Springs and sinkholes in the Ozark Plateaus Physiographic Province (Ozarks) in Arkansas were digitized from 1:24,000-scale topographic maps to produce a digital dataset of karst features. Karst landscapes generally are created from bedrock dissolution that results in distinctive landforms, including sinkholes, springs, caves, and sinking streams, and a high degree of interaction between surface water and groundwater. The dataset can be used to better understand groundwater flow in the karst landscape of the Arkansas Ozarks and potential effects of karst-feature density on water quality, geomorphology, water resources, and karst hazards. In the Ozarks, karst features are present in several limestone and dolomite formations (for example, the Boone Formation, Pitkin Limestone, and Powell Dolomite). Springs (points) and sinkholes (polygons and centroid points) were digitized from over 200 topographic quadrangle maps from 22 different counties with published dates ranging from 1942 to 2014. The digitization efforts using the topographic maps resulted in 805 springs and 1,242 sinkholes across the Arkansas Ozarks. This dataset represents the springs and sinkhole centroid points. Topographic maps were the only source of data used to provide a distribution from a single data source over the Ozarks in Arkansas. This karst-feature dataset will be a resource for years to come in karst science, water science, geomorphology, and other fields.

Springs and sinkholes in the Ozark Plateaus Physiographic Province (Ozarks) in Arkansas were digitized from 1:24,000-scale topographic maps to produce a digital dataset of karst features. Karst landscapes generally are created from bedrock dissolution that results in distinctive landforms, including sinkholes, springs, caves, and sinking streams, and a high degree of interaction between surface water and groundwater. The dataset can be used to better understand groundwater flow in the karst landscape of the Arkansas Ozarks and potential effects of karst-feature density on water quality, geomorphology, water resources, and karst hazards. In the Ozarks, karst features are present in several limestone and dolomite formations (for example, the Boone Formation, Pitkin Limestone, and Powell Dolomite). Springs (points) and sinkholes (polygons and centroid points) were digitized from over 200 topographic quadrangle maps from 22 different counties with published dates ranging from 1942 to 2014. The digitization efforts using the topographic maps resulted in 805 springs and 1,242 sinkholes across the Arkansas Ozarks. This dataset represents the sinkhole polygons from the digitization efforts. Topographic maps were the only source of data used to provide a distribution from a single data source over the Ozarks in Arkansas. This karst-feature dataset will be a resource for years to come in karst science, water science, geomorphology, and other fields.

This dataset was compiled to summarize discharge measurements from several published groundwater and surface-water studies in the Ozarks of southern Missouri and northern Arkansas. The discharge measurements were part of numerous USGS studies to assess interaction between streams and groundwater aquifers. A gaining stream is described as a surface-water stream that gains water from the groundwater aquifer and a losing stream is described as a surface-water stream that loses water to the groundwater aquifer. This product is intended to be used in surface-water and groundwater investigations assessing water quantity, quality, and availability. The product includes point data of discharge measurements digitized from previously published USGS studies.

This dataset was compiled to summarize discharge measurements from several published groundwater and surface-water studies in the Ozarks of southern Missouri and northern Arkansas. The discharge measurements were part of numerous USGS studies to assess interaction between streams and groundwater aquifers. A gaining stream is described as a surface-water stream that gains water from the groundwater aquifer and a losing stream is described as a surface-water stream that loses water to the groundwater aquifer. This product is intended to be used in surface-water and groundwater investigations assessing water quantity, quality, and availability. The product includes point data of discharge measurements digitized from previously published USGS studies.

