Definition
1. Opened channel at the yard is a channel for carrying away waste water which is not covered such as open drains and located in the yard.
2. Closed channel at the yard is a closed channel carrying away waster water made from plastic pipes, iron pipes, or covered channel and l
3. Opened channel outside the yard is a channel for carrying away waster water made openly such open drains and located outside the yard.
4. Closed channel outside the yard is a closed channel for carrying away waste water such such as using plastic pipes, iron pipes, or cove
5. No channel, for instance waste water disposed directly without going through channels, such as houses locasted on the river banks.