It is located at central part of Taiwan, nd connects to Central Mountain range in the east, nearby Miaolo stream of Wu river and Changhua Irrigation Association in the south-west, boundary of Tsaohu stream in the north. It just closes to Taichung Irrigation Association, and branches of Wu river across over to create this cultural land. In the territory, there are lots of mountains with beautiful scenery, so it has rich tourist resources. Because the elevation in this area starts from 50 meters to 750 meters, the terrain varies for different height with narrow bank. In the summer period, the torrential rain will result in serious damage of water intake, so that the maintenance cost is quite high. The climate here is mild and warm, and there has lots of rainfall in the summer and less rain in the winter. The average annual rainfall is 1,731 mm, 1,433 mm is for May, June, August, and September to occupy 82.2% for the whole year. The irrigation area of this Assocation is along with water system of Wu river and crossing over north-east corner of Nantou city, Mantou county, Tsaotun town, Kouhsing Hsiang, Puli town, Yuchih Hsiang, and Jenai Hsiang, Hsinshe Hsiang of Taichung county, Wufeng Hsiang, Wujih Hsiang, Fenyuan Hsiang of Changhua county, etc. 10 towns.
1. Irrigation water resources – The water resources of this Association is based on surface water to come from river, so it is greatly influenced by seasonal water supply. When the first crop cultivation encounters insufficient water supply or for the sake of serious damage on water intake, the water pumped from the ground will be supplemented. Also, the drainage water gates were is set-up to recycle use the return water. The surface water can be divided into two systems:
a. Wu river system : Nengkao canal etc., total 60 canals to irrigate area 11,845 ha. and occupy 95.4%.
b. Tsuoshui river system : Hsincheng canal etc., total 5 canals to irrigate area 567 ha. and occupy 4.6%.
2. Irrigation canals – There are 65 canals in the territory, and main canals in clued Peitou Hin canal, Lungchuan canal, Chiehlaomachu canal, Achaowu canal, and Nengkao canal.
3. Drainage canals – Main drainage canals in this territory include Chemlungpei drainage canal, Houhsiti drainage canal, Hsihsinpa drainage, Hsiweiliao drainage, Pipacheng drainage, Diaoshuehkou drainage, Chaofengpai drainage, Nieulukou drainage, Tapei drainage and Hsichoupei drainage, total 10 drainage canals with catching area 3,282 ha. and allowable drainage capacity is 847.59 cms.
Irrigation pattern and cultivation way
In this territory, the way of cultivation is divided in to double crop with cultivation area 11,854 ha. and single crop cultivation area has 558 ha.
Normal irrigation pattern : Nantou area (including Tucheng, Tsaotun, Chiehlao, Wufeng, Koli, etc. five stations) adopts large-scale region with continuous irrigation, and Nengkao area (including Tuchih, Puli, Fuhsin, etc. 3 stations) adopts small-area rotary timing irrigation. In Kouhsing station, for there is unable to connect to each irrigation canal and without irrigation water support, irrigation pattern adopts continuous irrigation.
If in the dry season and lacked of irrigation water, then it is handled according to the “Regulations on strategies for different irrigation systems for Irrigation Associations in dry period.”