Basin Scale

Ramon Margalef 's Mandala (e.g. Margalef 1997) describes the composition of phytoplankton communities, the relative abundance of component species, and their evolution (succession) as the result of a nutrient-turbulence balance (see also Reynolds 1997). If we accept Margalef 's Mandala as a valid interpretation of succession in freshwater ecosystems, one necessarily concludes that the analysis and understanding of the functional structure of phytoplankton communities and its evolution needs to be grounded on the knowledge of the physical processes of transport and mixing determining turbulence levels and nutrient distribution in the

The relative bio-optical variability within Lake Victoria was analyzed through the spatio-temporal decomposition of a 1997-2004 dataset of remotely-sensed reflectance ratios in the visible spectral range. Results show a regular seasonal pattern with a phase shift (around 2 months) between the south and north parts of the lake. Interannual trends suggested a teleconnection between the lake dynamics and El-Niñ o phenomena. Both seasonal and interannual patterns were associated to conditions of light limitation for phytoplankton growth and basin-scale hydrodynamics on phytoplankton access to light. Phytoplankton blooms developed during the periods of lake surface warming and water column stability. The temporal shift apparent in the bio-optical seasonal cycles was related to the differential cooling of the lake surface by southeastern monsoon winds. North-south differences in the exposure to trade winds are supported by the orography of the Eastern Great Rift Valley. The result is that surface layer warming begins in the northern part of the lake while the formation of cool and dense water continues in the southern part. The resulting buoyancy field is sufficient to induce a lakewide convective circulation and the tilting of the isotherms along the north-south axis. Once surface warming spreads over the whole lake, the phytoplankton bloom dynamics are subjected to the internal seiche derived from the relaxation of thermocline tilting. In 1997-98, El-Niñ o phenomenon weakened the monsoon wind flow which led to an increase in water column stability and a higher phytoplankton optical signal throughout the lake. This suggests that phytoplankton response to expected climate scenarios will be opposite to that proposed for nutrient-limited great lakes. The present analysis of remotely-sensed bio-optical properties in combination with environmental data provides a novel basin-scale framework for research and management strategies in Lake Victoria.

Natural flow regimes are of primary interest in designing environmental flows and therefore essential for water management and planning. The present study discriminated natural hydrologic variation using two different environmental classifications (REC-Segura and WFD-ecotypes) and tested their agreement with an a posteriori (hydrologic) classification in a Spanish Mediterranean basin (the Segura River, SE Spain). The REC-Segura was developed as a two-level hierarchical classification based on environmental variables that influence hydrology (climate and source-of-flow). The WFD-ecotypes were developed by the Spanish Ministry for the Environment to implement the Water Framework Directive (WFD) using hierarchical hydrologic, morphologic and physicochemical variables. The climate level in the REC-Segura broadly described the hydrologic pattern observed along the NW-SE aridity gradient of the basin. However, source-of-flow (defined by karstic geology) was only able to discriminate variation in flow regimes within one climatic category. The WFD-ecotypes, despite incorporating hydrologic variables, did not fully discriminate hydrologic variation in the basin. Ecotypes in tributary streams located in dry or semiarid climates embrace different flow regimes (both perennial and intermittent). There was little agreement between environmental and hydrologic classifications. Therefore, the authors advise against the use of environmental classifications for the assessment of environmental flows without first testing their ability to discriminate hydrologic patterns.

The relative bio-optical variability within Lake Victoria was analyzed through the spatio-temporal decomposition of a 1997-2004 dataset of remotely-sensed reflectance ratios in the visible spectral range. Results show a regular seasonal pattern with a phase shift (around 2 months) between the south and north parts of the lake. Interannual trends suggested a teleconnection between the lake dynamics and El-Niñ o phenomena. Both seasonal and interannual patterns were associated to conditions of light limitation for phytoplankton growth and basin-scale hydrodynamics on phytoplankton access to light. Phytoplankton blooms developed during the periods of lake surface warming and water column stability. The temporal shift apparent in the bio-optical seasonal cycles was related to the differential cooling of the lake surface by southeastern monsoon winds. North-south differences in the exposure to trade winds are supported by the orography of the Eastern Great Rift Valley. The result is that surface layer warming begins in the northern part of the lake while the formation of cool and dense water continues in the southern part. The resulting buoyancy field is sufficient to induce a lakewide convective circulation and the tilting of the isotherms along the north-south axis. Once surface warming spreads over the whole lake, the phytoplankton bloom dynamics are subjected to the internal seiche derived from the relaxation of thermocline tilting. In 1997-98, El-Niñ o phenomenon weakened the monsoon wind flow which led to an increase in water column stability and a higher phytoplankton optical signal throughout the lake. This suggests that phytoplankton response to expected climate scenarios will be opposite to that proposed for nutrient-limited great lakes. The present analysis of remotely-sensed bio-optical properties in combination with environmental data provides a novel basin-scale framework for research and management strategies in Lake Victoria.

