圖書典藏及影音數位平台

1.朴子溪大斷面測量 2.朴子溪基本資料調查分析 3.朴子溪水文分析 4.河川特性及現況水理分析

The regulation plan of Puzih River was completed by the former Taiwan Provincial Water Conservancy Bureau in 1987. Since, the global climate change makes the weather more unpredictable, in order to protect the river basin from flooding and prevent the river basin from over development, the Fifth River Management Office, WRA, MOEA conducted a study to revise the regulation plan of Puzih River in 2014. Puzih River is located in Chiayi county. It originates from Alishan (EL. 1,421m) and the river basin area is 427.6 km2.This evaluation project covers the reach of Puzih River from Jin-Fu bridge to Taiwan Strait with a total length of 60 km. Extreme value Type I Distribution was used for rainfall frequency analysis, several historical storms were used to analysis rainfall time distribution, and Dimensionless Unit Hydrograph methods was used to compute storm hydrographs of various return periods using 48 hours rainfall duration. The peak discharge of a 100-year return periods at outlet Puzih River was determined to be 2,975cms. Current capacity of Puzih river was calculated using Hec-Ras model. The results indicated that most reaches have capacities of 100-year return period peak discharge except the reach from X-sec.53~69 where levees have not yet built. River Improvement principles are as follows： (1) The environment and water resource utilization must be considered in the improvement plan. (2) The improvement of river cross sections must consider sediment transport capacities of each river reach in order to maintain stable river channel. (3) Levees should be built to protect flooded areas, and broken levees should be strengthened. (4) Elevations of drainage outlets should be considered to ensure proper drainage, the channel width showed be increased at locations of river bends to increase flow capacity. As shown in table 1, the channel width is at various river reaches were determined by empirical equations. The calculated width was compared with results determined in 1997 and 1998, and modified by existing river characteristics and topographical features. The implementation plan recommended by this project include： (1) Strengthen the revetments： A total of 4.05 km of floodwalls (1.0m height) are to be constructed along the right bank at X-sec.24~30 and the left bank at X-sec.65~67. (2) Construction embankment： A total of 0.7 km of embankment are to be constructed along the right bank of X-sec.23~24. The total construction cost for the revetment and embankment would be 410,424,000 NTD including 309,510,000 NTD of direct construction cost and 90,150,000 NTD of land acquisition cost. For the safety of the people living nearby the river, the project will be implemented in one Phase. The benefit to cost ratio of this project was estimated to be 0.20 without considering indirect and intangible benefit. The implementation of this regulation plan needs cooperation of various related agencies including land-use planning, water and soil conservation, transportation, local drainages, flood forecasting, ecological protection measure, flood rescue and shelter and ete.