圖書典藏及影音數位平台

近年來由於氣候變遷影響加劇，原本降雨量分布就不均的台灣，其降雨型態變得更加極端。其中南部低地區在莫拉克颱風之後，主要水庫如曾文、南化水庫淤積嚴重，使得有效庫容大幅下降，主要河川則堆積滿崩塌後的砂土，每逢大雨河川濁度飆高。整體水資源運用的條件變得更加嚴峻，水資源管理單位必須頻繁的對抗久旱不雨的情形，同時又必須做好防汛工作以備汛期間強降雨的侵襲。 以大高雄地區主要的供水系統高屏溪流域而言，其豐枯比達9：1，又無大型水庫以蓄豐濟枯，豐水期間常因原水濁度太高而難以運用，枯水期間則川流量不足而取不到水。今年遭逢台灣68年以來最嚴重的枯旱，水資源議題被廣泛討論，高屏大湖計畫在未取得共識之前推動執行有其困難性，由於高屏溪流域水資源運用比率仍低，為回應各界及NGO團體的建議，有必要針對高屏溪流域的水資源做檢討，重新檢視整體地面水、地下水及伏流水資源及其運用情況，以利後續水資源運用策略評析。

This project collated several major factors of wate resources such as use of water resources, water withdrawals of water supplied facilities and planning water resources construction. The development standard groundwater level were caculated by standard groundwater level index, SGI, and residual stream flow. Then these restrictions were used to limit groundwater exploitation and calculated groundwater, subsurface water resources under controlled impact. Next work was to eatimate benefits in terms of groundwater, subsurface water resources in order to complete the assessment of groundwater and subsurface water resources in middle and upper Gaoping River. 1. Basic Information Collection (1) Meteorological, hydrography, geology information and use of water resources, water withdrawals of water supplied facilities, planning water resources construction data were collected in this project. The exploitation of surface was 1.25billion tons and groundwater is 0.11 billion tons in Gaoping watershed during 2011 to 2015. (2) Total 6 meeting were held to collect suggestion from NGOs that consolidated as follows : (a)Water resources protection is priority. (b) People’s livelihood water is priority in water supply. (c)The exploitation of existing wells should be investigated in order to management effectively in groundwater. (d)Taiwan Water Corporation should ensure the deep groundwater pumping would not effect existing local groundwater supply in Ligang. (e) NGOs had a neutral stance on results of this project and reservations in water development of project area. 2. Investigation in-situ (1) Groundwater is the major recharge souce of stream before April and this trend reversed in wet season durig May to October. Then groundwater recharge to stream after wet season in the area of Ligang Bridge, Gaoshu Bridge and Gaomei Bridge. (2) Right bank of Laonong River from Gaomei Bridge to Ligang Bridge and Left side of Ailiao River at Gaoshu Bridge are the major area that stream recharge to groundwater. (3) Then mass balance of water chemistry is applied to calculate the exchange between surface water and groundwater in chosen area. The result showed totally groundwater recharge to stream, therefore the variation is high in different years. 3. Restrictive Exploitation of Groundwater (1) The development standard groundwater level were caculated by standard groundwater level index, SGI, and residual stream flow. Then these restrictions were used to limit groundwater exploitation and calculated groundwater, subsurface water resources under controlled impact. (2) The restrictive exploitation of groundwater is higher in downstream in project area that near Liling Bridge, because of recharge by stream water. Therefore the reduction of groundwater level makes groundwater resources decreased, so that variation of exploitation is huge in different years. 4. Restrictive Exploitation of Subsurface Water and Benefits of Water Development Ccases (1) The SGI360 groundwater level and residual stream flow were applied to estimate the restrictive exploitation of subsurface water in 14 locations. (2) The relations between exploitation and impact of stream waterand groundwater were estimated by numerical models and applied to inverse the restrictive exploitation of subsurface. (3) The benefits of water resources development were calculate by additional supply in Gaoping Weir, icrease storage of Nanhua reservoir, water support to Tainan system and increased discharge of Gaoping Weir. (4) The benefits of cases thar include subsurface water, groundwater and integrated cases were calculated in Figure.1. The suggestion location of different cases were listed as follows: (a) Location of case with 0.1 and 0.2 million tons subsurface waterper day is at Liling Bridge. (b) Locations of case with 0.3 million tons subsurface waterper day are at Liling Bridge (0.2 million tons) and Bridge of freeway No. 10 (0.1 million tons). (c) Locations of integrated case with 0.3 million tons that are at Liling Bridge (0.2 million tons subsurface water) and Bridge of freeway No.10(0.1 million tons groundwater). 5. Integrated case with 0.2 million tons subsurface water and 0.1 million tons groundwater has best benefit, thought groundwater level in dry years would limit exploitation of groundwater. So the subsurface water case with 0.3 million tons exploitation is the suggested proposal.