The irrigation and drainage system of general farmland can be roughly divided into water diversion, water leading, water delivery, water distribution and drainage. The designated level and management scope are based on the size of the irrigation and drainage areas, water source water volume, water channel capacity, topography, irrigation system and natural boundaries as well as other ground objects. The management system varies depending on the size of the system area.

1. Management rights and responsibilities are divided based on the independence of water sources, range of irrigation areas, length of canals etc.
2. If it is a canal sporadic area, and the irrigation area is small and limited to a certain scale, the management of the water diversion (water source) to the water supply channel is the responsibility of the irrigation workstation.
3. If the irrigation benefitting area of a lateral or sub-lateral canal is large, the length of the water channel is long, and it spans two irrigation workstations, workstation responsibilities will depend on the water channel location.
4. Water channels of the same level or system should be managed by workstations under the same unit.

Irrigation system refers to the water source reaching farmland from leading channels, main canals, lateral canals, sub-lateral canals, ditches. Among them, water sources and leading channels belong to water diversion engineering projects, main canals, lateral canals, sub-lateral canals belong to water delivery engineering projects, and ditches belong to water distribution engineering projects.

In the management organization system, water sources and leading channels are under the jurisdiction of water source workstations, main canals are under the jurisdiction of water channel workstations, and lateral canals, sub-lateral canals, and ditches are under the jurisdiction of irrigation workstations.

1.The division of responsibility depends on the water catchment area, basin scope, drainages length etc.

2.The Irrigation Association manages farmland drainage.

3.Drainage classification can be divided into(Article 6 of the Enforcement Rules for the Irrigation Act)

• Farmland drainage: Remove excess water stagnated on farmland surfaces and topsoil.
• Urban drainage: If the flat part of the drainage catchment area and the starting and ending points of the water channel are all within the range of the city (town), township, or street urban planning, it is recognized as urban drainage.
• Business drainage: Exclude waste water after business use and outflow water after hydropower generation.
• Regional drainage: If the flat land part of the drainage channel catchment area covers the urban planning area of a city (township), township, or street and receives rainwater and sewage, it is considered regional drainage.
• Other drainage: Exclude water that does not belong to items 1~3.

4.If there is no city (town), township or street plan for the water catchment area and it falls within the range of non-urban land use, the drainage classification is divided according to the following principles.

• If a single target accounts for more than 90% of the water catchment area, and the remaining 10% is from scattered areas, it is still considered single target drainage; if a single target water catchment area does not reach 90%, it is classified as regional drainage.However, if its lateral canals are classified as regional drainage according to the above principles, the main canal should also be classified as regional drainage.
• Those with catchment areas exceeding 10,000 hectares are classified as regional drainage.

5.The agency or individual responsible for the maintenance and management of drainage facilities in different drainage classifications is stipulated as follows in accordance with the Taiwan Province Drainage Facilities Maintenance and Management Regulations:

• Farmland drainage: A member of the Irrigation Association or other irrigation companies.
• Urban drainage: A county or city government office or a township or city government office.
• Business drainage:
  • Industrial zones are managed by industrial zone management agencies.
  • Factories or mines are presided over by a factory representative or mining director.
  • Power generation is the preserve of water storage companies.

Drainage system refers to the system which discharges surplus irrigation water from farmland into rivers and the ocean through small drainage, medium drainage, large drainage and main drainage. In the management organization system, small and medium drainage falls are under the jurisdiction of the irrigation workstation, and large and main drainage is the responsibility of the water channel workstation.