synthetic unit-hydrograph

例句：

1. 1. The hydrograph of the river shows that there is a lot of sediment in it.
   这条河流的水文图显示，里面有很多沉积物。
2. 2. The hydrograph of the region shows that there is a high level of pollution in it.
   该地区的水文图显示，污染水平很高。
3. 3. The hydrograph of the city shows that the water quality is very poor.
   城市的水文图显示，水质非常差。