Estimated Annual Uranium Loads in the Arkansas River Entering Kansas 2012-2016

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Southwest Kansas Groundwater Management District No. 3 (GMD3) requested that the Kansas Geological Survey (KGS) estimate annual uranium loads in the Arkansas River entering Kansas and express the loads in pounds per year. The KGS estimated uranium loads for the last five years (2012-2016). The climatic conditions for these years ranged from drought (2012) to near normal (2013, 2014, and 2016) to slightly wet (2015) based on the 12-month December value of the Standardized Precipitation Index for the Arkansas River watershed in Colorado. Although the estimated uranium concentration for a year with lower flow is generally higher than for a year with greater flow, the relative differences in the average and median flows during 2012-2016 are greater than those for the uranium concentration among the years, thus the flow has a more important influence on the annual load. This suggests that higher flow years in the past, such as during the most recent high-flow period of 1995-2000 when average annual flows exceeded 300 ft3/sec, would have had substantially greater total uranium loads than for 2012-2016. However, some of those loads passed downstream out of the GMD3 area because the Arkansas River flows were great enough during most of 1995-2000 to sustain flow past Ford County. The flows entering Kansas during 2012-2016 remained within GMD3 and seeped into the alluvial and High Plains aquifers underlying the river channel or were diverted for irrigation in Kearny and Finney counties. Thus, the uranium accumulated in the aquifer groundwater, on sediments of the alluvial and High Plains aquifers, and in the soils underlying the ditch irrigated areas and other areas where groundwater used for irrigation has been affected by Arkansas River infiltration.

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  • Report


  • critical issues, database publication, mineral resources, metal, kansas