KEYWORDS: Climate change adaptationriver basin planningwater investmentsnature based solutionstransboundary waterswater governance

Nitrate pollution in aquifers is a global concern. Spain has developed a national strategy to recover nitrate polluted aquifers aligned with the European Union (EU) policies, specifically through the water planning under the EU Water Framework Directive. River basin management plans use PATRICAL model results to define the maximum nitrogen surplus in each polluted aquifer for the first time. The maximum nitrogen surplus allows to reach the good status in each aquifer and the model provides the number of years required. Around 30% of the aquifers in Spain is currently heavily polluted by nitrates. Model results show that 90% of these aquifers can be recovered in next 6 -12 years by increasing nitrogen use efficiency and reducing nitrogen losses around 50%, which is in line with the EU Farm to Fork Strategy. The remaining aquifers require additional reductions to achieve the good status. In Spain this increase in nitrogen efficiency can be obtained with different measures including 30% reduction of current fertilization.

Water scarcity will increase in the world in the coming decades due to climate change, especially in areas that currently already have water scarcity, such as the Mediterranean area. In these areas, to guarantee water resources, systems’ sustainability is necessary to improve demand management and the development of non-conventional resources, such as treated wastewater reuse or seawater desalination. These non-conventional resources are highly energy-consuming; so, reducing energy costs is a key element in developing their use in different sectors, including agriculture. Combining photovoltaic solar energy with seawater desalination by reverse osmosis will reduce the cost of producing water to below 0.36 EUR/m3; so, this resource can be attractive for agriculture, as demonstrated in this work. The arrangement of bifacial solar modules in horizontal single-axis tracking systems increases the energy amount generated from the sun in one hour or more, improving the facility’s efficiency and reducing the desalinated water cost. The greater distance between the solar module lines, with a ground coverage ratio (GCR) = 0.3, makes for a better environmental integration of the facility and allows the development of agrovoltaic strategies, such as native flora planting and pollinator colonization.

Aquifers are ubiquitous, and their water is easy to obtain with low extraction costs. On many occasions, these characteristics lead to overexploitation due to important water level declines, reduction of river base flows, enhanced seawater intrusion, and wetland affection. The forecasted increase in water demands and global warming will impact the future availability of water resources. Conjunctive use of surface and subsurface waters can help in mitigating these impacts. There are two main conjunctive use strategies: artificial recharge (AR) and alternate conjunctive use (ACU). AR stores waters that are not to be used directly in aquifers. ACU utilizes groundwater in dry periods, while surface waters are preferred in wet ones; this allows the increase of water supply with lower dam storage, economic gains, and environmental advantages. Efficient conjunctive use can prevent soil salinization and waterlogging problems in semiarid countries due to excessive recharge from irrigation return flows or other origins. Groundwater is a neglected and generally misused resource to maintain environmental conditions. When considering the solution to a water resources problem, groundwater should always be part of the design as an alternative or a complementary resource. Aquifers have large inertia, and changes in their volumes are only noticeable after years of observations. Unfortunately, groundwater observation networks are much poorer than surface ones, something that should be changed if groundwater is to come to the rescue in these times of climate change. Human and material resources should be made available to monitor, control, analyze, and forecast groundwater.

The biomonitoring methods implemented by water authorities are mostly developed for perennial rivers, and do not apply to temporary rivers (TRs). We propose a new classification for TRs to better assess their ecological status. It arises from the LIFE+ TRivers project, which was conducted in the Catalan and the Júcar Mediterranean river basin districts (RBD). The European Water Framework Directive (WFD) provided two systems to set river types (systems A or B from Annex II), which have been officially used by water authorities across Europe to set “national river types” (NRTs). However, essential hydrological variables for TRs are largely omitted. NRTs established according to the WFD were compared with TR categories obtained by using a rainfall-runoff model, “natural flows prescribed regimes” (NFPRs), and with “aquatic phases regimes” (APRs) calculated by using TREHS software. The biological quality indices currently used in Spain, based on macroinvertebrates and diatoms (IBMWP, IMMI-T, and IPS), were compared with a “general degradation” gradient in order to analyze the two TR river classification procedures (NFPR and APR). The results showed that NRTs did not properly classify TRs, and that the APR classification identified ecologically meaningful categories, especially those related to stagnant phases. Four “management temporary river categories” based on APRs are proposed to be used for water managers to properly assess the ecological status of TRs.

