Flood shall be drained into the main channel or its distributary, or other rivers, lakes, or oceans. Special attention must be paid to the protection and maintenance of related structures and other important facilities. With approval of the superior authority, flood may be drained into other or newly constructed waterways.

To mitigate flood damages, the authority-in-charge may restrict use of land in the vicinity reached by flood through zoning regulation.
The authority-in charge shall formulate and implement the restriction and zoning regulation under preceding paragraph based on flood history records and forecasts after the approval and public announcement by the superior authority.

During a flood and before floodgates open, a reservoir administration agency shall notify all related agencies to take necessary protective measures.

Lower riparian landowners shall not obstruct stream flows from high land.

When draining flood water from high land to lower land by artificial means, a higher riparian landowner shall choose the locations and methods causing the least damages and compensate the lower riparian landowner.

Wastewater from factories and mines or urban sewerage shall be discharged into properly selected locations after adequate treatment.　If such wastewater or sewerage adversely affects water quality, human health, public interests, or interests of a third party, the authority-in-charge may place restrictions on or prohibit the discharge thereof, and those who suffer damages may claim compensations.

Where the storage or drainage of water causes damages to up or downstream riparian landowners, the person who causes the damages shall be liable unless the damages are caused by a force majeure event.

The proprietor of reservoir should conduct a detailed survey of land and improvements in the catchment area of reservoir that are likely to be flooded and propose a plan of acquisition, compensation, and relocation, which will be implemented after approval of the authority-in-charge.

(deleted)

When a stream is accidentally arrested at lower land, a riparian owner at higher land may at own costs restore the flow.

The authority-in-charge shall submit the standards, water level or time for opening and closing to its superior authority for approval and public announcement.

Any structure spanning over a waterway shall have passage in place for water to pass through. The cross sectional area of such passage shall be approved by the authority-in-charge.
If a waterway referred to under the preceding paragraph is for navigation, a bridge shall be built over the waterway and the elevation of bridge bottom and the length of bridge span shall be regulated by the authority-in-charge.

When installing a structure over a waterway or crossing the foundation of a water work facility, the proprietor shall apply for the approval of the authority-in-charge and construct under its supervision.
Digging and quarry activities are not allowed within a prescribed distance up and downstream the structure under the preceding paragraph, unless such activity is necessary for the safety and maintenance of water work. The safety distance shall be promulgated and publicly announced by the authority-in-charge.