太湖流域水供给服务供需时空演变分析

太湖流域是我国经济发展最快、人口最密集的地区之一。受土地利用和降水条件变化的影响,太湖流域水供给服务供需关系也发生着变化。通过分别设置1995～2015年太湖流域不同降水条件和土地利用变化情景,利用Invest模型定量评估水资源供给量,同时利用空间离散法定量评估水资源需求量,并进一步分析供需赤字和盈余区域的时空变化。结果表明:1995～2015年随着土地利用变化,尤其是建设用地的扩张(20年来涨幅达106%),水资源需求占供给量的比重由73%升至90%,需要依赖外来客水的县域面积占整个流域的比重由19%升至33%;2015年在不同降水条件下供需关系变化更为明显,降水量越少,供需赤字的县域越多,在干旱年份整个流域需求量占供给量的117%,供给量已不能满足需求量,且赤字县域的面积占整个流域的47%。两种情境下,太湖流域东北部水供给服务供需关系均比西南部紧张。作为影响太湖流域水资源供需变化的主要因素,土地利用和降水条件变化分别通过影响需求量和供给量改变供需关系。

An Analysis of Spatio-temporal Evolution of Water Supply and Demand in Taihu Basin

Abstract：Taihu Basin is one of the fastest growing economies and the most densely regions in China. Affected by changes in land-use/coverage and precipitation conditions, the relationship between water supply and demand in Taihu Basin has been changed. In this paper, we set the following scenarios to evaluate the water supply quantity and demand quantitatively, and analyze the spatio-temporal changes of the supply and demand deficit and surplus areas: one is that we kept the precipitation unchanging and only the land-use changed in Taihu Basin from 1995 to 2015;the other is that we set different precipitation conditions with other parameter unaltered in 2015. The results indicate that: first, the proportion of water demand in the supply increased from 73% to 90% and the proportion of county area relying on foreign water increased from 19% to 33% with the rapid change of land use and coverage during 1995-2015, especially the expansion of construction land up to 106% in the past 20 years. Second, in 2015, the change of supply and demand relationship was more obvious under different precipitation conditions. The lower the precipitation, the more counties with supply and demand deficit. Third, in the drought years, the proportion of water demand in the supply was up to 117% in the whole basin . It showed that, the water supply failed to meet the demand in the drought years. In both cases, the relationship between water supply and demand in the northeast of the taihu basin is more tense than that in the southwest. As the major factors influencing the relationship between water supply and demand in Taihu basin, the changes of land-use affect demand and the changes in precipitation conditions impact supply.