水庫淤砂再生資源技術研究(I)

Abstract

台灣地區位處亞熱帶季風氣候區，年降雨量相當可觀及驚人，然而其降雨量雖然豐富，但因台灣地區山高坡陡，河川流短湍急，受限於地形等自然條件影響，而且總雨量雖豐但卻豐枯差異極大的現象，因此水資源之利用常以建造水庫調節水量。然近年來隨著社會經濟之變遷與發展，我們對水資源之需求日益增加，但台灣地區又因地質條件不佳，山區地質鬆軟，且近年來山坡地大量開發，每逢颱風暴雨侵襲，常造成大量沖蝕崩塌，導致水庫嚴重淤積與水資源的匱乏。在優良壩址多已開發與水庫建造常遭民眾抗爭之情況下，如何維持及延長現有水庫壽命，實為當務之急。而水庫的壽命與泥砂之淤積程度兩者間互為關聯，欲減輕水庫內之泥砂淤積，除了防止泥砂於水庫內淤積外，適當的清淤措施更是必要的，因此，加強水庫維護管理與操作，積極研擬水庫淤砂資源化技術，使現有水庫得以永續利用之研究課題實是刻不容緩。暌諸國外先進國家，基於有效處理並減量控制廢棄物質，再生資源技術便成為極重要之研究領域。水庫淤砂因其質料過細並常富含黏土質，故若無任加何加工過程則無法成為有用骨材；且其因富含黏土及有機物質，故不能任意棄置，以避免二次污染事件。惟若能研究發展水庫淤砂再生資源之技術，除能大幅減量泥砂淤積廢棄，更可以因為再生資源本身之經濟價值，進而降低水庫清淤成本，提高水資源營運之經濟效益。本計畫第一年蒐集整理國內外水庫淤砂再生利用技術並進行可行性評估，及建立前述可行再生資源技術試驗流程，並進行評估檢討，以作為後續計畫進程之依據；第二年完成創新再生技術製程雛型；第三年擇定多座代表性水庫淤砂樣本，進行再生資源成品製作並進行市場調查；第四年擬完成前階段再生製品之市場需求及經濟分析，並評估各項技術轉移及推廣具體規劃，且辦理成果發表及推廣講習。

As situated in the subtropics, the island of Taiwan has humid climates of high precipitation. The rivers on the island are short in length and rapid in flow because of high mountains with steep slopes. Rainfalls over the year are abundant but subject to great seasonal variations. For effective utilization of water resources, reservoir are required to regulate stream flows in order to meet timely demand of water. Rapid economic development is recent years has caused ever increasing demand of water. And recent land development on the hillside slopes accelerates surface erosion in addition to the existing young and fragile geologic formations in mountain areas. Severe Soil erosion produces huge amount of sediments to enter into streams and settle down in reservoirs reducing storage capacity when typhoon storms hit the island. It is imperative that the existing reservoirs be maintained to function as originally expected since these days good dam sites are hard to come by and dam constructions are very difficult to start because of environmental concerns and expensive land acquisition. To reduce reservoir sedimentation, it becomes necessary to remove reservoir sediments to restore storage capacity in addition to mitigating reservoir silting. For sustainable use of existing reservoirs, it is important and urgent to develop suitable techniques for treatment of removed sediment as renewable materials for effective operation and maintenance of reservoirs.In most developed countries, quantity control over refuse and technology for renewable materials from refuse matters are major concerns in research and development. Sediments in reservoirs are mostly silt and clay, and are too fine to be used as fine aggregates for concrete. They contain a lot of organic matters and clay, and should be disposed of properly to prevent further environmental pollution. The technology for renewable materials from reservoir sediments will be able to not only reduce the sediment volume to be disposed of but also lower the net cost of sediment removal as a result of economic value of renewable materials. This project will take four years to complete. The scope of work includes : (1) information collection on re-use of reservoir sediments as renewable materials, evaluation and feasibility study, and test procedures setup for feasible techniques in the first year, (2) completion of primitive production process for renewable technique in the second year, (3) production of products using sediments from several representative reservoirs and market survey of the products in the third year, (4) analysis of market demand and economic evaluation of the products, plans for technology transfer and workshop for promotion in the fourth year.