A simulation of large-scale groundwater flow and travel time in a fractured rock environment for waste disposal purposes

2004 ◽  
Vol 18 (9) ◽  
pp. 1579-1593 ◽  
Author(s):  
Duke U. Ophori
Keyword(s):  
Groundwater Flow ◽  
Travel Time ◽  
Waste Disposal ◽  
Large Scale ◽  
Fractured Rock

scholarly journals A dual fracture model to simulate large-scale flow through fractured rocks

2002 ◽  
Vol 39 (6) ◽  
pp. 1302-1312 ◽  
Author(s):  
E Z Wang ◽  
Z Q Yue ◽  
L G Tham ◽  
Y Tsui ◽  
H T Wang
Keyword(s):  
Groundwater Flow ◽  
Large Scale ◽  
Fractured Rock ◽  
Network Models ◽  
Total Porosity ◽  
Seepage Flow ◽  
Fracture Network ◽  
Fracture Model ◽  
Rock Masses ◽  
Rock Matrix

Discrete fracture network models can be used to study groundwater flow in fractured rock masses. However, one may find that it is not easy to apply such models to practical projects as it is difficult to investigate every fracture and measure its hydraulic parameters. To overcome such difficulties, a dual fracture model is proposed. Taking into account the hydraulic characteristics of the various elements of the fracture system, a hydrogeological medium is assumed to consist of two components: the dominant fracture network and the fractured rock matrix. As the dominant fracture network consists of large fractures and faults, it controls the groundwater flow in rock masses. Depending on the permeabilities of the in-fill materials, these fractures and faults may serve as channels or barriers of the flow. The fractured rock matrix, which includes rock blocks and numerous small fractures, plays a secondary role in groundwater flow in such medium. Although the small fractures and rock blocks possess low permeability, their numbers and their total porosity are relatively large. Therefore, they provide large volume for groundwater storage. In this paper, the application of the proposed model to simulate the groundwater flow for a hydropower station before and after reservoir storage is reported. The implications of the results on the design of the station are also highlighted.Key words: seepage flow, dual fracture model, dominant fracture, fractured rock matrix, case studies, rock-filled dam.

scholarly journals Equity Effects of Congestion Charges: An Exploratory Analysis with MATSim

2017 ◽  
Vol 2670 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Lucas Meyer de Freitas ◽  
Oliver Schuemperlin ◽  
Milos Balac ◽  
Francesco Ciari
Keyword(s):  
Travel Time ◽  
Large Scale ◽  
Agent Based ◽  
Promising Tool ◽  
Travel Time Savings ◽  
Time Savings ◽  
Time Changes ◽  
High Level ◽  
Congestion Charging ◽  
Equity Effects

This paper shows an application of the multiagent, activity-based transport simulation MATSim to evaluate equity effects of a congestion charging scheme. A cordon pricing scheme was set up for a scenario of the city of Zurich, Switzerland, to conduct such an analysis. Equity is one of the most important barriers toward the implementation of a congestion charging system. After the challenges posed by equity evaluations are examined, it is shown that agent-based simulations with heterogeneous values of time allow for an increased level of detail in such evaluations. Such detail is achieved through a high level of disaggregation and with a 24-h simulation period. An important difference from traditional large-scale models is the low degree of correlation between travel time savings and welfare change. While traditional equity analysis is based on travel time savings, MATSim shows that choice dimensions not included in traditional models, such as departure time changes, can also play an important role in equity effects. The analysis of the results in light of evidence from the literature shows that agent-based models are a promising tool to conduct more complete equity evaluations not only of congestion charges but also of transport policies in general.

scholarly journals Improved representation of groundwater at a regional scale – coupling of mesocale Hydrologic Model (mHM) with OpeneGeoSys (OGS)

2017 ◽  
Author(s):  
Miao Jing ◽  
Falk Heße ◽  
Wenqing Wang ◽  
Thomas Fischer ◽  
Marc Walther ◽  
...  
Keyword(s):  
Time Series ◽  
Groundwater Flow ◽  
Groundwater Recharge ◽  
Large Scale ◽  
Groundwater Modeling ◽  
Coupled Model ◽  
Hydrologic Model ◽  
Source Modeling ◽  
Prediction Ability ◽  
Groundwater Head

