channel runoff

例句：

1. 1. The rainwater from the roof drains into the sewer system through the downspout.
   屋顶的雨水通过落水管流入下水道系统。
2. 2. The channel runoff carries nutrients and sediment downstream.
   渠道径流携带着养分和沉积物流向下游。
3. 3. The watershed area is responsible for channel runoff and flood control.
   水文区域负责渠道径流和洪水控制。