Gregory Nelson Email & Phone Number

Greater Salt Lake City Area

Denver

As a senior hydrogeologist with Knight Piesold I provide hydrogeological services to our clients across the globe. Primarily I am a groundwater modeler with experience using MODFLOW-USG on large regional groundwater models.

Boulder, Colorado

Updated and re-calibrated an existing regional, three-dimensional, numerical (MODFLOW-SURFACT) groundwater flow model in central Nevada. The model was re-calibrated using PEST, an automated parameter estimation software package. The model was used to assist in estimating future mine dewatering rates and depths, dewatering impacts to the regional water supply (based on the extent of the 10 ft drawdown contour), and subsidence due to dewatering.Managed two projects in Nevada to locate and install a production wells for two different mines. Each project involved locating the production well site, overseeing its construction, and conducting and analyzing an aquifer test. Managed and oversaw groundwater modeling for a mine in north Mexico. The project involved the development of a regional hydrogeologic conceptual model, conversion of the conceptual model to a numerical model (MODFLOW-SURFACT), calibration of the flow model (using PEST), and use of the model to estimate water supply yields for the mine.Refined a regional, numerical flow model (MODFLOW-SURFACT) from the U.S. Geological Survey for the purpose of defining flow paths at a small, local contaminated site in Kansas. Converted the model from MODFLOW to MODFLOW-SURFACT. Used particle tracks to determine a 25-year capture zone. Redefined the layering and hydrogeology at the site to more closely match site data.Created and utilized a two-dimensional, laterally averaged, hydrodynamic model (CE-QUAL-W2) to identify potential seasonal trends in stratification and turnover, and to evaluate potential seasonal dissolved oxygen concentrations for a proposed pit lake.

Converted a SEAWAT variable-density flow model of the various freshwater lenses on Cape Cod, Massachusetts, to a SEAWAT2000 model. Aided in the refinement of the model so that only the Pamet freshwater lens was simulated. Analyzed new pumping test data in AQTESOLV for various hydraulic properties that were applied to the model. This model is to be used to permit a new municipal well field and to estimate saltwater intrusion and upconing due to pumping.Utilized a regional, finite-element groundwater flow model (DYN System) of part of Long Island, New York, to investigate the transport of various VOCs. Performed particle tracking to determine flow paths. Investigated potential sources and source concentrations through transport modeling. Analyzed potential impacts to downgradient receptors including sole-source municipal supply wells.Developed an site conceptual model for a TCE plume in a fracture flow environment in New Jersey. The site conceptual model was used to identify possible source locations and potential receptors. Designed and analyzed results from aquifer tests on Cape Cod, Massachusetts, to determine the hydraulic properties of the aquifers. This was in support of the development of a new well field. Analysis involved evaluating horizontal anisotropy in the pumping data via AQTESOLV and evaluating vertical anisotropy through a spreadsheet model.Developed a monitoring plan, including wells and stream gauges for a site on Cape Cod, Massachusetts. Data from the monitoring would be used in developing a groundwater flow model of the area.Aided in the development of a hydrogeologic conceptual model of a highly fractured aquifer system contaminated with DNAPL in New Jersey. Provided support in developing a plan to investigate the connectivity of the fractures at the site. Reviewed site documents in support of DNAPL source location and timing.

Ms, Geophysics

Bs, Geophysical Engineering