Premium
Conduit Properties and Karstification in the Unconfined Floridan Aquifer
Author(s) -
Screaton Elizabeth,
Martin Jonathan B.,
Ginn Brian,
Smith Lauren
Publication year - 2004
Publication title -
groundwater
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.84
H-Index - 94
eISSN - 1745-6584
pISSN - 0017-467X
DOI - 10.1111/j.1745-6584.2004.tb02682.x
Subject(s) - electrical conduit , aquifer , karst , sink (geography) , hydrology (agriculture) , inflow , geology , groundwater , hydrograph , denudation , outflow , tracer , calcite , residence time (fluid dynamics) , environmental science , geochemistry , drainage basin , geotechnical engineering , paleontology , oceanography , physics , cartography , engineering , nuclear physics , geography , tectonics , mechanical engineering
Exchange of water between conduits and matrix is an important control on regional chemical compositions, karstification, and quality of ground water resources in karst aquifers. A sinking stream (Santa Fe River Sink) and its resurgence (River Rise) in the unconfined portion of the Floridan Aquifer provide the opportunity to monitor conduit inflow and outflow. The use of temperature as a tracer allows determination of residence times and velocities through the conduit system. Based on temperature records from two high water events, flow is reasonably represented as pipe flow with a cross‐sectional area of 380 m 2 , although this model may be complicated by losses of water from the conduit system at higher discharge rates. Over the course of the study year, the River Rise discharged a total of 1.9 × 10 7 m 3 more water than entered the River Sink, reflecting net contribution of ground water from the matrix into the conduit system. However, as River Sink discharge rates peaked following three rainfall events during the study period, the conduit system lost water, presumably into the matrix. Surface water in high flow events is typically undersatu‐rated with respect to calcite and thus may lead to dissolution, depending on its residence time in the matrix. A calculation of local denudation is larger than other regional estimates, perhaps reflecting return of water to conduits before calcite equilibrium is reached. The exchange of matrix and conduit water is an important variable in karst hydrology that should be considered in management of these water resources.