Mediterranean River Basin Research Articles

Basic tools for setting environmental flows at the regional scale: application of the ELOHA framework in a Mediterranean river basin

AbstractEcological limits of hydrological alteration (ELOHA) framework aims to set limits of hydrologic alteration based on empirical hydroecological relationships built along flow impairment gradients. These relationships can be specific for different natural flow regime types. The object of our study is testing the ELOHA method in the Ebro River Basin. Seven flow alteration–ecological response curves were obtained in the present study as preliminary guidelines for developing and calibrating environmental flow standards in the Ebro River Basin. For continental Mediterranean‐pluvial flow regime mean monthly flow in March was related to Plecoptera abundance (ELOHAs ±21% from baseline), and high flow magnitude and frequency were closely related to Plecoptera, Ephemeroptera and Trichoptera richness (ELOHAs for high flow magnitude and frequency were +18 and +54% the reference central value respectively). For nivo‐pluvial flow regime, high flow magnitude was found indicative of macroinvertebrate biodiversity and Coleoptera abundance (ELOHAS −12 and +23% from central reference value respectively). And for pluvio‐oceanic flow regime, mean monthly flow in January was indicative of the proportion of Gastropoda, Oligochaeta and Diptera taxa (GOLD index) (ELOHA +17% from baseline). These hydrological limits are endorsed by recent international reference works. Flow alteration–ecological relationships presented here were constructed from real monthly flow data records and macroinvertebrate samples at family level. ELOHA values obtained in this study pretend to be a starting point for implementing an environmental flow regime program in the Ebro River Basin. Copyright © 2016 John Wiley & Sons, Ltd.

Regional distribution and temporal changes in density and biomass of Didymosphenia geminata in two Mediterranean river basins

This study aimed to strengthen the knowledge of Didymosphenia geminata distribution in Spain, and to determine which environmental variables were related to its regional distribution and temporal changes in growth and production in two Ebro River tributary basins (Iregua and Najerilla¸ La Rioja Region). Living cells of D. geminata were present in 40% of the studied sites of both basins but only four of the sites developed massive growths. The diatom is widely distributed only in mountain areas of both basins (above 690 masl), which have low average annual air temperature (8.27 ± 0.28 oC) and low water Soluble Reactive Phosphorus (SRP) concentration (average value 0.024 ± 0.007 ppm). Massive growths occur in sites with high light intensity, hydrological regulation of river flow and the lowest measured SRP concentrations (below 0.018 ppm SRP). We carried out an intensive spatio-temporal survey in the Lumbreras River (Iregua basin), where the first massive growth was detected in La Rioja Region. The highest cell densities (1.6 × 105 cells cm−2) and biomass values (480 gDWm−2) were recorded in late summer. An increase in solar radiation and slight rise in water temperature were associated with an increase in biomass over time, but always in waters with low SRP concentration, the key factor that enhances massive growth development. The alteration of the natural streamflow in the Lumbreras River by the Pajares Reservoir and the fact that water is discharged from the hypolimnion (which decreases the summer river water temperature) are important factors in understanding why D. geminata shows such an increase in biomass in a Mediterranean river. This paper provides new insights into the importance of different factors controlling D. geminata massive proliferations in the Mediterranean climate zone, where it is assumed that the species should not develop such massive growths, compared to temperate zones where the majority of previous studies have been carried out. We suggest that changing the reservoir management strategy would be a very important contribution to the control of such significant developments.

