Water Supply and Groundwater Modeling

John J. Ward, RG, Groundwater Consultant

Water supply development is a multi-disciplinary effort, using the skills of civil engineers, geologists and geophysicists, as well as drilling, pump, and electrical contractors.    In addition to the larger-scale projects listed below,  I have worked with individual property owners on developing groundwater supplies for residential and agricultural needs in the western U.S.  I have also worked with industrial clients on development of power plant cooling water supplies, groundwater pumping for contaminant control, and on design and installation of disposal and deep injection wells.

Examples of my water supply experience are listed below:

  • Power Plant Supply, Arizona:  Managed wellfield design, costing, and performance evaluation for a 5.8 mgd power plant water supply, Arizona.  Designed deep supply wells, to 3,800 feet depths. Developed groundwater model to optimize number of supply wells, their spacings, and pumping rates; determined electrical power needs for wells, booster pumps, and conveyance piping.
  • Municipal Well Water Supply, Arizona:  Lead hydrogeologist on 2.3 mgd municipal groundwater supply expansion, Arizona.  For developer.
  • Mine Slurry Water, Arizona:  Hydrogeologic consultant on development of multiple high-capacity deep wells to supply mine and slurry water for coal mine, Arizona. Design of installation of production and monitoring wells to 1,000 feet depth. Conducted and analyzed long term aquifer tests from each well site.
  • Groundwater Control, California:  Designed, optimized locations and pumping rates, constructed, and operated remedial wellfield consisting of multiple production wells for groundwater cleanup, Los Angeles.
  • Power Plant Supply, Hawaii:  Developed groundwater supplies for two power plants. Also designed and installed deep injection wells for cooling water disposal.
  • Mine Supply, Florida:  Developed 5 mgd water supply for phosphate mine development in Central Florida.  Installed and tested deep supply wells into the Floridan Aquifer with 4,000 gpm capability.

Groundwater Modeling.    Proficient in the use of commonly used codes, such as Modflow, Surfact, MT3D, VS2D, soil gas transport, and automatic parameter estimation techniques.

Representative examples of use of subsurface flow models are listed below.

Large-Scale Groundwater Flow Models:

  • Arizona N-Multiple-Aquifer-System, 6,000 square miles, wellfield design and prediction of impacts, in support of Federal reserved water rights adjudication.
  • Arizona/New Mexico C-Multiple-Aquifer-System, 27,000 square miles, impacts of projected growth in groundwater use, in support of Federal reserved water rights adjudication.
  • Los Angeles Central Basin and Coastal Plain Aquifer System, 600 square miles, to develop effective dewatering designs and predict pumping rates, drawdowns, and contaminant transport due to groundwater rising into depressed section of interstate freeway.
  • New Mexico Roswell Artesian Basin, 4,500 square miles, wellfield design and prediction of impacts, tribal water rights adjudication.
  • New Mexico San Juan Basin, 21,000 square miles impacts from uranium mine dewatering on water levels and stream flow.

Subregional and Site Flow Models:

  • Los Angeles remedial wellfield, numerical groundwater model to optimize well locations and pumping ratesunder multi-objective operation (mass removal, capture).
  • Arizona Class I hazardous waste site,  saturated/unsaturated numerical flow model for siting of facility, development of impact predictions from various release scenarios.
  • California, dewatering of landfill addition, Yolo County. Predicted effects of landfill depth configurations based on seasonal water table fluctuations and flooding in adjacent waterway.
  • Arizona, variably saturated flow model of moisture migration through adobe and clayey soils to evaluate plausibility of off site water migration on building damage.
  • Arizona, Power plant wellfield design and optimization, linked numerical model with wellfield costing model to optimize wellfield configurations.
  • New Mexico, Agricultural wellfield design and simulation for feasibility evaluation of proposed replacement source of water.

Contaminant and Vapor Flow Models

  • Brine discharge into New Mexico River, transport model of remediation scenarios from brine discharge from Permain Basin into eastern New Mexico river and downstream reservoirs. Included geophysical and isotopic determination of sources of brine contamination.
  • New Mexico, transport model of tailings leakage into groundwater and streams, predicted natural attenuation times from various leakage interception strategies.
  • Arizona, contaminant migration from septic systems into potable groundwater using both analytical and numerical transport models.
  • California, numerical soil gas models to predict sweeping efficiency of SVE systems on deep vadose zone contamination from chlorinated solvents.
  • Arizona, soil vapor extraction modeling on effects of groundwater and capillary fringe volatile contaminant concentrations.