Summary of book. A Users Guide to Hydraulic Modelling and Experimentation provides a systematic, ... more Summary of book. A Users Guide to Hydraulic Modelling and Experimentation provides a systematic, comprehensive summary of the progress made through HYDRALAB III . The book combines the expertise of many of the leading hydraulic experimentalists in Europe and identifies current best practice for carrying out state-of-the-art, modern laboratory investigations. In addition it gives an inventory and reviews recent advances in instrumentation and equipment that drive present and new developments in the subject. The Guide concentrates on four core areas – waves, breakwaters, sediments and the relatively-new (but rapidly-developing) cross-disciplinary area of hydrodynamics/ecology. Progress made through the ‘CoMIBBS’ component of HYDRALAB III provides the material for a chapter focussed on guidance, principles and practice for composite modelling. There is detailed consideration of scaling and the degree of relevance of laboratory/physical modelling approaches for specific contexts include...
A synthesis of research fields is required for a sustainable future of our planet. One of the ing... more A synthesis of research fields is required for a sustainable future of our planet. One of the ingredients suggested for seemingly conflicting scientific traditions is to 'embrace the science of place'. Place-centered studies provide the best means we have for going beyond pattern to process and for identifying the actual mechanisms at work. Here we provide a case study in which we integrate a number of natural scientific disciplines. This interdisciplinary approach aims at sustainable management of natural resources such as water and biodiversity. We will demonstrate that the insights obtained go beyond the particular wetland we studied and have implications for preservation and restoration of wetlands elsewhere. The Biebrza River (NE-Poland) is an almost natural lowland river with a mean annual discharge of about 30 m 3 /s. In 1921 and 1925 two strict nature reserves were established in the valley wetlands, originally to protect elk population and mires. In 1993 these became part of the Biebrza National Park, covering more than 59,000 ha, protecting the wetlands in the upper, middle and lower Biebrza basins. Biebrza is quite undisturbed, making it for Europe a unique reference area for lowland valley mires and river floodplains. Nevertheless, it is changing and sustainable management needs proper scientific input. Regular field campaigns have determined ecological, surface and groundwater conditions and given insight in: plant-water relationships; effects of nutrient availability on floristic diversity; river ecosystem functioning; groundwater discharge to wetlands supporting habitat connectivity within natural fens; spatial and temporal heterogeneity of groundwater-surface water exchange processes; bush encroachment; and effects of changing land management. Analyses are supported by a suite of rainfall-runoff, hydraulic and groundwater models. It is shown that due to interdisciplinary research Biebrza is a showcase for the analysis of spatial patterns of plant communities and occurrence of plant species, hydrological features such as groundwater discharge, river flooding and concomitant chemical water types and nutrient availabilities. Embracing Biebrza research is of great value for three reasons: gain fundamental knowledge on the functioning of these types of ecosystems; realize effective preservation strategies for the Biebrza wetlands; and design restoration measures for deteriorated ecosystems elsewhere.
Over the past centuries natural river banks have been transformed into banks with artificial reve... more Over the past centuries natural river banks have been transformed into banks with artificial revetments or sheet piles to protect them from erosion. Important river features for flora and fauna have disappeared and the ecological quality of the river reduced dramatically. Recently, the importance of the ecological function of rivers has been getting more attention. One river restoration measure is the removal of man-made bank protections to increase habitat diversity and biodiversity of riparian areas and the river basin. The river morphology may change due to the freely eroding banks in the restored section. Reference projects show that the removal of bank protection along rivers may lead to the formation of bars (e.g. Schirmer et al., 2014). Bars increase morphological diversity, providing specific habitats for flora and fauna (Kurth and Schirmer, 2014). There is a lack of knowledge about the formation of bars related to the length and location of the removal of bank protection. T...
In the Netherlands not only riverine areas are susceptible to flooding problems. The low-lying po... more In the Netherlands not only riverine areas are susceptible to flooding problems. The low-lying polder areas are equally prone to water management problems as a result of current land use practices and expected climate changes. These problems are twofold: firstly, in periods with a precipitation surplus the polders experience flooding problems; secondly, in periods of drought there is a water shortage, which does not only affect the agricultural land use, but also the water quality of the surface water bodies in the polders. By only expanding the pumping capacity for individual polders these problems are not solved in a sustainable way. Thus, there is the need for new water management strategies. One of them is water storage. Storing water on a local scale can help to prevent the above mentioned problems. But, what effects does this have on natural values, and how should be dealt with the increasing demand of economic developments? This paper addresses these issues based on a study i...
