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Title: An assessment of the impact of Berkhamsted and Maple Lodge STWs on the Grand Union canal based on macroinvertebrate surveys
Author: Judy England
Document Type: Monograph
Macroinvertebrate surveys were carried out by NRA biologists nationwide to assess the water quality of rivers. In the Thames Region this includes monitoring the impact of effluent from major sewage treatment works. A protocol exists for the collecting of invertebrate samples from most river sites. This involves an active 3 minute kick/sweep sample with a 400mm deep, 1mm mesh-size sampling net, followed by a search of one minute in all other habitats. This method is employed when looking at the impact of most sewage works. Samples are taken upstream and downstream of where the effluent discharges into the watercourse. The situation is rather more complex where the effluent enters a canal or canalised river. Not only is the sampling itself more complex (requiring a dredge or grab) but also the lack of diverse habitats reduces the number of niches available for colonisation by macroinvertebrates. Developing projects for students gave us the opportunity to study the impact of two such STWs in more detail. Both projects were designed to identify the impact of the sewage effluent on the macroinvertebrate fauna of the canal and to investigate the distribution of the macroinvertebrates within the various habitats of the canal. Due to the different nature of the GUC at the two locations the sampling strategy varied. For this reason the two studies have been reported separately within this report with a overall discussion comparing the findings.
Publisher: National Rivers Authority
Publication Date: 1992
Publication Place: Peterborough
Subject Keywords: CanalsMacroinvertebratesBiological surveysEffluentsWater qualitySampling
Geographic Keywords: Grand Union CanalThamesHertfordshire
Extent: 33
Total file downloads: 352

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