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When the river does not naturally flow: a case study of unsustainable management in the Tagus River (Spain)
Abstract
This article assesses the main problems facing the Spanish Tagus River basin, and the management that has caused (or allowed) them. It examines the economic, social, environmental and political-institutional dimensions of Tagus River management in terms of sustainable development. We find that the institutions responsible for designing and implementing water policy in the Tagus basin have been unsuccessful in balancing the three classic dimensions of sustainability, resulting in systematic and recurrent failure to comply with the European Water Framework Directive and the principles of sustainable development.
... The project has a bottom-up, co-creation approach based on the need for local communities to address a common challenge, such as in the case of the Tagus River, which shows a poor state of conservation in its middle section in the Spanish demarcation. This river is intensively used for human activities (urban and industrial supply, irrigation, hydroelectricity, refrigeration, transfers, etc.), with environmental, social and economic consequences [30], and thus makes for an ideal candidate for the development of this citizen science project. ...
... This fact has significant influence on the deterioration of the rivers on the right bank of the Tagus River due to both its high regulation for supply and the contribution of wastewater. Taking into account the geographical situation of Madrid and its metropolitan area in the upper-middle zone, 85% of the water consumption of the entire basin is produced in an area where only 45% of the resources are available [30]. ...
Citizen science is considered one of the most appropriate tools to raise public awareness of environmental issues. With the aim of improving knowledge on river environments, this article presents a web application for mobile phones and other portable devices that allows, through the active participation of society, the collection of detailed and systematic information on the main problems facing rivers. The initiative uses a web viewer (Tagus Web Viewer—TagusWV) developed as a pilot project in the Tagus River basin (Spain). This web viewer allows information on river pressures to be collected and the aggregated data to be visualised and extracted for interpretation and analysis. Pressure is defined as any use or activity, legal/illegal, authorised/unauthorised, that has an impact on water quality, morphology, river dynamics or the ecosystem. The data are mainly collected by different groups of citizens. In addition to contributing to the environmental education of citizens involved in a river environment, the data provided in the TagusWV are of particular interest to river managers. The tool is designed to be relevant for any river basin in the world, by simply loading the map, the names of the rivers and the corresponding locations.
... This water transfer has given rise to a significant development of the tourist sector in the recipient region [24] and growth of irrigated land from 166,689 ha in 1984 to over 250,000 ha in 2004 [25]. This water infrastructure has also been a source of political and social tensions between donor and recipient basins, which still exist today [26]. ...
... This was also found by Lorenzo-Lacruz et al. [56] using data from 1961-2006 obtained from nine weather stations. Despite the observed negative trends in precipitation, the volume of water diverted by the Tagus-Segura transfer has followed an increasing trend since its inauguration in 1979 [26]. ...
During the second half of the 20th century, several Spanish rivers experienced a decrease in the availability of water resources which coincided with an increase in human water demands. This situation is expected to be exacerbated by climate change. This study analyses the evolution of annual streamflow in 16 sub-basins of the Tagus River basin (Spain) during the 1950–2010 period and its relationship with selected variables. Our main objective is to characterize changes in in-stream flows and to identify what factors could have contributed to them. First, we used non-parametric tests to detect trends in the hydro-climatic series. Then, we analyzed changes in the runoff coefficient and applied regression-based techniques to detect anthropic drivers that could have influenced the observed trends. The analysis revealed a general decreasing trend in streamflow and an increasing trend in air temperature, while trends in precipitation are less clear. Residuals from regression models indicate that the evolution of several non-climatic factors is likely to have influenced the decline in streamflow. Our results suggest that the combination of the expansion of forested areas (a 60% increase from 1950 to 2010) and irrigated land (a 400% increase since 1950) could have played an important role in the reduction of streamflow in the Tagus basin.
... As with other capacity expansion options, large scale transfers offer trade-offs between cost, revenue and reliability for the water managers (Zeff et al., 2014), with different inter-utility transfer agreement mechanisms offering risk reduction for both the water buyer and seller (Lund and Israel, 1995b;Caldwell and Characklis, 2013). Careful consideration of the impact of contractual transfer agreements on the environment is also key, with licensing agreements potentially benefiting consumers at the expense of increased risk to riverine habitats (O'Keeffe and De Moor, 1988;Wildlife Countryside Link, 2016;San-Martín et al., 2020). ...
... For example, analysis of climatic-hydrological relationships in the headwaters of the Tagus River in central Spain revealed that over-use of the Tagus-Segura Water Transfer in periods containing severe climatic droughts resulted in declined natural flow and lower reservoir levels in the transfer source region (Lorenzo-Lacruz et al., 2010). Further mismanagement of the transfer during critical periods affected economic activities in the transfer source region (Hernández-Mora and Del Moral, 2015), altered the downstream river environment through reduced hydraulic connectivity, and fuelled socio-political conflicts between the donor and recipient basins (San-Martín et al., 2020). ...
Faced with the prospect of climate change and growing demands for water, water resources managers are increasingly examining the potential for inter-basin water transfers to alleviate water shortages. However, water transfers are vulnerable to large-scale spatially coherent droughts which may lead to water shortages in neighboring river basins at the same time. Under climate change, increasingly severe droughts are also expected to have greater spatial extent. We have integrated climate, hydrological and water resource modeling to explore the resilience of new transfer schemes between two neighboring water companies in Southern England. An extended historical record of river flows and large ensemble of future flows derived from climate simulations were used to explore the effects of spatial and temporal drought variability. The analysis examines meteorological, hydrological and water resource drought events and how the spatial characteristics of these droughts may change with different transfer arrangements. Results indicate that all drought types examined are expected to increase in frequency and intensity throughout the twenty-first century, but a new transfer has the capability to increase the resilience of water supplies. The analysis also highlights the importance of testing new water infrastructure against drought events that are more extreme and have different spatial patterns to those in historical records, demonstrating the value of scenario-based approaches to adaptive water resource planning.
... Its purpose is supplying water to 132,000 hectares of irrigated crops and water for human consumption to around 3 million people in the southeast of Spain, so it is of great socioeconomic relevance. This water transfer is a subject of debate, since the volume of water transferred, even if it is on average lower than the maximum authorized annual volume (650 hm 3 ), is larger than the volume that keeps flowing into the Tagus River, with severe environmental impacts in its middle and lower reaches (San-Martín et al. 2020). ...
Incorporating the simulation of water management actions in hydrological models is paramount to enhance their reliability and usefulness. SWAT + (Soil and Water Assessment Tool) includes novelties in this aspect compared to its previous versions: the decision tables and the water allocation module provide enhanced capabilities for configuring management actions. Despite their potential, these features have not yet been applied due to their novelty. This study pioneers the use of SWAT + ’s new features applied in the Upper Tagus River Basin, a densely populated and highly regulated catchment. Irrigation, reservoir management, and various kinds of water transfers were incorporated in a SWAT + model of this basin. The implementation of management actions and their impact on the model performance were evaluated. The model accurately reproduced water demand for irrigation and water transfers, capturing both the demand volume and timing. The water sources were configured to meet most of the demand, with 73% of irrigation and 90% of water transfer requirements being satisfied. Release decision tables were configured for 31 reservoirs, resulting in an accurate simulation of outflow and storage in many of them. Incorporating management actions improved the streamflow simulation at the basin outlet, both considering the hydrograph and performance metrics (e.g., PBIAS was reduced by more than 50%). Some potential improvements in the model configuration and in the code were identified and will be addressed in future studies. This work provides a comprehensive guide to SWAT + ’s new features and the methodology employed, making it valuable for anyone working with the model.
