Assessing the recharge process and importance of montane water to adjacent tectonic valley-plain groundwater using a ternary end-member mixing analysis based on isotopic and chemical tracers

Tsung-Ren Peng; Wen-Jun Zhan; Lun-Tao Tong; Chi-Tsun Chen; Tsang-Sen Liu; Wan-Chung Lu

doi:10.1007/s10040-018-1741-2

Assessing the recharge process and importance of montane water to adjacent tectonic valley-plain groundwater using a ternary end-member mixing analysis based on isotopic and chemical tracers

Journal

Hydrogeology Journal

Journal Volume

26

Journal Issue

6

Pages

2041-2055

Date Issued

2018-09

Date

2018-09

Author(s)

Tsung-Ren Peng

Wen-Jun Zhan

Lun-Tao Tong

Chi-Tsun Chen

Tsang-Sen Liu

Wan-Chung Lu

DOI

10.1007/s10040-018-1741-2

URI

https://scholars.tari.gov.tw/handle/123456789/6701

Abstract

A study in eastern Taiwan evaluated the importance of montane water contribution (MC) to adjacent valley-plain groundwater (VPG) in a tectonic suture zone. The evaluation used a ternary natural-tracer-based end-member mixing analysis (EMMA). With this purpose, VPG and three end-member water samples of plain precipitation (PP), mountain-front recharge (MFR), and mountain-block recharge (MBR) were collected and analyzed for stable isotopic compositions (delta H-2 and delta O-18) and chemical concentrations (electrical conductivity (EC) and Cl-). After evaluation, Cl- is deemed unsuitable for EMMA in this study, and the contribution fractions of respective end members derived by the delta O-18-EC pair are similar to those derived by the delta H-2-EC pair. EMMA results indicate that the MC, including MFR and MBR, contributes at least 70% (679 x 10(6) m(3) water volume) of the VPG, significantly greater than the approximately 30% of PP contribution, and greater than the 20-50% in equivalent humid regions worldwide. The large MC is attributable to highly fractured strata and the steep topography of studied catchments caused by active tectonism. Furthermore, the contribution fractions derived by EMMA reflect the unique hydrogeological conditions in the respective study sub-regions. A region with a large MBR fraction is indicative of active lateral groundwater flow as a result of highly fractured strata in montane catchments. On the other hand, a region characterized by a large MFR fraction may possess high-permeability stream beds or high stream gradients. Those hydrogeological implications are helpful for water resource management and protection authorities of the studied regions.

Subjects

Groundwater recharge

Natural tracer

Montane water contribution

Hydrochemistry

Taiwan

Publisher

Springer

Type

journal article

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