1 Technical University Hamburg-Harburg, Hamburg, Germany 2 SEA Environmental Decisions, Little Hadham, United Kingdom 3 CEMAGREF, Lyon, France 4 Bundesanstalt für Gewässerkunde, Koblenz, Germany 5 RIZA, Aquatic Sediment Expert Centre, Lelystad, The Netherlands 6 TNO, Delft, The Netherlands 7 TNO, Apeldoorn, The Netherlands 8 University of Athens, Athens, Greece 9 Amt für Stromund Hafenbau, Hamburg, Germany 10 NGI, Oslo, Norway 11 TNO, Delft, The Netherlands 12 Cranfield University, Silsoe, United Kingdom

The relative bio-optical variability within Lake Victoria was analyzed through the spatio-temporal decomposition of a 1997-2004 dataset of remotely-sensed reflectance ratios in the visible spectral range. Results show a regular seasonal pattern with a phase shift (around 2 months) between the south and north parts of the lake. Interannual trends suggested a teleconnection between the lake dynamics and El-Niñ o phenomena. Both seasonal and interannual patterns were associated to conditions of light limitation for phytoplankton growth and basin-scale hydrodynamics on phytoplankton access to light. Phytoplankton blooms developed during the periods of lake surface warming and water column stability. The temporal shift apparent in the bio-optical seasonal cycles was related to the differential cooling of the lake surface by southeastern monsoon winds. North-south differences in the exposure to trade winds are supported by the orography of the Eastern Great Rift Valley. The result is that surface layer warming begins in the northern part of the lake while the formation of cool and dense water continues in the southern part. The resulting buoyancy field is sufficient to induce a lakewide convective circulation and the tilting of the isotherms along the north-south axis. Once surface warming spreads over the whole lake, the phytoplankton bloom dynamics are subjected to the internal seiche derived from the relaxation of thermocline tilting. In 1997-98, El-Niñ o phenomenon weakened the monsoon wind flow which led to an increase in water column stability and a higher phytoplankton optical signal throughout the lake. This suggests that phytoplankton response to expected climate scenarios will be opposite to that proposed for nutrient-limited great lakes. The present analysis of remotely-sensed bio-optical properties in combination with environmental data provides a novel basin-scale framework for research and management strategies in Lake Victoria.

Hydrological classification constitutes the first step of a new holistic framework for developing regional environmental flow criteria: the "Ecological Limits of Hydrologic Alteration (ELOHA)". The aim of this study was to develop a classification for 390 stream sections of the Segura River Basin based on 73 hydrological indices that characterize their natural flow regimes. The hydrological indices were calculated with 25 years of natural monthly flows (1980/81 -2005/06) derived from a rainfall-runoff model developed by the Spanish Ministry of Environment and Public Works. These indices included, at a monthly or annual basis, measures of duration of droughts and central tendency and dispersion of flow magnitude (average, low and high flow conditions). Principal Component Analysis (PCA) indicated high redundancy among most hydrological indices, as well as two gradients: flow magnitude for mainstream rivers and temporal variability for tributary streams. A classification with eight flowregime classes was chosen as the most easily interpretable in the Segura River Basin, which was supported by ANOSIM analyses. These classes can be simplified in 4 broader groups, with different seasonal discharge pattern: large rivers, perennial stable streams, perennial seasonal streams and intermittent and ephemeral streams. They showed a high degree of spatial cohesion, following a gradient associated with climatic aridity from NW to SE, and were well defined in terms of the fundamental variables in Mediterranean streams: magnitude and temporal variability of flows. Therefore, this classification is a fundamental tool to support water management and planning in the Segura River Basin. Future research will allow us to study the flow alteration-ecological response relationship for each river type, and set the basis to design scientifically credible environmental flows following the ELOHA framework.

