This association is located in the south-west area of Taiwan, and in the east to close to Pingtung county, in the west to close to the Taiwan straits, in the north to connect to Tainan county, and its terrain tilts from the east to the west. Climate is to belong to sub-tropical island type, and annual average rainfall is 1,680 mm. Most of the rainfall appears in the season of typhoon, and from Oct. to Mar. of next year is the dry period. Average temperature is 24℃, and the max. temperature is 36.9℃, the mini temperature is 9.6℃ Tsaokung and Chishan are sandy loam. Kangshan area is clay loam.
Before 1951, this irrigation area is wide to cover Kaohsiung city and 27 cities and towns within this territory including whole of Pingutng Irrigation Association, and extending to the south of Hengchun with length more than 100 km. However, later on, it was separately set-up by administrative adjustment and local demand.
1. Irrigation water resources – Surface water is to occupy 97.5%, and ground water is to occupy 2.5%. Main water resources come from Kaoping river, Laonung river, Chishan river, Erhjen river, Akungtien reservoir, and secondly, from Houchin stream, return flow, interception and ground water,etc.
2. Irrigation system – For the sake of geography and water system, this irrigation is divided into Tsaokung area, Kangshan area and Chishan area. Tsaokung area has the main water resources of Kaoping river, Chengching lake (Tapei lake) and Lienchih lake are the most famous one. Kangshan area has the main water resources from Erhjen river and Akungtien reservoir. Chishan area has the main water resources from Liaonung riverand Chishah tiver.