Ứng dụng công nghệ gis để cảnh báo lũ bùn đá và tìm địa điểm xây dựng thủy điện nhỏ, lấy ví dụ ở Lào Cai

Abstract

In creating the path for GIS analysis, it is important to determine the closest correlations between the interested phenomenon and others in order to assign the layers to be established. The factors generating mud flow in Bac Ha highlands, Laocai province are represented clearly on different cartographic and GIS materials, but with different correlation degrees. Using the method “geomorphologic analysis” the authors have found out the two main and determinant pairs of layers in best correlation, which can be applied for warning mud flow in the areas with geologico-geomorphologic situation similar to Bac Ha region. The first is the cruciform crossing between the river beds and the strike of rock layers; the second is the presence of a geological monocline structure with alternation of a member of easily alterable rocks and the one of resistant rocks. In prospecting for the construction site for small hydroelectric plant in the mountainous region the most significant information are the layers representing the system of longitudinal and transversal tectonic faults and correlatively the layer for the longitudinal and transversal valleys. The longitudinal valley can be used for the reservoir, the water - gap formed at the crossing point of the last by a transversal valley is very convenient for the installation of barrage