圖書典藏及影音數位平台

同安厝排水發源於台中西郊之大肚山下游排入烏溪排水路長度約為6公里，集水面積約為9.5平方公里，於民國98年7月18日公告治理計畫。惟近年來臺中市都市發展迅速，上游有台中精密機械科技創新園園區；中下游為多處市地重劃區；下游為台灣高鐵特定區，集水區內的土地利用情形已大幅改變，與91年經濟部水利規劃試驗所辦理「台中地區同安厝坑排水規劃報告」內容略有不同，有必要針對轄區排水系統進行全面性地文及水文環境生態進行檢討，以瞭解現況排水路特性，並提出改善規劃方案及管理建議，供工程單位實施之依據，以降低減少淹水問題，促進社會繁榮。

The Tong-an-chuo drainage originates in Taichung City. It goes through the Nan-tung District and the Wu-ri District. Finally, it flows into the Wu River. In 2002, the “Planning Report for the Tong-an-chuo-keng drainage in Taichung Area” was proposed by the Water Resources Institute, Water Resources Agency, MOEA to review flooding problems in this area. In 2009, A harness plan and land coverage boundaries had been announced. Thereafter, through land re-surveying, it was found that there were somewhat differences between announced land coverage boundaries and residents’ land boundaries. Therefore, land acquiring work could not be completed in the middle section of the Tong-an-chuo drainage. Thus, successive harness work was not smooth going and the middle section of the drainage became a bottleneck for flood mitigation. It has been 15 years since the planning work for the Tong-an-chuo drainage in 2002. The original harness works were hindered by land boundary differences. In recent years, the frequency of extreme rainfall events was increasing, and the catchment area was also changed after land development. Therefore, this project devotes to propose adequate solutions for drainage harness and land management in this area. After performing hydraulic simulations for existing conditions, it reveals that channel sections in the middle section of the drainage are too small, which can convey only 2-year to 5-year return period floods while other sections can convey 10-year or even 25-year return period floods. The Kalmaegi Typhoon in 2008 and the Saola Typhoon in 2012 caused floods in the middle section of the drainage due to channel section shortages. Besides, the Wang-tian channel is coincident with the Tong-an-chuo drainage in this section. Their objects are conflict. The formal is for irrigation purpose but the latter is for drainage purpose. Thus, separation works for irrigation and drainage are required. This project mainly extends widths of the middle section of the drainage, from existing 8~12m widths to projected 18m widths. In addition, separation works for the Wang-tian irrigation channel and the Tong-an-chuo drainage are included. The total engineering cost is NT$ 722.42 billions. Engineering works are scheduled in two stages according to their priorities. After performing benefit-cost analysis, the benefit-cost ratio of this project is 1.47. Engineering works proposed by this project are valuable because they can reduce people’s life and property losses, reduce disease transmission, improve society stability, promote life quality, balance local development and uplift international image.