Good Ecological Potential Research Articles

Development of innovative groynes to establish fish passability of regulated rivers based on the example of the Wien River, Austria. Part I: Impact of groyne parameters on water depth and velocity

AbstractRivers in Europe have been heavily modified over the last 200 years, with a significant impact on their ecology and environment. This also applies to rivers like the Wien River, Austria, which are designed as overwide concrete channels for the benefit of flood protection. To achieve a good ecological potential in such heavily modified water bodies, one key element is fish passability. This requires an increase in the water level at low flow conditions and a reduction of the flow velocity. The aim of this study is to assess whether groynes are suitable for this application. A design study was conducted to examine the effect of individual groyne parameters on water depths and velocities. Physical experiments were carried out in a laboratory flume at a scale of 1:8. In addition, a 2D numerical model was used. It was found that the groynes had to be submerged and the alignment had to be repelling to achieve both requirements. The configuration of the groyne height, distance and degree of obstruction parameters were crucial. The groyne angle and shape had a minor effect and can be used for fine‐tuning. The best groyne design created a passable section for fish. Thereby, and through sedimentation, the best design contributed to an ecological improvement. However, it did not create habitats and did not constitute a fullfledged restoration. In general, submerged groynes can fulfil the hydraulic requirements for fish passage in heavily modified water bodies with a fixed bed.

Water Quality Assessment of a Hydro-Agricultural Reservoir in a Mediterranean Region (Case Study—Lage Reservoir in Southern Portugal)

In regions where drought has become a common occurrence for most of the year and where agriculture is the main economic activity, the development of hydro-agricultural systems has made it possible to improve water management. Despite this, the intensification of agriculture combined with climate change leads to a potential decrease in water quality and water management practices are essential to improve agro-environmental sustainability. The aim of this study was to assess the water quality for irrigation and potential ecological status of the reservoir (using support chemical parameters). The results showed biological oxygen demand values above the maximum stipulated for an excellent ecological potential in all sampling periods except April 2018 and December 2020 (with the highest values of 10 mg L−1 O2 in dry periods). Most of the total nitrogen concentrations (TN) surpassed those stipulated for a good ecological potential (0.96 ≤ TN ≤ 2.44 mg L−1 N). In fact, TN and total suspended solids were the main parameters used for water classification. From the perspective of irrigation and according to FAO guidelines regarding infiltration rate, these waters presented light to moderate levels of restrictions. Thus, the results revealed that the decrease in the water quality status and its possible impact on the soil infiltration rate can be related, in part, to the meteorological conditions and to the intensive agricultural practices developed around the drainage basin. Despite that, as the Lage reservoir is part of Brinches–Enxoé hydraulic circuit, the water recirculation is also an important factor that may have affected the results obtained. Furthermore, the experimental design, integrating ecological status, irrigation parameters, and the impact on soil systems; using the same parameters from different perspectives; allowed us to have a global idea of water contamination and its impact on agroecosystems, improving river basin management processes.

Abiotic–Biotic Interrelations in the Context of Stabilized Ecological Potential of Post-Mining Waters

The creation of man-made reservoirs has become more common globally and provides many important technical, biological, and socio-economic functions. The study focused on abiotic–biotic and trophic interrelations responsible for ecological potential and biodiversity in potentially stabilized conditions of the aquatic ecosystem. Therefore, the analyses concerned 2014–2015 and 2018–2019, assuming repeatable hydrochemical conditions, in three chambers (C1–C3) of the Kamień sedimentation pond supplied through opencast mine drainage. The studies indicated eutrophic levels and at least good ecological potential. Phytoplankton were quite abundant at an average biomass of 10.0 mg L−1, while zooplankton and planktivorous fish were estimated at 0.51 mg L−1 and 74.3 g m−2, respectively The general order of the growth level in chambers was C-1 > C-2 > C-3, C-1 < C-2 < C-3, and C-1 < C-3 < C-2 for phytoplankton, zooplankton, and planktivorous fish, respectively, and indicated clear differences. Both mechanisms of the top-down and bottom-up effects were revealed in all chambers. Some significant differences between abiotic and biotic (i.e., fish density and biomass, phytoplankton density) factors were recorded on a temporal scale, whereas the density and biomass of planktivorous fish were significantly differentiated on a spatial scale. The stabilized conditions concerned relatively high biodiversity but quite abundant phytoplankton and lower zooplankton abundances, trophic efficiency, and eutrophy under the maximum ecological potential.

