国内典型城市降雨径流初期累积特征分析

提出以携带50%污染物负荷的径流定义初期雨水,选取累积50%污染物负荷的历时(T50)及对应累积径流深度(D50)两个参数,总结分析典型山地城市、平原城市、河网城市等6个城市17场降雨径流污染物累积特征.进一步以山地城市和平原城市为例,探讨了不同降雨强度、区域环境径流污染物累积特征及相互影响.结果表明,径流污染物累积趋势完全一致但特征不同,山地城市、河网城市、高原城市和河口城市表现为初期累积,平原城市则表现为中期累积.随着雨强增大,污染物D50骤增,T50锐减.相比平原城市,山地城市不同类型污染物D50更大、T50更小,山地城市和平原城市分别截留初期7.4mm和5.2mm径流可以控制50%污染物负荷.

Cumulative characteristics of runoff pollutants in typical domestic cities

The rainfall runoff with 50% pollutant load was defined as initial rainwater, and the time (T50) accumulating 50% pollutant loading and corresponding runoff depth (D50) was selected to analyze the cumulative characteristics of pollutants during 17 rainfall events in typical domestic mountainous city, plain city, river city, etc. Taken mountainous and plain cities as examples, the cumulative characteristics of different types of pollutants in the runoff were discussed and the effects of rainfall intensity and its regional environment were studied. The results indicated that the accumulation of runoff pollutants had the same trend but exhibited different characteristics. It tended to accumulate at mid-stage in plain city while at initial stage in other cities. With rainfall intensity increased, the D50 of pollutants increased greatly while T50 declined sharply. Pollutants in mountainous city had a higher D50 and a lower T50 than that in plain city. It was suggested that mountainous cities and plain city intercepting 7.4mm and 5.2mm runoff respectively could control 50% pollutant load.