Since the 1940's, hydrologists have used aquifer tests to estimate the hydrogeologic properties near test wells. Results from these tests are recorded in various files, databases, reports and scientific publications. The U.S. Geological Survey (USGS), Lower Mississippi-Gulf Water Science Center (LMG) is aggregating all aquifer test results from Alabama, Arkansas, Louisiana, Mississippi and Tennessee into a single dataset that is publicly available in a machine-readable format. This dataset contains information and results from 2,245 aquifer tests compiled for aquifers located in the LMG-Hydrogeologic Aquifer Test Dataset - December 2020. Descriptive statistics for the December 2020 dataset are presented in Table 1 (below) and in the Summary_Readme.pdf. Additionally, this dataset contains 6 attribute tables (.txt files) with additional information for various fields, a zip file containing the geospatial data, and the companion attribute table as a .txt file. THE LMG-HYDROGEOLOGIC AQUIFER TEST DATASET – DECEMBER 2020 IS AVAILABLE IN TWO FORMATS: 1) a tab delimited text (.txt) UTF-8 file and 2) an ESRI GIS point shapefile. FIELDS INCLUDED IN THE LMG-HYDROGEOLOGIC AQUIFER TEST DATASET – DECEMBER 2020: [a complete list of field names, their definitions and units are listed in the Summary_Readme.pdf file] Location data: USGS site identification number, local identification name, Public Land Survey System number, latitude, longitude, State and county. Well construction data: Construction date, well depth, Diameter of well, diameter of casing, depth to top of opening (screen) interval, depth to bottom of opening interval and length of the open interval. Aquifer data: Local aquifer name and code, national aquifer name and code, top of aquifer (altitude), bottom of aquifer, and thickness of aquifer. Groundwater test data: Test date, yield/discharge, length of time associated with yield, static water-level in feet below land surface, production water-level in feet below land surface associated with yield, drawdown associated with yield. Hydrogeologic data: Specific capacity, transmissivity, horizontal Conductivity, vertical conductivity, permeability and storage coefficient. Ancillary data: Method of test analysis and data source reference. DESCRIPTIONS OF ATTACHED FILES: Summary_Readme.pdf: a Portable Document Format (PDF) file with field names, definitions and units for the aquifer test dataset and the associated attribute tables. This file also contains summary statistics for aquifer test compiled through December 2020. LMG-HydrogeologicAqfrTestDataset_Dec2020.txt: a tab-delimited, UTF-8 text file of the attribute table associated with the LMG-HydrogeologicTestData_Dec2020 geospatial dataset. AtbtTbl_AqfrCd_Readme.txt: an UTF-8 text file containing information from the National Water Information System: Help System web page about USGS groundwater codes. (accessed December 4, 2019 at https://help.waterdata.usgs.gov/codes-and-parameters) AtbtTbl_FipsGeographyCodes.txt: a tab-delimited, UTF-8 text file of FIPS (Federal Information Processing Standards) codes, uniquely identifying States, counties and county equivalents in the United States. Note: to reduce the size of this file, city codes were removed. (accessed January 8, 2020 at https://www.census.gov/geographies/reference-files/2017/demo/popest/2017-fips.html). AtbtTbl_LocalAqfrCodes.txt: a tab-delimited, UTF-8 text file of eight-character string identifying an aquifer. Codes are defined by the "Catalog of Aquifer Names and Geologic Unit Codes used by the USGS. (accessed December 4, 2019 at https://help.waterdata.usgs.gov/aqfr_cd) AtbtTbl_NatAqfrCodes.txt: a tab-delimited, UTF-8 text file of ten-character strings identifying a National aquifer, or principal aquifer of the United States, that are defined as regionally extensive aquifers or aquifer systems that have the potential to be used as a source of potable water. (accessed December 4, 2019 at https://water.usgs.gov/ogw/NatlAqCode-reflist.html) AtbtTbl_TstMthdCodes.txt: a tab-delimited, UTF-8 text file of codes identifying the aquifer test analysis method when reported in the associated reference. AtbtTbl_DataRefNo.txt: a tab-delimited, UTF-8 text file of references for the source of the associated aquifer test result. CAVEAT: Some hydrogeologic test results reported in this dataset