Simulated groundwater residence times in two principal aquifers of the Mississippi embayment physiographic region

Dates

Publication Date: 2020-08-04
Time Period: 2019-01-01

Citation

Haugh, C.J., Knierim, K.J., and Kingsbury, J.A., 2020, Simulated groundwater residence times in two principal aquifers of the Mississippi embayment physiographic region: U.S. Geological Survey data release, https://doi.org/10.5066/P9X513WO.

Summary

Groundwater residence times and flow path lengths were simulated for two major aquifers of the Mississippi embayment region using particle tracking (Pollock, 2012; Starn and Belitz, 2018) in a regional groundwater-flow model (Haugh and others, 2020). The Mississippi embayment physiographic region includes two principal aquifer systems: the surficial aquifer system, which is dominated by the Quaternary Mississippi River Valley alluvial aquifer (MRVA), and the Mississippi embayment aquifer system, which includes deeper Tertiary aquifers and confining units. The groundwater residence time simulation focused on the MRVA and two hydrogeologic units of the Claiborne Group (CLBG) from the deeper system, including the middle Claiborne aquifer [...]

Summary

Groundwater residence times and flow path lengths were simulated for two major aquifers of the Mississippi embayment region using particle tracking (Pollock, 2012; Starn and Belitz, 2018) in a regional groundwater-flow model (Haugh and others, 2020). The Mississippi embayment physiographic region includes two principal aquifer systems: the surficial aquifer system, which is dominated by the Quaternary Mississippi River Valley alluvial aquifer (MRVA), and the Mississippi embayment aquifer system, which includes deeper Tertiary aquifers and confining units. The groundwater residence time simulation focused on the MRVA and two hydrogeologic units of the Claiborne Group (CLBG) from the deeper system, including the middle Claiborne aquifer (MCAQ) and lower Claiborne aquifer (LCAQ). A previously published groundwater flow model of the Mississippi embayment regional aquifer system provided the flow field for this analysis (Clark and Hart, 2009; Clark and others, 2011; and Haugh and others, 2020). Raster files were produced for seven model layers following the hydrogeologic framework for the MODFLOW groundwater-flow model of the Mississippi embayment from Clark and Hart (2009): one for the MRVA and six for the middle and lower Claiborne aquifers including four representing the MCAQ (layers 5 – 8) and two representing the LCAQ (layers 9 and 10). To determine the groundwater residence time, particles were distributed in model layers representing these aquifers using a volume-weighted algorithm then back-tracked until the particles exited the aquifer system, usually at the water-table surface. Particles were tracked under transient hydrologic conditions from March 31, 2014 backwards to January 1, 1870, then under steady-state conditions until they exited the aquifer system. The simulated residence time of each particle is the time the particle took to travel backwards from its initial location in the aquifer to its source of origin. Groundwater-residence time metrics were generated by statistically summarizing individual particles that started within each model cell. The flow-model grid resolution of one square mile was used to simulate groundwater residence times. The data were then resampled to a 1-square kilometer resolution of the National Hydrologic Grid (Clark and others, 2018). Computed metrics included the minimum, mean, maximum, standard deviation, as well as the 10th-, 20th-, 30th-, 40th-, 50th-, 60th-,70th-, 80th-, and 90th-percentiles along with the minimum, median, and maximum flow path length. Additionally, the portion of young groundwater (< 65 years old) and the mean residence time of the young portion were computed.

Contacts

Point of Contact :: Connor J Haugh
Originator :: Connor J Haugh, James A Kingsbury, Katherine J Knierim
Metadata Contact :: Connor J Haugh, Lower Mississippi-Gulf Water Science Center
Publisher :: Connor J Haugh
Distributor :: U.S. Geological Survey - ScienceBase
SDC Data Owner :: Lower Mississippi-Gulf Water Science Center
USGS Mission Area :: Water Resources

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CLBG10.zip		8.73 MB	application/zip
CLBG5.zip		8.4 MB	application/zip
CLBG6.zip		7.53 MB	application/zip
CLBG7.zip		8.18 MB	application/zip
CLBG8.zip		2.37 MB	application/zip
CLBG9.zip		4.73 MB	application/zip
MRVA.zip		4.99 MB	application/zip
Simulated_GW_ResidenceTimes_MRVA-MEAS.xml Original FGDC Metadata	View	42.99 KB	application/fgdc+xml

Related External Resources

Type: ScienceBase Repository

Groundwater withdrawal zones for drinking water from the Mississippi River Valley alluvial aquifer and Mississippi embayment aquifers	https://doi.org/10.5066/P9FZV4ED
Clark, B.R., Barlow, P.M., Peterson, S.M., Hughes, J.D., Reeves, H.W., and Viger, R.J., 2018, National-scale grid to support regional groundwater availability studies and a national hydrogeologic database: U.S. Geological Survey data release, https://doi.org/10.5066/F7P84B24.	https://doi.org/10.5066/F7P84B24

Type: Method

User Guide for MODPATH Version 6—A Particle-Tracking Model for MODFLOW	https://pubs.usgs.gov/tm/6a41/
Regionalization of Groundwater Residence Time Using Metamodeling	https://doi.org/10.1029/2017WR021531

Type: Citation

The Mississippi Embayment Regional Aquifer Study (MERAS): Documentation of a groundwater-flow model constructed to assess water availability in the Mississippi embayment	https://pubs.er.usgs.gov/publication/sir20095172
Clark, B.R., Hart, R.M., and Gurdak, J.J., 2011, Groundwater availability of the Mississippi embayment: U.S. Geological Survey Professional Paper 1785, 62 p.	https://pubs.usgs.gov/pp/1785/
Haugh, C.J., Killian, C.D., and Barlow, J.R.B., 2020, Simulation of water-management scenarios for the Mississippi Delta: U.S. Geological Survey Scientific Investigations Report 2019–5116, 15 p., https://doi.org/10.3133/sir20195116.	https://pubs.er.usgs.gov/publication/sir20195116

Type: Original Metadata

MODFLOW-2005 model used to evaluate water-management scenarios for the Mississippi Delta	https://water.usgs.gov/GIS/metadata/usgswrd/XML/sir2019-5116.xml

Purpose

Raster files of groundwater-age metrics were created from a model simulation designed to estimate groundwater residence times and flow paths as part of the U.S. Geological Survey National Water Quality Assessment project’s intensive principal aquifer analysis of the Mississippi River Valley alluvial aquifer and Mississippi embayment aquifer system. The simulated residence times are intended as approximate and relative estimates of groundwater ages throughout these aquifers, which may inform the understanding of geochemical and water-quality conditions and provide a measure of groundwater vulnerability to possible sources of contamination at the land surface. Statistical summaries of many tracked particles are intended to characterize the variability and uncertainty of residence time at the grid scale of 1 square kilometer.

Simulated groundwater residence times in two principal aquifers of the Mississippi embayment physiographic region

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