臺灣博碩士論文加值系統

非農業開發行為已成為山坡地土砂災害的重要誘因之一。雖然在「水土保持技術規範」中已明定，於開發過程中需設置臨時防災措施，但時有因開發行為的不同，導致現場用地浪費、耗資或施工不確實等現象。因此，本研究的主要目的在瞭解攔砂網於山坡地開發期間對沖蝕土砂攔阻的效益。
經由室內模擬降雨沖蝕試驗及野外田間沖蝕試驗，本研究已獲得細、粗網目攔砂網於不同坡地坡度、不同間距情況下的單寬土壤流失量及泥砂攔截率之估算方程式。設計者可根據開發基地平均坡度的條件、擬攔阻的土砂百分率及用地的限制等，估算攔砂網的施設間距。
攔砂網對逕流的攔截率普遍偏低，大致介於30%∼70%之間；尤其是當地表坡度逐漸陡升之後，逕流攔截率往往低於20%。雖然如此，攔砂網的設置仍具備減緩地表逕流流速及輸砂容量的功能。唯一需要注意的，是當地表逕流越網而過時所產生似投潭水的淘刷破壞，其結果將誘發網基的損毀與沖蝕溝的發生。若以經濟效益觀之，攔砂網的設置，除了可以有效控制坡地開發過程中所產生土砂的運移外，更可以縮小開發期間臨時沉砂池所需的用地與經費。倘若通過攔砂網之地表逕流的懸浮顆粒濃度可以符合排放水的標準，則對於坡地開發的臨時水土保持措施而言，攔砂網的設置亦不失為一種選擇。

Non-agricultural development on sloping lands has become one of the trigging factors that cause sediment disaster. Even though they are listed and required in the current “Soil and Water Conser-vation Regulation”, temporary disaster prevention measures often create side issues like less economic land use, capital increase, and defective installation. Therefore, the objective of this study is to in-vestigate the sediment trapping efficiency of silt fences.
Through indoor simulated erosion studies and outdoor plot studies, a series of silt fence interval estimation equations has de-veloped for the coarse- and fine-opening silt fence at different slope gradients and installation intervals. Users can use these equations to estimate the silt fence installation interval based upon the slope gradients, desired sediment trapping efficiency, and possible land use restrictions.
Silt fences do not provide sufficient detention efficiency for surface runoff. The runoff detention efficiency is within 30 — 70%, and it can be less than 20% as slope gradient increases. Neverthe-less, the installation of silt fence can greatly reduce runoff velocity and sediment transport capacity. On the other hand, the pseudo-plunging flow caused by surface runoff while it overflows the silt fence can initiate the scour at the toe of the fence. From the economic point of view, silt fence not only effectively controls on-site sediment, but also reduces the cost yet maintain economic land use. If the concentration of suspended solid in the surface run-off escaping from silt fences can meets the local requirements, choosing silt fences as temporary disaster countermeasure can be one of the operational options.

摘 要................................................I
ABSTRACT.............................................III
誌 謝................................................V
圖目錄...............................................VII
表目錄................................................XI
照片目錄.............................................XII
壹、前言...............................................1
貳、前人研究...........................................2
參、試驗方法與材料.....................................5
一、試驗區概況.....................................5
二、試區整地及攔砂網處理配置.......................9
三、逕流與沖蝕取樣................................10
四、攔砂網........................................12
五、室內人工模擬降雨試驗..........................13
肆、結果與討論........................................16
一、室外田間試驗..................................16
二、室內模擬降雨試驗..............................30
伍、結論與建議........................................65
參考文獻..............................................68

黃俊德，1976，評估暴風雨特性對土壤沖蝕影響，屏東農業專科學校農
專學報，第十七輯，pp.104~107。
Fisher L. S. and A. R. Jarrett, 1984, “Sediment Retention
Effi-ciency of Synthetic Filter Fabrics”, Transactions
of the ASAE, Vol.32, No.1, pp.429~436.
Jiang N., M. C. Hirschi, R. A. C. Cooke, J. K. Mitchell, 1997,
“Equation for Flow Through Filter Fabric”, Transactions
of the ASAE, Vol.40, No.4, pp.987~991.
Wischmeier, W. H., C. B. Johnson, and B. V. Cross, 1971, “A
Soil Erodibility Nomograph for Farmland and Construction
Sites”, J. Soil and Water Cons. Vol.26, pp.189~193.