The European Water Framework Directive (WFD) mandates to incorporate the participation of stakeholders and the general public in the development and updating of the river basin management plans. So far, the WFD implementation has been mainly focused on perennial rivers without considering temporary rivers properly, neither in biomonitoring programs nor participatory processes. This paper aims at adapting participatory processes in river basin management to enhance the inclusion of ecosystems with poor or no social recognition such as temporary rivers. To do so, we examined previous experiences of participatory processes conducted in the WFD and adapted them to propose and implement an approach for promoting stakeholders’ engagement in temporary rivers. The approach is based on a collaborative leadership, includes multiple participatory engagement mechanisms, uses future global change scenarios and the concept of ecosystem services at different stages of the process, and aims at involving stakeholders not only in the proposal of measures stage but in the diagnosis of the ecological status. It also includes an evaluation of participants’ satisfaction on the process. We tested our approach in temporary rivers from the Mediterranean region. We found that the combination of environmental education and citizen science activities, together with the inclusion of the ecosystem services concept, was the most useful way to raise awareness on the biodiversity and ecological value of temporary rivers and to promote stakeholders’ engagement. Workshops conducted during the diagnosis stage played an important role in both including stakeholders’ suggestions and increasing their knowledge on temporary rivers. Further, envisaging climate-related future scenarios allowed participants to incorporate measures that could tackle new and emerging pressures on these ecosystems. As future environmental changes will increase the proportion of rivers with temporary flow regimes, our approach can contribute to adapt current participatory processes to future needs.

En Espana se ha venido produciendo un cambio en el enfoque tradicional de aplicacion de medidas estructurales de defensa frente a las inundaciones a otro basado en la aplicacion de medidas de gestion. Esta evolucion tuvo un punto de inflexion en los anos 80 del siglo pasado, como consecuencia de las graves inundaciones ocurridas en el Levante y en el Pais Vasco, lo que significo el inicio de los trabajos de documentacion de las inundaciones historicas por Proteccion Civil, la puesta en marcha del Programa SAIH en los Organismos de Cuenca o el establecimiento de las bases tecnicas para la ordenacion de las zonas inundables. Un cambio cualitativo en la gestion de las inundaciones tuvo lugar como consecuencia de la entrada en vigor en el ano 2007 de la Directiva 2007/60, de evaluacion y gestion de los riesgos de inundacion, que ha supuesto una profunda modificacion del marco regulador de la gestion tradicional de las avenidas e inundaciones. Los elementos fundamentales de esta Directiva son la evaluacion preliminar del riesgo de inundacion, la elaboracion de mapas de peligrosidad y de riesgo y la elaboracion de los Planes de Gestion del Riesgo de Inundacion (PGRI). Todo ello ha contribuido a que las inundaciones en Espana pasaran de ser gestionadas como situaciones de crisis a que se aplicasen enfoques basados en la gestion de riesgos, incluyendo los derivados del cambio climatico (European Commission, 2014).

espanolEl Grupo de Trabajo sobre el Agua (WGoW) de la Federacion Mundial de Organizaciones de Ingenieria (WFEO), en el ambito de la contribucion de la ingenieria a los Objetivos de Desarrollo Sostenible (ODS) de las Naciones Unidas ha elaborado recientemente una monografia sobre la Gestion de sequias e inundaciones: Mejores practicas y contribucion de ingenieria, con informacion procedente de casos de estudio en todo el mundo. En este articulo se ofrece una sintesis de este informe, que esta disponible (en ingles) en la pagina web de la WFEO. EnglishWithin the contest of the contribution of engineering to United Nations Sustainable Development Goals (SOG), the Working Group on Water (WGoW) of the World Federation of Engineering Organizations (WFEO) has recently prepared a monograph on Managing droughts and floods: Best practices and engineering contribution, with information based on case studies around the world. This article presents a summary of the report, which is available (in English) on the WFEO web page.

