中国湖泊水量调节能力及其动态变化

湖泊水量调节是指湖泊生态系统通过洪水蓄积和径流补给实现水资源的再分配,进而减轻洪旱灾害。在围湖造田、退田还湖和气候变化影响下,科学评估我国湖泊水量调节能力现状及变化情况,是实现湖泊洪水调蓄功能和水资源调节功能评价的重要基础。基于全国湖泊调查数据,将全国划分为5个评价区,探讨了面向全国尺度的湖泊水量调节能力评价方法,在此基础上对全国湖泊的水量调节能力及其动态变化进行了分析评价。结果表明:(1)我国湖泊(面积1 km2)水量调节总量为1500.02亿m3,其中东部平原区和青藏高原区的调节量最高,分别占全国总量的44.46%和43.63%;(2)湖泊调节水量的效能以东部平原区最高(310.19万m3/km2),其次是东北平原与山区(191.19万m3/km2),围湖造田/退田还湖将导致该区湖泊水量调节能力明显削弱/增强;(3)近几十年来,我国湖泊水量调节能力呈小幅增长(增长量9.76亿m3,增幅0.65%),5个评价区仅蒙新高原区湖泊水量调节能力明显削弱,其余区域均呈不同程度增强,且以东部平原区增加最多,东北平原与山区增幅最大。研究可以为评估我国湖泊生态系统水量调节能力、分析土地利用变化对流域洪水调蓄和水资源调节功能的影响提供参考。

Status and dynamics of China's lake water regulation

Lakes provide humans with many different types of ecosystem goods and services that are necessary to sustain human livelihoods. In the past several decades, humanity has substantially increased its efforts to produce desired ecosystem goods from lakes, such as fish, food, and ornaments. However, these efforts have ignored other important ecosystem services from lakes such as water storage and damage mitigation from floods and droughts because lakes are important in regulating the hydrological cycle. The major impacts on the water regulation function of lakes are lake reclamation, returning croplands to lakes, and climate change by impacting the hydrological cycle. Scientific research on measuring the current status and dynamics of lakes in terms of their water regulation capacities can help improve lake ecosystem management in China by filling an important scientific blank. Managers want quick but effective evaluation methods to assess the water regulation capacity of lake ecosystems to clarify the vital role lakes play in supporting human well-being. In this paper, we try to address this scientific need by first conducting a regression analysis to construct a primary water regulation model that connects available water storage capacity to lake area, based on data from the book titled "Records for Chinese Lakes". We then evaluated the biophysical quantity of water regulation across China''s five lake zones and the temporal changes across the time-series based on the constructed models using regulation capacity and regulation efficiency indicators. From our analysis we had three main findings. First for lakes bigger than 1 km² in area, the water regulation capacity totaled 1500.02×10⁸ m³. The water regulation capacity of the Eastern Plain and the Tibetan Plateau were the highest among the five lake zones identified in this paper. The Eastern Plain and the Tibetan Plateau occupied 44.46% and 43.63% of the total capacity respectively. Second in terms of water regulating efficiency, the Eastern Plain was the highest among all five lake zones with a regulating efficiency of 310.19×10⁴ m³/km² followed by the Northeast China Plain and Mountain, which was 191.19×10⁴ m³/km². Lake reclamation (opposite efforts return croplands to lakes) would significantly weaken (strengthen) the water regulation capacity for lakes in these zones. Third in recent decades, the water regulation capacity for China''s lakes displayed a slight increasing trend of an absolute increase of 9.76×10⁸ m³ and a growth rate of 0.65%. Four lake zones (Inner Mongolia-Xinjiang was only zone not applicable) showed an increase in water regulation capacity with the largest absolute increase in the Eastern Plain, and the highest growth rate in the Northeast China Plain and Mountain. This paper lays the groundwork for creating a quick monitoring and assessment method to evaluate the water regulation capacity of China''s lakes. Also it is applicable to management by providing a means to assess the influence of land-use change on the water regulation capacity of lakes to buffer against flood and drought disasters. Lastly, this paper provides a basis for analyzing the trade-offs among ecosystem goods and services, thus it has real-world implications for managing lake ecosystems in China.