Until 1992, zebra mussels (Dreissena polymorpha) were an important food source for diving ducks i... more Until 1992, zebra mussels (Dreissena polymorpha) were an important food source for diving ducks in Lake Markermeer (The Netherlands). After 1993, the mussel biomass sharply declined, and the currentpopulation is in poor condition (maximum shell length <15 mm) compared to populations from adjacent Lake IJsselmeer. Lake Markermeer is characterized by high concentrations of total suspended matter (TSM), including 70% inorganic suspended sediments (ISS) affected by wind-driven resuspension, which may influence the food uptake by the mussels. We assessed whether the poor condition of the zebra mussels in Lake Markermeer could be attributed to the high TSM concentrations, and especially the fraction of ISS. In situ measurements of near-bottom TSM concentrations were linked to wind-driven wave action, and experiments were carried out using increasing natural sediment (NS) concentrations combined with a fixed concentration of a green alga (Scenedesmus obliquus) to determine the clearance...
The NERC and CEH trademarks and logos ('the Trademarks') are registered trademarks of NERC in the... more The NERC and CEH trademarks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner.
Defining the overall ecological status of lakes according to the Water Framework Directive (WFD) ... more Defining the overall ecological status of lakes according to the Water Framework Directive (WFD) is to be partially based on the species composition of the aquatic macrophyte community. We tested three assessment methods to define the ecological status of the macrophyte community in response to a eutrophication pressure as reflected by total phosphorus concentrations in lake water. An absolute species richness, a trophic index (TI) and a lake trophic ranking (LTR) method were tested at Europe-wide, regional and national scales as well as by alkalinity category, using data from 1,147 lakes from 12 European states. Total phosphorus data were W. E. Penning (&)
Aquatic macrophytes are one of the biological quality elements in the Water Framework Directive (... more Aquatic macrophytes are one of the biological quality elements in the Water Framework Directive (WFD) for which status assessments must be defined. We tested two methods to classify macrophyte species and their response to eutrophication pressure: one based on percentiles of occurrence along a phosphorous gradient and another based on trophic ranking of species using Canonical Correspondence Analyses in the ranking procedure. The methods were tested at Europe-wide, regional and national scale as well as by alkalinity category, using 1,147 lakes from 12 European states. The grouping of species as sensitive, tolerant or indifferent to eutrophication was evaluated for some taxa, such as the sensitive Chara spp. and the large isoetids, by analysing the (nonlinear) response curve along a phosphorous gradient. These thresholds revealed in these response curves can be used to set boundaries among different ecological status classes. In total 48 taxa out of 114 taxa were classified identically regardless of dataset or classification method. These taxa can be considered the most consistent and reliable indicators of sensitivity or tolerance to eutrophication at European scale. Although the general response of well known indicator species seems to hold, there are many species that were evaluated differently according to the database
Recently, aquatic macrophytes is widely applied to water quality improvement and ecological river... more Recently, aquatic macrophytes is widely applied to water quality improvement and ecological river restoration projects. On the other hand, the macrophytes can considerably alter flow resistance, thereby, conveyable capacity of a channel or river. In this study, the laboratory experiment in a glass-walled flume had been conducted to quantitatively investigate the effect of different morphology of submerged macrophytes on the flow resistance. The laboratory flume is rectangular in cross section and has dimensions of 15m length, 0.6m width and 0.6m height. A ply-wood floor was fabricated and fixed on the bed of flume in order to keep the macrophytes stable in the flume. Three common submerged species in tropical region was selected for this study, including Cabomba caroliana, the very flexible specie, Eichinodorus grandiflorus, the less flexible specie, and Nymphaea rubra, the floating leaved specie. The macrophyte was arranged in a patch located in the middle of flume with 6m length, ...
Aquatic plants (macrophytes) can have a large effect on river hydraulics and geomorphology. Thoug... more Aquatic plants (macrophytes) can have a large effect on river hydraulics and geomorphology. Though, the extent to how plant morphological plasticity actively influences these feedbacks has received little scientific attention. The nymphaeid macrophyte species Nuphar lutea (L.) Smith is characterized by a distinct leaf duality. Floating leaves shade most of the submerged leaves thereby limiting light penetration in the water. Despite their apparent negligible photosynthetic role, submerged leaves of N. lutea remain intact during summer and contribute a significant part to the total biomass. Our results indicate that the submerged leaves are crucial in plant-flow interactions and hence in the engineering potential of the plant, i.e. the capacity to locally reduce flow velocities and to promote sedimentation, including organic matter deposition. Plant individuals growing in running river water were compared to individuals from adjacent oxbow lake water. The number and size of submerged leaves were significantly higher for river standing individuals and the accumulated sediment contained significantly more organic matter, total nitrogen and total phosphorus, and was characterized by a lower carbon/nitrogen ratio and a finer grain size. We therefore argue that the submerged N. lutea canopy in rivers has the ability to create a high-nutrient, low hydrodynamic environment, resembling the conditions found in oxbow lakes.