Can Zooplankton Add Value to Monitoring Water Quality? A Case Study of a Meso/Eutrophic Portuguese Reservoir

Despite the key role of zooplankton communities in regulating the water quality of lentic ecosystems, they are absent from the list of biological elements of the Water Framework Directive (WFD) for the assessment of ecological status. Based on this, the present work was a case study that aimed to understand the relevance of zooplankton as a bioindicator for classifying the water quality of reservoirs. For one year and in each season, the water quality of the Torrão reservoir was assessed using the mandatory elements proposed by the WFD in the sampling year (second cycle) and the legislation currently applicable (third cycle). Additionally, zooplankton samples were collected to characterize the community dynamic. The water quality of the Torrão reservoir does not reach the WFD good ecological potential. Furthermore, with the updating of the criteria, the classification tends to get worse. Concerning the zooplankton, the occurrence of Cyclopoida and Bosmina are associated with lower water quality, as well as the collapse or low abundance of the Daphnia population, in the same periods. Low abundances of zooplankton are associated with better water quality, and the Shannon-Wiener diversity values decrease with the increase of the trophic state. High-efficiency feed filters and macrofiltrator organisms dominate the Torrão reservoir in all seasons, which is associated with low water quality. The Calanoida/Cyclopoida ratio shows a strong and negative association with the trophic state. The occurrence and abundance of species, Shannon-Wiener diversity, functional groups (high and low efficiency feed filters and macrofiltrators), and different ratios (large Cladocera/total Cladocera and Calanoida/Cyclopoida) are promising and valuable tools to determine the water quality status, and should be considered within the WFD metrics. Notwithstanding this, further research including reservoirs from different geographical areas with various trophic status and pressures must be analyzed.

Methodological Framework for Assessing Hydromorphological Conditions of Heavily Modified and Artificial River Water Bodies in Croatia

Water Framework Directive (WFD) guidance documents from 2019 provide a comprehensive review of methods and guidelines to improve the comparability of heavily modified water bodies (HMWBs) in the European Union. However, there is currently no common, single methodology for monitoring HMWBs and artificial water bodies (AWBs) or for determining maximum (MEP) and good ecological potential (GEP). This study presents the first assessment of hydromorphological conditions of HMWBs and AWBs in Croatia based on type-specific indicators. The typology of HMWBs and AWBs was based on distinct hydromorphological characteristics and modifications in order to be easily related to the uses of the water bodies. The classes of hydromorphological potential were graded from the theoretical MEP, which was determined by the score scale as the tolerated deviation from natural reference conditions, considering potential mitigation measures. The use of the water body and/or the effects on the wider environment were considered while determining MEP and choosing indicators included in monitoring and assessment. In the case of AWBs, the parameters dependent on natural reference conditions, which are non-existent, were omitted from the assessment. Only 27% of HMWBs and 2 out of 51 AWBs achieved good potential for all three hydromorphological elements. The most significant hydromorphological modifications include channelization, straightening, deepening and removal of riparian vegetation due to flood-protection management practices. In order to achieve the environmental objectives set out by the WFD, the Croatian water management system has to start implementing mitigation measures, especially related to natural flood management.

Ecological potential assessment and land use area estimation of agricultural lands based on multi-time images of Sentinel-2 using ANP-WLC and GIS in Bastam, Iran.

