Abstract

Fred Creek is a tributary of the Arkansas River which drains residential areas in south Tulsa County, Oklahoma. The aquifer that occupies Fred Creek is a complex of three interconnected deposits: (1) the highly weathered regolith of the Pennsylvanian siltstones in the valley floor, (2) the Quaternary stream alluvium filling the lower valley, and (3) the older Quaternary terrace deposits on the valley slopes. The aquifer is recharged through permeable colluvium zones by rainfall and by downward flow from the surface by snowmelt. Discharge is to the creek. The water table declines most during the spring and summer, controlled by water uptake by plants. Solution of matrix minerals by recharging water controls the chemistry of much of the calcium-bicarbonate groundwater. Modification of the main water type occurs when high concentration water from terrace deposits mixes with the water flowing down the valley.