横断山区水文区划

本文分析了横断山区径流的分布、水源补给、径流的年内分配等的地区差异,从中选取形成水文地域分异的最重要的水文特征值,作为划分水文区域的指标。文内将横断山区划分为两级水文区域,并阐述了每个水文区和水文亚区的基木特征。

HYDROLOGIC REGIONALIZATION OF THE HENGDUAN MOUNTAINOUS REGION

In the Hengduan Mountainous Region, landforms are quite varied, there is alternation of the mountains and rivers. Regions of lower and higher annual runoff or annual precipitation are interlaced with one another. Higher runoff (precipitation) are found in mountains while the lower are in the valleys.The seasonal distribution of runoff is uneven. The most abundant runoff occurs in summer. But in spring the runoff is less abundant than in autumn. In winter it is very little.Two-level schemes of hydrologic regionalization are adopted according to the annual runoff and seasonal distribution. The first-level is called hydrologic region, based on the amount of runoff (expressed in annual runoff depth).The Hengduan Mountainous Region may be divided into the following 4 belts of runoff according to the distribution of annual runoff depth, i.e., 1. Belt of abundant runoff, with annual runoff depth >900mm. 2. Belt of adequate runoff, with annual runoff depth 600-900mm. 3. Belt of normal runoff, with annual runoff depth 200-600mm. 4. Belt of scarce runoff, with annual runoff depth <200mm. A hydrologic region may be composed of 1 - 2 belts of runoff. The composition of one hydrologic region may be different from the others.The second-level is called hydrologic subregion, based on seasonal distribution of runoff.Thus, the Hengduan Mountainous Region may be divided into 4 hydro-logic regions and 7 hydrologic subregions.