recargado no es suficiente para disminuir la sobreexplotación del acuífero Boqueró

Recarga artificial de acuíferos. Revisión del conocimiento actual de la técnica

Nowadays, intensive exploitation of aquifers is seen as one of the main environmental issues worldwide together with other phenomena such as climate change, changes in land use, the disappearance of species, and so on. To that respect, the artificial groundwater recharge almost stands as the only solution in order to reduce directly the effects of aquifer exploitation. To be exact, the recharge of aquifers is the technique used to introduce water into the ground in order to meet water deficits in aquifers. This study deals with the hydraulics and hydrogeological aspects related to the technique by performing an exhaustive analysis of the existing literature published in the last decades about the definition of the technique itself, the available water sources to develop it, the long list of objectives that this technique shows, the phases of the hydrodynamic mechanism, the different technology developed recently in order to introduce it (surface and underground systems) and the most important issues related to it (clogging, emerging contaminants…). This way, this study aims to improve the knowledge acquired on artificial groundwater recharge in order for this technique to be taken into consideration as a valid option when reducing intensive exploitation of aquifers, especially in arid and semi-arid areas.La explotación intensiva de acuíferos se contempla en la actualidad como uno de los principales perjuicios medioambientales existentes a nivel global, junto con el cambio climático, los cambios en los usos del suelo, la desaparición de especies, etc. En este sentido, la recarga artificial de acuíferos se postula prácticamente como la única solución capaz de mitigar de un modo directo los efectos de la explotación intensiva de acuíferos. Concretamente la recarga de acuíferos es la técnica mediante la que se facilita la introducción en el terreno del agua con el fin de satisfacer los déficits hídricos existentes en los acuíferos. El presente trabajo aborda los aspectos relacionados con la hidráulica y la hidrogeología de la técnica realizando un exhaustivo análisis de la literatura existente, en las últimas décadas, en cuanto a la definición de la misma, las fuentes de agua disponibles para su desarrollo, el amplio elenco de objetivos que presenta, las fases del mecanismo hidrodinámico, la diferente tecnología desarrollada hasta la fecha para implementarla (dispositivos en superficie y en profundidad) y sus principales problemas asociados (colmatación, contaminantes emergentes…). De este modo, el trabajo pretende mejorar el conocimiento existente de la recarga artificial de acuíferos con el fin de que en las próximas décadas dicha técnica sea contemplada como una opción válida con la que reducir la explotación intensiva de acuíferos especialmente en zonas áridas y semiáridas.Financial support was provided partially by the Consellería de Agricultura, Medio Ambiente, Cambio Climático y Desarrollo Rural (Government of the Valencian Community, Spain), project Posibilidades de Aprovechamiento de Aguas Subterráneas Salobres en la Comunidad Valenciana. This study also has been conducted within the grant received from the Programa Nacional de Formación de Profesorado Universitario (FPU) conceded by the Spanish Ministry of Science to the first author

Calibration and validation of ET0 through an R-CRAN code in agricultural lands of south-east Spain

Currently, water demands from urban and agricultural use are increasing, especially in arid and semi-arid regions, such as the Mediterranean. This situation is expected to become worse with the climate change projections for the region, increasing the pressure, in both quantity and quality, on fresh water resources. Evapotranspiration (ET0) is a hydrologic variable with high uncertainty and considered incorrect in water balance estimations. However, its accurate assessment is essential to obtain the real value of available water to satisfy water demands, especially in extended agricultural areas such as the south-east of Spain. ET0 can be obtained using different equations with different levels of input data requirements, among them the Penman–Monteith option is the one recommended by the FAO (PMFAO), but its input data requirements are high. On the other hand, there are simpler options, such as the Hargreaves equation (ET0,HG), but there is not such a big agreement about its accuracy in the scientific literature. The main objection to the use of PMFAO is the lack of some of the required meteorological variables in most climate stations, forcing the use of simpler alternatives. This paper presents an R-CRAN code where the ET0,HG, parameterized by Samani, is calibrated and validated with the Allen model considering 18 statistical contrasts. Both ET0,HG results (pre- and post-calibrated) are compared with daily, monthly and annual results of the PMFAO. All meteorological data was provided by the CA52 Cartagena La Aljorra weather station, managed by the Agricultural Information System of the Murcia region (SE Spain). The main results show that daily, monthly and annual ET0,HG results after the Allen calibration and validation are similar to the PMFAO. However, a moderate underestimation of ET0,HG compared to PMFAO was identified. To sum up, the presented R-CRAN code provides an alternative to apply the ET0,HG method with few meteorological input requirements and, once calibrated, can be applied to extended data networks in other regions.This work was partially supported by the project GRE17-12 of the University of Alicante. Antonio Jodar-Abellan acknowledges financial support received from the Spanish FPU scholarship for the training of university teachers. In the same way, this work has been conducted within the Cátedra del Agua of the University of Alicante (https://catedradelaguaua.org/)

