Super-diffusion affected by hydrofacies mean length and source geometry in alluvial settings

Yin, Maosheng1; Zhang, Yong2; Ma, Rui1; Tick, Geoffrey R.2; Bianchi, Marco3; Zheng, Chunmiao4; Wei, Wei5; Wei, Song4; Liu, Xiaoting6

2020

10.1016/j.jhydrol.2019.124515

JOURNAL OF HYDROLOGY   影响因子和分区

0022-1694

1879-2707

Dissolved-phase contaminants experiencing enhanced diffusion (i.e., "super-diffusion") with a pronounced leading plume edge can pose risk for groundwater quality. The drivers for complex super-diffusion in geological media, however, are not fully understood. This study investigates the impacts of hydrofacies’ mean lengths and the initial source geometry, motivated by a hydrofacies model built recently for the well-known MADE aquifer, on the spatial pattern of super-diffusion for two-dimensional alluvial aquifer systems. Monte Carlo simulations show that the bimodal velocity distribution, whose pattern is affected by the hydrofacies’ mean lengths, leads to super-diffusion of solutes with a bi-peak plume snapshot in alluvial settings where advection dominates transport. A larger longitudinal mean length (i.e., width) for hydrofacies with high hydraulic conductivity (K) enhances the connectivity of preferential pathways, resulting in higher values in the bimodal velocity distribution and an enhanced leading front for the bi-peak plume snapshot, while the opposite impact is identified for the hydrofacies’ vertical mean length (i.e., thickness) on the bi-peak super-diffusion. A multi-domain non-local transport model is then proposed, extending upon the concept of the distributed-order fractional derivative, to quantify the evolution of bi-peak super-diffusion due to differential advection and mobile-mobile mass exchange for solute particles moving in hydrofacies with distinct K. Results show that the bi-peak super-diffusion identified for the MADE site and perhaps the other similar aquifers, which is affected by the initial source geometry at an early stage and the thickness and width of high-K hydrofacies during all stages, can be quantified by the mobile-mobile fractional-derivative model. Porous medium dimensionality and stochastic model comparison are also discussed to further explore the nature of bi-peak super-diffusion in alluvial systems.
© 2020 Elsevier B.V.

Super-diffusion Alluvial aquifer Hydrofacies model Monte Carlo simulation

SCI ; EI

英语

其他

Guangdong Provincial Key Laboratory of Urology[2017B030301012] ; Natural Science Foundation of Hubei Province[2019CFA013] ; National Natural Science Foundation of China[41722208]

Engineering ; Geology ; Water Resources

Engineering, Civil ; Geosciences, Multidisciplinary ; Water Resources

WOS:000517663700076

Elsevier B.V.

20200308037515

Advection ; Aquifers ; Geometry ; Groundwater pollution ; Groundwater resources ; Hydrogeology ; Intelligent systems ; Monte Carlo methods ; Porous materials ; Stochastic models ; Stochastic systems ; Velocity distribution ; Water quality

Groundwater:444.2 ; Water Analysis:445.2 ; Geology:481.1 ; Artificial Intelligence:723.4 ; Mathematics:921 ; Probability Theory:922.1 ; Mathematical Statistics:922.2 ; Materials Science:951 ; Systems Science:961

ENGINEERING

Web of Science

1.School of Environmental Studies, China University of Geosciences, Wuhan; Hubei; 430074, China
2.Department of Geosciences, University of Alabama, Tuscaloosa; AL; 35487, United States
3.British Geological Survey, Environmental Science Centre, Nottingham, United Kingdom
4.School of Environmental Science & Engineering, Southern University of Science and Technology, Shenzhen; Guangzhou; 518055, China
5.Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control & Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, Jiangsu Engineering Laboratory of Water and Soil Eco-remediation, School of Environment, Nanjing Normal University, Nanjing; 210023, China
6.College of Mechanics and Materials, Hohai University, Nanjing; Jiangsu; 210098, China

Yin, Maosheng,Zhang, Yong,Ma, Rui,et al. Super-diffusion affected by hydrofacies mean length and source geometry in alluvial settings[J]. JOURNAL OF HYDROLOGY,2020,582.

Yin, Maosheng.,Zhang, Yong.,Ma, Rui.,Tick, Geoffrey R..,Bianchi, Marco.,...&Liu, Xiaoting.(2020).Super-diffusion affected by hydrofacies mean length and source geometry in alluvial settings.JOURNAL OF HYDROLOGY,582.

Yin, Maosheng,et al."Super-diffusion affected by hydrofacies mean length and source geometry in alluvial settings".JOURNAL OF HYDROLOGY 582(2020).