The use of land-based ecological potential is a key management factor in achieving sustainable development and conserving soil and water resources. The purpose of this study is to use multi-time images of Sentinel-2 to determine the area of agricultural lands and evaluate their ecological potential in Bastam, Semnan Province, Iran. Therefore, in the first step, the most common agricultural lands (including apricot and grape orchards), field crops (including wheat and forage maize), and their phenological period were determined. Then, the information was classified using, namely support vector machine, maximum likelihood, and minimum distance. In the next step, soil, topography, and climate data were extracted according to expert opinions and the analysis of the basin's natural potential. The ecological evaluation models of the region were applied to homogeneous units, and after calculating the ecological potential index by the integrated ANP-WLC model, the ecological potential map was generated. The results of the land use classification showed that the support vector machine model and the minimum distance, respectively, had the best and worst performance with kappa coefficient of 0.82 and 0.61. The highest area of cultivated lands (3423 hectares) was estimated for wheat and the lowest (738 hectares) for forage maize. Moreover, the results of the ecological potential evaluation showed that 60% of apricot orchards, and 40.19% of the wheat fields, were in the class of good ecological potential. Overall, 2290 hectares were in the poor class, and 4030 hectares in the excellent class in terms of ecological potential.

Određivanje zagađenja vode reke Južne Morave (Srbija) statističkim i indeksnim metodama

Factor analysis/principal component analysis (FA/PCA), applied to 16 physico-chemical parameters at three different monitoring sites (Mojsinje, Korvingrad, and Ristovac) of the South Morava River in 2015, and from 2011-2018 for station Ristovac, extracted two and four varimax factors which explain 100.000 and 90.874 % of the total variance in water quality, respectively. The relationships among the stations and years obtained by cluster analysis (CA) categorize observed objects in different quality levels. Parameters responsible for pollution of the South Morava River are related to point (industrial/sewage effluents), non-point (runoff from arable land and erosion), and natural source (a mineral component of the river water). The results of the water pollution index (WPI) method for 2015 have shown that the South Morava River at Korvingrad station represents a "moderately polluted" water body (class III), but at Mojsinje and Ristovac station a "polluted" water body (class IV). The obtained ecological potential values indicated that water quality at the Korvingrad station corresponds to class II, "good ecological potential". The surface water at Mojsinje and Ristovac stations deviated from the required ecological water standards by the European Union Water Framework Directive (EU WFD), class III. The South Morava River had the highest load of nutrients (PO4-P and TP) and organic matter (TOC) at Ristovac station, which was confirmed by the index and comparative method (polluted water with poor ecological potential) in period from 2011-2018. A comprehensive analysis of the paper identified a decreasing trend in pollution of the South Morava River, primarily at Ristovac station.

Superação de dormência de sementes de Myrciaria glomerata O. Berg

Abstract Myrciaria glomerata O. Berg. (Myrtaceae) is a fruit tree native to the Brazilian Atlantic Forest with potential for use as food and medicine, besides having good ecological potential. However, this species is limited by low germination rates. Thus, this study aimed to evaluate different methods to overcome dormancy in seeds of M. glomerata and to improve seedling vigor. For this, two experiments were conducted. In Experiment 1, seven treatments were tested: a control treatment, immersion in water at 100 ºC for 30 seconds, immersion in concentrated sulfuric acid (H2SO4) for 1 and 5 minutes, immersion in an aqueous solution of gibberellic acid (GA3) at the concentrations of 250 and 500 mg L-1 for 24 h, and seeds homogenized with an aqueous solution of Stimulate® at a concentration of 5 mL kg-1 seed. In Experiment 2, six doses of Stimulate® were tested: 0, 5, 10, 15, 20, 25, and 30 mL kg-1 seed. The immersion of seeds in 250 and 500 mg L-1 GA3 contributes to increase germination rates, seed length, fresh mass, and dry mass compared to the control and the other methods tested. Immersions in water at 100 ºC and in H2SO4 are not recommended for M. glomerata. The treatment with Stimulate® at 15–25 mL kg-1 seed increased all characteristics analyzed. Immersion in 250 mg L-1 GA3 and Stimu-late® at 20–25 mL kg-1 seed efficiently stimulated seeds to overcome dormancy in M. glomerata, as well as improved seedling vigor.

