The RIBs are made up of one to five cells, each measuring approximately 350 feet long by 150 feet wide. They are built over a natural sand ridge ranging in thickness from 30 to 200 feet. Beneath these surficial sands is a dense concentration of semi-permeable clays known as the Hawthorn formation. The Hawthorn acts as a barrier separating shallow groundwater flow within the surficial sands from deeper, confined flow in the Floridan aquifer, which is comprised primarily of fractured limestones and dolomites.
In this region of West Orange and Southeast Lake Counties, shallow groundwater in the surficial sands follows primarily lateral flow patterns above the Hawthorn until reaching areas of low resistance that permit significant vertical flow downward into the Floridan aquifer, thus replenishing our drinking water supply. Initially of sufficient quality to meet most state and federal primary and secondary drinking water standards, the reclaimed water continues to be polished as it travels through the surficial sands and deeper limestones.