The Analytic Element Method (AEM) of ground-water modeling was used to
delineate wellhead protection areas (WHPAs) for existing and proposed
wells in Brooklyn Park, Minnesota by simulating steady-state flow in
two aquifers: the water-table aquifer (in glacial outwash) and the Fra
nconia-Ironton-Galesville bedrock aquifer. Ground-water time-of-travel
was used as the delineation criterion. Ground-water flow is significa
ntly affected by a buried bedrock valley underneath the City. Transmis
sivity values for the water-table aquifer are much higher in the burie
d bedrock valley and the hydraulic connection between the water-table
and the Franconia-Ironton-Galesville aquifers is more pronounced. The
Analytic Element Method does not utilize a grid mesh and incorporates
both regional-scale and more detailed, local-scale features in the sam
e solution. This feature of AEM provided for the simulation of the cit
y wells in the context of the regional flow field. Separate models, en
compassing an area of approximately 500 square miles, were developed a
nd calibrated for each aquifer using the Single Layer Analytic Element
Model (SLAEM) and then linked together using the Multi-Layer Analytic
Element Model (MLAEM). Ground-water travel-time zones and WHPAs were
delineated for the existing wells using reverse particle tracking.