Dynamic ecological water demand based on long-term ecological water consumption in Lake Daihai, 1975-2020

Abstract

生态需水是湖泊生态系统的重要指标，维持着湖泊生态系统的良性循环.以内蒙古中部半干旱湖泊岱海为研究对象，对湖泊动态生态需水进行分析.本研究在遥感和气象数据的基础上，获得1975-2020年长时间序列高精度水文要素数据，分析岱海水文要素时空演变规律；通过天然生态水深分析法、水深经验频率分析法和湖泊形态分析法分析岱海的水深随面积变化的关键水深；构建基于生态耗水规律的湖泊生态需水模型，计算自然状态下岱海生态需水动态变化范围.研究结果如下：岱海地区6-9月为丰水期，10月至次年5月为枯水期；45 a以来岱海水面面积呈显著下降趋势，近年来下降速率减缓；枯水期岱海适宜生态水深为8.72~9.92 m，丰水期为9.40~10.69 m，适宜生态需水量为5.62亿~7.71亿m³，适宜湖面面积为70.92~84.77 km².本文构建了长时间序列气候水文数据库，确定岱海动态生态需水范围可以实现对湖泊生态健康的实时监测，为相关规划与管理提供科学依据及可操作性指导，从而为岱海湖泊治理提供理论参考.;Ecological water demand is an important indicator of lake ecosystems, maintaining a virtuous cycle of lake ecosystems. Taking Lake Daihai as the research object, a semi-arid lake in central Inner Mongolia, the dynamic ecological water demand of the lake is analyzed. Based on remote sensing and meteorological data, this research obtains long-term series of high-precision hydrological element data from 1975 to 2020, and analyzes the temporal and spatial evolution of hydrological elements in Lake Daihai; Through the natural ecological water level analysis method, the water level experience frequency analysis method and the lake morphology analysis method, the key water relative depth of the Lake Daihai water level changing with the area is analyzed; Construct a lake ecological water demand model based on the law of ecological water consumption, and calculate the dynamic range of ecological water demand in Lake Daihai under natural conditions; The results of the study are as follows:June to September in Lake Daihai area is the wet season, October to May of the following year is the dry season; Over the past 45 years, the area of Lake Daihai has shown a significant decline, with a rate of decline of 2.3 km²/a, but the rate of decline has slowed in recent years; The suitable ecological water relative depth for Lake Daihai is 8.72-9.92 m in the dry season, and 9.40-10.69 m in the wet season. The suitable ecological water demand is 5.62-7.71 million m³, and the suitable area is 70.92-84.77 km². This paper uses remote sensing technology to obtain hydrological data, build a long-term climatic and hydrological database, and determine the range of dynamic ecological water demand in Lake Daihai can realize real-time monitoring of lake ecological health, and provide scientific basis and operability guidance for related planning and management of Lake Daihai.