应用InVEST模型对水库集水区水源涵养功能优化方案

Optimizing Program for the Water Conservation Function of the Reservoir Catchment Area with InVEST Model

基于InVEST模型在对浙江省临安市水涛庄水库集水区水源涵养功能分析的基础上,利用研究区内水源涵养能力较好的林型替换较差的林型,在综合对比各类替换模式后,进而提出提升研究区森林水源涵养功能的优化方案。结果表明:研究区森林水源涵养总量为3 189.39×10~4m^3,研究区森林平均水源涵养深度为594.82 mm(水源涵养功能可表现为水源涵养深度)。研究区内各林型中针阔混交林的水源涵养深度最大,为902.79 mm。不同森林类型在不同坡度级上的平均涵养深度均随坡度的增加而减小,在平坡(0°<α≤5°,α为坡度)上均达到最大;影响研究区水源涵养功能的最主要因素是下垫面特征和气候,其中下垫面特征中的土壤饱和导水率的影响最大,且土壤饱和导水率会随着植被的改善和群落的演替而提高。经优化模拟比较,在保证研究区油茶(Camellia oleifera)、毛竹(Phyllostachys heterocycla var.pubescens)等经济林正常经营的基础上,将研究区16°<α≤35°坡度级上除针阔混交林和阔叶林以外的森林类型全部替换成针阔混交林,森林水源涵养功能可提升41.07%。

With InVEST （Integrated Valuation of Ecosystem Services and Trade Offs） model, we analyzed the water conservation function in the Shuitaozhuang Reservoir Catchment in Lin’an, Zhejiang Province. After comparing the different types of replacement models, we put forward the optimal solution of the water conservation in the research area. The forest total water conservation quantity of research area was 3 189.39×10^4m^3. The average depth of water conservation was 594.82 mm. The water average retention of mixed conifer and broad-leaved forest shows the best performance, which was 902.79 mm. Water conservation capacity of different forest types at different slope grades decreases with the increasing of the slope, and reaches the maximum on the flat slope （0°〈 α ≤5°）. With the increasing of the slope, the maximum change of water conservation capacity is the coniferous broad-leaved mixed forest. Underlying surface and climate factors are two greatest factors that influence the water conservation in research area, and soil hydraulic conductivity is one of the most vital factor. Therefore, it is rational to improve the water conservation capacity by enhancing the vegetation coverage of the underlying surface effectively. Replacing forest vegetation with mixed conifer and broad-leaved forest improves water conservation except mixed conifer and broad-leaved forest. After comparing and analyzing different methods, we built 16°〈 α ≤35° gradient grade vegetation in the research area, and the water conservation was raised by 41.07%.