A new charophyte habitat with a stabilized good ecological potential of mine water

Each newly-created pond which is supplied with mine water gives the opportunity to study a unique ecosystem in context of possible conditions for biotic live. Therefore, this research aimed to assess a phytoplankton-based ecological potential against the trophic conditions and the risk of contamination with trace elements, and demonstrate the possibility to stabilize at least good water quality of a clarification pond. The gradual decrease in turbidity-related variables (including suspended solids and iron) and nutrients, on the one hand, and an increase in phytoplankton-related indicators, on the other hand, were the most evident. Besides, relative stability in trace elements (the best water quality class), trophic level (slightly eutrophic level) and ecological potential (maximum potential), and relative instability in sulfates and calcium were also recorded. The final stabilization of water habitat resulted in abundant growth of charophyte Nitella mucronata. This all suggested a new ecological opportunity for settlement of a rare species and important for biodiversity enhancement. Furthermore, the study revealed that a clarification pond did not pose any toxic risk from the elevated content of trace elements or the growth of toxic or potentially toxic cyanobacteria which is essential for proper functioning and management of water ecosystems.

Contribution of zooplankton as a biological element in the assessment of reservoir water quality

espanolLas politicas europeas sobre el agua tienen como objetivo lograr un buen estado ecologico en todos los cuerpos de agua. La Directiva Marco del Agua (DMA) definio un grupo de elementos biologicos para evaluar la calidad del agua. En embalses y lagos, el fitoplancton es el unico elemento biologico utilizado para la evaluacion de la calidad del agua. Sin embargo, el zooplancton es un enlace importante en la red trofica, ya que es capaz de controlar la comunidad de fitoplancton y ya se describio como un buen bioindicador, con alta sensibilidad a diferentes estreses ambientales. El objetivo principal de este trabajo es demostrar la capacidad de las comunidades de zooplancton para ser utilizadas en la evaluacion de la calidad del agua en los embalses. Se tomaron muestras trimestrales de un grupo de varios embalses en el norte de Portugal (Paradela, Alto Cavado, Alto Rabagao y Venda Nova) durante un ano, para evaluar la calidad del agua. Los parametros fisicos y quimicos, asi como las comunidades de fitoplancton, se estudiaron de acuerdo con las metricas propuestas por la DMA para esta tipologia de cuerpos de agua. Ademas, se muestrearon las comunidades de zooplancton en cada embalse, para comprender si su dinamica estacional esta influenciada por alteraciones de la calidad del agua. Los resultados muestran que los embalses presentan un buen potencial ecologico, de acuerdo con los valores de referencia de la DMA para los parametros fisicos y quimicos, asi como para las comunidades de fitoplancton, con caidas ocasionales del potencial ecologico para una calidad moderada, debido a las variaciones en los valores de O2 disuelto y fosforo total. Los resultados observados en la dinamica de las comunidades de zooplancton muestran que este elemento biologico es sensible a alteraciones en los embalses y proporciona una imagen mas detallada del estado del ecosistema. Las comunidades de zooplancton respondieron a alteraciones en el nivel del agua en el embalse, a los cambios en el estado trofico y en la calidad del agua, tanto a nivel taxonomico como desde una perspectiva funcional. Por lo tanto, las metricas propuestas por WFD para evaluar la calidad del agua de embalses, parecen ser insuficientes para comprender todas las alteraciones que ocurren en estos ecosistemas lenticos. EnglishEuropean water policies aim to achieve a good ecological status in all water bodies. The Water Framework Directive (WFD) defined a group of biological elements to assess water quality. In reservoirs and lakes, phytoplankton is the only biological element used for water quality evaluation. However, zooplankton is an important link in the trophic web, since it is able to control the phytoplankton community and was already described as a good bioindicator, with high sensitivity to different environmental stresses. The main goal of this work is to demonstrate the ability of zooplankton communities to be used in the evaluation of water quality in reservoirs. A group of four reservoirs in the north of Portugal (Paradela, Alto Cavado, Alto Rabagao, and Venda Nova) were sampled every three months, during one year, to assess the water quality. Physical and chemical parameters, as well as phytoplankton communities, were studied according to the metrics proposed by the WFD for this typology of water bodies. Additionally, zooplankton communities were also sampled in each reservoir, to understand if their seasonal dynamics are influenced by alterations of the water quality in the reservoirs. Results show that the reservoirs present a good ecological potential, according to WFD reference values for physical and chemical parameters and phytoplankton communities, with occasional drops to moderate ecological potential due to variations in the dissolved O2 and total phosphorus values. The results observed in the dynamics of zooplankton communities show that this biological element is sensitive to changes in the reservoirs and provides a more detailed image of the state of the ecosystem. Zooplankton communities responded to alterations in the water level in the reservoir, to shifts in the trophic status and in the water quality, both at the taxonomic level and on a functional perspective. Therefore, the metrics proposed by WFD to evaluate water quality in reservoirs seem to be insufficient to understand all the alterations that occur in these aquatic ecosystems.

