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Rodriguez A.,University of La Coruna | Bermudez M.,University of La Coruna | Rabunal J.R.,University of La Coruna | Puertas J.,University of La Coruna | And 3 more authors.
Journal of Computing in Civil Engineering | Year: 2011

Vertical slot fishways are hydraulic structures that allow the upstream migration of fish through obstructions in rivers. The appropriate design of a vertical slot fishway depends on the interplay between hydraulic and biological variables because the hydrodynamic properties of the fishway must match the requirements of the fish species for which it is intended. One of the primary difficulties associated with studies of real fish behavior in fishway models is that the existing mechanisms to measure the behavior of the fish in these assays, such as direct observation or placement of sensors on the specimens, are impractical or unduly affect the animal behavior. This paper proposes a new procedure for measuring the behavior of the fish. The proposed technique uses artificial neural networks and computer vision techniques to analyze images obtained from the assays by means of a camera system designed for fishway integration. It is expected that this technique will provide detailed information about the fish behavior, and it will help to improve fish passage devices, which is currently a subject of interest in the area of civil engineering. A series of assays has been performed to validate this new approach in a full-scale fishway model with living fish. We have obtained very promising results that allow accurate reconstruction of the movements of the fish within the fishway. © 2011 American Society of Civil Engineers. Source


Guanter L.,German Research Center for Geosciences | Guanter L.,University of Valencia | Ruiz-Verdu A.,National Institute for Aerospace Technology INTA | Odermatt D.,University of Zurich | And 6 more authors.
Remote Sensing of Environment | Year: 2010

Traditional methods for aerosol retrieval and atmospheric correction of remote sensing data over water surfaces are based on the assumption of zero water reflectance in the near-infrared. Another type of approach which is becoming very popular in atmospheric correction over water is based on the simultaneous retrieval of atmospheric and water parameters through the inversion of coupled atmospheric and bio-optical water models. Both types of approaches may lead to substantial errors over optically-complex water bodies, such as case II waters, in which a wide range of temporal and spatial variations in the concentration of water constituents is expected. This causes the water reflectance in the near-infrared to be non-negligible, and that the water reflectance response under extreme values of the water constituents cannot be described by the assumed bio-optical models. As an alternative to these methods, the SCAPE-M atmospheric processor is proposed in this paper for the automatic atmospheric correction of ENVISAT/MERIS data over inland waters. A-priori assumptions on the water composition and its spectral response are avoided by SCAPE-M by calculating reflectance of close-to-land water pixels through spatial extension of atmospheric parameters derived over neighboring land pixels. This approach is supported by the results obtained from the validation of SCAPE-M over a number of European inland water validation sites which is presented in this work. MERIS-derived aerosol optical thickness, water reflectance and water pigments are compared to in-situ data acquired concurrently to MERIS images in 20 validation match-ups. SCAPE-M has also been compared to specific processors designed for the retrieval of lake water constituents from MERIS data. The performance of SCAPE-M to reproduce ground-based measurements under a range of water types and the ability of MERIS data to monitor chlorophyll-a and phycocyanin pigments using semiempirical algorithms after SCAPE-M processing are discussed. It has been found that SCAPE-M is able to provide high accurate water reflectance over turbid waters, outperforming models based on site-specific bio-optical models, although problems of SCAPE-M to cope with clear waters in some cases have also been identified. © 2009 Elsevier Inc. All rights reserved. Source


Molina-Navarro E.,University of Alcala | Martinez-Perez S.,University of Alcala | Sastre-Merlin A.,University of Alcala | Del Pozo D.M.,Center for Hydrographic Studies
Limnetica | Year: 2012

The creation of dams in the riverine zone of large reservoirs is an innovative action whose primary goal is to create water bodies that ensure a stable level of water there.. We have termed these bodies of water 'limno-reservoirs' because their water level becomes constant and independent of the fluctuations occurring in the main reservoir. In addition, limno-reservoirs represent environmental initiatives with corrective and/or compensatory effects. Pareja Limno-reservoir, located near the left side of Entrepeñas Reservoir (Guadalajara province, central Spain), is one of the first initiatives of this type. We are investigating the hydrology, limnology, microbiology, siltation risk and other aspects of this site. This paper focuses on the limnological study of the Pareja Limno-reservoir. To conduct this research, twelve seasonal sample collections at two sampling points (the dam and inflow zones) have been made in Pareja Limno-reservoir (spring 2008-winter 2011). The primary goal of this study is to describe the limnological characteristics of the limno-reservoir, with especial interest in the study of the zooplankton community. The results of the study show that the Pareja Limno-reservoir follows a warm monomictic water stratification pattern. The highest nutrient concentrations were found in the winter, whereas the highest chlorophyll a and phytoplankton biomass values (dominated by Bacillariophyta) were found in the summer and autumn. The results obtained suggest that the Pareja Limnoreservoir is oligo-mesotrophic. The total zooplankton species richness was high, especially in the inflow zone. The most frequently found species are in agreement with those described in other studies performed on the Iberian Peninsula. Rotifers and copepods showed higher relative abundances than cladocerans. © Asociacion Iberica de Limnologia, Madrid. Spain. Source


Poikane S.,European Commission - Joint Research Center Ispra | Birk S.,University of Duisburg - Essen | Bohmer J.,Bioforum GmbH | Carvalho L.,UK Center for Ecology and Hydrology | And 16 more authors.
Ecological Indicators | Year: 2015

The Water Framework Directive is the first international legislation to require European countries to establish comparable ecological assessment schemes for their freshwaters. A key element in harmonising quality classification within and between Europe's river basins is an "Intercalibration" exercise, stipulated by the WFD, to ensure that the good status boundaries in all of the biological assessment methods correspond to similar levels of anthropogenic pressure. In this article, we provide a comprehensive overview of this international comparison, focusing on the assessment schemes developed for freshwater lakes. Out of 82 lake ecological assessment methods reported for the comparison, 62 were successfully intercalibrated and included in the EC Decision on intercalibration, with a high proportion of phytoplankton (18), macrophyte (17) and benthic fauna (13) assessment methods. All the lake assessment methods are reviewed in this article, including the results of intercalibration. Furthermore, the current gaps and way forward to reach consistent management objectives for European lakes are discussed. © 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND. Source


Aragon C.A.,Foundation Center for New Water Technologies | Ortega E.,Center for Hydrographic Studies | Ferrer Y.,Center for Hydrographic Studies | Salas J.J.,Foundation Center for New Water Technologies
Desalination and Water Treatment | Year: 2013

Since the 1st of January of 2006, all the agglomerations in the EU Member States must have a collection and treatment system for urban wastewater. The large and medium size populations were the first in being provided by treatment infrastructures, according to the 91/271/ EEC Directive's schedule, meanwhile the small populations (less than 2,000 population equivalent) have been pushed into the background. One of the objectives of the Spanish Programme on Sanitation and Wastewater Treatment (2007-2015) is to address the sanitation and treatment of small populations. However, the information regarding the status of sanitation in those populations is limited and not clear. In order to moderate this lack of information, the Centre for Studies and Experimentation of Public Works and the Centre for New Water Technologies, commissioned by the former Ministry of Environment, have conducted a study based on the compilation and analysis of both diverse official documents and direct inquiries to the responsible authorities in the matter. According to the information compiled, it can be concluded that the coverage of sanitation and wastewater treatment in small Spanish populations is less than 50% and it is estimated that more than 6,000 small size wastewater treatment plants should be built in the near future where long-term solutions must be promoted. © 2013 Balaban Desalination Publications. Source

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