Abstract. Most of the current large scale hydrological models do not contain a physically-based groundwater flow component. The main difficulties in large-scale groundwater modeling include the efficient representation of unsaturated zone flow, the characterization of dynamic groundwater-surface water interaction and the numerical stability while preserving complex physical processes and high resolution. To address these problems, we propose a highly-scalable coupled hydrologic and groundwater model (mHM#OGS) based on the integration of two open-source modeling codes: the mesoscale hydrologic Model (mHM) and the finite element simulator OpenGeoSys (OGS). mHM#OGS is coupled using a boundary condition-based coupling scheme that dynamically links the surface and subsurface parts. Nested time stepping allows smaller time steps for typically faster surface runoff routing in mHM and larger time steps for slower subsurface flow in OGS. mHM#OGS features the coupling interface which can transfer the groundwater recharge and river baseflow rate between mHM and OpenGeoSys. Verification of the coupled model was conducted using the time-series of observed streamflow and groundwater levels. Moreover, we force the transient model using groundwater recharge in two scenarios: (1) spatially variable recharge based on the mHM simulations, and (2) spatially homogeneous groundwater recharge. The modeling result in first scenario has a slightly higher correlation with groundwater head time-series, which further validates the plausibility of spatial groundwater recharge distribution calculated by mHM in the mesocale. The statistical analysis of model predictions shows a promising prediction ability of the model. The offline coupling method implemented here can reproduce reasonable groundwater head time series while keep a desired level of detail in the subsurface model structure with little surplus in computational cost. Our exemplary calculations show that the coupled model mHM#OGS can be a valuable tool to assess the effects of variability in land surface heterogeneity, meteorological, topographical forces and geological zonation on the groundwater flow dynamics.

CUDA-based solver for large-scale groundwater flow simulation

2011 ◽  
Vol 28 (1) ◽  
pp. 13-19 ◽  
Author(s):  
Xiaohui Ji ◽  
Tangpei Cheng ◽  
Qun Wang
Keyword(s):  
Groundwater Flow ◽  
Large Scale ◽  
Flow Simulation

Evaluation Indexes System for Assessing Road Construction with Recycled Waste Materials to Achieve Better Environmental Impacts

2011 ◽  
Vol 250-253 ◽  
pp. 1001-1006 ◽  
Author(s):  
De Zhen Chen ◽  
Cui Jie Geng ◽  
Wen Zhou Sun
Keyword(s):  
Energy Consumption ◽  
Environmental Impact ◽  
Waste Disposal ◽  
Large Scale ◽  
Construction Material ◽  
Bottom Ash ◽  
Road Construction ◽  
Waste Materials ◽  
Evaluation Indexes ◽  
Recycled Waste

Evaluation indexes system has been put forward in this paper for quantifying thesystematical energy consumption, resources consumption, total emissions’ change and waste disposal capacity in road construction with recycled waste materials involved. With help of this evaluation indexes system, the contributions to environmental improvement caused by recycling waste materials in road construction can be quantified through calculating savings on environmental impact potentials, savings on energy consumption, on virgin materials’ consumption and waste disposal capacity provided by road construction. Based on the construction project of a road section numbered No.20 EWK0+400 ~ EWK0+600 of North highway to Shanghai Pudong international airport, which was the first trial project of using several kinds of recycled waste materials including bottom ash from incinerators to replace commonly used materials such as gravel in large scale in road pavement, the results of the four indexes, namely, savings on energy consumption and virgin materials’ consumption, environmental impact potentials as well as waste disposal capacity were obtained. It was found out that with multi recycled waste materials replacing part of the common construction material, systematical energy consumption can be reduced by 30%, a large amount of virgin resource consumption can be avoid and road construction also provides a remarkable large “dumping site” for solid wastes; while at the same time environmental impact potentials were saved for most impact categories except for increase in Ecotoxicity, water chronic, which was caused by heavy metals’ leaching and can be prevented by pre-treatment. Those results are useful for guiding the utilization of recycled waste materials, as well as for developing new technology process and advanced materials in road construction.

Multiscale-finite-element-based ensemble Kalman filter for large-scale groundwater flow

2012 ◽  
Vol 468-469 ◽  
pp. 22-34 ◽  
Author(s):  
Liangsheng Shi ◽  
Lingzao Zeng ◽  
Dongxiao Zhang ◽  
Jinzhong Yang
Keyword(s):  
Finite Element ◽  
Kalman Filter ◽  
Groundwater Flow ◽  
Ensemble Kalman Filter ◽  
Large Scale ◽  
Multiscale Finite Element
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