... Two e-flow proposals were analyzed: one from official documents and the other, an alternative proposal. The case study was conducted at a highly controversial location that is experiencing significant hydrological changes due to high water demands (San Martín et al. 2020). Along the river reach to be studied, there are four protected areas belonging to the Natura 2000 Network, which are home to five fish species listed in the annexes of the Habitat Directive and eight water-related habitats of Community interest, including two riparian vegetation habitats and one river habitat. ...
An environmental flow (e-flow) regime is designed to mitigate the effects of hydrological changes on rivers and to achieve good environmental status of a river as required by the Water Framework Directive (WFD). Once the components of an e-flow regime have been defined, it is important to verify that it meets its objectives, ideally through field sampling. However, field sampling is often avoided due to its high cost and time demands. This paper presents a methodology for validating a proposed river flow regime prior to implementation, allowing its suitability to be assessed without the costs and delays associated with monitoring and ecosystem response studies. The method includes a hydrological process that compares the official flow regime with the natural regime, and a hydraulic simulation process that tests the flow regime in terms of habitability for fauna. The method is tested on four reaches of the Tagus River, which have undergone significant hydrological alterations, using two different environmental flow regime proposals: one official and the other proposed by the authors. The results show a significant reduction in the annual inflows under the official e-flow regime compared to the natural ones (about 25% of the natural total), as well as a simplification of the seasonal flow variation in all river reaches. In addition, the study shows that at the minimum flows proposed in the official regime, three of the stretches would experience conditions that may impede fish migration. This method of inspecting e-flows can be useful for testing mitigation measures for hydrological changes in the very early stages of their application.
... Social, cultural, and environmental values relating to water are often in conflict with economic values [38,39], more so than for most other commodities. We propose three social indicators focusing on the employment and, more specifically, on the intensity of water use in the generation of employment by economic sectors. ...
Given the need for water use to be a crucial consideration in sustainable development, an adequate water allocation system across economic sectors is essential, especially in the face of increasing seasonal and perennial water scarcity. In an attempt to facilitate a socially and economically efficient adaptation to the climate emergency, we propose a set of eleven socio-economic indicators to analyze the current water management. This set of indicators could help to quantify the interrelationship between water use and its economic perspective, as well as its social perspective through its impact on employment. Any demand for water not only includes the direct use of water but also its indirect use, referred to as virtual water. This is the water indirectly used through the other inputs in the production process (input–output methodology). These indicators are evaluated in the South-West Europe territory where, in light of increasing water scarcity, there is a need to orientate water allocation toward employment with less intensive water use, to more water productivity and to less environmental impacts. The results at river basin scales show that water use is more productive in the tertiary than in the secondary and primary sectors.
... La Ley 52/1980 tenía más novedades como la intención de que la infraestructura permitiese un desarrollo conjunto de las dos cuencas geográficas o la inclusión de un caudal mínimo del Tajo en Aranjuez(Melgarejo & López, 2009;MIMAM, 2000). No obstante, son muchas las opiniones que argumentan que ninguna de esas dos medidas ha impedido que la cuenca del Tajo haya sido afectada negativamente por el trasvase(Hernández-Mora et al., 2013;Larraz & Cano, 2013;Larraz & San-Martin, 2021;San Martín et al., 2015;San-Martín et al., 2020), a pesar de que las leyes del trasvase garantizaban la ausencia de efectos negativos para la cuenca cedente (Ley 21/1971, de 19 de junio, sobre el aprovechamiento conjunto Tajo-Segura). 3 "Sorprende asimismo que el enorme esfuerzo realizado por el Estado en materia de regulación hidráulica solo genere (…) cifras absolutamente despreciables (…) frente a los costes reales de estas infraestructuras y los enormes beneficios generados por su uso"(MIMAM, 2000, p. 405). ...
El trasvase Tajo-Segura (TTS) es el trasvase de agua intercuencas más grande y más controvertido de España. La problemática del trasvase es muy amplia y se ha abordado desde múltiples enfoques. Aunque suelen ser las cuestiones hidrológicas las que copan los titulares relacionados con el trasvase, realmente es la variable económica subyacente sobre la que pivota el debate de fondo, especialmente en la cuenca receptora. Además, la introducción del análisis económico y, especialmente el principio de recuperación de costes, como una de las principales innovaciones de la Directiva Marco de Agua no hace sino reforzar la importancia de la dimensión económica.
Siguiendo las recomendaciones de la Comisión Europea y otros investigadores sobre la necesidad de transparencia en la recuperación de los costes de los servicios del agua, el objetivo del presente artículo, contribuyendo a dicha transparencia, es calcular el importe global de las numerosas subvenciones que ha recibido el trasvase. Teniendo en cuenta este hecho, un segundo objetivo del artículo es evaluar y discutir la percepción establecida generalmente en la cuenca receptora del trasvase de que la tarifa que se paga por el agua trasvasada es muy elevada, para lo que se realizará una comparación con la evolución temporal de los precios de la cesta de la compra y el coste de los servicios de abastecimiento de agua y otros bienes similares.
... The shift from dryland to irrigated agriculture in certain parts of Spain has increased the region's need for water. Researchers used spectral approaches to represent natural hydrological processes for med-rivers and evaluate its responsiveness to land use changes and dam development [38][39][40] daily average discharge values for major rivers Warren River, Doring River, Salinas River, and Ebro River [41][42][43][44]. ...
... Curve A and Curve B are reported in Table S1 two elements: the reduction of the natural runoff registered in the basin since the 1980s and the choice of certain control parameters in the operating rule. Since the design of the transfer in the 1960s, the Tagus headwater suffered a reduction of natural inflows by 47% (San-Martín et al., 2020), thus leading to the under-exploitation of the infrastructure with respect to the design targets. Specifically, annual transferred volumes have averaged about 350 hm 3 since 1979 instead of the projected 600 hm 3 (Senent- Aparicio et al., 2021). ...
Study region: The Tagus-Segura aqueduct (TSA) is a large and strategic water transfer scheme in Spain that connects Entrepeñas and Buendía reservoirs in the Tagus river headwaters to the Segura river basin, a highly stressed Mediterranean area. Study focus: The operating rules of the TSA underwent several modifications over the years, and the debate about which are the optimal parameters to meet the interests of the parties involved is still open. We employed Evolutionary Multi-Objective Direct Policy Search to jointly optimize the re-operation of the headwaters dams and the water transfer policy with respect to four conflicting objectives: Tagus and Segura water demands, hydropower production and socioeconomic benefit of the population living on the shores of the headwaters reservoirs. We tested the optimization under the baseline and the 2027 scenario, which foresees an increased environmental flow (EF) in the Tagus river. New hydrological insights for the region: The proposed operating rule presents optimized control parameters, a higher degree of freedom and a transferred volume that cyclically varies according to the hydrological stage of the year. In the 2027 scenario, despite the increased EF, the deficit in the aqueduct shows a limited increase compared to the historical solution (+10%), while the storage deficit is strongly reduced (−73%). This benefits the population living on the reservoirs shores and also ensures more stability to the aqueduct functioning.
... This could be avoided in future studies placing the WTP question before the question about benefits perception. As a final remark, it is increasingly necessary to consult and involve all actors and stakeholders in decisions about water management 48,49 . Infrastructures such as dams and reservoirs have historically fulfilled an essential function in water supply and the generation of hydroelectric power. ...
