Publication Date
5-2020
Abstract
In any natural system, environmental and geomorphic responses are more extreme and frequent when caused or affected by human activities. Karst aquifers differ from other aquifer types in that they are composed of complex matrix, fracture, and conduit porosities. As valuable resources for societies and ecosystems, karst aquifers are highly vulnerable to pollution and must be well studied for proper protection.This study combines ongoing monitoring data with hydrochemistry data from sampling sites within the Honeycut Hollow Creek Watershed, Blanco County, Texas. Flow measurements revealed that the discharge of Honeycut Creek Spring does not respond to local precipitation. The wettest September in 2018 in recorded history in southcentral Texas resulted in minimum discharge, which is one order of magnitude lower than the discharge recorded from April 2017. During low flow conditions, the salinity of spring water is higher with elevated levels of nitrate and higher concentrations of other ions, especially sulfate.There has been little variation for water isotopes of Honeycut Creek Spring during 2017–2019, which may demonstrate relatively long residence time of groundwater and a deep flow path. This could also explain why the discharge of Honeycut Spring does not respond to local precipitation. The deuterium excess values of these spring water samples are close to 10‰, which may indicate little evaporation during precipitation and groundwater movement.These investigations aim to reveal the relationship between water quality of springs and local geoenvironmental conditions, evaluate the impact of long-term climate variations and wet and dry conditions on water quality, identify possible sources of nitrate among sampling sites, and ultimately generate a baseline model for a better understanding on how the karst aquifer responds to recharge events and potential contamination.
Rights Information
DOI
https://doi.org/10.5038/9781733375313.1039
Investigation of water quality and groundwater flow in a karst watershed in Blanco County, Texas
In any natural system, environmental and geomorphic responses are more extreme and frequent when caused or affected by human activities. Karst aquifers differ from other aquifer types in that they are composed of complex matrix, fracture, and conduit porosities. As valuable resources for societies and ecosystems, karst aquifers are highly vulnerable to pollution and must be well studied for proper protection.This study combines ongoing monitoring data with hydrochemistry data from sampling sites within the Honeycut Hollow Creek Watershed, Blanco County, Texas. Flow measurements revealed that the discharge of Honeycut Creek Spring does not respond to local precipitation. The wettest September in 2018 in recorded history in southcentral Texas resulted in minimum discharge, which is one order of magnitude lower than the discharge recorded from April 2017. During low flow conditions, the salinity of spring water is higher with elevated levels of nitrate and higher concentrations of other ions, especially sulfate.There has been little variation for water isotopes of Honeycut Creek Spring during 2017–2019, which may demonstrate relatively long residence time of groundwater and a deep flow path. This could also explain why the discharge of Honeycut Spring does not respond to local precipitation. The deuterium excess values of these spring water samples are close to 10‰, which may indicate little evaporation during precipitation and groundwater movement.These investigations aim to reveal the relationship between water quality of springs and local geoenvironmental conditions, evaluate the impact of long-term climate variations and wet and dry conditions on water quality, identify possible sources of nitrate among sampling sites, and ultimately generate a baseline model for a better understanding on how the karst aquifer responds to recharge events and potential contamination.
