热带地理

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南岭山地森林流域退水规律及影响因素

李泽华1(), 周平1(), 黄远洋2, 徐卫1, 谭兆伟1   

  1. 1.广东省科学院广州地理研究所 广东南岭森林生态系统国家野外科学观测研究站/广东省地理空间信息技术与应用公共实验室/ 广东省遥感与地理信息系统应用重点实验室,广州 510070
    2.重庆地质矿产研究院 自然资源部重庆典型矿产 生态修复野外科学观测研究站/重庆市万盛矿区生态环境保护修复野外科学观测研究站,重庆 401120
  • 收稿日期:2022-01-21 修回日期:2022-02-14 出版日期:2022-03-02
  • 通讯作者: 周平 E-mail:zehual@gdas.ac.cn;pzhou@gdas.ac.cn
  • 作者简介:李泽华(1985—),男,广东佛山人,博士,高级工程师,研究方向为水文物理规律模拟,(E-mail)zehual@gdas.ac.cn
  • 基金资助:
    广东省省级科技计划项目(2019B121202006);广东省科学院专项资金项目(2020GDASYL-20200103002);科技基础资源调查专项课题(2021FY100702)

Analysis of Streamflow Recession and Dominant Factors in Nanling Mountain Forest Catchment

Zehua Li1(), Ping Zhou1(), Yuanyang Huang2, Wei Xu1, Zhaowei Tan1   

  1. 1.Guangdong Nanling Forest Ecosystem National Observation and Research Station, Guangdong Open Laboratory of Geospatial Information Technology and Application, Key Lab of Guangdong for Utilization of Remote Sensing and Geographical Information System, Guangzhou Institute of Geography, Guangdong Academy of Sciences, Guangzhou 510070, China
    2.Observation and Research Station of Ecological Restoration for Chongqing Typical Mining Areas, Ministry of Natural Resources, Wansheng Mining Area Ecological Environment Protection and Restoration of Chongqing Observation and Research Station, Chongqing Institute of Geology and Mineral Resources, Chongqing 401120, China
  • Received:2022-01-21 Revised:2022-02-14 Online:2022-03-02
  • Contact: Ping Zhou E-mail:zehual@gdas.ac.cn;pzhou@gdas.ac.cn

摘要:

采用水文气象长期定位观测数据,结合基于事件尺度的退水速率与流量关系分析方法,对2019—2021年典型南岭山地森林流域的退水过程变化进行识别,探索退水特征与同期土壤水分、地下水埋深、潜在蒸散发和实际蒸散发的关联程度,深入了解山地森林流域退水规律及主要影响因素。结果表明:1)相同流量情况下,流域在枯水条件下比丰水条件退水速率更快;2)流域土壤入渗能力较强,降水能迅速补给土壤水和地下水,地下水对降水的响应较土壤水略有延迟;3)地下水埋深对流域退水有显著影响,土壤水分次之,与之相比潜在蒸散发和实际蒸散发的影响并不明显;4)地下水埋深是影响山地森林流域出口退水过程的最主要因素,由于地下水位低于河床位置,流域出口河段处于地下水补给区,因此地下水埋深越深,河道水向地下水渗失越快,从而导致流域出口退水速率加快。可见,地下水埋深是流域退水规律分析乃至枯水期径流模拟不可忽略的关键变量。

关键词: 南岭山地, 蓄泄关系, 枯水期径流, 土壤水分, 地下水补给, 蒸散发

Abstract:

Little attention has been paid to dry season streamflow and groundwater recharge dynamics compared to the systematic focus on measuring total annual streamflow changes associated with forest. However, in the tropics and subtropics, especially in regions with uneven seasonal distribution of precipitation, dry season streamflow and groundwater recharge are of great importance for the riverine ecosystem stability and downstream water supply safety. Recession analysis of -dQ/dt~Q is widely used for determining the catchment storage-discharge relationship and predicting dry season streamflow processes. When dQ/dt~Q plots of streamflow recession are constructed for individual events, the slopes of the curves are near constant in log space, but the intercepts vary with time. Previous studies used event-based analysis to hypothesize that the shifts in intercept in dQ/dt~Q curves were due to variations in concurrent evapotranspiration (ET), which is consistent with the dominant belief regarding controls on streamflow recession. On the contrary, increasing evidence suggests the possibility that other factors such as soil moisture, groundwater recharge, or active drainage network may play a role in dQ/dt variations. However, no consensus has been reached on the determinants of the shift. By using an event-based recession analysis, an experimental catchment with long-term hydrometeorological observations was selected to investigate the streamflow recession in the Nanling mountain forest. Our results showed that 1) faster recession rates were more likely to occur under dry conditions than those under wet conditions; 2) groundwater depth varied consistently with soil moisture in response to precipitation, indicating high soil infiltrability; 3) a significant correlation between the intercept a and concurrent groundwater depth demonstrated its potential role as explanatory variable of streamflow recession; 4) as a losing stream (groundwater depth always larger than 5.0 m near the catchment outlet), water loss to groundwater recharge appears to be the dominant factor affecting streamflow recession.

Key words: Nanling Mountain, storage-discharge relationship, low flow, soil moisture, groundwater recharge, evapotranspiration

中图分类号: 

  • S715.3