River barriers affect river dynamics and aquatic biota, altering the entire ecosystem. Nevertheless, dams and reservoirs provide goods like water supply and low-carbon energy that are becoming increasingly critical under current climate change. To know to what extent dams and reservoirs are important to the population, we explored social attitudes towards dams and reservoirs using a face-to-face questionnaire in two regions of contrasting climate and water security in Spain, a country with one of highest densities of dams in Europe. Results (N = 613) revealed a higher support for dams, mediated by the recognition of the services they provide, in the drier Mediterranean Malaga province (Andalusia), than in the wetter Atlantic Asturias province (Bay of Biscay), where water shortages are rare. Awareness of the impacts of the dams was more pronounced in Malaga, coupled with a higher willingness to pay for reconnecting rivers. Social awareness of both impacts and services provided by dams and reservoirs may depend on local climate and water security; different dam acceptance emphasizes the need to involve local citizens in the decision-making processes about water management.
... Water abstraction strongly affects rivers and streams in arid and semi-arid ecosystems, particularly where there is a Mediterranean climate, but climate change will also affect rainfall patterns across Europe acting as a stressor on the eel population (Benejam et al., 2010;San-Martín et al., 2020). Considering the Mediterranean region, natural and human-induced climate change, in combination with the overexploitation of water resources, has resulted in a 20% decrease in river run-off within the past half century, simultaneously increasing the frequency and duration of low flows (Karaouzas et al., 2018). ...
The Joint EIFAAC/ICES/GFCM Working group on eels (WGEEL) met by correspondence and video conference from September 21–28 in 2020 to assess the state of the European eel, investigate the effects of habitat loss on the eel stock and its management, review and update the Stock Annex, prepare the 2021 Data Call and report on any updates to the scientific basis of the advice, new and emerging threats or opportunities. Furthermore, data on fisheries landings, aquaculture and restocking are presented.
This research recovers the collective memory of elderly people who recall experiences lived alongside the Tagus River in the city of Toledo (Spain). The study develops an individual and collective narrative story to add to our understanding of the relationship between society and its environment during the years 1950–1970. A qualitative methodology is used through documentary analysis techniques and in-depth interviews. The results obtained from the testimonies reflect the influence that the Tagus River had as a natural heritage on the socialization and emotions of Toledo society. The sociological study carried out is unique, since it is the first in which, through collective memory, a contrast is made between the enjoyment of a natural fluvial environment in good condition compared to its current state of an ecosystem in deterioration.
An environmental flow regime can be used as a specific restoration measure to manage impacts on the river environment resulting from hydrological alterations or loss of structural or functional complexity of the ecosystem. With the entry into force of the WFD (Water Frame Directive), it is now also a measure to help achieve good environmental status. Once the values of its components are known, the regime should be tested to see if it can contribute to the achievement of the proposed objectives. However, the analysis of the validity of the proposal and its subsequent monitoring is not always carried out adequately. This paper presents a four-stage methodology for analysing the validity of a particular proposal prior to its implementation. The four stages include comparison with the natural regime, hydraulic simulation, validity in terms of habitability for fauna, its capacity to create habitat for fauna and a contrast with other proposals. This process is applied to the official environmental flow regime proposal for the third planning cycle in four sections of the middle course of the Tagus River (Spain). The results show that the official environmental flow regime is far from the natural regime, with very low minimum flows that do not contribute to the improvement of the fish habitat or to the conservation of the riverbanks. An alternative regime proposal is presented that gives better results than the official proposal. This proposed methodology can be useful as a control strategy prior to the implementation of an evironmental flow regime.
In rural areas, depopulation is mainly due to a lack of economic and employment opportunities. In this context, the reservoirs already built can be a source of socioeconomic development based on tourism and outdoor leisure activities. The condition for this development to materialize is that reservoir management considers these activities. In Central Spain, a process of rural depopulation has been generated in the municipalities around the reservoirs at the Upper Tagus River, as water management allows water transfers from the Tagus to the Segura River without taking into account regulations that prioritize and protect donor basin users. Through the comparison of reservoir water management and demographic data of two rural areas close to the reservoirs, this article reveals the direct relationship between reservoir management that enables recreational uses with its consequent socioeconomic development and the maintenance of the population in the territory. Consequently, reservoir water management based on the socioeconomic development of reservoir banks is necessary and a priority over transfers to another basin.
Sustainable development (SD) has become a popular catchphrase in contemporary development discourse. However, in spite of its pervasiveness and the massive popularity it has garnered over the years, the concept still seems unclear as many people continue to ask questions about its meaning and history, as well as what it entails and implies for development theory and practice. The purpose of this paper is to contribute to the discourse on SD by further explaining the paradigm and its implications for human thinking and actions in the quest for sustainable development. This is done through extensive literature review, combining aspects of the “Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and the Recursive Content Abstraction (RCA) analytical approach. The paper finds and argues that the entire issue of sustainable development centres around inter- and intragenerational equity anchored essentially on three-dimensional distinct but interconnected pillars, namely the environment, economy, and society. Decision-makers need to be constantly mindful of the relationships, complementarities, and trade-offs among these pillars and ensure responsible human behaviour and actions at the international, national, community and individual levels in order to uphold and promote the tenets of this paradigm in the interest of human development. More needs to be done by the key players—particularly the United Nations (UN), governments, private sector, and civil society organisations—in terms of policies, education and regulation on social, economic and environmental resource management to ensure that everyone is sustainable development aware, conscious, cultured and compliant.
The chapter describes the water institutions and water policies in Spain. A distinctive feature of water management in the country is the key role of basin authorities, where stakeholders are involved in all management decisions. Water policies entail very large investments in water technologies to ensure water security, with different degrees of success in terms of human provision and ecosystem protection. The evolving interplay between the federal and state water governance levels is illustrated through the main water conflicts in recent years. This strong institutional and policy setting seems powerless to offset the worsening water scarcity and degradation in basins.
Study region: Main international rivers of Iberia (SW Europe): Douro, Tagus and Guadiana.
Study focus: Iberia has long suffered from water scarcity which will worsen with projected reductions in rainfall and increases in temperature. Nonetheless, there has been almost no research concerning the future discharges of these rivers. We examine an ensemble of climate model projections from CMIP5 RCP 8.5 and use two downscaling methods to produce a range of changes in discharge using a physically-based, spatially-distributed hydrological model (SHETRAN) for historical (1961–1990) and future (2040–2070) periods.
New hydrological insights for the region: There is uncertainty in the sign of change in high (winter) discharges but most model runs show decreases in monthly, seasonal and annual discharges for all basins; especially for medium and low discharges, with all but one run showing future decreases. The magnitude of these decreases varies significantly for different CMIP5 ensemble members. However, autumn shows the biggest decreases (reaching −61% for the Douro, −71% in the Tagus, and −92% for the Guadiana) and the reductions are consistently larger for the Guadiana. This is the first study to explore a wide range of possible futures for these international basins. We show that, despite uncertainties in model projections, there is common behavior with reductions in mean and especially in low discharges which will have important implications for water resources, populations, ecology and agriculture.
