「嘉義Coin Master重劃區」出流管制規劃書：削減洪峰流量方案評估

Abstract

中文摘要 近年因氣候變遷，降雨分布不均，政府推動逕流分擔及出流管制相關法令，來面對未來開發土地的治理，而本報告著重於出流管制部分，假定一塊土地，檢驗其開發前後出流點的洪峰流量等等狀況。 本規劃選定嘉義一塊農地，進行重劃區建設，預計在基地內建設住宅區及學校和公園等等，打造一個舒適的地方，以吸引人口來到此地，促進當地經濟發展。 以swmm來演算開發前後差異，本計畫共有四個方案，其中有排水路設置、滯洪池及低衝擊開發設施。 四個減洪方案，設計後出流量均小於開發前和後的洪峰流量，在重現期100年時，減洪方案(2) 排水路+定點窪蓄+滯洪池，洪峰削減率達63%。以方案1各重現期來做逕流量比較，其逕流削減率均約45%。也可以看到在不同重現期下，方案(1) 排水路+定點窪蓄所造成的逕流削減率差不多。 在檢核洪峰流量時，三種重現期，方案二除了10年重現期，其餘均有最佳降低洪峰流量效果。 不同方案有其適合的重現期，例如，在重現期50年時，方案(3)及方案(4)，洪峰削減率均大於方案(1)，但在重現期10年卻是相反情形。

Abstract In recent years, due to climate change and uneven distribution of rainfall, the government has promoted runoff sharing and outflow control related laws to face the governance of future development land. This report focuses on the outflow control part, assuming a piece of land, and testing its outflow before and after development. Point flood peak flow and so on. This plan selects a piece of agricultural land in Chiayi for rezoning construction. It is expected that residential areas, schools and parks will be built in the base to create a comfortable place to attract people to this place and promote local economic development. Using swmm to calculate the difference before and after the development, there are four plans in this plan, including drainage roads, flood detention ponds and low-impact development facilities. In the four flood mitigation schemes, the outflow after design is less than the peak flow before and after the development. At the return period of 100 years, the flood mitigation scheme (2) drainage road + fixed-point depression + flood detention pond, the peak reduction rate reaches 63% . Comparing the runoff in each return period of Scheme 1, the runoff reduction rate is about 45%. It can also be seen that under different return periods, the runoff reduction rate caused by scheme (1) drainage road + fixed-point depression is similar. When checking the flood peak flow, there are three return periods, except for the 10-year return period in the second plan, the rest have the best effect of reducing the peak flow. Different plans have their own suitable return periods. For example, when the return period is 50 years, the peak reduction rate of plan (3) and plan (4) is greater than that of plan (1), but it is the opposite in the return period of 10 years. situation.