N, P, and COD conveyed by urban runoff: a comparative research between a city and a town in the Taihu Basin
Abstract Stormwater runoff containing various pollutants exerts adverse effects on receiving water bodies and deteriorates the urban aquatic environment. Although numerous studies have been conducted on runoff pollution, research comparing its characteristics in cities with those in towns is rare in the literature. To close this gap, the present study was conducted. The outflow concentration and peak value of N in the town were higher than those in the city in most conditions (at 75% and 67%, respectively). The second peak value of P in the town was higher and occurred earlier than the city. EMCs of TN and DTN in the town were 20%–60% (10%–50%) higher than those in the city. DTP accounted for 76.9%–83.3% of the total P (TP) in the town, which was generally higher than the city values of 50%–87.5%. According to our results, road runoff in the town contributed more to urban aquatic pollution, thus further research should concentrate on this particular type of runoff.