The objective of this article is to show that, along with the concepts of common property and common-pool resources, the concept of common patrimony can be relevant for analyzing collective natural resource management. We proceed in three steps. First, we present the concept of common patrimony and we distinguish it from common property and common-pool resources. We show that the notion of common patrimony allows identity, historical, territorial and institutional dimensions to be taken into account as it places social dimension at the center of the analysis. Second, we illustrate the common patrimony concept by using the case of water management policy in France. Third, we place common patrimony within the framework of social ecological economics and we identify links with other approaches addressing institutional dimensions of water resource management. We outline some research questions that can be developed to contribute to a better understanding of collective natural resource management.
The dispersion of chromium (total chromium and hexavalent chromium) from water of the River Jarama (Comunidad de Madrid, Spain) into the interstitial medium, into sediments and into adjacent gravel-pit lakes was studied. Twelve sampling stations were selected in the middle reaches of Parque Regional del Sureste de Madrid. Concentrations of total chromium in the water of the river were found to be higher than target concentrations for this chemical species in surface waters (Spanish Royal Decree no. 995/2000). Chromium was present in its hexavalent form, showing concentrations one order of magnitude higher than the quality standards for Cr VI. Pollution levels in sediments and interstitial water in the river banks were very high as well, thus forming a reservoir of chromium which could potentially spread the contaminant. The probability of chromium leaking out of the river channel and into the adjacent gravel-pit lakes seems rather low, as the latter showed chromium concentrations -in water and sediments- well below the acceptable quality levels. In addition to transport and accumulation of chromium in the fluvial ecosystem, nearby agricultural ecosystems are also badly affected by the contaminant. Due to its high carcinogenicity, the presence of hexavalent chromium in the River Jarama poses a major health risk. In particular, sprinkler irrigation should be avoided in farming in order to prevent inhalation of CrVI-polluted aerosols.
Energy Policy, 69 + (2014) 43-56. doi:10.1016/j.enpol.2013.10.069
A hydrochemical characterization of the "river-alluvial aquifer" system in the Quaternary deposits of the Jarama catchment has been performed, including the rivers Jarama, Henares, Manzanares, Tajuña and a part of Tajo, as well as the alluvial aquifer associated to the said fluvial net. The roles of agriculture and urban uses have been explored as possible sources of nitrogen pollution in surface and underground water resources. Two sampling campaigns were performed, in March (at the end of the winter) and in August of 2005 (when irrigation water demand was at its highest), with water samples collected at 35 sampling stations (16 wells on the alluvial aquifer and 19 fluvial stations). The medium and low areas of the Manzanares, Jarama, Tajuña, and Tajo rivers did not meet the standards of quality established by the Tajo Catchment Hydrologic, due to high levels of ammonia, QOD and. electric conductivity, attributable to the incorporation of water treatment effluents originating from urban areas, (in some areas, conductivity levels could be explained by the geological context). The medium and low areas of the alluvial aquifer (in each subcatchment) showed very high values of nitrate concentration and conductivity, making its use unsuitable for drinking and restricting it for agricultural irrigation. A clear concordance was found between the spatial distribution of nitrate pollution in the alluvial aquifer and the agricultural irrigated areas. Using the N/P ratio as an indicator of the agricultural or urban origin it is interpreted that nitrogen pollution is mainly of urban origin in the rivers and of agricultural precedence in the alluvial aquifer (attributable to the bad management of fertilization and irrigation). The problem is compounded when water from nitrogen polluted rivers is used for irrigation, transferring nitrogen of fluvial origin into the alluvial aquifer with the irrigation return flows (urban nitrogen + fertilizers nitrogen). On the other hand, it has been observed that the excess of irrigation reverts the natural dynamic of the aquifer, producing rises of the phreatic level in extensive areas during the summer. These results provide a scientific basis to consider the declaration of the Quaternary alluvial deposits of the Jarama catchment as a Vulnerable Zone to nitrate contamination of agricultural origin, as established in the Directive 91/676/EEC.
Rapport Final (octobre 1999) pour le programme interdisciplinaire de recherche "environnement, vie et sociétés" du CNRS.
Résumé: Aujourd’hui les pratiques agricoles font l’objet d’analyses tant du point de vue des valeurs environnementales (qualité de l’eau, utilisations de paysage, contaminations chimiques, biodiversité et espaces naturels, patrimoine naturel, etc.) que du point de vue des valeurs étroitement économiques (rentabilité, choix de cultures et de régime de culture, changement technologique, emploi rural...).
Dans cette étude nous posons les questions: (1) De la légitimité et de l'acceptation sociale du système Ipest d'indicateurs agro-environnementaux déjà développés par l'INRA-Colmar ; et (2) De la pertinence de ces derniers dans une gestion intégrée au niveau local et régional dans l'optique d'une agriculture contribuant aux objectifs d'une politique de développement durable.
Juger de la pertinence des indicateurs implique, certes, de penser en termes de "réfutabilité scientifique" mais aussi (et davantage) en termes de "sens" et de "pertinence" — c'est à dire, de les resituer dans leur contexte socio-institutionnel. Les indicateurs agro-environnementaux ici retenus ne répondent qu'à une partie des objectifs de l'agriculture durable, à savoir des objectifs environnementaux. Si les indicateurs du système d'évaluation Ipest développé par l'INRA-Colmar constituent un excellent support pour offrir une information concise, facilement compréhensible et reflétant la réalité, les aspects économiques et sociaux de l'activité agricole ne sont pas représentés. Pourtant, la signification accordée aux indicateurs relève à la fois d'un contexte socio-économique individuel et d'un processus politique et fait l'objet de négociation — implicite et explicite — entre acteurs (agriculteurs, décideurs, citoyens). La tâche de notre étude est de travailler cette dimension politique et socio-économique de la question de "qualité des indicateurs".
In a semiarid and drought-prone region, Spain has managed successfully for more than 50 years to increase water supply to meet ever-increasing demands through the construction of publicly funded hydraulic infrastructures. Inter-basin water transfers are the most expensive, controversial and complex supply-side tool used. Deteriorated freshwater ecosystems, disappearance of the free services and recreational opportunities aquatic ecosystems provide to society, and loss of development opportunities for upstream communities are some unintended consequences of this supply-side approach. Over the past decade this situation has become increasingly unstable, due to the scarcity of new supply augmentation alternatives, changes at the political level (EU environmental legislation, new political power in upstream regions) and the appearance of new stakeholders at the decision making table, with their concerns and resulting conflicts. As a result, ongoing water planning efforts are being delayed by competing demands over available resources and interregional conflicts, indicating the end of an era and demanding a shift from a competitive "using water" to "sharing water" risk- and trade-off governance approach.
In this article, the state of the art of the current debate on scalar politics and water governance is reviewed. The case of the Iberian Peninsula is considered in the light of the critical approach to the river basin as the unquestionable unit for water management. It is argued that when discussing ‘spatial fit’ issues, special attention should be given to changes in governance relationships and power structures. Key questions to be addressed include: When is the river basin an appropriate alternative? What types of decisions are to be taken at the basin scale? And what practices and rights can be endangered?