This paper proposes an interpolation model for monthly rainfall in large areas of complex orography. It has been implemented in the Iberian Peninsula (continental territories of Spain and Portugal), Balearic and Canary Islands covering a territory of almost 600.000 km2. To do this a data set that comprises a total number of 11,822 monthly precipitation series has been created (11,042 provided by the Spanish Meteorological Agency and 780 provided by the National Water Resources Information System of the Portuguese Water Institute). The data set covers the period from October 1940 until September 2005. The interpolation model has been based on the assumption of two different components on monthly precipitation. The first component reflects local and seasonal characteristics and 24 different mean monthly precipitation maps (12) and SDs maps (12) compose it. It considers the varying influence of physiographic variables such as altitude and orientation. The second precipitation component reflects the synoptic pattern that dominated each month of the series and it is composed by series of anomalies of monthly precipitation (780). Anomalies have been interpolated by means of ordinary kriging once local spatial continuity was assumed. Gridded maps of each variable have been developed at 200 m resolution following a hybrid methodology that implements two different interpolation techniques. The first technique applies a regression analysis to derive maps depending on altitude and orientation; the second one is a weighting technique to consider the non‐linearity of the precipitation/altitude dependence. Cross validation has been applied to estimate the goodness of both techniques. Results show an average annual precipitation of 655 mm/year. Although this figure is only 4% less than the estimate of MAGRAMA (2004), regional and local differences are highlighted when the spatial distribution is considered. The model constitutes a comprehensive implementation considering the availability of historical records and the need of avoiding slow calculations in large territories.

Simulations of water fluxes at high spatial resolution that consistently cover historical observations, seasonal forecasts, and future climate projections are key to providing climate services aimed at supporting operational and strategic planning, and developing mitigation and adaptation policies. The End-to-end Demonstrator for improved decision-making in the water sector in Europe (EDgE) is a proof-of-concept project funded by the Copernicus Climate Change Service program that addresses these requirements by combining a multimodel ensemble of state-of-the-art climate model outputs and hydrological models to deliver sectoral climate impact indicators (SCIIs) codesigned with private and public water sector stakeholders from three contrasting European countries. The final product of EDgE is a water-oriented information system implemented through a web application. Here, we present the underlying structure of the EDgE modeling chain, which is composed of four phases: 1) climate data processing, 2) hydrological modeling, 3) stakeholder codesign and SCII estimation, and 4) uncertainty and skill assessments. Daily temperature and precipitation from observational datasets, four climate models for seasonal forecasts, and five climate models under two emission scenarios are consistently downscaled to 5-km spatial resolution to ensure locally relevant simulations based on four hydrological models. The consistency of the hydrological models is guaranteed by using identical input data for land surface parameterizations. The multimodel outputs are composed of 65 years of historical observations, a 19-yr ensemble of seasonal hindcasts, and a century-long ensemble of climate impact projections. These unique, high-resolution hydroclimatic simulations and SCIIs provide an unprecedented information system for decision-making over Europe and can serve as a template for water-related climate services in other regions.

Se repasa, en el marco del contexto mundial, la evolución de la desalación en España. Una historia de más de medio siglo que arrancó donde el agua más escasea, en las Islas Canarias. Lo que comenzó siendo una solución puntual para resolver problemas concretos ha ido, al compás de los avances tecnológicos, de la reducción de costes y del control de su impacto, ganando relevancia. Pero hace quince años, el ritmo de implantación, se aceleró notablemente. En aquel contexto se tomaron rápidas decisiones, adoptadas sin el amplio consenso que requieren este tipo de infraestructuras. Sin embargo, la madurez tecnológica y, sobre todo, el tiempo están contribuyendo a clarificar la situación, propiciando que cada desaladora encuentre su lugar y, en fin, justificando la fuerte inversión efectuada. Con todo hay problemas aún pendientes de solución, en particular la incorporación de esta nueva fuente de agua en un sistema que integre todos los recursos, tanto los tradicionales como los nuevos. Ello exige que los usuarios acepten su sobrecoste como un nuevo seguro hídrico que permita garantizar el suministro de agua en todo momento. En cualquier caso, hay que concluir que la desalación en España juega, y continuará jugando un papel clave en el litoral mediterráneo y en algunas de sus islas más turísticas.

