Characterizing the temporal and spatial variability of spring discharge along the Colorado River near Colorado Bend State Park, central Texas.

摘要

Ordovician Ellenburger carbonates exhibiting complex karst development outcrop in San Saba and Lampasas Counties, Texas, near the highly incised Colorado River. Eight springs: Lemon Spring, Well House Spring, Gorman Spring, Gorman Cave Spring, Gorman Falls Spring, McLarrin Spring, and Sulphur Spring, were studied through an 18-month period to show temporal and spatial variability that are indicative of a complex hydrologic regime currently active within the region.;Fluid analyses and thermal monitoring of springs indicate that most springs are associated with shallow meteoric fluid circulation; however, some springs exhibit characteristics indicative of deep circulation with little or no mixing with the immediately adjacent meteoric environment. Four groundwater flow paths were recognized when analyzing the data gathered: (1) Proximal matrix/bedding plane flow; (2) Intermediate fracture/conduit flow; (3) Distal fracture/conduit flow; and (4) Deep circulation. Two springs represent flow pattern one, two represent flow pattern two, two represent flow pattern three and one spring represents flow pattern four.;Lineament analyses of digital orthophoto quarter quads (DOQQ's) and of existing cave maps provide information on primary groundwater flow. Caves and cave maps of the area were visited and studied to understand the speleogenesis within the region. Hypogene karst processes dominate with greater than two thirds exhibiting hypogene origins with varying degrees of epigene origins. No evidence of eogenetic paleokarst was identified.