Feeding inhibition tests as a tool for seston quality evaluation in lentic ecosystems: salinization impact

Environmental disturbance on freshwater ecosystems significantly impacts all levels of the trophic web. Salinity in lentic freshwater ecosystems, as a consequence of climatic changes, is rising concern in the scientific community. These alterations affect water quality, the composition and diversity of the aquatic communities. This study aimed to assess the seston quality of two lentic ecosystems, Crestuma reservoir and lake Vela, and evaluate the effects of salinity on food performance of Daphnia magna and Daphnia longispina (isolated from the referred ecosystems). Feeding inhibition tests were used to conduct these two evaluations. Physical and chemical water classification revealed a poor or good ecological potential of the two lentic ecosystems, according to WFD approach. To evaluate seston quality, filtered and unfiltered water samples from the lentic ecosystems were used as treatments. Although only summer samples from Crestuma presented good water quality, the results from the feeding inhibition tests showed that seston from lake Vela presented more nutritional quality. Concerning the assay to evaluate the salinity effect on Daphnia spp., a significant reduction in the filtration rate was observed. The NOEC value was 0.7 g/L NaCl and 0.8 g/L NaCl for D. magna and D. longispina C and V, respectively. The LOEC value was also distinct between species, being 1.0 g/L and 0.9 g/L, respectively. This work allowed to verify that feeding inhibition tests are not sensitive enough for assess the quality of natural waters. However, these tests are economically viable and have high sensitivity to evaluate NaCl effects on Daphnia spp.

Development of a Predictive Tool to Support Environmentally Sustainable Management in Port Basins

According to the Water Framework Directive, harbours that are classified as heavily modified water bodies must either reach or maintain good ecological potential. Moreover, following the marine spatial planning principles, the effects of port structure changes on water quality must also be considered. To support the sustainable management of harbour waters, we calculated flushing time (FT) through the use of a numerical model within the Civitavecchia port under different scenarios. To assess the effects of the realization of new infrastructure that will significantly alter the port configuration in the coming years, we also developed the flushing efficiency index (FEI). The increase in the harbour basin size due to the embankment extension result in high values of FT, particularly in the inner part of the port, in accordance with the highest values of the enrichment factor of the trace metals found in the sediment. The deterioration of water quality is confirmed by negative FEI values. Otherwise, the index assumes positive values after the realization of a second entrance in the southern part of Civitavecchia port, highlighting a drastic improvement in harbour water renewal. This study provides a low-cost and predictive tool to correctly address environmentally sustainable management of port activities.

Barriers for the ecosystem services concept in European water and nature conservation law

In the 2015 River Weser case the Court of Justice of the European Union (CJEU) appears to demand a rather strict one-dimensional protection of water quality under the EU Water Framework Directive (WFD). Article 4 WFD, the very essence of this EU directive, should then be read as a strict water quality assessment on good ecological potential and other ecological WFD criteria. This jurisprudence could surely be welcomed as it secures blue environmental interests, but it may at the same time easily be encountered and criticized as a contradiction of modern EU policy documents on sustainable development and green or blue growth, as it may de iure subordinate socio-economic interests. It also may exclude clusters of ecosystem services; not only provisioning and cultural services, but also other not legally protected regulating services. Here, a CJEU-induced limited testing on only a few limited ecological criteria of Article 4 WFD might tend to resemble the one-criterion testing of the Natura 2000 habitats assessment and its possible shortcomings in terms of sustainable multi-functionality. In the derogation regimes of both WFD and Habitats Directive only overriding public interests may outweigh environmental objectives. In a recent 2016 case on hydropower the CJEU makes it clear renewable energy production can be such an overriding public interest, but still not all interests or ecosystem services do qualify to be part of a weighing process in the derogation stage. We should be aware this may contrast with current EU environmental policy documents like Green Infrastructure and Blue Growth. It would help if EU policy documents could be more explicit that sustainable development might be the default throughout Europe, but not necessarily in WFD waters and Natura 2000 sites.

