CIV6745 Computational Methods in Water Engineering 2023 Review

1. Tasks You, as a consultant to the current owners of an industrial site, have been asked to develop an understanding of the impacts of pollution at the site described in Coursework 5. 2. Learning objectives To introduce to: • Modelling of groundwater flow and transport: grid setup, parameters, boundary conditions, source and sink terms; analysis of model results. • Identification of pumping strategies to meet groundwater demand and minimize solute concentrations in the pumped water and in the stream. 3. Site Representation Please refer to the information given in Coursework 5 for a thorough description of the hydrogeology of the site and its relevant parameters. Data concerning dispersion properties are given in Table 1. Table 1. Aquifer dispersion data. Longitudinal dispersivity (m) [αL = 0.1.L ] 50 Transverse dispersivity (m) [αH = 0.2.αL] 10 Porosity 0.18 In addition, there are two sources of pollution, an infiltration area and a lagoon, with the infiltration rates and the solute concentrations given in Figure 1. There is a proposed factory borehole (PW1) to pump 1000 m3/d, and a farm borehole (PW2) abstracting 500 m3/d. 4. Modelling tools Modelling of groundwater flow and solute transport should be performed using the MODFLOW 20051 and MT3DMS2,3 codes, respectively. Input and outputs of the two codes can be handled using USGS’s graphical user interface (GUI) ModelMuse Version v.5.1.1.04, which is available on lab computers. Before you embark in the coursework tasks, it is key you become familiar with this software through several related video tutorials, available here. 1 Harbaugh, A.W., 2005, MODFLOW-2005, The U.S. Geological Survey modular ground-water model—the Ground-Water Flow Process: U.S. Geological Survey Techniques and Methods 6-A16, variously p. 2 Zheng, C., 2010, MT3DMS v5.3: A modular three-dimensional multispecies transport model for simulation of advection, dispersion and chemical reactions of contaminants in groundwater systems. Supplemental User’s Guide, Technical Report, February 2010. 3 Bedekar, V., Morway, E.D., Langevin, C.D., and Tonkin, M., 2016, MT3D-USGS version 1: A U.S. Geological Survey release of MT3DMS updated with new and expanded transport capabilities for use with MODFLOW: U.S. Geological Survey Techniques and Methods 6-A53, 69 p., NFigure 1. Case study area 5. Groundwater flow simulation (a) You may adopt the groundwater flow model built in Coursework 5. However, you might have to increase grid resolution locally to improve accuracy in the flow field simulation. You can upload the base map posted on Blackboard (file base