Spatial scale effects on Chironomidae diversity and distribution in a Mediterranean River Basin

Chironomidae are a very common insect group in running waters of Greece; however, they have been rarely studied. The aim of this work was to investigate Chironomidae distribution and abundance in a Mediterranean intermittent river basin, identify the environmental factors that are linked to variation in their assemblages and to partition the influence of environmental and spatial components, alone and in combination, on Chironomidae community composition. Multivariate ordination techniques were used to assess the association between environmental variables and species abundance, while variation partitioning was performed using partial canonical correspondence analysis to understand the importance of different explanatory variables in Chironomidae variation. Chironomidae variation was divided into independent and joint effects of micro-scale (physical and chemical variables, microhabitat composition, etc.), meso-scale (land use/cover) and macro-scale (altitude and distance to source, etc.) variables. Stream width and depth, water discharge, land uses, pH, and ecological quality were the most important factors structuring Chironomidae assemblages. Micro-scale variables accounted for 55.6% of the total explained variation followed by meso-scale (10.7%) and macro-scale (10.4%) variables. The results of partial constraint analyses suggest that micro-scale variables play a major role in Chironomidae assemblages.

Adaptation strategies for water supply management in a drought prone Mediterranean river basin: Application of outranking method

The regional water allocation planning is one of those complex decision problems where holistic approach to water supply management considering different criteria would be valuable. However, multi-criteria decision making with diverse indicators measured on different scales and uncertainty levels is difficult to solve. Objective of this paper is to develop scenarios for the future imbalances in water supply and demand for a water stressed Mediterranean area of Northern Spain (Tarragona) and to test the applicability and suitability of an outranking method ELECTRE-III-H for evaluating sectoral water allocation policies. This study is focused on the use of alternative water supply scenarios to fulfil the demand of water from three major sectors: domestic, industrial and agricultural. A detail scenario planning for regional water demand and supply has been discussed. For each future scenario of climate change, the goal is to obtain a ranking of a set of possible actions with regards to different types of indicators (costs, water stress and environmental impact). The analytical method used is based on outranking models for decision aid with hierarchical structures of criteria and ranking alternatives using partial preorders based on pairwise preference relations. We compare several adaptation measures including alternative water sources (reclaimed water and desalination); inter basin water transfer and sectoral demand management coming from industry, agriculture and domestic sectors and tested the sustainability of management actions for different climate change scenarios. Results have shown use of alternative water resources as the most reliable alternative with medium reclaimed water reuse in industry and agriculture and low to medium use of desalination water in domestic and industrial sectors as the best alternative. The proposed method has several advantages such as the management of heterogeneous scales of measurement without requiring any artificial transformation and the management of uncertainty by means of comparisons at a qualitative level in terms of the decision maker preferences.

Detection and attribution of global change effects on river nutrient dynamics in a large Mediterranean basin

Abstract. Attributing changes in river water quality to specific factors is challenging because multiple factors act at different temporal and spatial scales, and it often requires examining long-term series of continuous data. Data consistency is sometimes hindered by the lack of observations of relevant water quality variables and the low and uneven sampling frequency that characterizes many water quality monitoring schemes. Nitrate and dissolved phosphate concentration time series (1980–2011) from 50 sampling stations across a large Mediterranean river basin were analyzed to disentangle the role of hydrology, land-use practices, and global climatic phenomena on the observed nutrient patterns, with the final aim of understanding how the different aspects of global change affected nutrient dynamics in the basin. Dynamic factor analysis (DFA) provided the methodological framework to extract underlying common patterns in nutrient time series with missing observations. Using complementary methods such as frequency and trend analyses, we sought to further characterize the common patterns and identify the drivers behind their variability across time and space. Seasonal and other cyclic patterns were identified as well as trends of increase or decrease of nutrient concentration in particular areas of the basin. Overall, the impact of global change, which includes both climate change and anthropogenic impacts, on the dynamics of nitrate concentration across the study basin was found to be a multifaceted process including regional and global factors, such as climatic oscillations and agricultural irrigation practices, whereas impacts on phosphate concentration seemed to depend more on local impacts, such as urban and industrial activities, and less on large-scale factors.

