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地下水(Ground water),是指赋存于地面以下岩石空隙中的水,狭义上是指地下水面以下饱和含水层中的水。在国家标准《水文地质术语》中[1],地下水是指埋藏在地表以下各种形式的重力水。其中潜水指保水带中第一个具有自由表面的含水层中的水,潜水面上一般无稳定的隔水层,具有自由表面。潜水在重力作用下,有从水位高处流向水位地处的趋势。潜水可以通过地表接受大气降水、凝结水、地表水的直接补给,因而水位、流量和化学成分会随时间变化而变化。潜水的埋藏深度指潜水面至地表面的距离,即潜水位埋深一般也叫做地下水位埋深。地下水埋深变化是地下水资源量变化的最直接的表现,是地下水变化研究中最重要的控制性指标[2]。
湿地是一种独特的生态系统,它是陆地和水的相互作用中形成的一种自然复合体,分布在世界各地与森林和海洋并称为全球三大生态系[3, 4]。地下水是湿地的重要组成部分,影响到整个湿地生态系统的稳定性[5, 6]。湿地地下水位的变化通常会侧面体现人为活动的影响或气候的变化[7-9],另一方面地下水埋深影响着土壤含水量、含盐量和植被的生长发育[10-12]。若尔盖湿地是世界上面积最大、保存最完好的高原泥炭沼泽湿地[13],近些年来随着全球气候变化和社会经济的发展,若尔盖湿地面临湿地萎缩、草场退化和沙化等问题[14]。开展对湿地地下水位埋深的研究有利于为保护区制定相关保护政策提供重要的数据支撑,本文以若尔盖湿地花湖区域五个地下水位监测点2015-2016的数据来分析地下水位的季节性和年度变化。
Monitoring of Groundwater Depth around Huahu Lake in Zoige Alpine Wetland
doi: 10.12172/202008060001
- Received Date: 2020-08-06
- Available Online: 2021-01-18
- Publish Date: 2021-04-20
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Key words:
- Zoige /
- Wetland /
- Groundwater /
- Groundwater depth
Abstract: Groundwater is an important part of wetland, which plays an important role in the changes of wetland ecosystem and affects the stability of the whole wetland ecosystem. In order to investigate the change of groundwater depth around Huahu lake in Zoige alpine wetland, we analyzed the data of groundwater depth obtained from 6 locations around Huahu lake in Zoige alpine wetland from 2015 to 2017. The results were as follows: (1) Huahu-3 was the shallowest among the 6 monitoring locations, with an average depth of 14.9 cm (inter-annual variation was 2−34 cm); Huahu-5 was the deepest with groundwater depth, with an average phreatic depth of 128.3 cm (inter-annual variation was 67−197 cm). The maximum difference in annual average groundwater depth was 113.4 cm. (2) On the whole year, the highest groundwater level occurred in February and December, while the lowest in June and September. When comparing average value of annual extreme difference of groundwater depth of each monitoring location in 2015 and 2016, it was found that the annual extreme difference of groundwater depth of Huahu-3 monitoring location was the smallest, only 23.1 cm, while that of Huahu-4 was the largest, reaching 100.5 cm. This suggested that the variation varied greatly not only in groundwater depth among the 6 monitoring locations, but also in the seasonal changes of groundwater depth. Seasonal variation of groundwater depth was smaller in areas with shallower annual groundwater depth, but greater in areas with deeper groundwater depth. In this study, the variations of groundwater depth around Huahu lake in Zoige alpine wetland was analyzed in order to provide relevant data support for the protection and management of Zoige wetland.