Long-Term Variations in Spring Water Mean Transit Time in a Forested Headwater Catchment in Japan
Long-Term Variations in Spring Water Mean Transit Time in a Forested Headwater Catchment in Japan
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DOI：
10.3390/w14233925
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发表时间：
2022-12
期刊：
影响因子：
3.4
通讯作者：
Isabela Silveira Baptista;M. Tsujimura;Y. Onda
中科院分区：
文献类型：
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作者：
Isabela Silveira Baptista;M. Tsujimura;Y. Onda
在这项研究中，我们采用了一种新的方法，利用水的稳定同位素浓度和空气中的SF6浓度来研究日本森林水源集水区泉水平均传输时间（MTT）的时间变化。我们从2010年6月到2021年11月对该地区进行了监测，包括2011年10月发生的森林间伐。SF6浓度用于估计泉水的表观年龄，并用于启动参数校准，以确定每个研究期间可能的最佳MTT。利用指数活塞流模型估计了泉水稳定同位素的d-过剩变化，从而评估了MTT。MTT在40至55个月之间，在森林变薄后不久有增加的趋势。相比之下，MTT在变薄后缩短了大约6年。结果表明，森林砍伐后流域水文过程特征发生了长期变化。该研究表明，使用联合示踪方法来调查森林管理措施对水文响应的影响，可以改善结果，并可用于更好地管理森林和地下水资源。
In this study, we applied a new methodology that utilized stable isotopic concentrations of water and SF6 concentrations of the air to investigate temporal variations in the spring water mean transit time (MTT) of a forested headwater catchment in Japan. We monitored the area from June 2010 to November 2021, including the forest thinning that occurred in October 2011. The SF6 concentrations were used to estimate the apparent age of the spring water, which was used to initiate a parameter calibration that determined the best possible MTT for each study period. The MTT was evaluated by estimating the d-excess variations of the spring water stable isotopes using the exponential piston flow model. The MTT ranged from 40 to 55 months and tended to increase soon after the forest was thinned. In contrast, the MTT was shorter by approximately 6 years after thinning occurred. The results indicate that the characteristics of the hydrological processes in the catchment underwent long-term changes after the forest was thinned. This study demonstrates that using combined tracer methods to investigate the hydrological response to forest management practices improved the results and can be used for better forest and subsurface water resource management.