Se aporta información sobre la descripción original, sinonimias, taxonomía, distribución, morfología, ciclo vital, hábitat y estado de conservación de las diez especies de náyades (moluscos bivalvos de la superfamilia Unionoidea) nativas de la península Ibérica: Margaritifera auricularia (Spengler, 1793), M. margaritifera (L., 1758), Potomida littoralis (Cuvier, 1798), Unio mancus Lamarck, 1819, U. gibbus Spengler, 1793, U. delphinus Spengler, 1793, U. tumidiformis Castro, 1885, U. ravoisieri Deshayes, 1847, Anodonta anatina (L., 1758) y A. cygnea (L., 1758). Se restablece Unio delphinus, Spengler, 1793 como el nombre válido para la especie ibérica conocida hasta la fecha como Unio pictorum y se cita por primera vez la presencia de Unio ravoisieri Deshayes, 1847 en la península Ibérica. Además se ilustran las conchas y detalles anatómicos de todas las especies, incluyendo, cuando se conoce, la forma y dimensiones de sus gloquidios así como información sobre los peces hospedadores de los mismos. También se aportan las recomendaciones que, como expertos, consideramos deben llevarse a cabo por parte de las autoridades encargadas de la gestión de la biodiversidad para garantizar la conservación futura de las especies de este grupo animal tan amenazado.
The Water Framework Directive (WFD) represents a significant departure from prior water management and planning practices in Spain. The traditional water policy, oriented towards supply augmentation to meet increasing water demands, is required to shift focus and prioritize the protection of the aquatic environment and ecological health. Despite the long hydrological planning history in Spain, little information was available on the ecological status of surface and ground waters prior to the implementation of the WFD. The requirements of the Directive have implied a significant effort for Spanish authorities to develop all biological, hydromorphological and chemical data required to determine the status of water bodies.
This study provides a first national overview of the ecological, chemical and overall
status of Spanish surface water bodies (rivers, lakes, transitional and coastal), identifies
the most problematic areas and discusses the consistency and adequateness of
the methods and indicators used across basins. To carry out the analysis, we use the
status information contained in the draft or approved River Basin Management Plans
(RBMPs) available at this point. Our results show that almost 50% of all surface
waters in Spain are in poor status, mainly due to their poor ecological status. 43% of
surface water bodies have not yet been evaluated so the information presented in the
study is necessarily partial and incomplete. Available data shows that rivers and transitional waters are the water bodies in poorest status. The Southern basins draining
into the Atlantic Ocean show the worst rank, with over 53% of surface waters in poor
status. The lack of reference conditions to measure some key indicators such as fish fauna and most hydromorphological conditions, impedes making robust comparisons
across basin districts at this point.
The “Convention on Co-operation for Protection and Sustainable Use of Portuguese-Spanish River Basins,” effective since January 2000, corresponds to a new and expected phase on bilateral water resources issues, applying to a basin-wide ecosystem protection of all shared rivers and aiming at risk prevention improvement on those basins. After a brief analysis of shared water resources and uses and of the current and foreseen Portuguese water resources planning, legal, and institutional contexts, an identification is made of water problems to be solved in common or bilaterally and some of the downstream impacts. Thereafter, a brief description of the Convention provisions is presented, relating it to International Law and to European Union (EU) water policy, namely to the Water Framework Directive. The compatibility of both active documents is analyzed, as well as the needs for institutional capacity building and for monitoring their application, with special emphasis on the Portuguese case, taking into account the two countries' differing institutional water organization, water planning development stages and methodologies, and the public participation tradition on decision-making processes. Special emphasis is given to the relevance of the Convention's institutional boards to the common implementation process.
Se ha realizado una caracterización hidroquímica del sistema �río-acuífero aluvial� situado en los depósitos cuaternarios de la cuenca del Jarama, incluyendo los ríos Jarama, Henares, Manzanares, Tajuña y una parte del Tajo, así como el acuífero aluvial asociado a dicha red fluvial. Se ha explorado el papel de los usos agrícolas y urbanos como fuentes potenciales de contaminación por nitrógeno de los recursos hídricos superficiales y subterráneos.Se realizaron dos campañas de muestreo, en marzo (final del invierno) y agosto de 2005 (cuando la demanda de agua para riego era máxima), con recogida de muestras de agua en 35 estaciones de muestreo (16 pozos sobre el acuífero aluvial y 19 estaciones fluviales). En los tramos medios y bajos de los ríos Manzanares, Jarama, Tajuña y Tajo no se alcanzaban los objetivos de calidad establecidos en el Plan Hidrológico de la Cuenca del Tajo, debido a los elevados valores de amonio, DQO y conductividad eléctrica, atribuibles a la incorporación de efluentes de depuradora procedentes de las áreas urbanas (los niveles de conductividad pueden explicarse por el propio contexto geológico en algunas zonas). Los tramos medios y bajos del acuífero aluvial (en cada subcuenca) mostraron valores muy elevados de nitrato y conductividad, imposibilitando su uso para el abastecimiento y restringiéndolo para el riego agrícola. Se aprecia una clara concordancia entre la distribución espacial de la contaminación por nitrato en el acuífero aluvial y las zonas agrícolas de regadío. Utilizando el cociente N/P como indicador del origen agrícola o urbano de la contaminación por nitrógeno, se interpreta una procedencia principalmente urbana en los ríos y una procedencia agrícola en el acuífero aluvial (atribuible a las malas prácticas de riego y abonado). El problema se complica cuando los riegos se realizan con aguas fluviales contaminadas por nitrógeno, produciéndose un trasvase de nitrógeno de origen fluvial hacia el acuífero aluvial con los retornos de riego (nitrógeno urbano + nitrógeno de los fertilizantes). Por otra parte, se ha observado que el riego en exceso invierte la dinámica hídrica natural del acuífero, produciendo ascensos en el nivel freático en amplias zonas durante el verano. Estos resultados proporcionan una base científica para considerar la de claración de los aluviales cuaternarios de la cuenca del Jarama como Zona Vulnerable a la contaminación por nitrato de origen agrícola, tal como se establece en la Directiva 91/676/CEE.
Paper was originally presented at 1992 UN Rio Earth Summit. How can countries safeguard natural resources for future generations as they strive to reduce poverty with economic growth. Environmental Economics and Sustainable Development discusses practical options to reconcile these multiple environmental, economic and social goals. It explains how to place an economic value on the long-term benefits of natural resources and on the socio-economic development activities that affect the environment. The author shows how to gauge the environmental impact of projects early in the evaluation cycle. The links with environmental macroeconomics are also discussed.
El estudio de los moluscos de agua dulce llevado a cabo en la Comunidad de Madrid permite citar 33 especies, de ellas 25 son de gasterópodos y ocho son de bivalvos. De estas especies, 23 ya habían sido citadas previamente en esta área, aunque la mayoría con otros nombres, bien porque en la actualidad son sinónimos, o bien por determinaciones erróneas. Para las 33 especies, identificadas en un total de 463 muestras analizadas, junto con el estudio de los ejemplares conservados en el Museo Nacional de Ciencias Naturales, se aportan datos taxonómicos y breves descripciones, así como información sobre los hábitats en los que se han encontrado. Se indica también si habían sido citados previamente en el área y el nombre asignado por los diferentes autores. De acuerdo con los datos bibliográficos manejados, un total de nueve especies se citan por primera vez en la región: Pseudamnicola (Pseudamnicola) subproducta, Pseudamnicola (Corrosella) hinzi, Lymnaea stagnalis, Stagnicola palustris, Gyraulus (Gyraulus) chinensis, Gyraulus (Torquis) laevis, Ferrissia (Pettancylus) clessiniana, Oxyloma (Oxyloma) sarsii y Pisidium subtruncatum. Entre las especies citadas por otros autores, cabe mencionar que “Islamia” coronadoi, Anisus (Disculifer) vortex y Segmentina nitida, no han podido ser localizadas. Stagnicola palustris se cita por primera vez, aunque sólo se han encontrado conchas. Dos especies, Potamopyrgus antipodarum y Gyraulus chinensis, son introducidas; la primera de ellas, considerada como invasora, presenta una amplia distribución. Del mismo modo citamos Lymnaea stagnalis y Oxyloma (Oxyloma) sarsii, que sólo se han encontrado en un centro de jardinería, por si incidentalmente pudieran extenderse a hábitats naturales en la región.