Summary of book. A Users Guide to Hydraulic Modelling and Experimentation provides a systematic, ... more Summary of book. A Users Guide to Hydraulic Modelling and Experimentation provides a systematic, comprehensive summary of the progress made through HYDRALAB III . The book combines the expertise of many of the leading hydraulic experimentalists in Europe and identifies current best practice for carrying out state-of-the-art, modern laboratory investigations. In addition it gives an inventory and reviews recent advances in instrumentation and equipment that drive present and new developments in the subject. The Guide concentrates on four core areas – waves, breakwaters, sediments and the relatively-new (but rapidly-developing) cross-disciplinary area of hydrodynamics/ecology. Progress made through the ‘CoMIBBS’ component of HYDRALAB III provides the material for a chapter focussed on guidance, principles and practice for composite modelling. There is detailed consideration of scaling and the degree of relevance of laboratory/physical modelling approaches for specific contexts include...
A synthesis of research fields is required for a sustainable future of our planet. One of the ing... more A synthesis of research fields is required for a sustainable future of our planet. One of the ingredients suggested for seemingly conflicting scientific traditions is to 'embrace the science of place'. Place-centered studies provide the best means we have for going beyond pattern to process and for identifying the actual mechanisms at work. Here we provide a case study in which we integrate a number of natural scientific disciplines. This interdisciplinary approach aims at sustainable management of natural resources such as water and biodiversity. We will demonstrate that the insights obtained go beyond the particular wetland we studied and have implications for preservation and restoration of wetlands elsewhere. The Biebrza River (NE-Poland) is an almost natural lowland river with a mean annual discharge of about 30 m 3 /s. In 1921 and 1925 two strict nature reserves were established in the valley wetlands, originally to protect elk population and mires. In 1993 these became part of the Biebrza National Park, covering more than 59,000 ha, protecting the wetlands in the upper, middle and lower Biebrza basins. Biebrza is quite undisturbed, making it for Europe a unique reference area for lowland valley mires and river floodplains. Nevertheless, it is changing and sustainable management needs proper scientific input. Regular field campaigns have determined ecological, surface and groundwater conditions and given insight in: plant-water relationships; effects of nutrient availability on floristic diversity; river ecosystem functioning; groundwater discharge to wetlands supporting habitat connectivity within natural fens; spatial and temporal heterogeneity of groundwater-surface water exchange processes; bush encroachment; and effects of changing land management. Analyses are supported by a suite of rainfall-runoff, hydraulic and groundwater models. It is shown that due to interdisciplinary research Biebrza is a showcase for the analysis of spatial patterns of plant communities and occurrence of plant species, hydrological features such as groundwater discharge, river flooding and concomitant chemical water types and nutrient availabilities. Embracing Biebrza research is of great value for three reasons: gain fundamental knowledge on the functioning of these types of ecosystems; realize effective preservation strategies for the Biebrza wetlands; and design restoration measures for deteriorated ecosystems elsewhere.
Over the past centuries natural river banks have been transformed into banks with artificial reve... more Over the past centuries natural river banks have been transformed into banks with artificial revetments or sheet piles to protect them from erosion. Important river features for flora and fauna have disappeared and the ecological quality of the river reduced dramatically. Recently, the importance of the ecological function of rivers has been getting more attention. One river restoration measure is the removal of man-made bank protections to increase habitat diversity and biodiversity of riparian areas and the river basin. The river morphology may change due to the freely eroding banks in the restored section. Reference projects show that the removal of bank protection along rivers may lead to the formation of bars (e.g. Schirmer et al., 2014). Bars increase morphological diversity, providing specific habitats for flora and fauna (Kurth and Schirmer, 2014). There is a lack of knowledge about the formation of bars related to the length and location of the removal of bank protection. T...
In the Netherlands not only riverine areas are susceptible to flooding problems. The low-lying po... more In the Netherlands not only riverine areas are susceptible to flooding problems. The low-lying polder areas are equally prone to water management problems as a result of current land use practices and expected climate changes. These problems are twofold: firstly, in periods with a precipitation surplus the polders experience flooding problems; secondly, in periods of drought there is a water shortage, which does not only affect the agricultural land use, but also the water quality of the surface water bodies in the polders. By only expanding the pumping capacity for individual polders these problems are not solved in a sustainable way. Thus, there is the need for new water management strategies. One of them is water storage. Storing water on a local scale can help to prevent the above mentioned problems. But, what effects does this have on natural values, and how should be dealt with the increasing demand of economic developments? This paper addresses these issues based on a study i...
