992 resultados para catchment management


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Genetic analysis, using single locus probes for genomic DNA, revealed that the juvenile Atlantic salmon populations in the Rivers Leven, Rothay and Troutbeck were related but genetically distinct. This genetic differentiation is greater than might be expected (by comparison with other salmon populations in the UK) and it is recommended that no action is taken which might promote genetic exchange between the three rivers. Thus, future fisheries management practices should treat the salmon from each site as separate genetic stocks. It is unlikely that any attempts to encourage fish currently spawning in the River Leven (downstream of Windermere) to utilize the upper catchment will be successful. The faster growth rate of juvenile salmon in the River Leven, compared with the River Rothay, probably results from a difference in temperature between the inflowing streams and the main outflow of Windermere. Precocious sexual maturation of some male parr was found in all three populations but the incidence (13-33%) is well within the range reported for other waters. Because of their enhanced growth rate, it is likely that some of the precocious males in the River Leven were 0+ fish. A very high incidence of hybridization (>18%) between Atlantic salmon and brown/sea trout was found in Troutbeck but not in the other rivers. Mitochondrial DNA analysis of these hybrids revealed them to be the product of several, independent cross-fertilizations involving both sexes of both species. The implications of this finding are discussed in relation to the availability of suitable spawning sites in Troutbeck.

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The present report was prepared for the Water and Food Challenge Program project “Optimizing the management of a cascade of reservoirs at the catchment level” (MK3). It constitutes the baseline assessment of fish and fisheries in the Sesan River Basin. The objective of the MK3 project is to contribute knowledge and recommendations so that cascades of reservoirs corresponding to hydropower dams in the Mekong Basin are managed in ways that are more fair and equitable for all water users. This project seeks to understand at the catchment scale the cumulative upstream and downstream consequences of management decisions taken for multiple reservoirs. Revised rules for water storage infrastructure management will in particular take into account fisheries and agricultural potential as well as hydropower gen

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This is the assessment and exploitation of eel (Anguilla anguilla. L) stocks in the River Thames and its catchment performed by the Polytechnic of Central London and The Thames Water Authority Research Project between April 1985 and April 1986. The report makes an examination of the pre-pollution history of the Thames eel fishing industry to permit an assessment of the recovery of the eel stock following the cleaning up of the Tideway. Archive material shows that the 19th Century stock was larger and more widely distributed than it is today, and the natural recruitment of elvers to the system is now much smaller. Sampling of commercial catches and trapping studies, including comparisons of different mesh sizes, have been undertaken in order to develop a statistical model of the Inner Estuary eel stock and its fishery. Local migrations and activity throughout the year are studied. Electro—fishing methods and eel traps are compared using mark-recapture techniques in order to develop an accurate means of assessing relative abundance and distribution. Work so far has concentrated mainly on the Rivers Darent and Roding but a preliminary distribution map for the whole catchment has been prepared. An experimental trapping site was established on the River Darent to investigate natural recruitment and up—river migration of elvers and juvenile eels. 1790 small eels were taken in 1985 providing information on the scale, timings and factors affecting the migration.

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This is the Review of discharge consents, River Irwell catchment report produced by the North West Water Authority (NWWA) in 1979. The purpose of this Report is to make recommendations for the revision of consents for discharges within the catchment of the River Irwell, downstream and including the River Medlock in Manchester. This revision has the sole objective of recognising the present effluent and river water quality - proposals for long term river water quality objectives are to be put forward in other Reports. The report identifies the existing situation regarding the legal status of effluent discharges from Authority and non-Authority owned installations within the catchment, details the determinant concentration limits included in existing discharge consents (where appropriate) and proposes the limits to be included in the reviewed consents. The reviewed consents will reflect the quality of effluent achievable by good operation of the existing plant based on 1977 effluent quality data but taking into account any improvements, extensions etc. that have been or are about to be carried out and any known further industrial and/or housing development in the works drainage area.

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This is the Intensive biological survey of the Glaze Brook catchment May 1981 report produced by the North West Water Authority in 1981. The aim of this report is to identify those pollution problems not identified during the routine biological water quality surveys, and to check the suitability of the routine biological sampling point. This report looks at an intensive biological water quality survey of the Glaze Brook catchment which was carried out by Biol. (S) on 13th-15th May, 1981. Kick samples of invertebrates were taken at 5 sites and all invertebrates were identified and counted in the field. The most significant water quality observations in the report were from: Borsdane brook, Pennington brook, Glaze brook, Amberswood brook, Cunningham brook, Old Mill brook, Shakerley brook, Astley brook and Shaw brook.

