The irrigation area of this Association is located in the northern part of Taiwan, Which includes Taipei, Taoyuan, and Hsinchu counties. It can be divided into four irrigation areas, namely Taoyuan , Hukou, Tahsi and Hsinhai according to the physical features and irrigation system. The total irrigation area is 24,597 hectares (2006). The main irrigation system consists of Taoyuan Canal, Kuanfu Canal and sub-canals in Tahan River basin and storage ponds.
The climate in this region is sub-tropical climate with humid and hot weather.
Therefore, crops grow all the year long. The annual average temperature is 21℃. The summer is long and a high temperature with and average of 27.6℃. The winter is short and lower temperature with and average of 15℃. The annual average rainfall is 2,000 mm. Uneven distribution of rainfall in different seasons that it has more rainfall in summer than in winter. The effective rainfall in the irrigation season makes up 25%~30% of the total amount of water irrigated.
The main crop occupying the 95% of farmland in the irrigation area is paddy rice, which can be grown twice a year. The remained 5% of farmland in this area is planted with sweet potatoes, melons, vegetables, etc.
The farmland soil in the irrigation area belongs mainly to clay loam that has low permeability. It may be classified as light clay soil, clay loam, sandy clay loam, and sandy loam soil.
The river here is short and torrential, so the rain is stayed only a short time. The dry land must depend on ponds drilled along the terraces with natural rain reservoir for irrigation water resources are Shihmen dam, Taoyuan Canal, Kuangfu Canal Tahan stream, and various ponds and weirs.
Irrigation pattern and cultivation way
The whole area is double-cropped cultivation. In general, the first crop is completed around the tomb-sweeping festival, and the time required for irrigation is approx.120 days. The second crop cultivation shall be completed before autumn begins, and needs about 110 days for irrigation. In the field, the water requirement is 2,000 mm (that is 20,000 cubic meters/ha. Of Shihmen dam, or other water resources and past water required, canal conveyance loss volume, irrigation period, etc. and program a project for rotational irrigation. Each working station’s staff will discuss irrigation program with irrigation group before implementation.
In this area, irrigation water in field is evidently deficit and unable to reach the target of second crop of cultivation. The water resources were shortage and unable to supply the plant potato and tea tree, or even to desert without cultivation any crops. It is an urgent need here for irrigation facilities.