Until 1992, zebra mussels (Dreissena polymorpha) were an important food source for diving ducks i... more Until 1992, zebra mussels (Dreissena polymorpha) were an important food source for diving ducks in Lake Markermeer (The Netherlands). After 1993, the mussel biomass sharply declined, and the currentpopulation is in poor condition (maximum shell length <15 mm) compared to populations from adjacent Lake IJsselmeer. Lake Markermeer is characterized by high concentrations of total suspended matter (TSM), including 70% inorganic suspended sediments (ISS) affected by wind-driven resuspension, which may influence the food uptake by the mussels. We assessed whether the poor condition of the zebra mussels in Lake Markermeer could be attributed to the high TSM concentrations, and especially the fraction of ISS. In situ measurements of near-bottom TSM concentrations were linked to wind-driven wave action, and experiments were carried out using increasing natural sediment (NS) concentrations combined with a fixed concentration of a green alga (Scenedesmus obliquus) to determine the clearance...
The NERC and CEH trademarks and logos ('the Trademarks') are registered trademarks of NERC in the... more The NERC and CEH trademarks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner.
Defining the overall ecological status of lakes according to the Water Framework Directive (WFD) ... more Defining the overall ecological status of lakes according to the Water Framework Directive (WFD) is to be partially based on the species composition of the aquatic macrophyte community. We tested three assessment methods to define the ecological status of the macrophyte community in response to a eutrophication pressure as reflected by total phosphorus concentrations in lake water. An absolute species richness, a trophic index (TI) and a lake trophic ranking (LTR) method were tested at Europe-wide, regional and national scales as well as by alkalinity category, using data from 1,147 lakes from 12 European states. Total phosphorus data were W. E. Penning (&)
Aquatic macrophytes are one of the biological quality elements in the Water Framework Directive (... more Aquatic macrophytes are one of the biological quality elements in the Water Framework Directive (WFD) for which status assessments must be defined. We tested two methods to classify macrophyte species and their response to eutrophication pressure: one based on percentiles of occurrence along a phosphorous gradient and another based on trophic ranking of species using Canonical Correspondence Analyses in the ranking procedure. The methods were tested at Europe-wide, regional and national scale as well as by alkalinity category, using 1,147 lakes from 12 European states. The grouping of species as sensitive, tolerant or indifferent to eutrophication was evaluated for some taxa, such as the sensitive Chara spp. and the large isoetids, by analysing the (nonlinear) response curve along a phosphorous gradient. These thresholds revealed in these response curves can be used to set boundaries among different ecological status classes. In total 48 taxa out of 114 taxa were classified identically regardless of dataset or classification method. These taxa can be considered the most consistent and reliable indicators of sensitivity or tolerance to eutrophication at European scale. Although the general response of well known indicator species seems to hold, there are many species that were evaluated differently according to the database
Recently, aquatic macrophytes is widely applied to water quality improvement and ecological river... more Recently, aquatic macrophytes is widely applied to water quality improvement and ecological river restoration projects. On the other hand, the macrophytes can considerably alter flow resistance, thereby, conveyable capacity of a channel or river. In this study, the laboratory experiment in a glass-walled flume had been conducted to quantitatively investigate the effect of different morphology of submerged macrophytes on the flow resistance. The laboratory flume is rectangular in cross section and has dimensions of 15m length, 0.6m width and 0.6m height. A ply-wood floor was fabricated and fixed on the bed of flume in order to keep the macrophytes stable in the flume. Three common submerged species in tropical region was selected for this study, including Cabomba caroliana, the very flexible specie, Eichinodorus grandiflorus, the less flexible specie, and Nymphaea rubra, the floating leaved specie. The macrophyte was arranged in a patch located in the middle of flume with 6m length, ...
Aquatic plants (macrophytes) can have a large effect on river hydraulics and geomorphology. Thoug... more Aquatic plants (macrophytes) can have a large effect on river hydraulics and geomorphology. Though, the extent to how plant morphological plasticity actively influences these feedbacks has received little scientific attention. The nymphaeid macrophyte species Nuphar lutea (L.) Smith is characterized by a distinct leaf duality. Floating leaves shade most of the submerged leaves thereby limiting light penetration in the water. Despite their apparent negligible photosynthetic role, submerged leaves of N. lutea remain intact during summer and contribute a significant part to the total biomass. Our results indicate that the submerged leaves are crucial in plant-flow interactions and hence in the engineering potential of the plant, i.e. the capacity to locally reduce flow velocities and to promote sedimentation, including organic matter deposition. Plant individuals growing in running river water were compared to individuals from adjacent oxbow lake water. The number and size of submerged leaves were significantly higher for river standing individuals and the accumulated sediment contained significantly more organic matter, total nitrogen and total phosphorus, and was characterized by a lower carbon/nitrogen ratio and a finer grain size. We therefore argue that the submerged N. lutea canopy in rivers has the ability to create a high-nutrient, low hydrodynamic environment, resembling the conditions found in oxbow lakes.
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