Aquatic risk assessment of priority and other river basin specific pesticides in surface waters of Mediterranean river basins

To meet good chemical and ecological status, Member States are required to monitor priority substances and chemicals identified as substances of concern at European Union and local/river-basin/national level, respectively, in surface water bodies, and to report exceedances of the environmental quality standards (EQSs). Therefore, standards have to be set at national level for river basin specific pollutants. Pesticides used in dominant crops of several agricultural areas within the catchment of Mediterranean river basins (‘Mondego’, ‘Sado’ and ‘Tejo’, Portugal) were selected for monitoring, in addition to the pesticides included in priority lists defined in Europe. From the 29 pesticides and metabolites selected for the study, 20 were detected in surface waters of the river basins, seven of which were priority substances: alachlor, atrazine, chlorfenvinphos, chlorpyrifos, endosulfan, simazine and terbutryn, all of which exceeded their respective EQS values. QSs for other specific pollutants were calculated using different extrapolation techniques (i.e. deterministic or probabilistic) largely based on the method described in view of the Water Framework Directive. Non-acceptable aquatic risks were revealed for molinate, oxadiazon, pendimethalin, propanil, terbuthylazine, and the metabolite desethylatrazine. Implications of these findings for the classification of the ecological status of surface water bodies in Portugal and at the European level are discussed.

A decision support system to find the best water allocation strategies in a Mediterranean river basin in future scenarios of global change

Global change refers to climate changes, but also demographic, technological and economic changes. Predicted water scarcity will be critical in the coastal Mediterranean region, especially for provision to mid-sized and large-sized cities. This paper studies the case of the city of Tarragona, located at the Mediterranean area of north-eastern Spain (Catalonia). Several scenarios have been constructed to evaluate different sectorial water allocation policies to mitigate the water scarcity induced by global change. Future water supply and demand predictions have been made for three time spans. The decision support system presented is based on the outranking model, which constructs a partial pre-order based on pairwise preference relations among all the possible actions. The system analyses a hierarchical structure of criteria, including environmental and economic criteria. We compare several adaptation measures including alternative water sources, inter-basin water transfer and sectorial demand management coming from industry, agriculture and domestic sectors. Results indicate that the most appropriate water allocation strategies depend on the severity of the global change effects.

Emission factor estimation of ca. 160 emerging organic microcontaminants by inverse modeling in a Mediterranean river basin (Llobregat, NE Spain)

Starting from measured river concentrations, emission factors of 158 organic compounds out of 199 analyzed belonging to different groups of priority and emerging contaminants [pesticides (25), pharmaceuticals and hormones (81), perfluoroalkyl substances (PFASs) (18), industrial compounds (12), drugs of abuse (8) and personal care products (14)] have been estimated by inverse modeling. The Llobregat river was taken as case study representative of Mediterranean rivers. Industrial compounds and pharmaceuticals are the dominant groups (range of 104mg·1000inhab−1·d−1). Personal care products, pesticides, PFASs and illegal drugs showed a load approximately one order of magnitude smaller. Considered on a single compound basis industrial compounds still dominate (range of ca. 103mg·1000inhab−1·d−1) over other classes. Generally, the results are within the range when compared to previously published estimations for other river basins. River attenuation expressed as the percentage fraction of microcontaminants eliminated was quantified. On average they were around 60–70% of the amount discharged for all classes, except for PFASs, that are poorly eliminated (ca. 20% on average). Uncertainties associated with the calculated emissions have been estimated by Monte-Carlo methods (15,000 runs) and typically show coefficients of variation of ca. 120%. Sensitivities associated with the various variables involved in the calculations (river discharge, river length, concentration, elimination constant, hydraulic travel time and river velocity) have been assessed as well. For the intervals chosen for the different variables, all show sensitivities exceeding unity (1.14 to 3.43), tending to amplify the variation of the emission. River velocity and basin length showed the highest sensitivity value. Even considering the limitations of the approach used, inverse modeling can provide a useful tool for management purposes facilitating the quantification of release rates of chemicals into the aquatic environment.