This is 1 of 12 papers prepared by participants attending the workshop ''Risk Assessment in European River Basins-State of the Art and Future Challenges'' held in Liepzig, Germany on 12-14 November 2007. The meeting was organized within the framework of the European Commission's Coordination Action RISKBASE program. The objective of RISKBASE is to review and synthesize the outcome of European Commission FP4-FP6 projects, and other major initiatives, related to integrated risk assessment-based management of the water/ sediment/soil environment at the river basin scale.

Natural flow regimes are of primary interest in designing environmental flows and therefore essential for water management and planning. The present study discriminated natural hydrologic variation using two different environmental classifications (REC-Segura and WFD-ecotypes) and tested their agreement with an a posteriori (hydrologic) classification in a Spanish Mediterranean basin (the Segura River, SE Spain). The REC-Segura was developed as a two-level hierarchical classification based on environmental variables that influence hydrology (climate and source-of-flow). The WFD-ecotypes were developed by the Spanish Ministry for the Environment to implement the Water Framework Directive (WFD) using hierarchical hydrologic, morphologic and physicochemical variables. The climate level in the REC-Segura broadly described the hydrologic pattern observed along the NW-SE aridity gradient of the basin. However, source-of-flow (defined by karstic geology) was only able to discriminate variation in flow regimes within one climatic category. The WFD-ecotypes, despite incorporating hydrologic variables, did not fully discriminate hydrologic variation in the basin. Ecotypes in tributary streams located in dry or semiarid climates embrace different flow regimes (both perennial and intermittent). There was little agreement between environmental and hydrologic classifications. Therefore, the authors advise against the use of environmental classifications for the assessment of environmental flows without first testing their ability to discriminate hydrologic patterns.

Traditionally, the problems in predicting sediment yield at the basin scale are related to model's high data requirements, the focus on a limited amount of erosion and sediment transport processes and a general lack of systems knowledge. Here, we explore the performance of semi-quantitative approaches to predict mean annual area-specific sediment yield (SSY) at the scale of small to medium-sized basins.

An overview is given of decision making frameworks for Ecological Risk Assessment (ERA) used for sediment in a number of European countries. These frameworks fall into two categories: • Biological Effects-Based Assessment of in situ risks (referred to as in situ BEBA); • Biological Effects-Based Assessment of the ex situ quality of dredged sediments (referred to as ex situ BEBA).

The St. Lawrence River is subject to various anthropological pressures that can entail negative consequences for the ecosystem. As a result of the third and fourth St. Lawrence Action Plans, the current vision of sustainable management of this river and its main functions emphasizes the need for sound risk-based assessment approaches to support management Manuscript

Multitiered frameworks that are designed for risk assessment of contaminated sediment rely on sediment quality guidelines (SQGs) at the first tier or screening level. In the case of contamination by multiple pollutants, results can be aggregated under indices such as the mean quotient. A decision is then reached (e.g., to dispose of dredged materials in open water) without further investigation, provided that the SQGs or the specific values of indices or quotients derived from the SQGs are not exceeded. In this way, SQGs and quotients play a critical role in environmental protection. As part of the development of a tiered framework to assess the environmental risk of materials dredged from the St. Lawrence River, we evaluated various quotients based on SQGs available for this river with a data set that matches chemistry and toxicity test endpoints. The overall efficiency of all tested quotients was rather low, and we then examined factors such as sediment grain size, nutrients, metal-binding phases (e.g., Al, Fe), and dissolved organic carbon to explain misclassified samples. This examination led to the design of a modified tier 1 framework in which SQGs are used in combination with decision rules based on certain explanatory factors. Integr Environ

