HUSCAP logo Hokkaido Univ. logo

Hokkaido University Collection of Scholarly and Academic Papers >
Graduate School of Engineering / Faculty of Engineering >
Peer-reviewed Journal Articles, etc >

Heat as a Tracer for Examining Depth-Decaying Permeability in Gravel Deposits

Files in This Item:
Final manuscript for HUSCAP.pdf1.64 MBPDFView/Open
Please use this identifier to cite or link to this item:

Title: Heat as a Tracer for Examining Depth-Decaying Permeability in Gravel Deposits
Authors: Sakata, Yoshitaka Browse this author
Issue Date: Apr-2015
Publisher: Wiley-Blackwell
Journal Title: Groundwater
Volume: 53
Issue: S1
Start Page: 21
End Page: 32
Publisher DOI: 10.1111/gwat.12236
PMID: 25047679
Abstract: Depth dependence of permeability can appear in any geologic setting; however, vertical trends in alluvial gravel deposits are poorly understood because of the high variability of hydraulic conductivity K in monotonic sequences. This paper examines the sensitivity of depth-decaying permeability through heat transport simulation around a river's losing reach in the Toyohira River alluvial fan, Japan. Observed variations in groundwater temperature indicate that heat fluxes are dominant in the shallow zone, despite a vertical hydraulic gradient. In eight cases with different conditions (presence or absence of exponential decay trend, large or small variogram range, and cell isotropy or anisotropy) 1000 K realizations are stochastically generated throughout a cross-sectional model. The groundwater flow and heat transport are transiently calculated, and the averaged root mean square error RMSE?</mml:mover> is used for sensitivity comparison. The variance of RMSE?</mml:mover> shows that small RMSE<mml:mo stretchy="true">?</mml:mover> realizations are effectively reproduced with vertical trend assumed. Plausible realizations of <mml:mover>RMSE<mml:mo stretchy="true">?</mml:mover> below a given threshold were obtained only when a vertical trend was assumed. The most plausible realization almost completely matched the observations. However, the number of plausible realizations per case was 10 and the median <mml:mover>RMSE<mml:mo stretchy="true">?</mml:mover> were insensitive to all the conditions. Statistical testing suggested that these plausible realizations may be statistically significant, aiding in generating a connected K zone for high heat flows. The cell anisotropy condition had the smallest effect on the simulation. Thus, effective modeling of the vertical trend contributes to heat transport; however, the model's efficiency is low without detailed information about the sedimentary structure.
Rights: This is the peer reviewed version of the following article: Groundwater, Volume 53, Issue S1, pages 21–32, April 2015, which has been published in final form at
Type: article (author version)
Appears in Collections:工学院・工学研究院 (Graduate School of Engineering / Faculty of Engineering) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)

Submitter: 阪田 義隆

Export metadata:

OAI-PMH ( junii2 , jpcoar_1.0 )

MathJax is now OFF:


 - Hokkaido University