Effects of water flow regulation on ecosystem functioning in a Mediterranean river network assessed by wood decomposition

Mediterranean rivers are extensively modified by flow regulation practises along their courses. An important part of the river impoundment in this area is related to the presence of small dams constructed mainly for water abstraction purposes. These projects drastically modified the ecosystem morphology, transforming lotic into lentic reaches and increasing their alternation along the river. Hydro-morphologial differences between these reaches indicate that flow regulation can trigger important changes in the ecosystem functioning. Decomposition of organic matter is an integrative process and this complexity makes it a good indicator of changes in the ecosystem. The aim of this study was to assess the effect caused by flow regulation on ecosystem functioning at the river network scale, using wood decomposition as a functional indicator. We studied the mass loss from wood sticks during three months in different lotic and lentic reaches located along a Mediterranean river basin, in both winter and summer. Additionally, we identified the environmental factors affecting decomposition rates along the river orders. The results revealed differences in decomposition rates between sites in both seasons that were principally related to the differences between stream orders. The rates were mainly related to temperature, nutrient concentrations (NO2−, NO32−) and water residence time. High-order streams with higher temperature and nutrient concentrations exhibited higher decomposition rates compared with low-order streams. The effect of the flow regulation on the decomposition rates only appeared to be significant in high orders, especially in winter, when the hydrological characteristics of lotic and lentic habitats widely varied. Lotic reaches with lower water residence time exhibited greater decomposition rates compared with lentic reaches probably due to more physical abrasion and differences in the microbial assemblages. Overall, our study revealed that in high orders the reduction of flow caused by flow regulation affects the wood decomposition indicating changes in ecosystem functioning.

Statistical analysis and ANN modeling for predicting hydrological extremes under climate change scenarios: The example of a small Mediterranean agro-watershed

The purpose of this study was to create a modeling management tool for the simulation of extreme flow events under current and future climatic conditions. This tool is a combination of different components and can be applied in complex hydrogeological river basins, where frequent flood and drought phenomena occur. The first component is the statistical analysis of the available hydro-meteorological data. Specifically, principal components analysis was performed in order to quantify the importance of the hydro-meteorological parameters that affect the generation of extreme events. The second component is a prediction-forecasting artificial neural network (ANN) model that simulates, accurately and efficiently, river flow on an hourly basis. This model is based on a methodology that attempts to resolve a very difficult problem related to the accurate estimation of extreme flows. For this purpose, the available measurements (5 years of hourly data) were divided in two subsets: one for the dry and one for the wet periods of the hydrological year. This way, two ANNs were created, trained, tested and validated for a complex Mediterranean river basin in Crete, Greece. As part of the second management component a statistical downscaling tool was used for the creation of meteorological data according to the higher and lower emission climate change scenarios A2 and B1. These data are used as input in the ANN for the forecasting of river flow for the next two decades. The final component is the application of a meteorological index on the measured and forecasted precipitation and flow data, in order to assess the severity and duration of extreme events.

Temporal variability of suspended sediment transport and rating curves in a Mediterranean river basin: The Celone (SE Italy)

In the Mediterranean region suspended sediment transport is the predominant process in sediment export in most river basins. The aim of this paper is to analyze suspended sediment variability over a period of 12months in the Celone river, a temporary river located in the Puglia region (SE-Italy), and to evaluate sediment rating curves for estimating suspended sediment concentrations for subsequent load calculations. Similarly to most temporary rivers, the Celone river shows relevant differences among mean daily flows and the extreme instantaneous flows during floods. To take into account these peculiarities, the rating curves were developed as a function of hydrological conditions: high, normal and low flows. Continuous measures of streamflow and frequent samplings of suspended solid concentrations (SSCs) during flood events, normal flow and low flow were used. The plot of the SSC against discharge takes the form of a hysteresis loop. Clockwise, anticlockwise and mixed-shaped loops were observed. Suspended sediment yield was found to be in the range of 250–384tkm−2y−1. The results show that about 94% of the total suspended materials were transported during the high flow regime, while less than 0.1% were under low flow conditions. Moreover, it was observed that 90% of the total annual suspended loads were moved between November to May. Flash floods that occur in summer exhibit the highest values of SSC. The proposed method, which was based on sediment rating curves, has proved to be valuable to generate SSC data for high and normal flows although it tends to underestimate the highest values. It can represent a useful tool for water resource managers who need a quick and inexpensive method, specific for temporary rivers, to evaluate suspended sediment yield.