A method to estimate optimal renovation period of solar photovoltaic modules

Renewable energy sources are essential to reduce the negative impacts on the environment caused by burning fossil fuels. Using solar photovoltaic installations in recent years means that decision-makers must consider infrastructure renewal decisions. An expenditure framework to achieve the optimal renovation period of photovoltaic modules is proposed here from an economic standpoint. This approach includes not only the investment and maintenance costs but also energy and emissions savings. A sensitivity analysis was carried out using a case study in south-eastern Spain, achieving that the optimal renovation period ranges between 17.0 and 24.7 years. Many factors are studied to identify those with the greatest influence on this indicator. Installing a solar power system is always a profitable choice considering that the installation lifetime is 25 years. Neglecting the influence of these limits may cause potential savings not fully exploited.CRUE-CSICSpringer Natureresearch project "DESENREDA" through the 2021 call "Estancias de movilidad en el extranjero Jose Castillejo" of the Ministerio de Universidades CAS21/00085project "Hi-Edu Carbon" Erasmus Plus Programme, Key Action KA22021, action type 2021-1-SK01-KA220-HED-00002327

Converting a Water Pressurized Network in a Small Town into a Solar Power Water System

The efficient management of water and energy is one challenge for managers of water pressurized systems. In a scheme with high pressure on the environment, solar power appears as an opportunity for nonrenewable energy expenditure reduction and emissions elimination. In Spain, new legislation that eliminates old taxes associated with solar energy production, a drop in the cost of solar photovoltaic modules, and higher values of irradiance has converted solar powered water systems into one of the trendiest topics in the water industry. One alternative to store energy (compulsory in standalone photovoltaic systems) when managing pressurized urban water networks is the use of head tanks (tanks accumulate water during the day and release it at night). This work intends to compare the pressurized network running as a standalone system and a hybrid solution that incorporates solar energy supply and electricity grids. The indicator used for finding the best choice is the net present value for the solar power water system lifespan. This study analyzed the possibility of transferring the energy surplus obtained at midday to the electricity grid, a circumstance introduced in the Spanish legislation since April 2019. We developed a real case study in a small town in the Alicante Province, whose findings provide planning policymakers with very useful information in this case and similar case studies.Antonio Jodar-Abellán acknowledges financial support received from the Spanish FPU scholarship for the training of university teachers. In the same way, this work has been partially funded by the Cátedra del Agua of the University of Alicante and the Diputación Provincial de Alicante (https://catedradelaguaua.org/)

Evaluación de la degradación del suelo y sequías en una región árida utilizando índices de sequía, índice de vegetación ajustado al suelo modificado y datos de sensores remotos Landsat