have not been through the USGS data review and approval process to receive the Director’s approval. Any such data are considered PROVISIONAL and subject to revision. PROVISIONAL data are released on the condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its use. NOTE: -- If you have data you would like added to this dataset or have found an error, please contact the USGS so we may incorporate them into the next version of the LMG- Hydrogeologic Aquifer Test dataset. Table 1. Summary-descriptive statistics for the LMG-HYDROGEOLOGIC AQUIFER TEST DATASET – December 2020. [USGS, U.S. Geological Survey; NWIS, National Water Information System; n, number of wells] USGS-NWIS NATIONAL STANDARD AQUIFER NAME AND CODE n MAXIMUM MINIMUM MEAN MEDIUM DEVIATION Specific capacity (gallons per minute per foot) All well data 1733 15000 0.0025 84 8.7 552 Alluvial aquifers (N100ALLUVL) 21 723 0.98 57 12 161 Mississippi River Valley alluvial aquifer (N100MSRVVL) 185 10000 0.06 265 72 864 Other aquifers (N9999OTHER) 3 50 1.20 18 2.1 28 Coastal lowlands aquifer system (S100CSLLWD) 913 15000 0.05 93 12 645 Mississippi embayment aquifer system (S100MSEMBM) 429 641 0.01 13 4 44 Southeastern Coastal Plain aquifer system (S100SECSLP) 99 71 0.10 6.2 3.7 8.7 Ozark Plateaus aquifer system (S400OZRKPL) 30 16 0.16 3.6 1.7 4.2 Edwards-Trinity aquifer system (S500EDRTRN) 0 -- -- -- -- -- Unknown National aquifer 53 972 0.0025 59 10 151 Transmissivity (square feet per day) All well data 1549 260678 1.3 12366 5080 20711 Alluvial aquifers (N100ALLUVL) 26 41700 450 9294 8422 8420 Mississippi River Valley alluvial aquifer (N100MSRVVL) 146 171800 236 31934 24431 28074 Other aquifers (N9999OTHER) 4 26000 24 8506 4000 11822 Coastal lowlands aquifer system (S100CSLLWD) 703 260678 1.5 15585 8000 23875 Mississippi embayment aquifer system (S100MSEMBM) 456 36000 1.3 4618 2406 6006 Southeastern Coastal Plain aquifer system (S100SECSLP) 114 80000 5.00 3652 1340 8838 Ozark Plateaus aquifer system (S400OZRKPL) 36 4983 42 1056 534 1262 Edwards-Trinity aquifer system (S500EDRTRN) 1 161 161 161 161 -- Unknown National aquifer 63 84486 5.9 11103 4345 16908 Horizontal hydraulic conductivity (feet per day) All well data 749 1077 0.01 72 50 82 Alluvial aquifers (N100ALLUVL) 6 321 39.88 160 176 106 Mississippi River Valley alluvial aquifer (N100MSRVVL) 46 400 6.88 182 190 134 Other aquifers (N9999OTHER) 4 269 92.00 183 185 95 Coastal lowlands aquifer system (S100CSLLWD) 268 1077 1.00 93 81 85 Mississippi embayment aquifer system (S100MSEMBM) 271 370 0.02 54 43 52 Southeastern Coastal Plain aquifer system (S100SECSLP) 109 230 0.30 31 14 36 Ozark Plateaus aquifer system (S400OZRKPL) 33 1.9 0.01 0.54 0.31 0.58 Edwards-Trinity aquifer system (S500EDRTRN) 0 -- -- -- -- -- Unknown National aquifer 12 267 16.00 104 54 99 Permeability (gallons per day per square feet) All well data 497 8375 0.12 736 400 947 Alluvial aquifers (N100ALLUVL) 12 2400 328 1307 1270 602 Mississippi River Valley alluvial aquifer (N100MSRVVL) 43 7891 110 1926 1785 1174 Other aquifers (N9999OTHER) 0 -- -- -- -- -- Coastal lowlands aquifer system (S100CSLLWD) 263 8375 11 796 636 973 Mississippi embayment aquifer system (S100MSEMBM) 165 1300 0.12 235 177 237 Southeastern Coastal Plain aquifer system (S100SECSLP) 0 -- -- -- -- -- Ozark Plateaus aquifer system (S400OZRKPL) 0 -- -- -- -- -- Edwards-Trinity aquifer system (S500EDRTRN) 0 -- -- -- -- -- Unknown National aquifer 14 4158 201 1390 1204 963 Storage coefficient (dimensionless) All well data 490 1.62 6.30E-10 0.0083 0.00051 0.081 Alluvial aquifers (N100ALLUVL) 21 0.08 0.0002 0.0053 0.00054 0.017 Mississippi River Valley alluvial aquifer (N100MSRVVL) 82 0.09 0.0001 0.0081 0.0013 0.016 Other aquifers (N9999OTHER) 1 0.0006 0.0006 0.0006 0.0006 -- Coastal lowlands aquifer system (S100CSLLWD) 233 0.72 6.30E-10 0.0054 0.0005 0.048 Mississippi embayment aquifer system (S100MSEMBM) 100 1.62 0.000012 0.0180 0.00027 0.16 Southeastern Coastal Plain aquifer system (S100SECSLP) 16 0.006 0.00003 0.0005 0.0002 0.0015 Ozark Plateaus aquifer system (S400OZRKPL) 0 -- -- -- -- -- Edwards-Trinity aquifer system (S500EDRTRN) 0 -- -- -- -- -- Unknown National aquifer 37 0.05 0.000078 0.0062 0.00067 0.014 This dataset was developed as part of the U.S. Geological Survey, Mississippi Alluvial Plain Regional Water-Availability Study.