LIFE Segura-Riverlink as a green infrastructure approach to recover the longitudinal connectivity: preliminary data of the fish-based assessment.

Event Abstract Back to Event LIFE Segura-Riverlink as a green infrastructure approach to recover the longitudinal connectivity: preliminary data of the fish-based assessment. Francisco José Oliva-Paterna1*, Ana Sánchez-Pérez1, Fátima Amat-Trigo1, José Manuel Zamora-Marín1, David Verdiell-Cubedo1, Ana Ruiz-Navarro2, Francisco Javier Sanz-Ronda3, Eduardo Lafuente4 and Mar Torralva1 1 University of Murcia, Spain 2 Faculty of Science and Technology, Centre for Ecology, Environment and Sustainability, Bournemouth University, United Kingdom 3 ITAGRA.CT. Centro Tecnológico Agrario y Agroalimentario, Spain 4 Confederación Hidrográfica del Segura, Spain Habitat connectivity is a central factor in shaping aquatic and riverine biological communities, however, few tools exist to maintain and recover this attribute at large scale in fluvial systems. The Segura-Riverlink is a LIFE Programme project which aims to promote and support the environmental recovery of a fluvial sector of the Segura River Basin (more than 50 km long in its main river). The main purpose is to demonstrate and validate management measures for the development of a Green Infrastructure (GI) approach into the context of Mediterranean river basins characterized by a high impact in their connectivity. The project will recover the longitudinal connectivity removing a significant number of artificial barriers to restore fish passage and will also support other best practices of riverine restoration. Restoration actions will include the removal of small weirs and the construction of effective fish passage systems and monitoring will assess the performance of these actions with the hope of validating the GI approach to river basin management and its possible extension to the official management programmes. The project will also develop a Land Custody Network to integrate private owners in the river management and in agreeing good practices. The initial fish-based assessment was completed with significant baseline data showing exotic invasive fishes as dominant and Luciobarbus sclateri as the target species to assess changes at population levels. The project’s outcomes will protect local aquatic and riverine habitats, allow fish reproductive movements along an important fluvial sector, improve ecosystem services, and build a framework of scientific and social knowledge to improve river management quality and to help the implementation and enforcement of EU policy and legislation on biodiversity conservation. Keywords: fluvial systems, green infrastructure, Longitudinal connectivity, Fish passage, Land Custody Network Conference: XV European Congress of Ichthyology, Porto, Portugal, 7 Sep - 11 Sep, 2015. Presentation Type: Poster Presentation Topic: Life Cycles, Migration and Connectivity Citation: Oliva-Paterna F, Sánchez-Pérez A, Amat-Trigo F, Zamora-Marín J, Verdiell-Cubedo D, Ruiz-Navarro A, Sanz-Ronda F, Lafuente E and Torralva M (2015). LIFE Segura-Riverlink as a green infrastructure approach to recover the longitudinal connectivity: preliminary data of the fish-based assessment.. Front. Mar. Sci. Conference Abstract: XV European Congress of Ichthyology. doi: 10.3389/conf.FMARS.2015.03.00161 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 02 Nov 2015; Published Online: 28 Nov 2015. * Correspondence: Dr. Francisco José Oliva-Paterna, University of Murcia, Murcia, Spain, fjoliva@um.es Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Francisco José Oliva-Paterna Ana Sánchez-Pérez Fátima Amat-Trigo José Manuel Zamora-Marín David Verdiell-Cubedo Ana Ruiz-Navarro Francisco Javier Sanz-Ronda Eduardo Lafuente Mar Torralva Google Francisco José Oliva-Paterna Ana Sánchez-Pérez Fátima Amat-Trigo José Manuel Zamora-Marín David Verdiell-Cubedo Ana Ruiz-Navarro Francisco Javier Sanz-Ronda Eduardo Lafuente Mar Torralva Google Scholar Francisco José Oliva-Paterna Ana Sánchez-Pérez Fátima Amat-Trigo José Manuel Zamora-Marín David Verdiell-Cubedo Ana Ruiz-Navarro Francisco Javier Sanz-Ronda Eduardo Lafuente Mar Torralva PubMed Francisco José Oliva-Paterna Ana Sánchez-Pérez Fátima Amat-Trigo José Manuel Zamora-Marín David Verdiell-Cubedo Ana Ruiz-Navarro Francisco Javier Sanz-Ronda Eduardo Lafuente Mar Torralva Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. 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Special issue: analysis and modelling of sediment transfer in Mediterranean river basins

