南四湖流域产水量空间格局与驱动因素分析

The Spatial Pattern of Water Yield and Its Driving Factors in Nansi Lake Basin

流域生态系统产水服务功能的空间化和定量化评估,对流域水资源管理、优化配置以及提高流域水生态保护效率具有重要意义。以山东省南四湖流域为研究对象,基于1990—2013年土地利用、降水、蒸散以及土壤属性等基础地理数据,以InVEST模型为基础,评估和模拟南四湖流域近25 a的产水量,并采用ArcGIS分析产水量的空间分布格局以及变化趋势,探讨了降水、地形等自然地理要素以及人口、土地利用和国内生产总值(GDP)等社会经济因素与产水量空间格局动态变化之间的关系,并在此基础上划分出南四湖流域生态系统产水功能区。研究结果表明:流域产水量在空间格局上呈现出由东向西递减的趋势,东部、东北部等山区、丘陵地区产水量高,西部平原地区产水相对较低;受自然地理要素影响,流域产水量空间分布与社会经济发展水平即GDP、人口密度的空间分布格局有较大差异。近25 a来,流域产水量呈现减少趋势,且产水量峰值区域由东北部向偏南地区转移,最低值区由西部向中部地区转移。降水、海拔和坡度等地理环境与产水量的空间变化呈显著正相关,其中降水量的相关程度最强;人口、GDP等社会经济数据与产水量变化也呈显著正相关,主要原因在于城市化的发展,城市建设用地等不透水层增加,促进了流域产水量。研究结果可以为流域水资源政策制定以及社会经济发展规划等宏观决策提供科学支撑。

The quantitative assessment on spatial pattern of ecosystem service of water yield in a basin has important significance for management and optimal allocation of water resource, and improvement of ecological and environmental conservation capacity. Based on basic geographical data of land use, meteorology and soil attribute in the study area, the paper used INVEST model to evaluate the amount of water yield in Nansi Lake Basin, quantitatively assessing the spatial distribution feature of water supply ability from 1990 to 2013 in the whole basin. The relationships between the dynamic spatial pattern of water yield and natural geographic elements such as precipitation, landform, and socioeconomic factors such as GDP and population were discussed. The basin was divided into several zones according to the water resources function. The result showed that the spatial pattern of water yield presents a decreasing trend from east to west, water yield being high in the east and northeast, and water yield being relatively low in west and other regions in Nansi Lake Basin. Affected by natural geographical elements, the spatial distribution of water yield is inconsistent with the spatial distribution of social economic development level, namely GDP and population. Water yield in the basin was in decreasing trend in past 25 years, and the peak area of water yield shifted from the northeast to the south area, but low yield area shifted from the west to the central region. There are significant positive correlations between the variation of water yield and physical geographical environment factors, such as precipitation, DEM and slope, and the correlation between the variation of water yield and precipitation is the strongest. There are significant positive correlations between variation of water yield and social economic factors of GDP and population, since urbanization caused the increase of urban construction land and other impervious surfaces which promoted water yield. The results of the study provide scientific support for water resources policy, social and economic development planning, and macro decision making.