Urban Waters Federal Partnership - Edwards Aquifer Recharge Zone Monitoring Network
Contaminants in the Edwards aquifer
Where do they come from and how do they get there?
Science Center Objects
The USGS Texas Water Science Center is implementing a more complete and integrated monitoring network for the Edwards aquifer to improve the understanding of aquifer water quality and establish a baseline for measuring future water-quality changes.
Data from this study can be used to address these primary objectives:
- Long-term trends in water quality, with particular emphasis on nutrients and organic contaminants including pesticides, pharmaceuticals, and wastewater compounds.
- How surface water - groundwater interaction affects water quality changes over a range of hydrologic conditions.
Edwards Aquifer conceptual model
The San Antonio segment of the Edwards aquifer (hereafter, the Edwards aquifer), located in south-central Texas is a karst groundwater system that provides important water resources to the region, provides habitat for endemic and endangered species, and supplies major spring systems such as Comal Springs and San Marcos Springs.
In the face of increasing pressures from urbanization, a better understanding of the sources, fate, and transport of anthropogenic contaminants in the aquifer is needed to improve water management decision-making capabilities.
Additionally, the role of surface water-groundwater interaction, and effects on water quality under a range of flow conditions, is needed to understand urbanization impacts to the aquifer. Sources of anthropogenic constituents to the aquifer, such as nutrients, pesticides, pharmaceuticals, and other wastewater compounds and the influences of different land-cover types, are largely unknown.
Approach
Seco Creek sinkhole in Medina County provides direct recharge to the Edwards Aquifer.
An approach integrating real-time data logging, discrete sample collection, and automated sampling is being used to obtain water-quality data on major ions, nutrients, organic contaminants, and selected isotopes (hydrogen, oxygen, nitrogen, and strontium) in rainfall, recharging surface water, unconfined groundwater, confined groundwater, and spring discharge.
Continuous surface-water and groundwater measurements
Selected sites will include:
- Precipitation collection sites on the urbanized and rural portion of the Edwards aquifer recharge zone
- Surface water sites, selected to represent urban and rural surface-water runoff
- Groundwater sites with contrasting properties, including urban and rural settings and shallow unconfined and deeper confined groundwater wells
- Comal spring #1 –a major discharge point of the aquifer and integrator of regional aquifer flowpaths
Routine sampling
Routine samples have been collected at regular intervals through multiple years with the objective of covering a range of aquifer flow conditions.
Event-based sampling
Event-based samples have been collected in response to storm events from surface water sites, groundwater sites, and the spring discharge site. Additionally, precipitation samples have been collected and characterized for water quality.
More about other Urban Waters Federal Partnership projects
Urban Waters Federal Partnership Cooperative Matching Funds Projects
The Urban Waters Federal Partnership (UWFP) reconnects urban communities—particularly those that are overburdened or economically distressed—with their waterways by improving coordination among federal agencies.
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Date published: September 23, 2019Status: ActiveUrban Waters Federal Partnership - Edwards Aquifer Recharge in a Developing Landscape
San Antonio Texas consistently ranks as one of the fastest growing large cities in the United States. Urban development can affect groundwater quality as trees and open space are replaced by buildings and roads, increasing the amount of urban runoff draining directly into the Edwards aquifer. A network of sophisticated surface water and groundwater monitoring sites is being used to help...
Contacts: Douglas Schnoebelen -
Date published: February 25, 2019Status: ActiveUrban Waters Federal Partnership - Suspended Sediment and Nutrient Delivery to the Gulf of Mexico
Suspended sediment and nutrients from greater San Antonio can affect instream ecological health of the San Antonio River and ultimately impact Gulf of Mexico bays and estuaries. Real-time monitoring in urban and rural parts of the river basin may provide a glimpse into the importance of urban sediment and nutrient sources. Real-time sensors provide a tool to better understand and manage water...
