圖書典藏及影音數位平台

雙溪水庫集水區面積為8.97平方公里，現況植生情形良好，惟氣候變遷可能引發豪雨洪水事件，誘發集水區崩塌，導致大量土砂流入水庫，影響水庫壽命或供水穩定，因此，本計畫針對水庫集水區進行相關調查，瞭解崩塌潛勢，並觀測水砂資料，提供未來水庫營運及管理參考。

In this project, we discussed about topographic variations and collapse characteristics of catchment, potential analyses and hierarchy management suggestions of collapse, evaluations of geological safety, observations and integrated analyses of water-sand. The annual soil losses is 10,765m3,including 1,212m3 caused by landslide and 9,553m3 by soil erosion. Referring the characteristics of landslide, the susceptible level of collapse slope is from 4 to 5, orientation is from northeast to southeast. The collapse potential analysis of 200-years return period reveals that high collapse potential slope only appear at one of the upstream slope and at the slope on the left bank beside the dam, the others are middle potential slope. As to the aspect of collapse hierarchy management, natural recovery management is suggested to the landslide areas where 4 sites are in the reservoir catchment and 7 of the 10 sites are at downstream. Only 3 downstream places (D_06, D_07 and D_08) should transfer to local government to deal with. The geological safety assessment results show the landslide occurrence probability on sensitive slope A is very low, no rocks will fall from the slope top in the future but the dip slopes need to be concerned. And the result of lower sensitive slope B is that rock mass at left dam base is steady but might collapse to river due to the erosion of basal slope while the upper rock mass does not have such problem. It is recommended that stabilization or curtain grouting could be applied to intensify the loading ability of rock base or use drain facility to collect the water passed through curtain grouting when building dam. The evaluation of Dinglan bridge annual flow is 37,080 thousand square meter. The formula of discharge -sediment yield rating curve is Qs=9.95Q1.3061 which the average volume of sediment yield is 2,766 tons.There are two factors making the difference between sand yield into river and slope sand producing: one is the ratio of fine and coarse grain has not been considered and the other is the sand yield only concern particles in the water but not the quantity of movement.