Habitat rehabilitation in urban waterways: the ecological potential of bank protection structures for benthic invertebrates

Compensating for the adverse ecological impacts of waterway development and improving their ecological functioning to achieve good ecological potential (GEP) have become mandatory within the European Union (EU). The technical rehabilitation measures presented here aim to functionally minimize the hydraulic impacts of navigation on aquatic biota in highly urbanized waterways. Their ecological functioning and potential to enhance biodiversity locally was assessed by comparing their macro-invertebrate community composition with nearby non-restored sites. Rehabilitation led to lower hydraulic impact on the littoral zone, which in turn led to the presence of otherwise missing macrophytes and the occurrence of organic mud habitats colonized by invertebrates typically rare in urban waterways. While the control sites were dominated by few, mostly invasive taxa in vast numbers, the rehabilitated sites exhibited a highly diverse community with 22 protected mollusc and insect taxa typically found in the oxbow communities of natural rivers. This major improvement was however not detected using the core metrics of the legally required national assessment tools of the EU Water Framework Directive. Overall results proved the success of this type of rehabilitation measure with respect to improving biodiversity, but they also showed the limiting and key factors influencing the macro-invertebrate communities of highly deteriorated urban waterways. Indeed, future implementations of this type of rehabilitation measure should consider spatial extent, water exchange rates, temporal succession of vegetation and adaptive management to improve its ecological functioning.

Integracja systemu zarządzania ryzykiem powodziowym i ochroną wód na przykładzie doliny Warty między Koninem a Obornikami

The aim of the study was the analysis of the integration of a flood risk management and water protection system in a selected section of the Warta Valley with taking into consideration the guidelines of the Water Framework Directive and the Floods Directive. The structure of the valley is comprised within a distance of 201.1 km by stretches of: an urstromtal, between the towns of Konin and Śrem, and the Warta gorge stretch between Śrem and Oborniki. High environmental values of the valley are shown, related to the presence of conservation areas and, on the other hand, a high flood hazard risk, resulting e.g. from advancing land development in the valley and its low retention capacity. The Integrated Water Resources Management guidelines conception was used in the analysis, inlcuding pointing out the directions of relations between minimizing flood risk and protection of natural values of the Warta River and its valley. Spatial distribution of the flood hazard and risk in the Warta Valley was also analyzed. A detailed analysis covered activities of a technical and non-technical character intended to stop the growth of flood risk. In the field of water conservation, the considered objectives included: achieving and maintaining a good ecological potential of waters or the risk of failing to achieve it, which is determined by a high urbanisation ratio, draining of an open-pit lignite mine, extensive morphological change in the river bed and pollution discharged into the waters from land used for agriculture. The results proved that one of the most significant factors directly impacting the environmental condition and ecological potential of the waters is the activity related to flood risk reduction. Potential threats to the functioning of NATURA 2000 areas characterized by high natural values were also indicated.

Facilitating political decisions using species distribution models to assess restoration measures in heavily modified estuaries

The European Water Framework Directive requires a good ecological potential for heavily modified water bodies. This standard has not been reached for most large estuaries by 2015. Management plans for estuaries fall short in linking implementations between restoration measures and underlying spatial analyses. The distribution of emergent macrophytes – as an indicator of habitat quality – is here used to assess the ecological potential. Emergent macrophytes are capable of settling on gentle tidal flats where hydrodynamic stress is comparatively low. Analyzing their habitats based on spatial data, we set up species distribution models with ‘elevation relative to mean high water’, ‘mean bank slope’, and ‘length of bottom friction’ from shallow water up to the vegetation belt as key predictors representing hydrodynamic stress. Effects of restoration scenarios on habitats were assessed applying these models. Our findings endorse species distribution models as crucial spatial planning tools for implementing restoration measures in modified estuaries.

