适用于雨水稀少、水体环境容量大，且一定量污水不影响河流的地区。浙江地区

Applies to scarce rainfall, a large body of water environmental capacity, and a certain amount of water does not affect the river area. More abundant rain in Zhejiang province, the narrow part of the river, sewage mixed with water, a greater impact on the environment, and therefore the implementation of limitations

It is suitable for areas where rainwater is scarce, water environment capacity is large, and a certain amount of sewage does not affect rivers. Zhejiang area is more abundant rain, some river narrow, sewage mixed into the water body, the environmental impact is greater, so the implementation has limitations

It is suitable for areas with few rainwater, large environmental capacity of water body, and a certain amount of sewage does not affect the river. In Zhejiang Province, there is abundant rainfall, some rivers are narrow, and sewage is mixed into water body, which has great impact on the environment, so the implementation is limited