Bob Smith

Thanks!

Colleagues, The GWB website suggests that the "thereda2020.tdat" GWB would be released in April 2020; any idea on when this might actually occur? Thanks Bob Smith

Hi, I am trying Xt2 to simulate a field experiment that my group conducted in the “Anderson” well gallery at the Rifle, CO site to created a bioactive zone using recirculation wells. In the experiment, water was pumped from a production well (M-07) and amended with urea and molasses using a metering pump and an in line pipe-mixer for 12 days and reinjected (well M-02) up-gradient. The pumping well was shut off and the reactive zone was monitored for 400+ days. I understand how to create the recirculation cell in Xt2 (GWB12), but I am struggling with an approach to add the urea and molasses to the injected water. Can two fluids be injected simultaneously into a single well? Or should I look for another approach such as creating a fictive solid placed in the grid block with the well with a defined, constant release rate? Any insights would be welcome. In addition, the Goldschmidt Reactive Transport Workshop was great. Thanks Bob Smith

I have been using React (Release 8.05 build 3829) to model a continuously stirred tank reactor (CSTR) using the “flush” option and have discovered the “cutoff” option does not work as I expected. I have run a set of simulation with react .05 kg/day of Br-, cutoff = .1 kg and time start = 0 days, end = 7 days time start = 0 days, end = 14 days time start = 0 days, end = 21 days for these three cases the total amount of Br- reacted from the React_output.txt files is 350, 700, and 1050 g, respectively. First, all these values exceed the 0.1 kg (100 g) “cutoff” and second there is a linear coupling between “cutoff” and the length of the simulation. One of the input files is attached however I find this behavior in all the simulations that I have tried. Thanks Bob Smith 100818_Tracer.rea

Tom, I vote for "Knoxville, TN, USA (coincident with Goldschmidt" I am planning on having my post-doc attend. Thanks Bob Smith Univ. of Idaho

Tim Ginn of UC-Davis and I are preparing to attempt to link The Geochemist’s Workbench (professional) with the UCODE (a universal inversion code) software in order to inverse model biogeochemical experiments to recover kinetic and microbial parameters. Initially we will be working with results from batch biogeochemical experiments, but ultimately we would like to recover similar parameters from column/field experiments/observations. Does anyone have experience with this type of linkage (or using PEST/ Visual PEST)? Thanks Bob Smith Distinguished Professor of Subsurface Science Biological and Agricultural Engineering University of Idaho

In using a cation exchange model in XT, a cation exchange capacity is required. Is this the capacity of each node or the capacity of the entire flow domain? Thanks Bob Smith