Hydrological classification constitutes the first step of a new holistic framework for developing regional environmental flow criteria: the "Ecological Limits of Hydrologic Alteration (ELOHA)". The aim of this study was to develop a classification for 390 stream sections of the Segura River Basin based on 73 hydrological indices that characterize their natural flow regimes. The hydrological indices were calculated with 25 years of natural monthly flows (1980/81-2005/06) derived from a rainfall-runoff model developed by the Spanish Ministry of Environment and Public Works. These indices included, at a monthly or annual basis, measures of duration of droughts and central tendency and dispersion of flow magnitude (average, low and high flow conditions). Principal Component Analysis (PCA) indicated high redundancy among most hydrological indices, as well as two gradients: flow magnitude for mainstream rivers and temporal variability for tributary streams. A classification with eight flowregime classes was chosen as the most easily interpretable in the Segura River Basin, which was supported by ANOSIM analyses. These classes can be simplified in 4 broader groups, with different seasonal discharge pattern: large rivers, perennial stable streams, perennial seasonal streams and intermittent and ephemeral streams. They showed a high degree of spatial cohesion, following a gradient associated with climatic aridity from NW to SE, and were well defined in terms of the fundamental variables in Mediterranean streams: magnitude and temporal variability of flows. Therefore, this classification is a fundamental tool to support water management and planning in the Segura River Basin. Future research will allow us to study the flow alteration-ecological response relationship for each river type, and set the basis to design scientifically credible environmental flows following the ELOHA framework.

This is 1 of 12 papers prepared by participants attending the workshop ''Risk Assessment in European River Basins-State of the Art and Future Challenges'' held in Liepzig, Germany on 12-14 November 2007. The meeting was organized within the framework of the European Commission's Coordination Action RISKBASE program. The objective of RISKBASE is to review and synthesize the outcome of European Commission FP4-FP6 projects, and other major initiatives, related to integrated risk assessment-based management of the water/ sediment/soil environment at the river basin scale.

1 Technical University Hamburg-Harburg, Hamburg, Germany 2 SEA Environmental Decisions, Little Hadham, United Kingdom 3 CEMAGREF, Lyon, France 4 Bundesanstalt für Gewässerkunde, Koblenz, Germany 5 RIZA, Aquatic Sediment Expert Centre, Lelystad, The Netherlands 6 TNO, Delft, The Netherlands 7 TNO, Apeldoorn, The Netherlands 8 University of Athens, Athens, Greece 9 Amt für Stromund Hafenbau, Hamburg, Germany 10 NGI, Oslo, Norway 11 TNO, Delft, The Netherlands 12 Cranfield University, Silsoe, United Kingdom

This is 1 of 12 papers prepared by participants attending the workshop ''Risk Assessment in European River Basins-State of the Art and Future Challenges'' held in Liepzig, Germany on 12-14 November 2007. The meeting was organized within the framework of the European Commission's Coordination Action RISKBASE program. The objective of RISKBASE is to review and synthesize the outcome of European Commission FP4-FP6 projects, and other major initiatives, related to integrated risk assessment-based management of the water/ sediment/soil environment at the river basin scale.

This is 1 of 12 papers prepared by participants attending the workshop ''Risk Assessment in European River Basins-State of the Art and Future Challenges'' held in Liepzig, Germany on 12-14 November 2007. The meeting was organized within the framework of the European Commission's Coordination Action RISKBASE program. The objective of RISKBASE is to review and synthesize the outcome of European Commission FP4-FP6 projects, and other major initiatives, related to integrated risk assessment-based management of the water/ sediment/soil environment at the river basin scale.

