基于InVEST模型的金沙江流域干热河谷区水源涵养功能评估

Abstract

以金沙江流域干热河谷区1990年、2000年、2010年和2019年4期Landsat遥感影像为基础数据，通过目视解译和最大似然相结合的方法进行土地利用类型分类，定量分析金沙江流域干热河谷区土地利用类型的时间变化与空间转移过程；采用InVEST模型，结合气象、土壤和地形等数据评估了1990-2019年金沙江流域干热河谷区及不同土地利用类型的产水功能和水源涵养功能。结果表明：1）1990-2019年金沙江流域干热河谷区土地利用类型以草地、乔木林地和耕地为主；近30年来，灌木林地、建设用地、交通运输用地和水域的面积不断增加，建设用地面积增幅最大；草地、乔木林地、耕地和裸地面积均减少。2）1990-2019年，建设用地、灌木林地、交通运输用地和水域面积的增加来源于草地、耕地和乔木林地。3）金沙江流域干热河谷区多年平均产水量为26.09×10⁸ m³，水源涵养量为7.26×10⁸ m³，产水量的变化与分布直接影响着区域的水源含养量；平均水源涵养能力68.74 mm，呈现上升-下降-上升的波动变化趋势。4）1990-2019年不同土地利用类型的水源涵养量变化明显，不同地类平均水源涵养量的大小依次为耕地 > 草地 > 建设用地 > 乔木林地 > 交通运输用地 > 灌木林地 > 裸地 > 水域。;Using Landsat remote sensing images in 1990, 2000, 2010 and 2019, land use types in the dry-hot valley area of Jinsha River Basin are classified by combining visual interpretation with maximum likelihood, and the spatiotemporal change and transfer process of land use types in the dry-hot valley area of Jinsha River Basin are also studied. The InVEST model combining meteorological, soil and topographic data are used to evaluate the water-producing and water-conserving function of different land use types in the dry-hot valley area of Jinsha River Basin from 1990 to 2019. The main conclusions are as follows:(1) from 1990 to 2019, grassland, forestland and cultivated land were the main types of land use in the dry-hot valley area of Jinsha River Basin. In the past 30 years, the area of shrubland, construction land, transportation land and water area has been increasing continuously and the area of grassland, forestland, cultivated land and bareland has been decreased. (2) The area increase in construction land, shrubland, transportation land and water area came from grassland, farmland and forestland from 1990 to 2019. (3) In the dry-hot valley area of Jinsha River Basin, the annual average water yield was 26.09×10⁸ m³, the water conservation amount was 7.26×10⁸ m³, and the average water conservation capacity was 68.74 mm showing a fluctuation of up-down-up. (4) From 1990 to 2019, the water conservation amount of different land use types changed significantly, and the average water conservation amount of different land types was from large to small:farmland > grassland > construction land > forestland > transportation land > shrubland > bareland > water area.