台灣地形高低起伏變化大，形成河川源短流急，且含砂量大。又近年不斷向都市集中發展，造成平地資源開發幾近飽和狀況下，使得山坡地開發案日漸增多。為避免與減少造成地表土流失及下游洪害之產生，需設置滯洪設施加以處理。本研究係以伽瑪形入流歷線、抽水出流歷線模式之設計理念，依據無因次滯洪理論分析法，利用數學解析方式探討受制已知入流歷線及洪峰消減程度相互影響下，其滯洪容積對時間變化之模式，進而推求該滯洪池之最大滯洪容積。

Due to undulated terrain in Taiwan, most rivers are inherent in high gradient, rapid velocity, and high silt contents. In recent decades, urban areas have been over populated and developed and left rare natural resources. As a result, more and more projects are developed in the slopeland. In order to decrease surface soil loss and minimize damages in downstream area, construction of detention facilities are necessary. The objective of this study is analyzing the detention volume change of detention ponds with rainfall under the gamma inflow hydrograph model. The minimum detention volume of detention ponds can be calculated, and the proposed estimation model of detention volume can be used for the design of detention facilities during the hillside development.