Using a Bayesian belief network to diagnose significant adverse effect of the EU Water Framework Directive on hydropower production in Norway

We evaluate the multi-criteria methodology employed by Norwegian authorities to screen and prioritise a large number of hydropower licences due for revision of their environmental and production conditions. We structured the national licence screening methodology using the multi-criteria decision analysis theory implemented in Bayesian Network (BBN) software. We show how BBNs can be used to diagnose the overall importance of different criteria implicit in the licence screening project's methodology. The diagnostic analysis finds that hydropower loss criteria were considerably more import than environmental criteria in explaining which licences were given lower licence revision priority. We also use the BBN to assess the trade-offs between environmental impacts and hydropower. Using the licence ranking by Norwegian authoities, we provide an interpretation of the ‘significant adverse effect’ for Norwegian hydropower of achieving Water Framework Directive. The national-level estimates of significant adverse effect are likely to be high, given the limited number of mitigation measures that were assessed in the national screening study. The paper discusses the importance of further regional and local assessment of all available measures to achieve good ecological potential in Norwegian water courses.

Good Ecological Potential – A Credible Objective for Water Management?

It is notable that of the environmental objectives of the Water Framework Directive (wfd), good ecological potential has been given less attention. The Weser case has made it possible to establish a more detailed understanding of ‘ecological potential’. An analysis indicates that the main approach to implementing ‘ecological potential’, the non-wfd mitigation-measure approach, creates discontinuity among the environmental objectives, which the wfd reference method does not. Even if the mitigation-measure approach accommodates enhancements, bodies of water are still not classified in accordance with the wfd. If a body of water is incorrectly classified, both good ecological potential and the non-deterioration prohibition should not be binding, as the ‘ecological status’ has not been determined. Furthermore, two different and uncoordinated forms of ‘ecological potential’ establish diverging quality standards, and risk legal uncertainty and inconstancy among Member States.

Assessing and predicting the hydromorphological and ecological quality of federal waterways in Germany: development of a methodological framework

In Europe, the so-called Water Framework Directive was established to achieve a good ecological status of natural water bodies by 2015. In the case of heavily modified and artificial water bodies, the principle of a good ecological potential (GEP) applies. Methods have been developed for the evaluation of natural water bodies. However, these methods do not take the uniqueness of the assessment of heavily modified and artificial water bodies into consideration. On behalf of a working group on water issues of the federal states and the federal government (called LAWA), a nationwide assessment method of the GEP has been developed and its application has been verified within the framework of a practical project. Federal Waterways were not sufficiently considered. Hence we have been prompted to develop an assessment method for heavily modified and artificial water bodies, especially for federal waterways. Nearly 80% of the German federal water bodies are designated as heavily modified and artificial. The inclusion of federal waterways allows the unique characteristics of large rivers to be integrated in the methodological framework. Hereinafter, the results of the first working steps of the investigation as well as the methodological framework will be presented.

Ecosystem Health of Lake Tamrangabeel, Bongaigaon District, Assam, India with Special Reference to Aquatic Insect Assemblage

This study investigated the ecosystem health of a floodplain lake, Tamrangabeel of Bongaigaon district, Assam, India using aquatic insects as bioindicator. The aquatic community of Tamrangabeel was represented by 37 species belonging to 19 families and 5 orders. Shannon –Wiener diversity index (Shannon Hꞌ) values were recorded less than 1 in all the sites of the lake which indicated perturbed condition of the lake. Order Hemiptera was found to be the largest order with highest number of species. Eudominant species recorded in this lake were Micronecta siva (order Hemiptera) and Cloeon sp. (order Ephemeroptera). Biological Monitoring Working Party (BMWP) Score, Average Score per taxon (ASPT), and Stream Invertebrate Grade Number-Average Level (SIGNAL) Score reported from the study reflected good ecological potential as well as slightly impacted nature of the water body. The values of different environmental variables of water of all the sites of the lake were found conducive for aquatic life. This study provided an early warning of perturbation of the lake which is to be addressed before it is too late.