source of runoff meaning in English

补给水源
径链源
径流源

Because small watersheds are the source of runoff and sediment into big rivers and also the joint of river to overall basin , the established various comprehensive prevention and harness systems in small watersheds are the basic treatments and effective way for controlling soil and water loss
小流域是大江大河产水、产沙的源头，是江河与面上联结的纽带，在小流域中修建的各种综合防治体系，是治本清源的做法，是有效防治水土流失的形式。