SOLUTIONS (2013 to 2018) is a European Union Seventh Framework Programme Project (EU-FP7) that aims to deliver a solution-oriented conceptual framework for the evidence-based development of environmental policies with regard to water quality and its protection against contamination. This project will integrate innovative chemical and effect-based monitoring tools with a full set of exposure, effect and risk assessment models and strategies to assess abatement options. Uniquely, SOLUTIONS takes advantage of (i) expertise of leading European scientists of major FP6/FP7 projects on chemicals in the water cycle, (ii) access to the infrastructure necessary to investigate the large basins of the Danube and Rhine as well as relevant Mediterranean basins as case studies, and (iii) innovative approaches for stakeholder dialogue and support. In particular, the EU Water Framework Directive (WFD) Common Implementation Strategy (CIS) working groups, International River Commissions, and water works associations will be directly supported with consistent guidance for the early detection, identification, prioritization, and abatement options for chemicals in the water cycle. A set of predictive models and tools will support stakeholders' management decisions by benefiting from the wealth of data generated from monitoring and chemical registration. SOLUTIONS will provide a specific emphasis on concepts and tools for the impact and risk assessment of complex mixtures of emerging pollutants, their metabolites and transformation products. Analytical and effect-based screening tools will be applied together with ecological assessment tools for the identification of toxicants and their impacts. Beyond state-of-the-art monitoring and management, tools will be elaborated allowing risk identification for aquatic ecosystems and human health. The SOLUTIONS approach will provide transparent and evidence-based suggestions of River Basin Specific Pollutants for the case study basins and support future review of priority pollutants under the WFD as well as potential abatement options.

The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content.

The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content.

This is 1 of 12 papers prepared by participants attending the workshop ''Risk Assessment in European River Basins-State of the Art and Future Challenges'' held in Liepzig, Germany on 12-14 November 2007. The meeting was organized within the framework of the European Commission's Coordination Action RISKBASE program. The objective of RISKBASE is to review and synthesize the outcome of European Commission FP4-FP6 projects, and other major initiatives, related to integrated risk assessment-based management of the water/ sediment/soil environment at the river basin scale.

This is 1 of 12 papers prepared by participants attending the workshop ''Risk Assessment in European River Basins-State of the Art and Future Challenges'' held in Liepzig, Germany on 12-14 November 2007. The meeting was organized within the framework of the European Commission's Coordination Action RISKBASE program. The objective of RISKBASE is to review and synthesize the outcome of European Commission FP4-FP6 projects, and other major initiatives, related to integrated risk assessment-based management of the water/ sediment/soil environment at the river basin scale.

There are numerous approaches for integrating multiple lines of evidence (MLOE) data in a sediment quality triad assessment, but most rely at least partially on best professional judgment (BPJ), which can be problematic in application to large data sets or in a regulatory setting where the assessment protocol needs to be transparent and consistently reproducible. This study presents an approach for standardizing triad-based assessments and evaluate the extent to which it captures and reproduces the assessments of experts employing BPJ on the same data. The framework is based on integrating answers to two questions: 1) Is there biological degradation at the site, and 2) Is chemical exposure at the site high enough to potentially result in a biological response? The efficacy of the framework was assessed by applying it to data from 25 sites and comparing the site classifications to those of six experts who were provided the same data. The framework produced an answer that better matched the median classification of the experts than did five of the six experts. Moreover, the bias in response was less than that obtained from some of the experts, and the errors were relatively evenly divided between sites classified as more impacted or less impacted than the median expert classification. The framework was also applied and found to distinguish well sites from known degraded and reference areas within California. While the framework suggested here is not the only one possible and should be supplemented with BPJ when additional data beyond that included in the framework are available, the framework provides a validated means for using a triad based approach in large-scale assessments, such as those for Clean Water Act (CWA) 305b programs or regulatory decisions, where transparency in the decision process is critical.

This is 1 of 12 papers prepared by participants attending the workshop ''Risk Assessment in European River Basins-State of the Art and Future Challenges'' held in Liepzig, Germany on 12-14 November 2007. The meeting was organized within the framework of the European Commission's Coordination Action RISKBASE program. The objective of RISKBASE is to review and synthesize the outcome of European Commission FP4-FP6 projects, and other major initiatives, related to integrated risk assessment-based management of the water/ sediment/soil environment at the river basin scale.

This is 1 of 12 papers prepared by participants attending the workshop ''Risk Assessment in European River Basins-State of the Art and Future Challenges'' held in Liepzig, Germany on 12-14 November 2007. The meeting was organized within the framework of the European Commission's Coordination Action RISKBASE program. The objective of RISKBASE is to review and synthesize the outcome of European Commission FP4-FP6 projects, and other major initiatives, related to integrated risk assessment-based management of the water/ sediment/soil environment at the river basin scale.