This paper reviews the hydraulic paradigm in Spain and its evolution over the last 100 years to the current decentralisation process of "agua para todos", i.e. where different regional governments vie for control over 'scarce' water resources and defining the concept of hydro-solidarity between regions. Recent events seem to point to a new hydraulic bureaucracy at the sub-national level due to the political devolution currently taking place in Spain, where water has an increased political value in electoral terms. Water has strategic importance in single-issue politics and territorial identity, as compared to traditional left/right ideologic cleavage politics for both national and regional parties in the Spanish multilevel electoral system. This refers to an aspect – openly discussed in Spain but rarely analysed – the 'political returns' on water (or 'political rent-seeking'). This also points to spatial dimensions of the definition of state, identity, and access to resources in a semiarid country. This historical process of decentralisation of water is highlighted with particular reference to key events in recent Spanish history, including the Hydraulic Plan of the 1930s, its reappearance in the 1993 National Hydrological Plan, a revised version in the year 2001, and a final change in paradigm in 2005 at the national level. This suggests that the hydraulic paradigm is re-enacted at the regional government level. Thus it is argued that a multi-scalar analysis of Spanish water decentralisation is essential in order to understand change and stasis in public policy paradigms related to water.
La adecuación del trasvase Tajo-Segura a los criterios generales que sirven de base a la legislación que regula las transferencias de agua, el análisis de la política tarifaria y el balance económico de su gestión entre 1979 y 1995 son los principales temas que se abordan en este artículo. El modelo de explotación del Acueducto Tajo-Segura significó una ruptura en el sistema de financiación de las obras hidráulicas por el Estado, se perseguía que los usuarios fuesen los que corriesen con las inversiones y con los gastos de funcionamiento, buscando la autosuficiencia, al tiempo que la obtención de recursos adicionales para el cumplimiento de las obligaciones compensatorias con la cuenca cedente. La explotación del ATS y sus resultados económicos se han visto condicionados por la planificación de las obras y por la infrautilización que se ha venido haciendo de las mismas, lo que ha repercutido en un encarecimiento del agua conducida y ha servido para cuestionar la rentabilidad del trasvase.
The main aims of this paper are the study of the degree of correspondence of the Tajo-Segura hydraulic transfer (TST) to the general criteria that are in the base of the legislation about water transfers, the analysis of tax policy and the economic imbalance of the TST management between 1979 and 1995. The exploitation model of TST meant a breakdown in the financing system of hydraulic works by the State. The aim was the customers to cover investments and ordinary expenses in a search for economic autonomy. At the same time one of the goals was to produce enough surpluses to economically compensate the institution that owned the transferred water originally. The exploitation of TST and its economic results have been conditioned by the planning of the works and by the underemployment that the built facilities have suffered, this factors leading to the rise of the price of transferred water and the questioning of TST economic results.
The Henares-Jarama-Tajo river system is the largest drainage basin in the Province of Madrid, Spain. This area is characterized by the presence of intensive urban and industrial activities influenced by a continental Mediterranean climate with rainfalls presenting substantial fluctuations along the different seasons. This research aimed to monitor seasonal variations in concentrations of 22 pharmaceutically active compounds (PhACs) in this river system and to establish the potential risk of sublethal effects on aquatic organisms. A total of 10 sampling sites were selected along the river system with samples collected in each of the four seasons during a year-round schedule. Most of the PhACs detected were present in sampling sites downstream in the vicinity of the most populated cities (i.e. Madrid, Guadalajara and Alcalá de Henares). Only two PhACs, fluoxetine and paraxantine, were detected in all sites regardless of the season, and showed median (+/- interquartile range) concentrations of 21.4 (+/-31.2) ng L(-1) and 8.5 (+/-5.3) ng L(-1), respectively. Other PhACs were detected with a frequency >80% and included, caffeine, diphenylhydantoin, hydrochlorotiazide, ibuprofen, ketoprofen, diclofenac, sulfamethoxazole, atenolol, naproxen, carbamazepine and propanolol. Seasonal variations were observed with the highest concentrations in December and the lowest in September. By combining measured environmental concentrations with toxicity data (either publicly available or obtained experimentally in our laboratory), and by calculating an Maximum Risk Index (MaxRI) that each combination of PhACs should have for non exceeding the risk threshold, a high potential for long-term risk (MaxRI<10) was estimated for most of the sampling sites and sampling dates. This research allowed the characterization of the potential risk for each of the PhACs to exert sublethal effects on aquatic organisms using acute screening methods, justifying the need for chronic data in order to refine the risk of these compounds to aquatic organisms.
La mayoría de los economistas tiende a considerar al agua como un factor de producción más que es necesario, en mayor o menor medida, para las diferentes actividades humanas, siendo el indicador de la importancia del mismo su precio o los resultados monetarios derivados de su uso. Si, por el contrario, reconocemos que el agua es un medio o activo social que proporciona un conjunto amplio de funciones ambientales -no siempre expresables en términos monetarios- es decir, que existen interdependencias físicas entre el agua, la economía y el medio ambiente, nos veremos obligados a replantear las nociones que nos permitan comprender tanto la importancia de dicho activo como el papel de las instituciones en la definición de los criterios adecuados para su gestión.
The aim of this study was to integrate hydrochemical and sediment data in order to obtain a picture of the pollution state of the Tagus River along central Spain. This area is of special interest because tributaries from the Madrid region are discharged and no previous data were available. Waters and sediments were sampled between 2002 and 2004 from selected sites before and after Jarama River confluence (Madrid city input). The samples were analysed for more than 50 parameters, including those of physico-chemical nature and those reporting the pollution caused by both metals and organic compounds. The quality of waters for different uses has been tested and statistical quality indexes of both global and partial type has also been established. Sediments pollution state was evaluated by comparison with general quality standards. A high degree of pollution and general degradation was observed in the Tagus River downstream the Jarama River input. The pollution of waters is mainly related to parameters indicators of organic pollution from urban sewage. In sediments, a dramatic increase in the concentration of trace metals was found in different points, exceeding toxicological threshold. Further studies would be necessary for organic pollutants and also to evaluate the remobilization potential.
Wolfgang Sachs argues for environmental human rights as a fundamental prerequisite to end the violence of development. He outlines the numerous conflicts over natural resources in the struggle for livelihoods and argues for a transition to sustainability in the more affluent economies, in both the North and South, as a necessary condition for the safeguarding of the subsistence rights of those whose livelihood depends on direct access to nature. Development (2004) 47, 42–49. doi:10.1057/palgrave.development.1100016
Anthropic pressure deteriorates river water quality, so authorities need to identify the causes and define corrective action. Physically based water quality models are a useful tool for addressing physico-chemical pollutants, but they must be calibrated with an amount of data that is often unavailable. In this study we explore the characterization of a model to design corrective intervention in the context of sparse data. A calibration indicator that is both simple and flexible is proposed. This approach is applied to the Middle Tagus Basin in central Spain, where the physico-chemical concentration of pollutants is above legal standards. We quantify the effects of the main existing pressures (discharge from wastewater treatment plants, agricultural diffuse pollution and a major inter-basin water transfer) on the receiving waters. In particular, the study finds that wastewater treatment plant effluent concentrations should be reduced to up to 0.65 mg/L of ammonium and 0.55 mg/L of phosphate to achieve the environmental goals. We propose and prioritize a set of policy actions that would contribute to the good status of surface water bodies in the region.
