station serves to assess the situation with respect to background water quality and biological aspects, which may vary locally and regionally. Drinking water intake points, irrigation canal off-take points and tail-end entry point should be considered for monitoring. Sampling stations should be located upstream and downstream of significant pollution outfalls like city sewage drains and industrial effluent outfalls and at the entry point of the wetland, lake, Dam and on the outlet side of it. All samples must be representative, which means that the determinants in the sample must have the same value as the water body at the place and time of sampling. In order to achieve this it is important that the sample is collected from well-mixed zone. A homogeneity test must be performed to identify the well-mixed zone. Additional downstream stations are necessary to assess the extent of the influence of an outfall, and you should locate the point of recovery. In large rivers a balance has to be found between the selection of a few stations giving poor coverage, and the selection of more stations having different substrates and dissimilar fauna, which cannot be compared spatially. In order to enable comparisons among sampling stations, it is essential that all stations be sampled approximately at the same time. Not more than two weeks should elapse between the sampling of the first and last station in a river or lake system. Sites for biological sampling should match with sites for chemical sampling. Biological sampling stations need to be selected with proper attention to representative habitats (kind of substrate, depth and flow). All sampling stations in a certain river should preferably be ecologically similar. To increase biological and chemical comparability, they should have similar substrate (sand, gravel, rock, or mud), depth, presence of rifles and pools, stream width, flow velocity, bank cover, human disturbances, etc. The conventional location of macro-invertebrate sampling stations in rivers arises not only from an assumed uniformity of substrate and fauna, but also from the ease with which it may be sampled by means of hand nets and stone lifting or kicking, and from the ease of access. For the estimation of the oxygen exchange rate of the river, a measurement of cross section is required. Any station should be typical with respect to the cross section of the river. The sampling team normally has to carry an appreciable burden of sampling gear and water samples, and the distance they can walk is limited. Easily accessible sites
station serves to assess the situation with respect to background water quality and biological aspects, which may vary locally and regionally. Drinking water intake points, irrigation canal off-take points and tail-end entry point should be considered for monitoring. Sampling stations should be located upstream and downstream of significant pollution outfalls like city sewage drains and industrial effluent outfalls and at the entry point of the wetland, lake, Dam and on the outlet side of it. All samples must be representative, which means that the determinants in the sample must have the same value as the water body at the place and time of sampling. In order to achieve this it is important that the sample is collected from well-mixed zone. A homogeneity test must be performed to identify the well-mixed zone. Additional downstream stations are necessary to assess the extent of the influence of an outfall, and you should locate the point of recovery. In large rivers a balance has to be found between the selection of a few stations giving poor coverage, and the selection of more stations having different substrates and dissimilar fauna, which cannot be compared spatially. In order to enable comparisons among sampling stations, it is essential that all stations be sampled approximately at the same time. Not more than two weeks should elapse between the sampling of the first and last station in a river or lake system. Sites for biological sampling should match with sites for chemical sampling. Biological sampling stations need to be selected with proper attention to representative habitats (kind of substrate, depth and flow). All sampling stations in a certain river should preferably be ecologically similar. To increase biological and chemical comparability, they should have similar substrate (sand, gravel, rock, or mud), depth, presence of rifles and pools, stream width, flow velocity, bank cover, human disturbances, etc. The conventional location of macro-invertebrate sampling stations in rivers arises not only from an assumed uniformity of substrate and fauna, but also from the ease with which it may be sampled by means of hand nets and stone lifting or kicking, and from the ease of access. For the estimation of the oxygen exchange rate of the river, a measurement of cross section is required. Any station should be typical with respect to the cross section of the river. The sampling team normally has to carry an appreciable burden of sampling gear and water samples, and the distance they can walk is limited. Easily accessible sites
GUIDELINES_FOR_WATER_RESOURCES_MONITORING_AND_POLLUTION_CONTROL_-FINAL_VERSION.docx