This report is a study conducted on the Arkansas River Alluvial Aquifer south of Dardenelle, Yell County, Arkansas. The study delineates the groundwater flow characteristics between the river alluvium and the Arkansas River. Data collected from municipal supply wells and U.S.G.S exploration wells was used to construct a MODEFLOW groundwater model. A two-layer model was used for determining the hydraulic conductivity K for both an upper (layer 1) and (layer 2) lower zones within the alluvium. The modeling indicates that there is during periods of pumping groundwater flow is from the river into the alluvium. Water quality analysis also indicates that there is mixing of alluvial and river waters, especially in the areas closest to the river

The publication includes the following plates, tables, and maps:

• Map of Dardanelle area
• Map of area covered in groundwater model
• Model area showing the elevation of the bottom of Layer 2
• Model area showing the elevation of the bottom of Layer 1
• Model area showing the top of Layer 1
• Grain size analysis and hydraulic conductivity based on graphs of analyses
• Grain size distribution curve for sediment taken from 5 ft (1.5m) depth at the Meeks well site
• Table showing Dardanelle Well Production Summary, Year 2000
• Potentiometric surface map generated by steady-state groundwater model layer 2K value 175 ft/d
• Potentiometric surface map generated by steady-state groundwater model layer 1 K value 175 ft/d
• Potentiomertic surface map generated by steady-state groundwater model layer 2 K value 400 ft/d
• Potentiomertic surface map generated by steady-state groundwater model layer 1 K value 400 ft/d
• Maps for comparing model head distribution with water level measurements in wells and the Arkansas River
• Table of water quality data from the Arkansas River, Dardanelle municipal wells, and USGS monitoring wells
• Piper diagram comparing relative concentrations of major ions in waters from the Arkansas River, Dardanelle wells, and U.S.G.S. exploration wells

*Includes: 35 p., 12 figs., 3 tables

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