Hydrologic and water-quality characteristics for Calf Creek near Silver Hill, Arkansas, and selected Buffalo River sites, 2001-2002

Abstract

The Buffalo River and its tributary, Calf Creek, are in the White River Basin in the Ozark Plateaus physiographic province in north-central Arkansas. A better understanding of the hydrology and water quality of Calf Creek is of interest to many, including the National Park Service, which administers the Buffalo National River, to evaluate its effect on the hydrology and water quality of the Buffalo River. The streamflow and water-quality characteristics of Calf Creek near Silver Hill, Arkansas, were compared to two sites on the Buffalo River upstream (near Boxley, Arkansas) and downstream (near St. Joe, Arkansas) from the confluence of Calf Creek for calendar years 2001 and 2002. Annual and seasonal loads were estimated for Calf Creek for nutrients, dissolved organic carbon, and suspended sediment and compared with loads at sites on the Buffalo River. Flow-weighted concentrations and yields were computed from estimated annual loads for comparison with other developed and undeveloped basins. Streamflow varied annually and seasonally at the three sites. The Buffalo River near St. Joe had the largest annual mean streamflow (805 to 1,360 cubic feet per second for 2001 and 2002) compared to the Buffalo River near Boxley (106 and 152 cubic feet per second for 2001 and 2002) and Calf Creek (39 and 80 cubic feet per second for 2001 and 2002). Concentrations of nutrients, suspended sediment, and fecal indicator bacteria generally were greater in samples from Calf Creek than in samples collected from both Buffalo River sites. Bacteria and suspended-sediment concentrations were greater in samples collected during high-flow events at all three sites. The Buffalo River near Boxley had the lowest concentrations for nutrients, suspended sediment, and fecal indicator bacteria. Estimated annual loads of the nutrients, suspended sediment, and organic carbon for 2001 and 2002 demonstrated substantial variability between the three sites and through time. Estimated loads for nutrients at the Buffalo River near St. Joe were 7 to 27 times the median loads estimated for Calf Creek and suspended sediment loads were as much as 120 times greater. Dissolved organic carbon loads were 16 to 20 times greater at the Buffalo River near St. Joe than for Calf Creek. The Buffalo River near Boxley had the smallest annual loads for all constituents except for suspended sediment, which were slightly greater than suspended sediment loads estimated for Calf Creek. Higher loads would be expected at the Buffalo River near St. Joe because of the larger basin area and larger volume of streamflow. Likewise, estimated loads for all three sites were greater during seasons that had greater streamflow than during seasons with more frequent periods of base-flow conditions. The highest daily loads occurred in the fall and winter of 2001 and the winter and spring of 2002.Flow-weighted concentrations generally were higher for Calf Creek than concentrations for the two sites on the Buffalo River and for typical flow-weighted concentrations found in undeveloped basins. However, the flow-weighted concentrations were lower than concentrations in a developed basin. Annual yields calculated for Calf Creek were higher than the two sites on the Buffalo River and sites that are representative of undeveloped basins but lower than a site representative of a developed basin. The Buffalo River near Boxley had yields that were less than the yields typical of undeveloped basins.