This dataset was compiled to summarize discharge measurements from several published groundwater and surface-water studies in the Ozarks of southern Missouri and northern Arkansas. The discharge measurements were part of numerous USGS studies to assess interaction between streams and groundwater aquifers. A gaining stream is described as a surface-water stream that gains water from the groundwater aquifer and a losing stream is described as a surface-water stream that loses water to the groundwater aquifer. This product is intended to be used in surface-water and groundwater investigations assessing water quantity, quality, and availability. The product includes flow-line data digitized along National Hydrography Dataset (NHD) flow lines and between adjacent discharge measurements (that is, seepage flow-line reaches). The seepage flow-line reaches include a calculation to determine if discharge between the upstream and downstream measurement points is increasing (termed "Gain"), decreasing (termed "Lose"), or remaining neutral if the net change in discharge is not greater than the error (termed "Neutral"). Original seepage-run studies included estimates of discharge measurement error and some studies estimated error along the seepage flow-line reach; however, because of the variety of ways that error was calculated in the original studies and to create a consistent error estimation for the entire spatial dataset, error was assumed to be 10% of the largest discharge measurement along the seepage flow-line reach. Contribution of discharge from tributaries and springs that emerge before flowing into the stream was taken into account, such that the net change in discharge between the upstream and downstream measurement points was calculated as the downstream discharge minus the total discharge from the upstream measurement point and from tributaries/springs. This calculation quantifies the amount of groundwater flow entering the stream as diffuse or point discharge, presumably into the stream bed. The net change in discharge was additionally calculated as the downstream discharge minus the total discharge from both the upstream measurement point and from surface-water tributaries only. This calculation quantifies the amount of groundwater entering the stream as discrete springs adjacent to the stream and diffuse or point groundwater flow directly to the stream bed. A positive net change in discharge results in the seepage flow-line reach gaining discharge (that is, "Gain") and a negative net change in discharge results in the seepage flow-line reach losing discharge (that is, "Lose"). Designations of gaining, losing, or neutral streams may vary between this dataset and the original studies because of differences in how error was calculated and other interpretations made in the seepage-run studies. Users are encouraged to refer to the source reports for further details about data collection methods, results, and interpretations of stream-aquifer dynamics. This spatial dataset is meant to provide a digital compilation of seepage studies in the Ozarks and to create a consistent dataset across studies completed over 24 years.

This dataset was compiled to summarize discharge measurements from several published groundwater and surface-water studies in the Ozarks of southern Missouri and northern Arkansas. The discharge measurements were part of numerous USGS studies to assess interaction between streams and groundwater aquifers. A gaining stream is described as a surface-water stream that gains water from the groundwater aquifer and a losing stream is described as a surface-water stream that loses water to the groundwater aquifer. This product is intended to be used in surface-water and groundwater investigations assessing water quantity, quality, and availability. The product includes flow-line data digitized along National Hydrography Dataset (NHD) flow lines and between adjacent discharge measurements (that is, seepage flow-line reaches). The seepage flow-line reaches include a calculation to determine if discharge between the upstream and downstream measurement points is increasing (termed "Gain"), decreasing (termed "Lose"), or remaining neutral if the net change in discharge is not greater than the error (termed "Neutral"). Original seepage-run studies included estimates of discharge measurement error and some studies estimated error along the seepage flow-line reach; however, because of the variety of ways that error was calculated in the original studies and to create a consistent error estimation for the entire spatial dataset, error was assumed to be 10% of the largest discharge measurement along the seepage flow-line reach. Contribution of discharge from tributaries and springs that emerge before flowing into the stream was taken into account, such that the net change in discharge between the upstream and downstream measurement points was calculated as the downstream discharge minus the total discharge from the upstream measurement point and from tributaries/springs. This calculation quantifies the amount of groundwater flow entering the stream as diffuse or point discharge, presumably into the stream bed. The net change in discharge was additionally calculated as the downstream discharge minus the total discharge from both the upstream measurement point and from surface-water tributaries only. This calculation quantifies the amount of groundwater entering the stream as discrete springs adjacent to the stream and diffuse or point groundwater flow directly to the stream bed. A positive net change in discharge results in the seepage flow-line reach gaining discharge (that is, "Gain") and a negative net change in discharge results in the seepage flow-line reach losing discharge (that is, "Lose"). Designations of gaining, losing, or neutral streams may vary between this dataset and the original studies because of differences in how error was calculated and other interpretations made in the seepage-run studies. Users are encouraged to refer to the source reports for further details about data collection methods, results, and interpretations of stream-aquifer dynamics. This spatial dataset is meant to provide a digital compilation of seepage studies in the Ozarks and to create a consistent dataset across studies completed over 24 years.

This data set represents the extent of the Ozark Plateaus aquifer system in the states of Missouri, Kansas, Oklahoma, Arkansas, and Illinois.

