Taichung Irrigation Association is located at the west of Taiwan and bounded from terrace of Tatushan, and the irrigation area has been divided into two parts. The one from the east of Tatushan to the Taichung basin between Central Mountain range, and another one from the west of Tatushan to western coast of Tatu, Chingshui, Tachia, Wanli, etc. plains. The rainfall per year is about 1,200-2,000 mm. Although it is rich of rain, the distribution is uneven and belongs to sub-tropical zone. The annual average temperature is about 22℃. From May to Sept. is rainy season and enriches with water resources. From Nov. to April of next year is dry period with less water. However, there are many typhoons in July, Aug, and September. In the territory, Wanli, Houli, Hsinshe, and Tatushan are red soil. Tachia, Chingshui area belongs to grey sandy land. The soil in rest area is loam and sandy loam. The irrigation area of this Association covers Taichung city, Taichung county and Miaoli county’s Wanli, Tunghsial, Chaolan, Sanyi, etc. 32 cities and towns.
The irrigation water of this area belongs to intake river flow, and main irrigation water resources come from Yaan river, Tachia river and Wu river. They are originated from Central Mountain range, and in the dry period, the water supplement comes from water pumping of under ground. Except Tamaopu canal, Tatu canal pumping the water from ground for irrigation, the rest canals are directly connected to river gate for irrigation. Main canals of water system of Taan river include Chaolan canal, Houli canal, Chikung canal, Hsintien canal, Chenkou canal, Wanli canal, Jihnan canal, Chiuchangli canal, Tingtien canal, etc. The main canals of water system of Tachia river include Paineng canal, Tungshihpian canal, Papao canal, Hulutun canal, Neipu canal, Wufu canal, Kaomei canal, Huyen, and Erh canal, etc. Main canals of water system of Wu river include Tatu canal, Wangtien canal, Jantsuoyuan canal, and Tatuliao canal. There are total 43 main canals and 125 lateral canals.
Irrigation pattern and cultivation way
1. Paddy field irrigation – There are double-cropped cultivation in this irrigation area, and the main crops is rice. Bisides, it is devided by river system with 10,806 ha. of Taan river, 15,431 ha. of Tachia river, and 3,707 ha. of Wu river.
2. Upland crops irrigation – Since 1986, till today, the irrigation area of this Association has reached to be 400 ha. There are more than 1,000 Households of farmers under application including the scope of Chuolan town, Miaoli county, Wanli town, Tungshih town of Taichung vounty, Hsinshe town, Shihkang Hsiang, Houli Hsiang, and Waipu Hsiang. Flowers cultivation and net-type organic vegetables cultivation must be the trend for future development in Houli terrace.