This is 1 of 12 papers prepared by participants attending the workshop ''Risk Assessment in European River Basins-State of the Art and Future Challenges'' held in Liepzig, Germany on 12-14 November 2007. The meeting was organized within the framework of the European Commission's Coordination Action RISKBASE program. The objective of RISKBASE is to review and synthesize the outcome of European Commission FP4-FP6 projects, and other major initiatives, related to integrated risk assessment-based management of the water/ sediment/soil environment at the river basin scale.

This is 1 of 12 papers prepared by participants attending the workshop ''Risk Assessment in European River Basins-State of the Art and Future Challenges'' held in Liepzig, Germany on 12-14 November 2007. The meeting was organized within the framework of the European Commission's Coordination Action RISKBASE program. The objective of RISKBASE is to review and synthesize the outcome of European Commission FP4-FP6 projects, and other major initiatives, related to integrated risk assessment-based management of the water/ sediment/soil environment at the river basin scale.

This is 1 of 12 papers prepared by participants attending the workshop ''Risk Assessment in European River Basins-State of the Art and Future Challenges'' held in Liepzig, Germany on 12-14 November 2007. The meeting was organized within the framework of the European Commission's Coordination Action RISKBASE program. The objective of RISKBASE is to review and synthesize the outcome of European Commission FP4-FP6 projects, and other major initiatives, related to integrated risk assessment-based management of the water/ sediment/soil environment at the river basin scale.

This paper proposes a landscape planning and
management method for river basins within the context of
the European Landscape Convention (ELC) and European
Water Framework Directive (WFD). This method has been
applied to the Zir Valley in Ankara, Turkey. Landscape
planning is identified by the ELC (European Treaty Series
No. 176, 2000) as an important, forward-looking action to
enhance, restore or create landscapes. The ELC also states
that landscape management should promote sustainable
development to ensure the non-degradation of landscapes
and to help harmonize inevitable changes. The WFD
(Directive 2000/60/EC of the European Parliament and of
the Council, 2000) is a set of guidelines for managing large
bodies of water. Its principle directive is to identify water
bodies and the adjacent land areas that influence, and
are influenced by, those water bodies. These are called
River Basin Districts, and act as essential physiographic
landscape units. While several regulations related to environmental
planning, and used on a national as well as
European basis, tend to utilize the same tools in practice,
there are dissimilarities in how they are specifically applied
and little effort is being made to promote a cooperative
approach. In this paper, a National Approach for River
Basin Management is proposed. This approach, which
includes a landscape planning and management method
based on landscape form and function, was developed to
address the common purposes of the ELC and WFD.

This is 1 of 12 papers prepared by participants attending the workshop ''Risk Assessment in European River Basins-State of the Art and Future Challenges'' held in Liepzig, Germany on 12-14 November 2007. The meeting was organized within the framework of the European Commission's Coordination Action RISKBASE program. The objective of RISKBASE is to review and synthesize the outcome of European Commission FP4-FP6 projects, and other major initiatives, related to integrated risk assessment-based management of the water/ sediment/soil environment at the river basin scale.

This chapter presents strategic framework for managing sediment risk at the basin and site-specific scale. The excerpts are from the regulations made and implemented in European Union. Effective and sustainable management strategies focus on the entire sediment cycle, rather than on one site at a time. The mission of SedNet is to be a European network for environmentally, socially and economically viable practices of sediment management at the river basin scale. One of the main aims of SedNet is to develop a document containing recommendations in the form of guidance and key-solutions for integrated, sustainable sediment management (SSM), from local to river basin scale (SSM Guide). Second, in line with the new regulatory focus of the Water Framework Directive (WFD), SedNet addresses river basin-wide management and basin-wide sediment management, in particular. Third, although most guidance documents have been generated for specific aspects of sediment management, such as dredged material disposal or environmental management a basin-scale approach must integrate various sediment goals and provide a universal framework.

This is 1 of 12 papers prepared by participants attending the workshop ''Risk Assessment in European River Basins-State of the Art and Future Challenges'' held in Liepzig, Germany on 12-14 November 2007. The meeting was organized within the framework of the European Commission's Coordination Action RISKBASE program. The objective of RISKBASE is to review and synthesize the outcome of European Commission FP4-FP6 projects, and other major initiatives, related to integrated risk assessment-based management of the water/ sediment/soil environment at the river basin scale.