Ain Sefra is part of the Ksour Mountains and it's situated in southwestern Algeria, where the climate is arid. The study area is progressively facing regression and degradation exacerbated by climate change. These trends point to a significant acceleration of desertification and drought and the loss of production systems that play a critical social, ecological, and economic role in the region. To better understand the natural hazard of dryness in Ain Sefra and the impact of climate change, we used various drought indices and remote sensing data. Hence, analyzing precipitation records from 1965 to 2021, through several drought indices, droughts were identified as a recurring phenomenon. Moreover, the frequency of successive dry years is relatively high. There were three most extended continuous dry periods. The first phase lasted seven years from 1980 to 1987, the second twelve years from 1994 to 2006, and the third nine years from 2012 to 2021. Calculation of the Modified Soil-Adjusted Vegetation Index (MSAVI) for five multidate satellite images allowed us to follow the evolution of land use elements in this region from 1977 to 2017. Indeed, the study of these multi-temporal images reveals a considerable growth of sands, moving towards the north and northeast of the zone during the last decades. The combination of drought indices and remote sensing seems to be most promising; whose results are valuable tools for guidance and decision support to local and regional authorities.Ain Sefr, en las montañas Ksour, está situada en el suroeste de Argelia, donde el clima es árido. El área de estudio se enfrenta progresivamente a la regresión y degradación exacerbada por el cambio climático. Estas tendencias apuntan a una aceleración significativa de la desertificación y la sequía y a la pérdida de sistemas de producción que desempeñan un papel social, ecológico y económico crítico en la región. Para comprender mejor el peligro natural de la sequía en Ain Sefra y el impacto del cambio climático, se varios índices de sequía y datos de teledetección. Al analizar los registros de precipitación desde 1965 hasta 2021, a través de varios índices de sequía, se identificaron las sequías como un fenómeno recurrente. Además, la frecuencia de años secos sucesivos es relativamente alta. Hubo tres períodos secos continuos más prolongados. La primera fase duró siete años, de 1980 a 1987, la segunda doce años, de 1994 a 2006, y la tercera nueve años, de 2012 a 2021. El cálculo del Índice de Vegetación Ajustado al Suelo Modificado (MSAVI) para cinco imágenes satelitales multifecha nos permitió seguir la evolución de los elementos de uso del suelo en esta región desde 1977 hasta 2017. De hecho, el estudio de estas imágenes multitemporales revela un crecimiento considerable de arenas, moviéndose hacia el norte y noreste de la zona durante las últimas décadas. La combinación de índices de sequía y sensores remotos parece ser muy prometedores, pues sus resultados son valiosas herramientas de orientación y apoyo a la decisión de los entes locales y regionales.Financial support to perform this study was provided partially by the University Center Salhi Ahmed Naama (Argelia). Antonio Jodar-Abellan acknowledges financial support received form the XTREME Spanish National Project (Ref: PID2019-109381RB-I00/AEI/10.13039/501100011033)

Assessing Water Shortage through a Balance Model among Transfers, Groundwater, Desalination, Wastewater Reuse, and Water Demands (SE Spain)

Currently, water demands are increasing notoriously, spreading the pressure on available water resources around the world in both quantity and quality. Similarly, the expected reduction of natural water inputs, due to climate change, depicts a new level of uncertainty. Specifically, Southeast Spain presents water scarcity due to its aridity—irregular and scarce precipitation and high evapotranspiration rates—combined with the competition between several water demands: environment, agricultural dynamics, urban-tourist activities, and industry. The study area of this work is the most relevant functional urban area of Alicante province (SE Spain), where the administration of water management is carried out by a range of authorities at different levels as the consequence of a complex historical development of water governance schemes: at the national, regional, and local levels. This study analyzes 21 municipalities and proposes a conceptual model which was developed by including different origins of water inputs—surface resources, groundwater, desalination, wastewater reuse, or interbasin transfers—and water demands with information obtained from 16 different sources. Our main results denote a relevant water deficit of 72.6 hm3/year even when one of the greatest rates of desalinated water and reused wastewater in Europe are identified here. This negative balance entails restrictions in urban development and agricultural growth. Thus, presented results are noteworthy for the water policy makers and planning authorities, by balancing the demand for water among various end users and providing a way for understanding water distribution in a context of scarcity and increasing demand, which will become one of the most challenging tasks in the 21st century.This research was funded partially by the project Life Empore (grant number: Life15 ENV/ES/000598) coordinated by the University Institute of Water and Environmental Sciences of the University of Alicante and by the project Asesoramiento y Asistencia Científico-Técnica en la elaboración del Plan de Acción Territorial de Alicante y Elche (grant number: UTECERCLEJORNET1-18ª) coordinated by the UTE Cercle & Jornet Llop Pastor companies and the University of Alicante. Antonio Jodar-Abellan acknowledges financial support received from the Spanish FPU scholarship for the training of university teachers. In the same way, this work has been conducted within the Cátedra del Agua of the University of Alicante (https://catedradelaguaua.org/)

