隨機河系網之建構模擬

Random Channel Networks Growth and Modeling

陳樹群(Su-Chin Chen) ； 陳聯光(Lien-Kuang Chen)

《中華水土保持學報》 27卷4期 (1996/12) Pp. 283-292

https://doi.org/10.29417/JCSWC.199612_27(4).0004

摘要

本研究在簡化條件下，以隨機法則建構一擬似之河系網，即忽略地文、水文、土壤、地質和植被等因子，將一傾斜平面套上網格，由此網格點上水流可能之五個方向（右、右下、下、左下及左），以隨機法則為網格點選擇一水流方向，繼而連結相鄰各個格點之水流方向，再計算其累積流向；然後以流體流動時具有牽引相鄰流體而匯流的觀念，重新由八個方位指定各網格動之水流方向，再計算其累積流向；長、寬皆為1m之網格，其累積流向可視為其集流面積。於此，所模擬得之河系網的流域特性和河相特性，如河川密度D_k約等於0.31，分歧比R_b介於3.63 ～ 4.21，流常比R_l，介於2.30～2.73，面積比R_a介於2.03～2.85.採用R_b和R_l關係法所得之碎形維度d介於1.38～1.64，而網格法則介於1.36～1.51，此皆和自然河系網之流域及河相特性相近。

關鍵字

隨機 ； 河系網 ； 累積流向 ； 碎形

並列摘要

This research is carried out for constructing river networks with random topology and various factors such as geological, hydrological and vegetative assumed to be same in a watershed. Firstly, for every grid, one direction out of five possible flow directions was randomly selected, then the flow from each grid was connected to calculate the accumulated flow. However, the networks thus generated from the random method were found to be more curvy than actual rivers. Hence, eight flow directions method was then used to smoothen them out. Finally, the simulated results obtained for the a square watershed show that the drainage density is nearly 0.31; bifurcation ratios are between 3.63 and 4.21; river length ratios are between 2.30 and 2.73; area ratios are between 2.0 and 2.85; fractal dimensions are between 1.38 and 1.64 (using R_b and R_l relationship) and between 1.36 and 1.51 (using grid method). These results are observed to be consistent with the actual river networks.

並列關鍵字

Random ； Channel Network ； Accumulated Flow ； Fractal