A summary of the evolution of desalination in Spain, spanning over half a century of history, follows. What started as a solution to resolve occasional water shortages in islands where natural surface and ground water resources were scarce, has gained more relevance with technological advancements, less expensive production costs and at the same time minimizing the impact on the environment. But fifteen years ago, the normal pace of history underwent an about-turn with the sudden construction of a significant number of desalination plants. The speed, and on occasions the haste, involved in many of the decisions, brought about some imbalance between the different players that were involved. Time, and above all, technological advancement have clarified the situation, and most of the desalination plants that were built have managed to find their place, thus justifying the investment that was made. But there are still some stages to address, particularly that of integrating these plants in the joint water resource operation systems. In this regard, consumers must accept that desalination plants competing with traditional water resources, greatly improve the guarantee of supply, and in fact act as a new water insurance that, indeed, has a cost. Today however, and particularly in the future, desalination in Spain plays and will continue to play an essential role, especially in the southeast Mediterranean region and in some of the more touristic islands. The following is a brief history.

The Water Framework Directive 2000/60/EC implemented by the European Union established as the main objectives to achieve a "good ecological and chemical status" of the surface water and a "good quantitative and chemical status" of groundwater bodies. One of the major pressures affecting water bodies comes from the use of pesticides and their potential presence in the water ecosystems. For this purpose, the reliable determination of pesticides and their transformation products (TPs) in natural waters (both surface and groundwater) is required. The high number of compounds potentially reaching the aquatic environment makes extraordinary difficult, if not impossible, to investigate all these compounds even using the most powerful analytical techniques. Among these, liquid chromatography coupled to high-resolution mass spectrometry is emphasized due to its strong potential for detection and identification of many organic contaminants thanks to the accurate-mass full spectrum acquisition data. This work focuses on wide-scope screening of many pesticides and their TPs in surface water and groundwater samples, collected between March and May 2017, in the Júcar River Hydrographical Basin, Spain. For this purpose, a home-made database containing more than 500 pesticides and TPs was employed. Analyses performed by liquid chromatography coupled to quadrupole-time of flight mass spectrometry (LC-QTOF MS) allowed the identification of up to 27 pesticides and 6 TPs. The most detected compounds in groundwater were the herbicides atrazine, simazine, terbuthylazine, and their TPs (atrazine-desethyl, terbumeton-desethyl and terbuthylazine-desethyl). Regarding surface water, the fungicides carbendazim, thiabendazole and imazalil, the herbicide terbutryn and the TP terbumeton-desethyl were also detected. These results illustrate the wide use of these compounds (in the present or in the recent past) in the area under study and the vulnerability of the water bodies, and are in accordance with previous findings in other water bodies of the different Spanish Hydrographic systems.

Droughts are one of the gravest natural threats currently existing in the world and their occurrence and intensity might be exacerbated in the coming years due to climate change. The severe impacts that droughts cause to inland water resources and to the associated socio-economic activities justify the continuous monitoring of the drought. The case study presented shows a practical application of a distributed drought monitoring system implemented in a real river basin district, the Júcar River Basin District (43,000km2), where drought periods of marked intensity have occurred historically and the climate ranges from humid in the north to semiarid in the south. Five drought indices have been applied: Standardised Precipitation Index (SPI) for meteorological drought; Palmer Drought Severity Index (PDSI) and a new soil moisture index (HI), for edaphic drought; Normalised Difference Vegetation Index (NDVI) for the vegetation activity; and Spanish Status Index (SI), for the operational drought. All indices are standardised to compare them. The relationship between the standardised operational drought index SI and the long-term meteorological indices, SPI-12 or SPI-24, show that in a medium size basin the concept of "prolonged drought" required by the European Commission under the Water Framework Directive could be defined by the use of accumulated precipitation indices. The number of months to be accumulated depends on the size of the basin and the water management system properties. In large basins, such as the Júcar river basin (22,000km2), there are significant deviations due to the spatial distribution of the drought. The use of a unique aggregated indicator could hide a significant drought in a specific area, or on the other hand show a non-real drought. Evolution of drought indices for each water management system must be accompanied by spatially distributed drought maps to better understand the drought status and its evolution.