A hydrogeologic framework of the Ozark Plateaus aquifer system was constructed as the base for a groundwater flow model developed as part of the U.S. Geological Survey Water Availability and Use Science Program to aid in the understanding of groundwater availability in select aquifer systems of the United States. The Ozark Plateaus aquifer system study area (hereinafter referred to as the “Ozark system”) is nearly 70,000 square miles and includes parts of Arkansas, Kansas, Missouri, and Oklahoma. A hydrogeologic framework was constructed to represent the altitudes and thicknesses of nine hydrogeologic units within the Ozark Plateaus aquifer system - . the Western Interior Plains confining system, Springfield Plateau aquifer, the Ozark confining unit, Ozark aquifer (divided into the upper, middle, and lower Ozark aquifers to better capture the spatial variation in the hydrologic properties), the St. Francois confining unit, the St. Francois aquifer, and the Basement confining unit. The formations that make up the hydrogeologic units of the Ozark system range from Pennsylvanian to Cambrian age. The scope of effort included the compilation and interpretation of hydrogeologic altitudes from geophysical, lithologic driller description, and well cutting logs. The final compiled dataset included more than 23,000 individual altitude points (excluding synthetic points) representing the nine hydrogeologic units. Shorthand names were used to identify points, extents, and raster surfaces corresponding to each hydrogeologic unit. WIPCS = Western Interior Plains confining system SPA = Springfield Plateau aquifer OCU = Ozark confining unit UOA = upper Ozark aquifer MOA = middle Ozark aquifer LOA = lower Ozark aquifer SFCU = St. Francois confining unit SFA = St. Francois aquifer BCU = basement confining unit

A hydrogeologic framework of the Ozark Plateaus aquifer system was constructed as the base for a groundwater flow model developed as part of the U.S. Geological Survey Water Availability and Use Science Program to aid in the understanding of groundwater availability in select aquifer systems of the United States. The Ozark Plateaus aquifer system study area (hereinafter referred to as the “Ozark system”) is nearly 70,000 square miles and includes parts of Arkansas, Kansas, Missouri, and Oklahoma. A hydrogeologic framework was constructed to represent the altitudes and thicknesses of nine hydrogeologic units within the Ozark Plateaus aquifer system - . the Western Interior Plains confining system, Springfield Plateau aquifer, the Ozark confining unit, Ozark aquifer (divided into the upper, middle, and lower Ozark aquifers to better capture the spatial variation in the hydrologic properties), the St. Francois confining unit, the St. Francois aquifer, and the Basement confining unit. The formations that make up the hydrogeologic units of the Ozark system range from Pennsylvanian to Cambrian age. The scope of effort included the compilation and interpretation of hydrogeologic altitudes from geophysical, lithologic driller description, and well cutting logs. The final compiled dataset included more than 23,000 individual altitude points (excluding synthetic points) representing the nine hydrogeologic units. Shorthand names were used to identify points, extents, and raster surfaces corresponding to each hydrogeologic unit. WIPCS = Western Interior Plains confining system SPA = Springfield Plateau aquifer OCU = Ozark confining unit UOA = upper Ozark aquifer MOA = middle Ozark aquifer LOA = lower Ozark aquifer SFCU = St. Francois confining unit SFA = St. Francois aquifer BCU = basement confining unit

A hydrogeologic framework of the Ozark Plateaus aquifer system was constructed as the base for a groundwater flow model developed as part of the U.S. Geological Survey Water Availability and Use Science Program to aid in the understanding of groundwater availability in select aquifer systems of the United States. The Ozark Plateaus aquifer system study area (hereinafter referred to as the “Ozark system”) is nearly 70,000 square miles and includes parts of Arkansas, Kansas, Missouri, and Oklahoma. A hydrogeologic framework was constructed to represent the altitudes and thicknesses of nine hydrogeologic units within the Ozark Plateaus aquifer system - . the Western Interior Plains confining system, Springfield Plateau aquifer, the Ozark confining unit, Ozark aquifer (divided into the upper, middle, and lower Ozark aquifers to better capture the spatial variation in the hydrologic properties), the St. Francois confining unit, the St. Francois aquifer, and the Basement confining unit. The formations that make up the hydrogeologic units of the Ozark system range from Pennsylvanian to Cambrian age. The scope of effort included the compilation and interpretation of hydrogeologic altitudes from geophysical, lithologic driller description, and well cutting logs. The final compiled dataset included more than 23,000 individual altitude points (excluding synthetic points) representing the nine hydrogeologic units. Shorthand names were used to identify points, extents, and raster surfaces corresponding to each hydrogeologic unit. WIPCS = Western Interior Plains confining system SPA = Springfield Plateau aquifer OCU = Ozark confining unit UOA = upper Ozark aquifer MOA = middle Ozark aquifer LOA = lower Ozark aquifer SFCU = St. Francois confining unit SFA = St. Francois aquifer BCU = basement confining unit