Impacts of the urbanization on non-point source pollution in Suzhou

Non-point source (NPS) pollution is the prominent source of water pollution. Urbanization has greatly influenced on the urban NPS pollution by changing the hydrology of watersheds. A review was conducted on the international researches of urbanization impacts on urban NPS pollution. As an example of Suzhou urban area, an investigation on urban NPS of Suzhou had been done in different land use area, indicating the median values of Event Mean Concentrations (EMC) of COD, SS, NH3-N, TN and TP are 199mg/L, 156mg/L, 5.56 mg/L, 14.98 mg/L and 1.51 mg/L, the pollution loads are 8034t, 6887t, 277t, 573t and 58t respectively. About 18%–53% of the whole pollution loads are contributed by NPS, indicating that the urban NPS is the major factor for the river quality degradation, the higher level of the urbanization is, the worse the water quality is. Controlling the urban NPS is therefore tremendously significant to maintain the sustained and healthy development of urban.