Groundwater Models 101: The Necessity of Calibration

Why and how to calibrate a groundwater model, and why it’s critical to model functionality and project success.

Reliable, calibrated groundwater models that accurately represent real-world hydrological conditions are critical for informed decision making and effective project planning.

Model calibration

Developing reliable groundwater models requires calibration, or adjusting model parameters within reasonable ranges, to ensure simulated outputs match observed data from historical records.

Calibration typically begins with selecting key parameters—such as hydraulic conductivities and boundary conditions—then iteratively modifying the parameters while comparing model predictions to historic groundwater level data. Effective calibration improves the model’s predictive capabilities, increases confidence in output accuracy, and provides sound analyses for management decisions.

The model’s ability to replicate observed stream flows and groundwater levels under varied hydrological conditions confirms model calibration for both surface and groundwater modeling. Reliable models demonstrate consistent performance across diverse conditions and serve as critical decision support tools for accurate groundwater management.

The potential consequences of inadequate groundwater models

Producing usable groundwater or adding reclaimed water back into a basin is more complex than just sinking a well and firing up a pump. Launching a project for groundwater production, aquifer recharge, or conjunctive use without first modeling the basin can result in expensive, and potentially catastrophic, consequences.

An inadequate model, or no model at all, leads to uninformed decisions, possible failure to produce targeted volumes, and potentially irreversible contamination of the potable water supply.

For example, a municipal client wants to add reclaimed water to their groundwater basin and needs an accurate and calibrated groundwater model for existing wells, current groundwater flow, potential contaminant sources, and the boundaries of their coastal saltwater aquifer.

A comprehensive groundwater basin model will reveal how the recharge water will affect their existing wells and help prevent seawater intrusion into their freshwater aquifer.

Launching the reclaimed water project without a model to guide their decisions could result in permanent aquifer contamination from a petroleum or landfill plume, or seawater intrusion—both irreversible errors that would permanently contaminate the potable water supply and drastically increase water production and purification costs.

Calibrated groundwater model = confident, informed decisions

Whether evaluating the impact of fluctuating rainfall, anticipating future pumping scenarios, or predicting potential contaminant effects on potable water supplies, precise models provide utility leaders with a comprehensive understanding of the intricate interactions between groundwater systems and human activities.

Models are invaluable for effective basin management strategies, recharge, and conjunctive use, and they safeguard the ability to provide communities with a reliable, clean water supply.

A robust, calibrated groundwater model empowers utility leaders to navigate the complexities of groundwater resources with confidence and make informed decisions supporting sustainable water management practices.

Groundwater Modeling 101

We hope you found this essential guide to groundwater modeling helpful. If you missed the first two installments on choosing the right provider and the different groundwater models, you can find them here and here.