Contacts: Douglas Schnoebelen -
Date published: May 29, 2018Status: ActiveEdwards Aquifer Recharge Zone Surface-water and Groundwater Interaction
The effects of urbanization across the recharge zone in Bexar County and potential impact on the water quality in the Edwards aquifer is a topic of specific concern for the City of San Antonio. The USGS Texas Water Science Center is simultaneously collecting water-quality data from surface-water runoff sites and paired shallow groundwater wells within the recharge zone of the Edwards aquifer...
Contacts: Stephen Opsahl, MaryLynn Musgrove -
Date published: May 29, 2018Status: ActiveNational Water-Quality Assessment Project in Texas - Surface Water Activities
The USGS National Water-Quality Assessment (NAWQA) Project was established by Congress in 1992 to answer the following question:
What is the status of the Nation’s water quality and is it getting better or worse?
Since 1992, NAWQA has been a primary source of nationally consistent data and information on the quality of the Nation’s streams and groundwater. Data and...
Contacts: Patricia Ging, MaryLynn MusgroveAttribution: Oklahoma-Texas Water Science Center -
Date published: May 29, 2018Status: ActiveEdwards Aquifer Groundwater Model Uncertainty Analysis
USGS Texas Water Science Center (TXWSC) is undertaking a 1.5-year study to assess parameter and predictive uncertainty in the Edwards Aquifer Authority MODFLOW Model using both linear and non-linear techniques. The Edwards Aquifer Authority (EAA) uses two models simulating the periods from 2001 to 2015 (verification model) and the drought of record of 1947-1958 (drought of record model).
Contacts: Linzy Foster, Michael N Fienen
Water-quality observations of the San Antonio segment of the Edwards aquifer, Texas, with an emphasis on processes influencing nutrient and pesticide geochemistry and factors affecting aquifer vulnerability, 2010–16
As questions regarding the influence of increasing urbanization on water quality in the Edwards aquifer are raised, a better understanding of the sources, fate, and transport of compounds of concern in the aquifer—in particular, nutrients and pesticides—is needed to improve water management decision-making capabilities. The U.S. Geological Survey...
Opsahl, Stephen P.; Musgrove, MaryLynn; Mahler, Barbara; Lambert, Rebecca B.
New insights into nitrate dynamics in a karst groundwater system gained from in situ high-frequency optical sensor measurements
Understanding nitrate dynamics in groundwater systems as a function of climatic conditions, especially during contrasting patterns of drought and wet cycles, is limited by a lack of temporal and spatial data. Nitrate sensors have the capability for making accurate, high-frequency measurements of nitrate in situ, but have not yet been evaluated for...
Opsahl, Stephen P.; Musgrove, MaryLynn; Slattery, Richard N. Source, variability, and transformation of nitrate in a regional karst aquifer: Edwards aquifer, central Texas.
Many karst regions are undergoing rapid population growth and expansion of urban land accompanied by increases in wastewater generation and changing patterns of nitrate (NO3−) loading to surface and groundwater. We investigate variability and sources of NO3− in a regional karst aquifer system, the Edwards aquifer of central Texas...
Musgrove, MaryLynn; Opsahl, Stephen P.; Mahler, Barbara; Herrington, Chris; Sample, Thomas; Banta, John
Quality of surface-water runoff in selected streams in the San Antonio segment of the Edwards aquifer recharge zone, Bexar County, Texas, 1997-2012
During 1997–2012, the U.S. Geological Survey, in cooperation with the San Antonio Water System, collected and analyzed water-quality constituents in surface-water runoff from five ephemeral stream sites near San Antonio in northern Bexar County, Texas. The data were collected to assess the quality of surface water that recharges the Edwards...
Opsahl, Stephen P.-
Date published: May 8, 2018Water-Quality Data Characterizing the San Antonio Segment of the Edwards Aquifer With an Emphasis on Processes Influencing Nutrient and Pesticide Concentrations and Factors Affecting Aquifer Vulnerability, 2010-2016
This data release documents water-quality data collected from April 2010 through December 2016 by the U.S. Geological Survey in cooperation with the San Antonio Water System from across the San Antonio segment of the Edwards aquifer with particular emphasis on nutrients and pesticides.
Attribution: Oklahoma-Texas Water Science Center