Natural environmentThe irrigation area administered by this office is located in the northwest part of Taiwan, namely Taoyuan and Zhongli in Taoyuan County. It is commonly known as the Taoyuan Plateau, which slopes from southeast to northwest and borders the natural environment of the Taiwan Strait. From the high terrain in the southeast, it stretches towards the northwest coast in a 1:100 gradient slope. The rivers in this area are short in length, and the rainwater retaining time is quite brief, thus usable water sources are limited. It has always been a dry field and cultivation is in the power of the weather. Ponds are usually built along the sloping undulations of the plateau to collect rainwater for irrigation. Therefore, the arable land area on the plateau at that time was approximately 27,000 hectares, but the ponds covered an area of more than 8,000 hectares, and are found in different sizes scattered around the area in more than 10,000 locations, which is comparable to the stars in the sky and can be seen everywhere, becoming the characteristics of this area. However, water used for irrigation is still insufficient to achieve the goal of second cropping due to the influence of climate and rainfall. In the unfortunate scenario of a long drought, the farmers are always anguished to find the water source depleted, the crop withered, and the dry pond cracked. Consequently, some of the rice paddy fields are used for planting sweet potatoes and tea trees, or even abandoned. Therefore, local farmers are in pressing need of water conservancy infrastructures that can provide stable water sources.
According to Taiwan's agricultural climate division, this area is located in the northern part of Taiwan and presents a hot and humid subtropical climate with an average temperature of 21 ℃, which is suitable for crop growth throughout the year. Summers are long with an average of 27.6 ℃, while winters are short with an average of only 15 ℃. According to statistics, the average annual precipitation is about 2,000 mm. Although the seasonal distribution of rainfall is typically higher in summer, winter is still not overly dry. The rice growth period in this region is from February to October every year. During this 9-month period, the effective rainfall utilization rate is about 20% or more.
Clay loam is predominant in this region, with 39%. It has the highest proportion of soil, followed by sandy loam with 26%, while light clay accounted for about 18.6%, and sandy clay loam the least, accounting for only 16.4%.
The administrative irrigation area of this office is within the scope of Taoyuan Canal’s single canal irrigation system. Since the Guangfu Canal at the end of Taoyuan Canal and most canals below Shimen are all irrigation systems that draw water from Dahan River, the government decided to carry out integration of these irrigation systems starting with the merger of two irrigation areas, Daxi and Hukou in 1956. Later in 1970, the 5,176 hectares of irrigation area belonging to the Xinhai Irrigation Association was annexed into this office’s administrative jurisdiction. The integration has expanded this office’s administrative area, which covers 25 administrative districts including Taoyuan City, New Taipei City and Hsinchu County, with an irrigated area that has increased to 34,568 hectares. During the implementation of the Farmland Water Conservancy Association Improvement Plan from 1975 to 1982, the irrigated area was 31,056 hectares. However, due to increasing population, industrial and commercial development, and the changes in social structure, several farmlands in irrigation areas have been converted for other uses, which has reduced the number of cultivated lands. Therefore, according to statistical records, irrigated area was only 28,241 hectares in 1984, 26,235 hectares in 1989, 25,983 hectares in 1995, and 22,677 hectares in 2017.
According to terrain and irrigation system, it is divided into 4 main parts:
10 administrative districts in Taoyuan City: Taoyuan, Zhongli, Daxi, Bade, Guishan, Luzhu, Guanyin, Xinwu, and Yangmei, with an irrigated area of 21,348 hectares. In 1989 it reduced to 20,192 hectares and became 20,032 hectares in 1995.
Xinwu District and Yangmei District of Taoyuan City, Hukou Township and Xinfeng Township of Hsinchu County, with an irrigated area of 3,834 hectares. In 1989 it reduced to 3,802 hectares, and in 1995 it became 3,801 hectares.
Taoyuan City’s Daxi District and New Taipei City’s Yingge District have an irrigated area of 802 hectares. In 1989 it reduced to 611 hectares, and in 1995 it became 604 hectares.
New Taipei City's Sanxia, Shulin, Tucheng, Banqiao, Zhonghe, Yonghe, Yingge, Xindian, Sanchong, Xinzhuang, Taishan, Wugu, Luzhou, among other administrative districts, with an irrigated area of 2,239 hectares. In 1989 it reduced to 1,634 hectares, and in 1995 it became 1,546 hectares.