River Network Pattern and Watersheds Morphology Within North-West Part of Pacific Seismic Belt

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Project title

Code/計畫編號

NSC99-2923-E492-001

Translated Name/計畫中文名

西北太平洋地震帶河川網路與集水區型態研究

Funding Organization/主管機關

National Science and Technology Center for Disaster Reduction

Co-Investigator(s)/共同執行人

江申(計畫主持人)

Department/Unit

National Science and Technology Center for Disaster Reduction

Website

https://www.grb.gov.tw/search/planDetail?id=2158234

Year

2010

Start date/計畫起

01-08-2010

Expected Completion/計畫迄

31-07-2011

Co-Investigator(s)

Kwan-Tun Lee

Bugetid/研究經費

657千元

ResearchField/研究領域

土木水利工程

集水區係地面上以分水嶺為界之區域，其水文反應可視為該區域降雨特性與地文特性所衍生之特徵函數。其中，降雨之特性可由降雨頻率分析求得，而集水區之地文特性則表現於該集水區之河川網路型態、集水區內之地表特性以及此兩者之組合。近年此領域之研究顯示，在最小能量消耗下河川網路型態及集水區地文特性(河川網路型態及地表特性)之不斷或緩慢變化之演育(evolution)可由平衡(equilibrium)以及最佳化(optimal)之觀點解釋(Rodriges-Iturbe, Rinaldo, 1997)。此種演育遵循自我相似(self-similarity)、自我相仿(self-affinity)以及自我組織(self-organization)之原則。亦即在相對穩定之條件下，集水區之河川網路型態有著最佳型態(good-composed)之傾向，反之亦然。本計畫將以西北太平洋地震帶上過去地質活動較活躍以及地質年代較年輕之集水區為研究對象，此類區域之河川系統演育係受過去持續或決定性強度之動態地質及地文因子影響。因此，其河川系統之演育應可由強度及非平衡(non-equilibrium)狀態辨識。本研究首先假設此類強度之衝擊以及非平衡可經由確認中尺度DEM 資料之河川網路型態之不規則及異常情況等特性得出。其次之假設為此集水區特性亦與集水區之空間區位以及其內所發生之各種水災害(水災、土石流、坡地崩坍以及河床變遷等)之間有所關聯。本計畫之主要工作步驟如下： 1. 河川網路結構以及集水區地文特性之辨認方法建立、分析模式之建構以及程式撰寫發展，使用之軟體工具為ArcGIS以及自行發展之軟體。 2. 將辨認及分析方法應用至不同集水區並描述河川網路型態於空間區位上之關聯性以及集水區之地貌、河床底質等地文特性之特徵。 3. 分析比較集水區之不同河川網路特徵包含集水區荷頓級序、分岔比、Shannon 熵度、河川長度、集水面積、水力幾何參數…等，以得到可描述集水區受影響強度以及不平衡狀態之指數。 4. 對選定研究對象區域使用較高解析度之DEM分析其河川網路型態與地文特性之關聯性，以及不同解析度下此關聯性之改變。 5. 對選定研究對象區域中探究集水區之空間區位以及災害發生強度與河川網路演化強度，以及其與不平衡強度之間之關聯。本研究計畫之水文分析與模式建立，將分別由台俄雙邊個別執行，而後再進一步整合雙邊之研究結果，以建立一套河川網路型態以及集水區地表特性辨認之方法。本計畫之執行包括台灣及俄羅斯選定集水區之現地調查以及舉行聯合研討會（至少每年一次），本國際合作計畫擬透過台俄雙方學者之合作，包括基本地文與水文資料交換，以及水文模式建立之經驗交流，藉由討論與訓練研習機會，以改進雙方之水文模擬精度，並能夠共同發表國內與國際期刊論文。 Generally, the investigation of river network composition and watersheds morphology (fluvial geomorphology), constituting one of the key patterns of land surface, is a fundamental question of Earth Sciences. Recent ideas in this research field are the equilibrium and optimal, in the sense of minimum energy expenditure, river network evolution under constant or slowly varying conditions (Rodriges-Iturbe, Rinaldo, 1997). It follows to such network behavior as self-similarity, self-affinity and self-organization. That is to say, under relatively stable conditions the river systems tend to some “good composed” form and vice-versa. This project is concentrated on studies of river network and watersheds of active ocean-continental zones, the north-west part of Pacific seismic belt as an example. An evolution of river systems in such regions is under increased or determinative impact of dynamic geological and geomorphologic factors. So, it should be characterized by high intensity and pronounced non-equilibrium state. Initial hypothesis is these intensity and non-equilibrium could be investigated on the base of middle-scale DEM via ascertainment the irregularities and abnormalities in watershed composition. Second one is these properties of watersheds are related to spatial localization and peculiarities of different fluvial-related hazards – floods, debris flows, landslides and riverbed deformations. Main steps of the project are: 1. To develop new methodology and program package for river network structure and watershed morphology detailed analysis on the base of Arc Map tools. 2. Applying new tools to explore a number of basins of selected range, to describe the spatial relation of river network pattern and watershed composition under impact of volcanism, different tectonic displacements, bedrock variety and local active sedimentation. 3. Comparing watershed images to different characteristics of river network (e.g. ordering, coefficients of Horton’s laws, Shannon entropy, fractal dimension) and basin morphology (e.g. diagrams of average elevation, slope, width and shear stress index against distance to outlet along streams), to find a good indicators of intensity and non-equilibrium of watershed evolution. 4. With some basins, where detailed DEM are available, to investigate the dependencies between basin structure-morphological characteristics and DEM resolution. 5. With some basins, where appropriate data are available, to access the spatial localization and intensity of different hazard events (floods, debris flows, landslides and riverbed deformations) relate to characteristics of intensity of river system evolution and its non-equilibrium state. The project performance include field investigations on a few watersheds in Taiwan and Russia (Sakhalin and Kamchatka), which will be selected as most interesting from point of view of the project subject. Cooperation between Taiwanese and Russian teams in framework of the project include the interchange of methodology, soft and data, participation in joint field investigations, holding the joint workshops (at least one per year), preparing the joint publications.

Keyword(s)

水文反應
河川網路型態
hydrological response

DSpace CRIS

River Network Pattern and Watersheds Morphology Within North-West Part of Pacific Seismic Belt

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