Based on a large amount of publicly available data, several studies ha
ve previously examined the flow of formation waters in different parts
of the Alberta basin, offering various interpretations as to the caus
es of the observed pressure regime and flow pattern; however, there ha
s been no synthesis of these diverse studies on a basin-wide basis. Ac
cordingly, these studies are critically reviewed in this paper and syn
thesized in a new basin-scale model of the flow of formation waters in
the Alberta basin. The proposed regional-scale model has significant
implications for understanding hydrocarbon migration pathways, ore gen
esis, the geothermal regime, and deep waste disposal in the Alberta ba
sin. Several flow systems, each one driven by a differ ent mechanism,
are identified, together with the main processes leading to the nonhyd
rostatic pressures observed in the basin. Two megahydrostratigraphic s
uccessions and associated flow systems are recognized. The first succe
ssion corresponds to the pre-Cretaceous passive-margin stage of basin
development, and consists of thick, carbonate-dominated aquifer system
s separated by shaly aquitards and evaporitic aquicludes. A northeastw
ard basin-scale flow system is driven by basin topography, with rechar
ge in Montana and discharge in northeastern Alberta. Southwest-to-nort
heast regional-scale flow adjacent to the fold and thrust belt is prob
ably the result of past tectonic processes. The salinity of formation
water in pre-Cretaceous aquifers is high, and generally increases both
northward and with depth. This variability is the result of increased
water-rock reactions (mineral solubility) with increased temperature,
and of incomplete flushing by meteoric water. As a result of salinity
variations, flow-retarding buoyancy effects can be important. The sec
ond megahydrostratigraphic succession corresponds to the post-Jurassic
foreland stage of basin evolution, and consists of thick, shaly aquit
ard systems and relatively thin sandstone aquifers. In the southwester
n part of the basin, flow in isolated aquifers is driven southwestward
by erosional rebound in the thick intervening shales, downdip toward
the fold and thrust belt. The salinity of formation waters in the post
-Jurassic aquifers is low. Mixing of waters and interference between t
he major flow systems takes place along the pre-Cretaceous unconformit
y where successively older pre-Cretaceous aquifers subcrop from west t
o east. Flow in shallow local systems at the top of the sedimentary su
ccession is driven by local topography.