Abstract |
Section 303(d) of the Federal Clean Water Act requires states to identify waterbodies that are not meeting water quality standards and to develop total maximum daily pollutant loads for those waterbodies. A total maximum daily load (TMDL) is the amount of a pollutant that a waterbody can assimilate without exceeding the established water quality standards for that pollutant. Through a TMDL, pollutant loads can be allocated to point sources and nonpoint sources discharging to the waterbody. The study area for this project is part of the Poteau River watershed near Fort Smith in western Arkansas. The study area is part of the Arkansas Department of Environmental Quality (ADEQ) Planning Segment 3I and is located within the Arkansas River Valley ecoregion. Land use in the study area is about 49% pasture and 28% forest. Reach 11110105-001 of the Poteau River was included on the draft 2004 Arkansas 303(d) list as not supporting the aquatic life use due to exceedances of numeric criteria for turbidity. The applicable numeric criteria for turbidity for this reach are 21 NTU (primary value) and 40 NTU (storm-flow value). ADEQ historical water quality data were available for one location within the study area. These data were analyzed for long term trends, seasonal patterns, relationships between concentration and stream flow, and relationships between turbidity and total suspended solids (TSS). These analyses showed no significant seasonal pattern or relationship between concentration and stream flow, but higher turbidity levels tended to correspond with higher TSS values. |