This article presents a brief analysis of sustainable development in the context of contemporary productive forces and production relationships, as well as their contradictions regarding the limits of nature. For this particular evaluation, it was necessary to present a logical critique of ecological economics and environmental economics. To corroborate this inherent contradiction, certain data were included, such as surplus food production, the use of agrochemicals, the increasing average temperature of the planet due to the emission of greenhouse gases, and inequality in the distribution of income. Subsequently, an analysis of these data was performed. Finally, some general elements related to a new way of thinking about the productive forces and production relationships were proposed, which focus on a production dynamic directed toward basic human needs instead of market needs.
Conventional water management strategies, that serve solely socio-economic demands and neglect changing natural conditions of the river basins, face significant challenges in governing complex human-hydrological systems, especially in the areas with constrained water availability. In this study we assess the possibility to harmonize the inter-sectoral water allocation scheme within a highly altered human-hydrological system under reduction in water availability, triggered by projected climate change applying scenario-based approach. The Tagus River Basin headwaters, with significant disproportion in the water resources allocation between the environmental and socio-economic targets were taken as a perfect example of such system out of balance. We propose three different water allocation strategies for this region, including two conventional schemes and one imposing shift to sustainable water management and environmental restoration of the river. We combine in one integrated modelling framework the eco-hydrological process-based Soil and Water Integrated Model (SWIM), coupled with the conceptual reservoir and water allocation modules driven by latest bias-corrected climate projections for the region and investigate possible water allocation scenarios in the region under constrained water availability in the future. Our results show that the socio-economic demands have to be re-considered and lowered under any water allocation strategy, as the climate impacts may significantly reduce water availability in the future. Further, we show that a shift to sustainable water management strategy and river restoration is possible even under reduced water availability. Finally, our results suggest that the adaptation of complex human-hydrological systems to climate change and a shift to a more sustainable water management are likely to be parts of one joint strategy to cope with climate change impacts.
Please cite this article in press as: Antiguedad, I., et al., A simple multi-criteria approach to delimitate nitrate attenuation zones in alluvial floodplains. Four cases in southwestern Europe. Ecol. Eng. (2016), http://dx. a b s t r a c t Four alluvial floodplains were selected in the European southwestern lowland area: the rivers Ebro, Bidasoa, Tagus (Spain) and the Garonne (France) were chosen. They have some common characteristics (alluvial aquifers, connectivity with the river, nitrate pollution) but differ in other important aspects (water table fluctuations, flooding dynamics, landscape control, land use, agricultural practices, climate). A comparative study considering nitrogen and carbon sources and the way they interact in the riparian zone was conducted in order to test a simple approach to delimitate permanent nitrate attenuation zones and to evidence the importance of site-specific attributes. The observation was based on a detailed monthly monitoring during a year ensuring data at high and low water periods. The tested approach results in a useful tool to spatially delimitate the attenuation zones. However, this approach is difficult to apply in areas where pollution sources are very diverse in type and in both time and space. This leads us to conclude that a general conceptual model cannot capture all the factors needed to understand the nitrate removal dynamics of a riparian zone. Hence, the study combines observation-conceptualization framework with river-riparian-upland connectivity and source-pathway-target continuity.
Spain and Portugal share four important Iberian rivers, namely from North to South: the Minho- Limia, Douro, Tagus and Guadiana. They all discharge into the Atlantic Ocean. The catchment areas of these basins total 44.8% of the Iberian Peninsula and represent about 46% of the annual surface discharge. These shared rivers account for 740 km of the 1214 km border between the two countries. Very few countries in the world have four shared rivers with four different configurations (see Figure 1), occupying so much of their territory.
Howe and Easter analyze existing evidence on direct and indirect benefits attributable to water, as well as the potential costs of interbasin transfers, and examine feasibility of alternatives. Originally published in 1971. © The johns Hopkins University Press 1971, Earthscan 1971, 2011. All rights reserved.
Economic instruments are being promoted as a desirable alternative to public sector action in the allocation and management of natural resources. A wide body of literature has developed that critically analyzes this phenomenon as part of a wider project of 'neoliberalization of nature', trying to uncover the underlying rationale and commonalities of geographically specific phenomena. The case of water is at the vanguard of these processes and is proving to be particularly contentious. In the European Union water policies are increasingly emphasizing the application of economic instruments to improve the allocative equity and economic efficiency in the use of scarce resources. However, there are few analyses of how these instruments are really working on the ground and whether they are meeting their objectives. This paper aims to contribute to this debate by critically analyzing the experience with water markets in Spain, the only country in the European Union where they are operative. It looks at water permit sales during the 2005-2008 drought period using the Tajo-Segura transfer infrastructure. The paper describes how the institutional process of mercantilización of water works in practice in Spain. It shows that the use of markets requires an intense process of institutional development to facilitate and encourage their operation. These institutions tend to favor the interests of clearly identifiable elites, instead of the public interest they supposedly promote.
The seasonal distribution of polycyclic aromatic hydrocarbons, polychlorinated biphenyls, organochlorine pesticides, organophosphorus pesticides, triazines and other organic pollutants in surface seawater from the Mar Menor lagoon (SE Spain) was characterized from spring 2009 to winter 2010 by stir bar sorptive extraction and thermal desorption followed by capillary gas chromatography coupled to mass spectrometry (SBSE-GC-MS). The most ubiquitous pollutants were chlorpyrifos, chlortal-dimethyl, terbuthylazine, naphthalene and propyzamide throughout the year. Insecticides and herbicides were predominant in summer and spring, and fungicides were more abundant in autumn and winter. Chlorpyrifos was predominant in autumn and spring; herbicides (propyzamide, terbuthylazine and terbuthylazine-desethyl) in autumn and fungicides (flutolanil, boscalid, cyprodinil) in autumn and winter. The highest concentrations for the majority of pollutants were detected in autumn as consequence of air and surface/ground water inputs, and above all of desorption from terrigenous materials deposited in sediments by two intense flash flood events (September 2009).
In the Mar Menor lagoon (SE Spain) recent changes in the nearby agricultural practices, from extensive dry crop farming to intensively irrigated crops, have increased nutrient and particulate inputs through the principal watercourse that flows into the lagoon, the Albujón wadi. The concentration of nutrients and suspended sediments in the waters has risen, increasing phytoplankton densities and diminishing water column transparency. As a result of these environmental changes, the traditional main macrophyte of the Mar Menor, Cymodocea nodosa (Ucria) Ascherson, has been replaced by the macroalga Caulerpa prolifera (Forsskal) Lamouroux creating changes in the sediment characteristics with profound consequences to benthic communities and also to local fishing and tourism. In the study area, seagrass respiration exceeded photosynthesis while the macroalga presented positive rates of net photosynthesis. C. prolifera is better adapted to these new conditions of light and nutrient concentration and has expanded its distribution, occupying most of the bottom of the lagoon and restricting C. nodosa to small patches in very shallow areas, where plant growth is not limited by light and no C. prolifera can be found because of photoinhibition and emersion stress.