Land-use changes and precipitation cycles to understand hydrodynamic responses in semiarid Mediterranean karstic watersheds

This research was funded partially by the Central University of Ecuador and by the projects RESERVOIR (PRIMA programme supported by the European Union under grant agreement no. 1924) and BBVA2021-Leonardo2 along with local companies (projects Comunidad Regantes 220-I and Comunidad Regantes 1-20T). Antonio Jodar-Abellan acknowledges financial support received from the project BBVA2021-Leonardo2. In the same way, this work has been conducted within the Catedra del Agua of the University of Alicante (catedradelaguaua.org). Moreover, authors acknowledge the reviewers of the manuscript whose comments contributed greatly to improve this paper.Non-planned agricultural land abandonment is affecting natural hydrological processes. This is especially relevant in vulnerable arid karstic watersheds, where water resources are scarce but vital for sustaining natural ecosystems and human settlements.However, studies assessing the spatiotemporal evolution of the hydrological responses considering land-use changes and precipitation cycles for long periods are rare in karstic environments. In this research, we selected a representative karstic watershed in a Mediterranean semiarid domain, since in this belt, karst environments are prone to land degradation processes due to human impacts. Geographic Information Systems-based tools and hydrological modeling considering daily time steps were combined with temporal analysis of climate variables (wavelet analysis) to demonstrate possible interactions and vulnerable responses. Observed daily flow data were used to calibrate/ validate these hydrological models by applying statistic indicators such as the NSE efficiency and a selfdeveloped index (the ANSE index). This new index could enhance goodness-of-fit measurements obtained with traditional statistics during the model optimization. We hypothesize that this is key to adding new inputs to this research line. Our results revealed that: i) changes in the type of sclerophyllous vegetation (Quercus calliprinos, ilex, rotundifolia, suber, etc.) from 81.5% during the initial stage (1990) to natural grasslands by 81.6% (2018); and, ii) decreases in agricultural areas (crops) by approximately 60% and their transformation into coniferous forests, rock outcrops, sparsely natural grasslands, etc. in the same period. Consequently, increases in the curve number (CN) rateswere identified as a result of land abandonment. As a result, an increase in peak flow events jointlywith a relevant decrease of the average flow rates (water scarcity) in the watershed was predicted by the HEC-HMS model and verified through the observed data. This research provides useful information about the effects of anthropogenic changes in the hydrodynamic behaviour of karstic watersheds andwater resource impacts, especially key in water-scarce areas that depict important hazards for the water supply of related populations and natural ecosystems.Central University of EcuadorEuropean Commission 1924Comunidad de Madrid 220-ICatedra del Agua of the University of Alicant

A method to estimate optimal renovation period of solar photovoltaic modules

Renewable energy sources are essential to reduce the negative impacts on the environment caused by burning fossil fuels. Using solar photovoltaic installations in recent years means that decision-makers must consider infrastructure renewal decisions. An expenditure framework to achieve the optimal renovation period of photovoltaic modules is proposed here from an economic standpoint. This approach includes not only the investment and maintenance costs but also energy and emissions savings. A sensitivity analysis was carried out using a case study in south-eastern Spain, achieving that the optimal renovation period ranges between 17.0 and 24.7 years. Many factors are studied to identify those with the greatest influence on this indicator. Installing a solar power system is always a profitable choice considering that the installation lifetime is 25 years. Neglecting the influence of these limits may cause potential savings not fully exploited.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This work was supported by the research project “DESENREDA” through the 2021 call “Estancias de movilidad en el extranjero Jose Castillejo” of the Ministerio de Universidades (CAS21/00085) and for the project “Hi-Edu Carbon” Erasmus Plus Programme, Key Action KA22021, action type (2021–1-SK01-KA220-HED-000023274