The characteristic conditions found in most Mediterranean and many other semiarid regions are those situations where current water use already equals and often exceeds water availability and where the hydro-meteorological regime shows a strong variability. In addition, water demand is commonly out-of-phase in relation to water resources, especially at the seasonal scale. If those areas rely on surface water resources to a large extent, they are particularly vulnerable to severe erosion (because of scarce vegetation cover of the soil and high rainfall intensity/energy), loss of fertile soils and subsequent sedimentation of reservoirs that are designed for water supply. As a consequence, this loss of reservoir retention volume may lead to a significant reduction of water availability within a period of a few years or decades. Therefore, erosion and sedimentation issues have to be taken into account when analysing and implementing long-term sustainable strategies to secure future water supply through water management and to sustain soil productivity through land-use management in upstream catchments. In this context, it is necessary to focus research and innovative management issues on “typical” scales in time and space. From a scientific perspective, the adequate spatial process scales range from the plot to field or river-reach scale. The model scale also ranges from plot scale but expands to the meso-scale of river basins up to several thousands of square kilometres. From a management perspective, the spatial scale of interest is the meso-scale (or intermediate to large catchments scale) because this is the scale most relevant for management of water and land resources. Furthermore, it is important to account for the relevant landscape components (and their driving processes), such as hillslopes (runoff and erosion processes on the soil surface), channel network (transfer from sources i.e. connectivity and sediment transport in river systems) and lakes or reservoirs (deposition of sediments). The scientifically sound assessment of generation, transfer and storage processes of water and sediment fluxes can be conducted in a dynamic and quantitative way by field monitoring, on the one hand, and the application and adaptation of adequate hydrological and sediment-transport models, on the other. Due to upstream–downstream relationships, connectivity factors that influence runoff generation, sediment production and water resources, as well as the effects of water management measures, usually affect the entire area of river basins and thus need to be included in this assessment. This special issue of the Journal of Soils and Sediments deals with the research questions identified above. It comprises 11 articles with different methodological backgrounds (monitoring/measurement techniques, methods of data analysis and process-oriented modelling); from different Mediterranean regions, in particular from the Iberian Peninsula, Europe, and from northeast Brazil; different spatial scales (from micro-catchments covering a few hectares up to the large catchments of the Lower Ebro and the Upper Jaguaribe, i.e. the scale of 10 km); and different time scales (from the event scale, i.e. a few hours, up to several decades). Most of the articles are based on selected presentations given at the 6th International Conference on Water Resources and Environment Research that was convened at Koblenz (Germany) from 3 to 7 June 2013. The focus of the conference was to foster an integrative understanding of water and the J. C. de Araujo (*) Department of Agricultural Engineering, Federal University of Ceara, Fortaleza, CE 60356-000, Brazil e-mail: jcaraujo@ufc.br

Sensitivity analysis of a sediment dynamics model applied in a Mediterranean river basin: Global change and management implications

