圖書典藏及影音數位平台

鹿寮溪水庫位於台南市白河區馬稠後與嘉義縣水上鄉牛稠埔溪交界處，係於民國28年興建完工，隸屬台糖公司所有及管理，水庫位置如圖1所示。目前水庫淤積非常嚴重，庫容已由完工時之378萬立方公尺，降至目前(103年) 之78.8萬立方公尺，淤積率達80%，為活化水庫及提高水資源利用 ，亟須辦理更新改善。 本署南區水資源局及本所於民國95年至105年間陸續辦理更新改善可行性規劃相關計畫，目前已完成工程可行規劃及正進行二階環評調查分析。依前期環評敏感區位查詢結果，本計畫部分工程位於地質法公告之地質敏感區，依「地質敏感區基地地質調查及地質安全評估作業準則」規定，應辦理區域調查及細部調查，並完成「基地地質調查及地質安全評估結果」報告及送審作業，爰辦理本計畫，以利後續推動。

Lu-Liao-Creek reservoir is located in Baihe district of Tainan City on the junction of NiuchouBu River and is owned by Taiwan Sugar Company. Due to severe siltation, it is in urgent need of renewal and improvement. According to the previous planning projects, rehabilitation project of Lu-Liao-Creek Reservoir is a feasible plan in order to obtain the stable water supply for the water source in Chia Yi Area, including dredging to the original storage capacity、heightening of the dam structure、 Yun-Shui River cross reginal water diversion project and downstream water transfer pipe. After checking the contents of this project, the structure sites of spillway and water diversion channel during construction、earthwork stacking site and cross reginal water diversion tunnel overlap with geologically sensitive areas that publicly announced by the Ministry of Economic Affairs. Therefore, according to the Geological Act, it needs to conduct geological survey and assessment. The survey result indicates that the slope near the exit of the spillway belongs to a potential area of rock debris. The east slope of the earthwork stacking site is a dip slope, which is a potential area of rock slides. The west slope is an anaclinal slope, and the upper part of the slope belongs to a potential area of rock debris. Above the diversion tunnel has the characteristics of dip slope because the slopes are close to the layer attitude, but the slope is not greater than the dip of the strata, not a dangerous dip slope. Geological survey and drilling results show that the area that spillway will be sited is a river bank erosion slope with steep terrain.Exposed lithologies include sandstone with mudstone (Liushang formation), mudstone with sandstone (Erchungchi formation) and sandstone interbeds with mudstone (Erchungchi formation), The colluvium and the lateritic terrace deposits. The stratum attitude is about N20 ° E / 20 ° NW. The earthwork stacking site area belong to Erchungchi formation with exposed lithologies including sandstone with mudstone and sandstone interbeds with mudstone, unconsolidated strata mainly consist of terrace deposits, with the strike of N30 ° ~ 40 ° E and the direction of 22 ° ~ 40 ° to the northwest. The strata of the diversion tunnel belong to Kanchialiao formation, and the exposed lithologies are mainly sandstone interbedded with mudstone with N8 ° ~ 42 ° E, inclined to the northwest 18 ° ~ 26 °. Slop stability analysis results under the conditions before and after the development are summarized below: 1. Spillway areas：Slope stability before the development factor of 1.19 to 1.20, the main shear strain zone in the slope of the collapse of the soil layer location, indicating that the area does have landslide potential exist. The safety factors of slope stability can be increased to 1.54 ~ 1.72 after the protections, anchor rods and wire mesh reinforced shotcrete, are applied to the upper slope of the spillway exit and the slope top ,which will meet the basic requirements of the code. 2. Earthwork stacking site：The safety factor of slope at earthwork stacking site under normal condition is 2.364 , and the safety factor is 1.234 when the earthquake condition is present. The safety factor after earthwork stacking is 3.198 and 1.379, respectively, which is higher than that of the slope before landfill , It shows that filling can improve slope stability. The analysis results of the earthwork slope in the filling area shows that the safety factor under normal condition and earthquake condition are 1.794 and 1.203 respectively, which all meet the recommended safety factors. 3. The diversion tunnel and the geologically sensitive area overlap only in a linear pattern with small area above the middle section of the tunnel. The tunnel is constructed at least 45 meters below the surface of the earth， which will not change the original terrain and surface. After analyzing the range of disturbance zone caused by tunnel excavation is limited, which should not cause the deformation of surface subsidence. Therefore, the stability of the whole slope should not be at risk. According to the investigation and assessment, the area where spillway will site is the collapse-and-slide high potential area of rock debris, and some appropriate surface protections are needed to increase the slope safety factor to meet the requirements of the code. The works of earthwork stacking are basically conducive to the stability of the whole slope，however, attention should still be paid to the drainage, greening and slope protection of the stacking area and both sides of the slope. In terms of diversion tunnel, the development process did not change the topography, and according to the result of the analysis shows that the development of the tunnel has no detrimental effect on the stability of the slope, but should pay attention to the issue of topsoil erosion in the future development.