Hydrologic and water-quality characteristics for Bear Creek near Silver Hill, Arkansas, and selected Buffalo River sites, 1999-2004

Abstract

The purpose of this report is to describe and compare the hydrologic and water-quality characteristics of Bear Creek near Silver Hill, Arkansas, to two sites on the Buffalo River upstream from the confluence of Bear Creek, to a site on Calf Creek, a smaller tributary to the Buffalo River, to selected undeveloped sites across the Nation, and to a developed site in Arkansas. A better understanding of the hydrology and water quality of Bear Creek is of interest to many, including the National Park Service, which administers the Buffalo National River, to evaluate its effects on the hydrology and water quality of the Buffalo River. The streamflow at Bear Creek near Silver Hill varied seasonally and annually from January 1999 to March 2004. The mean annual streamflow at Bear Creek for calendar years 1999 to 2003 was 86.0 cubic feet per second. The highest annual mean streamflow occurred in 2002 (158 cubic feet per second) and the lowest annual mean streamflow occurred in 1999 (56.4 cubic feet per second). The mean annual streamflow for calendar years 1999 to 2003 at the Buffalo River near Boxley and Buffalo River near St. Joe was 102 and 881 cubic feet per second, respectively. Concentrations of nitrogen measured for Bear Creek generally were greater than concentrations measured at the two Buffalo River sites and were similar to concentrations measured at Calf Creek. Concentrations of phosphorus measured at Bear Creek generally were greater than concentrations measured at the two Buffalo River sites and were similar to concentrations measured at Calf Creek. Fecal indicator bacteria concentrations generally were greater at Bear Creek than concentrations measured at the Buffalo River and similar to concentrations at Calf Creek. Bear Creek had significantly greater suspended-sediment concentrations than the Buffalo River near Boxley and the Buffalo River near St. Joe and similar concentrations to Calf Creek. Nutrients, dissolved organic carbon, and suspended-sediment loads at Bear Creek and two Buffalo River sites varied because of differences in land use and contributing drainage area for each site. In general, the Buffalo River near St. Joe had the greatest annual loads of nutrients, dissolved organic carbon, and suspended sediment. The Buffalo River near Boxley had the least annual nutrient and suspended-sediment loads amongthe three sites. Buffalo River near Boxley had lesser annual loads than the other two sites probably because of the higher percentage of forested land in the basin and smaller contributing drainage area. Mean annual nutrient, dissolved organic carbon, and suspended- sediment yields computed for Bear Creek were greater than yields computed for both of the Buffalo River sites. Bear Creek had greater median annual nutrient yields than selected undeveloped basins across the Nation and less median annual nutrient yields than the Illinois River south of Siloam Springs, Arkansas, which is representative of a developed basin. Bear Creek had greater median annual flow-weighted nutrient concentrations than the Buffalo River near St. Joe, the Buffalo River near Boxley, and selected undeveloped sites across the Nation. Bear Creek had less median flow-weighted nutrient concentrations than the Illinois River.