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Keywords

Water quality standards, public water supply, aquatic life

Abstract

The West Fork of the White River (WFWR) exceeds the water quality standard for turbidity (10 NTU) set by the Arkansas Department of Environmental Quality and, since 1998, the river has been on Arkansas’s 303 (d) list of impaired water bodies unsuitable for aquatic life because of turbidity exceedances. To understand the factors that could be related to turbidity, total suspended solids (TSS), total inorganic suspended solids (TISS), total volatile suspended solids (TVSS), sestonic chlorophyll-a (Chl-a) concentrations, and turbidity were measured on three sample dates from nine sites on the WFWR. As the site location changed in the downstream direction, turbidity values generally increased from less than 5 NTU (nephelometric turbidity units) at upstream sites to greater than 10 NTU on average at the two most downstream sites. A similar trend was observed in TSS, TISS, TVSS and sestonic chlorophyll-a concentrations, and regression analysis showed that TISS and TVSS were significantly related to turbidity across the WFWR. The multiple regression analysis for all collected data showed that TISS alone accounted for 73% of the variation in turbidity values. Where the turbidity exceeded 10 NTU, there were select soil series (Enders-Allegheny complex and Sloan, Razort, Taloka, and Pickwick silt loams) in the riparian zone that were not present in the upstream soils matrix. The reaches of the WFWR which had both elevated turbidity values and the selected soils composed on 6% (2.2 km) of the river length, and suggested that properties of those soil series should be investigated further as a contributing factor to increased turbidity at downstream sites of the WFWR.

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