Search results for "Drainage"

River Contracts for Innovation in Territorial Governance

2016

Emerged in France in 1980s as agreements oriented to the requalification of rivers and lakes, river contracts represent an important outcome of the decentralization process, developed in Europe in reply to the growing institutional fragmentation. In this scenario, rivers have become a dialectic arena in which the exploitation and management of water resources came to terms with environmental instances, and offered the breeding ground for concerted efforts between policy makers, stakeholders and communities. In this chapter, the analysis is focused on the river contract model and the related set of instruments capable of supporting concerted and participatory management processes both with r…

Pesticides in the Ebro River basin: Occurrence and risk assessment

2016

In this study, 50 pesticides were analyzed in the Ebro River basin in 2010 and 2011 to assess their impact in water, sediment and biota. A special emphasis was placed on the potential effects of both, individual pesticides and their mixtures, in three trophic levels (algae, daphnia and fish) using Risk Quotients (RQs) and Toxic Units (TUs) for water and sediments. Chlorpyrifos, diazinon and carbendazim were the most frequent in water (95, 95 and 70% of the samples, respectively). Imazalil (409.73 ng/L) and diuron (150 ng/L) were at the highest concentrations. Sediment and biota were less contaminated. Chlorpyrifos, diazinon and diclofenthion were the most frequent in sediments (82, 45 and 2…

Biological quality metrics: their variability and appropriate scale for assessing Streams

2006

The concept of spatial scale is at the research frontier in ecology, and although focus has been placed on trying to determine the role of spatial scale in structuring communities, there still is a further need to standardize which organism groups are to be used at which scale and under which circumstances in environmental assessment. This paper contributes to the understanding of the variability at different spatial scales (reach, stream, river basin) of metrics characterizing communities of different biological quality elements (macrophytes, fishes, macroinvertebrates and benthic diatoms) as defined by the Water Framework Directive. For this purpose, high-quality reaches from medium-sized…

Muskelveränderungen durch Saugdrainagen Eine rasterelektronenmikroskopische, transmissionselektronenmikroskopische, lichtmikroskopische und morphomet…

1983

In die Ruckenmuskulatur von 22 mannlichen, ausgewachsenen Wistar-Ratten wurde ein Drainagesystem eingelegt und die Wirkung des Unterdruckes auf die Muskulatur analysiert. Nach kurzester Liegezeit waren die Drainagesysteme durch ein Koagulat verschlossen. Im Unterschied zu den Kontrolltieren, bei denen sich lediglich Fibrin-Gerinnsel und Erythrozyten-Konglomerationen fanden, sahen wir im Rasterelektronenmikroskop bei den mit Unterdruck behandelten Tieren intakte Muskeln im Lumen der Drainage. Fibrin, Muskelfasern und Erythrozyten bildeten einen Verschluspfropf, der das funktioneile System der Saugdrainage unwirksam werden lies. Veranderungen in drainagefernen Muskelbezirken konnten lichtmikr…

Effects of climate change on the urban drainage system of Palermo

Questa ricerca mira a studiare la risposta al cambiamento climatico di un sistema di drenaggio urbano. Riconosciuto dal mondo scientifico come un delle più grandi sfide del XXI secolo, il cambiamento climatico rischia di mettere alla prova i centri abitati: più frequenti precipitazioni, alluvioni e ondate di calore saranno i problemi più impegnativi che le città dovranno affrontare. Ciò potrebbe comportare serie conseguenze per le infrastrutture urbane come i sistemi di trasporto e le reti di drenaggio. Nello specifico, in caso di forti precipitazioni e alluvioni il pericolo è che i sistemi di drenaggio esistenti si rivelino inadeguati. In questo caso le strade vengono sommerse dall'acqua c…

Artificial dam lakes as suitable habitats for exotic invertebrates: Ostracoda ecology and distribution in reservoirs of the Eastern Iberian Peninsula

2014

Reservoirs are the most common deep lakes in Spain, as a consequence of water needs and dry climate. Although these aquatic systems can play an important ecological role in such an area with few large natural lakes, they can also provide new habitats for exotic species, which can colonize ecosystems that native species have not explored yet. Here we present our results for a biannual survey of the ostracod fauna from 24 reservoirs in Xuquer River basin. We check which variables affect ostracod presence, test for differences between winter and summer assemblages, and compare our data with previous available ostracod records from the same river drainage network. Our results reveal that ostrac…

Climate change impact on SWAT simulated streamflow in western Kenya

2009

12 pages (3/4 p.); International audience; Weather and climate extremes such as droughts and floods have far reaching impacts in Kenya. They have had implications in a variety of sectors including agriculture, water resources, health, energy, and disaster management among others. Lake Victoria and its catchment support millions of people and any impact on its ability to support the livelihoods of the communities in this region is of major concern. Thus, the main objective of this study was to assess the potential future climatic changes on the Nzoia catchment in the Lake Victoria basin, and how they might affect streamflow. The Soil and Water Assessment Tool was used to investigate the impa…

Introduction to Hydrology

2013

Hydrology deals with the occurrence, movement, and storage of water in the earth system. Hydrologic science comprises understanding the underlying physical and stochastic processes involved and estimating the quantity and quality of water in the various phases and stores. The study of hydrology also includes quantifying the effects of such human interventions on the natural system at watershed, river basin, regional, country, continental, and global scales. The process of water circulating from precipitation in the atmosphere falling to the ground, traveling through a river basin (or through the entire earth system), and then evaporating back to the atmosphere is known as the hydrologic cyc…

Efficacy of lumen-apposing metal stents or self-expandable metal stents for endoscopic ultrasound-guided choledochoduodenostomy: a systematic review …

2020

Abstract Background Endoscopic ultrasound (EUS)-guided biliary drainage is becoming an option for palliation of malignant biliary obstruction. Lumen-apposing metal stents (LAMS) are replacing self-expandable metal stents (SEMS). The aim of this meta-analysis was to evaluate the efficacy and safety of LAMS and SEMS for EUS-guided choledochoduodenostomy (EUS-CDS). Methods A meta-analysis was performed using PRISMA protocols. Electronic databases were searched for studies on EUS-CDS. The primary outcome was clinical success. Secondary outcomes were technical success, reintervention, and adverse events. We used the random effects model with the DerSimonian–Laird estimation, and the results were…

Dimensional analysis and stage-discharge relationship for weirs: a review

2017

Deducing the weir flow stage-discharge relationship is a classical hydraulic problem. In this regard Buckingham’s theorem of dimensional analysis can be used to find simple and accurate formulas to obtain the rating curves of different weir types. At first, in this review paper the rectangular weir that is a very common hydraulic structure is studied. It is indicated that the crest shape, approach channel width, obliquity (angle between the weir crest and the direction normal to the flow motion) and vertical inclination (pivot weir) are the key-parameters affecting the flow over the rectangular weirs. The flow over the triangular, labyrinth, parabolic, circular, elliptical, and W-weirs are …