Colorado Plateau Uplands

Figure 5: Colorado plateau aquifers

This Colorado Plateau consists of layers of consolidated sedimentary rock which form broad plateaus and mesas, separated by deep canyons.  The numerous sedimentary rock layers are visible in the Grand Canyon walls, and each rock layer has unique aquifer characteristics dependent on the numbers of sedimentary bedding planes, fractures and cracks, and interconnected rock fractures.  Some sedimentary rocks maintain their original pore spaces (porosity), such as the Coconino Sandstone (see Figure 5) which originated from white-sand dunes.  In some places, these layers of sedimentary rock contain caverns and caves, for example in the Redwall Limestone. These caves were produced by large ground water flows through rock fractures which then dissolved the rock forming large caverns.   Therefore, a well constructed in the consolidated sedimentary aquifers of the Colorado Plateau may yield little water if the borehole does not intercept sufficient fractures transmitting water, or in the extreme, the well may yield sufficient volumes of ground water that has had little filtering.