Climate change and land-use change are major factors influencing sediment dynamics. Models can be used to better understand sediment production and retention by the landscape, although their interpretation is limited by large uncertainties, including model parameter uncertainties. The uncertainties related to parameter selection may be significant and need to be quantified to improve model interpretation for watershed management. In this study, we performed a sensitivity analysis of the InVEST (Integrated Valuation of Environmental Services and Tradeoffs) sediment retention model in order to determine which model parameters had the greatest influence on model outputs, and therefore require special attention during calibration. The estimation of the sediment loads in this model is based on the Universal Soil Loss Equation (USLE). The sensitivity analysis was performed in the Llobregat basin (NE Iberian Peninsula) for exported and retained sediment, which support two different ecosystem service benefits (avoided reservoir sedimentation and improved water quality). Our analysis identified the model parameters related to the natural environment as the most influential for sediment export and retention. Accordingly, small changes in variables such as the magnitude and frequency of extreme rainfall events could cause major changes in sediment dynamics, demonstrating the sensitivity of these dynamics to climate change in Mediterranean basins. Parameters directly related to human activities and decisions (such as cover management factor, C) were also influential, especially for sediment exported. The importance of these human-related parameters in the sediment export process suggests that mitigation measures have the potential to at least partially ameliorate climate-change driven changes in sediment exportation.

Key issues for determining the exploitable water resources in a Mediterranean river basin

One of the major difficulties in water planning is to determine the water availability in a water resource system in order to distribute water sustainably. In this paper, we analyze the key issues for determining the exploitable water resources as an indicator of water availability in a Mediterranean river basin. Historically, these territories are characterized by heavily regulated water resources and the extensive use of unconventional resources (desalination and wastewater reuse); hence, emulating the hydrological cycle is not enough. This analysis considers the Jucar River Basin as a case study. We have analyzed the different possible combinations between the streamflow time series, the length of the simulation period and the reliability criteria. As expected, the results show a wide dispersion, proving the great influence of the reliability criteria used for the quantification and localization of the exploitable water resources in the system. Therefore, it is considered risky to provide a single value to represent the water availability in the Jucar water resource system. In this sense, it is necessary that policymakers and stakeholders make a decision about the methodology used to determine the exploitable water resources in a river basin.

A management and optimisation model for water supply planning in water deficit areas

• A global optimisation model was developed aimed to maximise the value of water use. • Modelling for solving water imbalances at river basin level. • Optimisation model including water scarcity cost and water quality issues. • Water losses and network connections were integrated in the model. The integrated water resources management approach has proven to be a suitable option for efficient, equitable and sustainable water management. In water-poor regions experiencing acute and/or chronic shortages, optimisation techniques are a useful tool for supporting the decision process of water allocation. In order to maximise the value of water use, an optimisation model was developed which involves multiple supply sources (conventional and non-conventional) and multiple users. Penalties, representing monetary losses in the event of an unfulfilled water demand, have been incorporated into the objective function. This model represents a novel approach which considers water distribution efficiency and the physical connections between water supply and demand points. Subsequent empirical testing using data from a Spanish Mediterranean river basin demonstrated the usefulness of the global optimisation model to solve existing water imbalances at the river basin level.

Mapping Ecological Processes and Ecosystem Services for Prioritizing Restoration Efforts in a Semi-arid Mediterranean River Basin

Semi-arid Mediterranean regions are highly susceptible to desertification processes which can reduce the benefits that people obtain from healthy ecosystems and thus threaten human wellbeing. The European Union Biodiversity Strategy to 2020 recognizes the need to incorporate ecosystem services into land-use management, conservation, and restoration actions. The inclusion of ecosystem services into restoration actions and plans is an emerging area of research, and there are few documented approaches and guidelines on how to undertake such an exercise. This paper responds to this need, and we demonstrate an approach for identifying both key ecosystem services provisioning areas and the spatial relationship between ecological processes and services. A degraded semi-arid Mediterranean river basin in north east Spain was used as a case study area. We show that the quantification and mapping of services are the first step required for both optimizing and targeting of specific local areas for restoration. Additionally, we provide guidelines for restoration planning at a watershed scale; establishing priorities for improving the delivery of ecosystem services at this scale; and prioritizing the sub-watersheds for restoration based on their potential for delivering a combination of key ecosystem services for the entire basin.

