Using a Numerical Groundwater Model to Understand Water Resources and Sustainability for the City of Flagstaff

AMEC was contracted by the City of Flagstaff to conduct a comprehensive 100-year water resource sustainability study.  The study aims to identify available and sustainable water resources for the City of Flagstaff over the next 100 years and to understand the affects growth and variable climate conditions will have on the City’s water resources.  As part of the study, a numerical groundwater flow model was developed and provided to the City of Flagstaff as a tool to aid with municipal water management decisions today and in the future.

The numerical groundwater flow model was developed using MODFLOW.  The flow model was based on the United States Geologic Survey’s Northern and Central Arizona Groundwater Regional Flow Model.  The model was refined and additional features important to the City’s water budget were added to the model including reclaimed water, surface water recharge features, and local pumping wells.  The model will be used to test future water planning scenarios given projected population growth and possible future drought and wet conditions.  The model will also be used to predict impacts to local surface water and groundwater supplies. The predictive simulations will assist the City of Flagstaff with future planning and development of their groundwater, surface water, and reclaimed water supplies, such that sustainability of these precious resources can be achieved.