Sampling Surface Water Sample Clauses

Sampling Surface Water. The water quality of a lake, reservoir or river can vary in space and time according to natural morphological, hydrological, chemical, biological and sedimentological processes. Major storms may cause significant longer-term changes in water quality. Pollution of natural bodies of surface water is widespread because of human activities, such as disposal of sewage and industrial wastes, acidification of rainfall by gas emissions to the atmosphere, land clearance, deforestation, mining, and use of pesticides. Surface-water quality may also be significantly affected by agriculture, industry, mineral and energy extraction, urbanization and other human actions, as well as by atmospheric inputs. In general, the selection of sampling sites is based on how representative they are. Considerations of the local representativeness of the sampling point at the stream site may be based on preliminary surveys, taking into account the hydrology and morphology of the water body.