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This is the Intensive biological survey of the Glaze Brook catchment: Supplementary report on the water quality as indicated by macrophytes produced by the North West Water Authority in 1981. This report describes the results of the macrophyte survey including data on their distribution and the prevailing water quality (nutrient status and toxic metal contamination) It supplements the initial report,TS-BS-81-3, which described the macroinvertebrate survey. The aim of this project is to describe the distribution of macrophytes within the river, paying attention to areas where weed growth may directly affect water quality or amenity usage, and describe the distribution of toxic metals. In the survey 16 sites of 500 m lengths of river were analysed, noting the relative abundance and percentage cover of the macrophytes present, plant score and Community Description Class (C.D.C.) were computed.

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This is the River habitat survey and geomorphological evaluation of the Glaze Brook Catchment report produced by the Environmental Research and Consultancy of the University of Liverpool in 2002. The major aims of the project were to provide baseline information on river habitats in the Glaze catchment using standard River Habitat Survey (RHS) methods (sampling 25% of the catchment length) and, through the geomorphological audit, to assess the distribution and intensity of geomorphological processes, notably sediment transfer, sources and sinks. This information was then used to develop informed management recommendations. The Glaze catchment is a heavily modified watercourse of generally poor habitat quality. The most important factors contributing to the low quality of the sites are poor bank and channel features; low diversity/absence of channel vegetation; paucity of bankside trees and, to a lesser extent, a lack of channel substrate diversity. The high degree of modification relates principally to extensively resectioned banks and channels plus extensive culverting in the urban parts of the catchment.

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This is the report on the strategic stock assessment survey of the Colton Beck catchment in 1994 with particular reference to salmonids in Colton Beck, River Ea, River Gilpin and Rusland Pool. This report forms one part of the third year of a triennial survey programme for the South West Cumbria and South Cumbria catchments. It was produced by the National Rivers Authority in 1994. Colton Beck had excellent densities of sea trout (Salmo trutta) and a small population of salmon (Salmo salar) in its lowest reaches. The total productivity was very good throughout the catchment. Stocking of sea trout fry in 1993 has enhanced the population with survivors through to parr probably adding to the scoring of double class A at two sites in the survey in 1994. Stocking was not undertaken in 1994, but the population appears to be maintaining itself at a very high level.

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This is the Brown trout habitat assessment on the River Bela catchment produced by the Environment Agency North West in 1997. The Environment Agency (EA) and its predecessor the National Rivers Authority undertook strategic fish stock assessments in 1992 and 1995 on the River Bela catchment. These surveys found low numbers of brown trout {Salmo trutta) at some sites. Following this, habitat evaluation assessments were undertaken on the eleven poorest sites Factors probably responsible for declining trout populations on the three main tributaries of the Bela catchment include: Overgrazing by farm stock; Lack of suitable cover for parr; the absence of suitable spawning areas; existing potential of certain areas within the catchment not being utilised, due to poor dispersal. Habitat Improvement Schemes (H.I.S) are discussed and prioritised.

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From the area under report 17 species, 15 endemic and 2 exotic, of freshwater fish have been identified. Of these, 8 species are commonly found in the catches and are of fishery significance. The fact that small fish species which have no fishery importance also support life in other trophic levels of this ecosystem is well exemplified by the interaction of the birds and mammals with these species. A scientific management and monitoring of the reservoir waters as well as the remaining segments of forests are recommended to salvage the wild life and vegetation from a possible rapid deterioration within years.

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The Channel Catchments Cluster (3C) aims to capitalise on outputs from some of the recent projects funded through the INTERREG IVa France (Channel) England programme. The river catchment basins draining into the Channel region drain an area of 137,000km2 and support a human population of over 19M. Throughout history, these catchments, rivers and estuaries have been centres of habitation, developed through commerce and industry, providing transport links to hinterland areas. These catchments also provide drinking water and food through provision of agriculture, fisheries and aquaculture. In addition, many parts of the region are also economically important now for the tourism and leisure industries. Consequently, there is a need to manage the balance of these many and varied human activities within the catchments, rivers, estuaries and marine areas to ensure that they are maintained or restored to good environmental condition . This document highlights some of the recent work carried out by projects within the INTERREG IVa programme that provide tools and techniques to assist in the achievement of these goals.

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Dissertação de Mestrado, Gestão da Água e da Costa, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2010

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Dissertação de Mestrado, Gestão da Água e da Costa, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2010

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Dissertação de Mestrado, Gestão da Água e da Costa, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2010

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Dissertação de mestrado, Ecohidrologia, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015