Significant changes in the Júcar River Basin District’s hydrology in the Mediterranean side of Spain, have been observed during last decades. A statistical change-point in the year 1980 was detected in the basins’ hydrological series in the main upper river, Júcar and Túria basins. In the study scope are, the North Atlantic Oscillation (NAO) is linked with the winter precipitations in the Upper Basins, which are here responsible for the major part of streamflow. So changes in the rainfall has an important effect in the natural river flows. The statistical analysis detected a change at NAO’s seasonal pattern, what means a considerable reduction of winter rainfalls in the Upper River basins located in the inland zone which is simultaneously the water collection and reservoirs area (a − 40% of water resources availability since 1980). Hydro-meteorological data and a Water Balance Model, Patrical, have been used to assess these water resources’ reduction. Results points out to the change in the Basin’s precipitation pattern in the inland areas (upper basins), associated to Atlantic weather patterns, as the main cause, while it has not been detected in the coastal areas. All these changes implies water stress for water resources planning, management and allocation, where more than 5.2 million people and irrigation of 390,000 ha are served, joint to the time variability, an important territorial imbalance exists between resources and demands. Thus, in the main upper basins, with the biggest streamflow’s reductions, locate the largest reservoirs in terms of water resources collection and reserves.

Hydropower generation represents an important contribution to meeting the challenges of today's increasing world energy needs. It uses about 44% of water in Europe, and it is the main user of water in most OECD countries. However, in most cases, the energy sector is not a water consumer. The largest part of these withdrawals is immediately returned into the environment, being able to be used by other sectors, which is its most prominent characteristic. In order to understand the water energy nexus and the challenges that the environment and other water users face, the European Commission proposed the use of water accounts in order to measure the influence of each water user, infrastructure and management decision to the total economic value of water resources in a given basin. In this sense, the SEEA-W is the most well-known approach of hybrid accounting as it provides a standard approach to compare results between different regions. This research analyses hydropower production in the Jucar River Basin (Spain), which is currently water-stressed by consumptive demands, within the SEEA-W approach. The results demonstrate that the SEEA-W approach needs some improvement in order to represent hydropower production properly.

When the regime of a river is not perennial, there are four main difficulties with the use of hydrographs for assessing hydrological alteration: i) the main hydrological features relevant for biological communities are not quantitative (discharges) but qualitative (phases such as flowing water, stagnant pools or lack of surface water), ii) stream flow records do not inform on the temporal occurrence of stagnant pools, iii) as most of the temporary streams are ungauged, their regime has to be evaluated by alternative methods such as remote sensing or citizen science, and iv) the biological quality assessment of the ecological status of a temporary stream must follow a sampling schedule and references adapted to the flow- pool-dry regime. To overcome these challenges within an operational approach, the freely available software tool TREHS has been developed within the EU LIFE TRIVERS project. This software permits the input of information from flow simulations obtained with any rainfall-runoff model (to set an unimpacted reference stream regime) and compares this with the information obtained from flow gauging records (if available) and interviews with local people, as well as instantaneous observations by individuals and interpretation of ground-level or aerial photographs. Up to six metrics defining the permanence of water flow, the presence of stagnant pools and their temporal patterns of occurrence are used to determine natural and observed river regimes and to assess the degree of hydrological alteration. A new regime classification specifically designed for temporary rivers was developed using the metrics that measure the relative permanence of the three main phases: flow, disconnected pools and dry stream bed. Finally, the software characterizes the differences between the natural and actual regimes, diagnoses the hydrological status (degree of hydrological alteration), assesses the significance and robustness of the diagnosis and recommends the best periods for biological quality samplings.

ABSTRACTPrecipitation is a major concern in water resources studies. Being a main variable, the inefficiency of historical ground network, particularly at higher altitudes where precipitation and runoff augmentations are expected, constitutes a major drawback. This work analyses the competence of Spanish historical precipitation network and explores the physiographic influence of elevation and orientation at a national scale. The usefulness of slopes is also explored. Nearly 12 000 monthly precipitation series recorded from the 19th century until the hydrological year 2004/2005 over a high‐resolution topographic map (200 m) of Spanish territory are used. Comparable statistics and precipitation lapse rates are managed once a completion of gaps is accomplished. Then, Spanish yearly rates range from 0.3 to 1.2 mm m−1, reaching 1.5 mm m−1 in Northern Iberian Peninsula, diminishing at highest altitudes.Conclusions address the inefficiency and uncertainties revealed by historical ground networks as well as the variable relationship existing between precipitation and physiographic parameters, such as altitude and orientation.