Water use in arid rural systems and the integration of water and agricultural policies in Europe: the case of Andarax river basin

Water is a precious resource in arid rural areas with irrigated agriculture. Nonetheless, water and agricultural policies in Europe show different management scopes and objectives, usually translated in divergent drivers of rural change. This paper has a double aim: to propose a specific method for quantitative biophysical analysis of water use in rural systems with the multi-scale integrated analysis of societal and ecosystem metabolism approach and to show the usefulness of this method for the assessment of the integration of water and agricultural policies. The river basin scale is chosen, since it is the socioecological unit for water management established in the water framework directive 2000/60/CE. A multi-scale water use accounting is provided for a Mediterranean river basin in Andalusia, integrating water cycle, ecosystems and social levels. Particularly focusing on agricultural production, a relevant set of indicators is proposed in order to analyze and compare different metabolic patterns. Finally, the integration of water and agricultural planning is assessed in terms of external (biophysical) and internal (economic, institutional) constraints of the new water-use patterns generated by the scenarios posed in these policies. While on a European level water policy is ambitious in terms of ecological conservation, the lack of integration within the common agricultural policy and the entanglement of multiple scales of political and economic organization of local ruralities blur its priority in a rather slow transition to a new water culture.

A hydro-sedimentary modeling system for flash flood propagation and hazard estimation under different agricultural practices

Abstract. A modeling system for the estimation of flash flood flow velocity and sediment transport is developed in this study. The system comprises three components: (a) a modeling framework based on the hydrological model HSPF, (b) the hydrodynamic module of the hydraulic model MIKE 11 (quasi-2-D), and (c) the advection–dispersion module of MIKE 11 as a sediment transport model. An important parameter in hydraulic modeling is the Manning's coefficient, an indicator of the channel resistance which is directly dependent on riparian vegetation changes. Riparian vegetation's effect on flood propagation parameters such as water depth (inundation), discharge, flow velocity, and sediment transport load is investigated in this study. Based on the obtained results, when the weed-cutting percentage is increased, the flood wave depth decreases while flow discharge, velocity and sediment transport load increase. The proposed modeling system is used to evaluate and illustrate the flood hazard for different riparian vegetation cutting scenarios. For the estimation of flood hazard, a combination of the flood propagation characteristics of water depth, flow velocity and sediment load was used. Next, a well-balanced selection of the most appropriate agricultural cutting practices of riparian vegetation was performed. Ultimately, the model results obtained for different agricultural cutting practice scenarios can be employed to create flood protection measures for flood-prone areas. The proposed methodology was applied to the downstream part of a small Mediterranean river basin in Crete, Greece.

Chemometric modeling of organic contaminant sources in surface waters of a mediterranean river basin

Chemometric methods are applied to the analysis and interpretation of large multivariate datasets obtained in environmental monitoring studies. Concentrations of multiple organic compounds were measured in river samples taken from several sampling sites, at various geographical locations, during a number of campaigns and/or sampling time periods. Samples were collected and analyzed as part of an extensive multi-annual monitoring program from a mediterranean river basin (in Catalonia, at the northeast of Spain) by the Water Quality Regional Agency. Due to the great amount of multivariate data stored in environmental databases and to their complexity, chemometric modeling methods such as Principal Component Analysis (PCA) and Multivariate Curve Resolution with Alternating Least-Squares (MCR-ALS) coupled with appropriate mapping representations are proposed for the evaluation of the environmental quality of the studied rivers. Results achieved in this study are intended to be a contribution to water quality assessment and evaluation of contamination of surface waters in river basins, and to support public policies of environmental control and management of the regions under study.