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Quality of first flush of rainwater from urban area: short review

As a result of changes in social, economic, and political relations, undesirable phenomena are created that have an adverse effect on the urban environment. Surface runoff represents one of several risks to environmental policy, causing the major problem in urban agglomerations. In an urbanized area, it causes an increased runoff volume and the flood peak. Also, it affects increasing the contamination of urban rainwater. The significant problem of surface runoff formation in urban river basins is the accumulation of pollutants on the surface of paved areas during the rainless period. In the case of the formation of surface runoff, these substances come into movement. It is assumed that the most polluted rainwater is in the initial phase of runoff formation. However, not all authors agree with the statement. In some literature, this phenomenon is termed the first flush. Given the above facts, the study focuses on surface runoff characteristics in terms of its quality and quantity in the initial phase of surface runoff formatting. The study aims to summarize and compare the results of several studies to evaluate the first rainwater flush in an urbanized area.