Evaluating Calibration of
Held During the 2019 Fall Week of Water
NWRA is Pleased to Introduce our Instructor:
Keith Halford, Halford Hydrology LLC
Groundwater models frequently are calibrated to better predict changes in water levels and spring discharges from pumping. Calibration minimizes differences between measured and simulated responses, while estimating plausible hydraulic property distributions and honoring conceptual models. Water levels, water-level changes, discharges, and changes in discharge are quantifiable measures that typically can be compared formally in an objective function. Water-table altitudes greater than land surface, head-differences between wells, and transmissivities from aquifer tests are additional measures that can be compared quantitatively, albeit, with additional subjectivity and numerical difficulties. Plausibility of simulated hydraulic property estimates is difficult to quantify, but considered more easily when reduced to a vertically integrated measure such as transmissivity. Differences between numerical and conceptual models can be assessed qualitatively with integrated results and simple visualizations. An example of integrating results is summing recharge volumes between mountain ridges and valley floors. Water-level profiles is a simple visualization for comparing simulated and measured gradients. Predictive utility of calibrated models depends on agreement between measured and simulated responses and qualitative agreement between conceptual and numerical models.
The workshop will address necessary elements for evaluating calibration of groundwater models. Topics include; (1) Designing groundwater-flow models for calibration, stress-response approach, (2) Developing an objective function with additional measurements such as transmissivity observations, (3) Comprehensively visualizing model results with Excel, Model Viewer, and Google Earth. Stress-response models that simulate part of Death Valley regional groundwater-flow system will be used as examples. Presented material will be appropriate for individuals who develop or review groundwater-flow models. Examples and software for viewing water-level profiles, hydrographs, and hydraulic-property distributions are intended for individuals with experience in developing groundwater-flow models with MODFLOW.
Contact Hours Available / CEU approval for attendees
2019 Fall Week of Water Exhibitor
September 24, 2019
1:00 p.m. - 5:00 p.m
5650 Riggins Court
Reno, NV 89502
August 31, 2019:
$75 NWRA Members
$100 Non Members
August 31, 2019:
$100 NWRA Members
$125 Non Members
Add-On the Borehole Geophysical Logging Workshop, September 23rd:
Cancellation Policy: All cancellations must be received in writing and sent to NWRA via fax to 775-473-5473, mailed to P.O. Box 8064, Reno, NV 89507, or e-mailed to email@example.com. Cancellations received within 7 days of the start of the event will not be refunded, however substitutions are welcome. All other cancellation requests will receive a refund minus a 25% administrative fee. If you have purchased the registration with a credit card, the convenience fee is non-refundable.