We studied the effect of severe fluctuations in flow on the distribution of bottom fauna of the upper Kennebec River. During the years 1964–1970, discharges below Wyman Dam ranged from 8.5 m3/sec to an average daily high of about 170 m3/sec. Slow currents resulting from low flows appeared to limit the diversity and abundance of swift-water aquatic insects on the river-bottom below the dam. Sampling stations above the impoundment averaged 19 aquatic insect genera, while those below the dam averaged 11. About 19 genera were found at stations where the current near bottom fluctuated from 0.5 m/sec to 0.9 m/sec while only 4 genera were found at stations where the fluctuations were from 0.1 to 0.5 m/sec. Aquatic insects adapted for swift water such as Rhyacophila, Chimarra, Iron, Blepharocera, Acroneuria, and Paragnetina were more abundant above the impoundment than below, and were absent from those stations below the impoundment with the lowest current velocities.
Aquest article presenta una anàlisi sobre les relacions històriques i actuals
entre el capital, l'obra civil, els regadius i l'energia hidroelèctrica en el procés
de regulació hidrològica a Espanya. El paisatge i l'ordenació del territori en
moltes conques hidrogràfiques de la península Ibèrica està totalment condicionat
per les transformacions antròpiques que han suposat els pantans.
Aquestes obres, sovint controvertides, tenen una doble vessant: beneficis a
molta distància (regadius, subministrament d'aigua de boca, producció d'energia
elèctrica, etc.) i problemes a curta distància (expropiació de pobles, pèrdua
de terres de conreu, aïllament de valls, etc). A partir d'un repàs històric del
desenvolupament de les diferents obres hidrogràfiques espanyoles es mostren
les relacions que tradicionalment han tingut el capital privat amb les grans
obres públiques i com aquestes, en el cas de l'energia hidroelèctrica, han servit
per crear un paisatge d'aigua on aquesta mancava.
Water level fluctuations below a hydroelectric dam on the Connecticut River produce a freshwater "intertidal" zone. Along a transect in this zone from high to low water mark benthic invertebrates increased markedly in density and taxonomic diversity. Community composition shifted from chironomid–oligochaete predominance on the most exposed sites to mollusc predominance on the least exposed sites.
Spain and Portugal share a substantial part of their water resources: basins of the MiñTo, Límia, Duero, Tajo, and Guadiana Rivers. The 1964 and the 1968 Agreements are good examples of the cooperation possibilities between countries in this field. Given that these Agreements have been totally developed, that new questions have appeared on the international scene, and given the political, economic, and social evolution of both countries there is a need to reach a new agreement. Conversations were initiated in 1993 and concluded in 1998 with the signing of the Albufeira Convention. This agreement is based on the wealth of experience accumulated by both countries, and it establishes a framework for the exploitation and protection of water resources, acknowledging each country's right to manage the waters within its territory. The agreement, which is applied to all the basins, deals with situations derived from extreme phenomena, such as droughts and floods in the same way as the problems derived from accidental pollution incidents. Likewise, the cooperation organisms for the application and the development of the conventional framework are established in it.
The influence of climate variation on the availability of water resources was analyzed in the headwaters of the Tagus River basin using two drought indices, the standardized precipitation index (SPI) and the standardized precipitation evapotranspiration index (SPEI). This basin is highly regulated and strategic, and contains two hyperannual reservoirs that are the origin of the water supply system for Mediterranean areas of southeast Spain. The indices confirmed that drought conditions have prevailed in the headwaters of the Tagus River since the 1970s. The responses in river discharge and reservoir storage were slightly higher when based on the SPEI rather than the SPI, which indicates that although precipitation had a major role in explaining temporal variability in the analyzed parameters, the influence of temperature was not negligible. Moreover, the greatest response in hydrological variables was evident over longer timescales of the climatic drought indices. Although the effect of climate variability on water resources was substantial during the analyzed period, we also showed a major change in hydrological–climatic relationships in regulated systems including reservoir storage and outflow. These were closely related to changes in external demand following commencement of the water transfer system to the Júcar and Segura basins after the 1980s. The marked reduction in water availability in the basin, which is related to more frequent droughts, contrasts with the amount of water transferred, which shows a clear upward trend associated with increasing water demand in the Mediterranean basin.
To alleviate Arizona's dependence on groundwater, the federal government subsidized construction of the Central Arizona Project (CAP) to import water from the Colorado River. In exchange for the subsidy, Arizona reformed its groundwater law to eliminate common-property pumping and to ban groundwater mining after the year 2025. We build a model of water resource development in which imported water is a capacity constrained backstop. The model is applied to quantify the welfare effects of alternative CAP construction dates and Arizona groundwater laws. We reach two general conclusions. First, CAP was completed 86 years too early, in 1987, at a deadweight loss of 2.612 billion) than it corrected ($0.810 billion). The exchange was worse than doing nothing at all.
There are a number of reports in the literature which describe the occurrence of so-called emerging pollutants, such as pharmaceuticals, in surface water. Few of these studies have reported values from large cities in relatively arid areas, such as in Spain. The persistence of some pharmaceuticals to usual wastewater treatments allows their discharge into surface waters. It is increasingly evident that mental health problems are of special concern for public health since psychiatric drugs are used in large amounts. Compared to other countries, Spain has a high pharmaceutical consumption rate, and Madrid metropolitan area is one of the most densely populated areas in Europe. The aim of the present study was to determine the presence of different psychoactive pharmaceuticals and metabolites in the main rivers of Madrid metropolitan area: Jarama, Manzanares, Guadarrama, Henares and Tajo. Sampling was done downstream of ten sewage treatment plants (STP) discharging into these rivers. Control points upstream of STPs discharge points were also sampled. Pharmaceutical compounds and metabolites for analysis were selected according to human consumption and prescription rates in Madrid, and the availability of valid techniques for detection. We observed residues of the antidepressants fluoxetine (80% of the sampling sites), citalopram (60%) and venlafaxine (100%), the anxiolytics nordiazepam (90%), oxazepam (80%) and 7-aminoflunitrazepam (10%) and the anticonvulsant carabamazepine (70%). Measured concentrations equalled or exceeded those reported for other geographical areas, although there is a pronounced lack of information for the anxiolytics and venlafaxine. This is of special concern given that Wyeth-Ayerst's venlafaxine, Effexor, was the 10th greatest selling pharmaceutical worldwide in 2006. We conclude that the origin of pharmaceutical pollution in the rivers of Madrid is mainly the discharge of sewage treatment plants in Madrid's metropolitan area and a comprehensive monitoring program should be implemented.
A study into levels of contamination by organochlorine compounds (insecticides and PCBs) and heavy metals (Cd and Pb) in the water/sediment system of the Southeast Regional Park (SERP) in Madrid, Spain, has been carried out. Residue levels of xenobiotics were determined in surface and underground waters and sediments from selected sites throughout the protected area. The results showed these contaminants to be widespread throughout the studied area. p,p'-DDT concentration levels were consistently higher than its metabolite p,p'-DDE, indicating a recent use of this organochlorine insecticide in the area. PCB levels exceeded, in the majority of the cases, the levels taken as the maximum (100 ng/microl) for highly polluted waters. Cd and Pb levels found in water samples were under the detection limits of the methodology used. Pb levels found in sediment samples were higher than Cd.