抚仙湖水位持续下降成因及2023年多因子贡献定量评估

Causes of continuous decline in water level of Fuxian Lake and quantitative evaluation of contributions of multiple factors in 2023

摘要

【目的】抚仙湖水位持续下降，影响着流域内的生态环境以及流域周边的生产生活，探究抚仙湖水位下降的成因对保护抚仙湖环境和实现抚仙湖社会经济价值有着重要意义。【方法】应用分布式水文模型WEP-L(Water and energy transfer processes in large river basin)模型对抚仙湖流域1956—2023年水资源量进行模拟，以多年平均天然状态下抚仙湖水量净收支为基础，通过观测数据、贡献率和水量平衡方程的计算，确定气象干旱、星云湖出流改道、用水耗水与外排水等因素对2023年抚仙湖水量减少的贡献率。【结果】结果表明：(1)抚仙湖水位整体呈缓慢下降趋势，下降速率为0.12 m·a^-1,2023年抚仙湖水位较多年平均水位下降了1.6 m;(2)1956—2023年抚仙湖全流域入湖水量呈下降趋势，2023年抚仙湖水量净收支为-1.11×10⁸ m³,比多年平均天然状态下的9.3×10⁷ m³减少了2.04×10⁸ m³;(3)经水量平衡方程计算可知，降雨量的减少和气温升高导致的湖面蒸发量的增加对抚仙湖水量净收支减少的贡献率为65.7%,星云湖改道工程的贡献率为19.6%,用水耗水与外排水的贡献率为14.7%。【结论】抚仙湖水位下降受到多因素的影响，揭示了气候变化对其的主导作用，可为抚仙湖流域管理者制定水资源调配策略提供科学依据，对保障抚仙湖生态安全有着重要意义。

Abstract

[Objective] The persistent decline in the water level of Fuxian Lake has significantly impacted the ecological environment within its basin and the production and livelihoods in surrounding areas. Investigating the causes of this decline is crucial for protecting Fuxian Lake's ecosystem and realizing its socio-economic value.[Methods] A distributed hydrological model, Water and Energy Transfer Processes in Large River Basin(WEP-L), was applied to simulate the water resource volume of the Fuxian Lake Basin from 1956 to 2023. Based on the long-term average net water balance under natural conditions, the contributions of meteorological drought, the diversion of outflow from Xingyun Lake, water consumption, and external drainage to the reduction of Fuxian Lake's water volume in 2023 were quantified using observational data, contribution rate analysis, and the water balance equation.[Results] The result showed that:(1) the water level of Fuxian Lake generally showed a slow declining trend at a rate of 0.12 m·a^-1, with a drop of 1.6 m below the multi-year average water level.(2) From 1956 to 2023, the inflow into Fuxian Lake from the entire basin showed a declining trend. In 2023, the net water balance of Fuxian Lake was-111 million m³, a decrease of 204 million m³ compared with the 93 million m³ under the multi-year average natural conditions.(3) According to the calculation of the water balance equation, the contribution rate of reduced precipitation and increased lake evaporation caused by rising temperatures to the net water balance decline of Fuxian Lake was 65.7%, the contribution rate of the Xingyun Lake diversion project was 19.6%, and the contribution rate of water consumption and external drainage was 14.7%.[Conclusion] The decline in Fuxian Lake's water level is influenced by multiple factors. The study highlights the dominant role of climate change, providing a scientific basis for watershed managers to formulate water resource allocation strategies and holding great significance for ensuring the ecological security of Fuxian Lake.

关键词

WEP-L模型 / 水位下降 / 抚仙湖流域 / 气候干旱 / 水量平衡方程 / 贡献率 / 参数敏感性 / 影响因素

Key words

WEP-L model / water level decline / Fuxian Lake Basin / meteorological drought / water balance equation / contribution rate / parameter sensitivity / influencing factors

基金资助

云南省重点研发计划项目(202303AC100020)

国家重点研发计划课题(2023YFF1304201)