||TMDL for Turbidity for Wabbaseka Bayou, AR.
||FTN Associates, Little Rock, AR.; Environmental Protection Agency, Dallas, TX. Region VI.
Water pollution ;
Surface waters ;
Water quality standards ;
US EPA ;
TMDL(Total Maximum Daily Load) ;
Total Maximum Daily Load ;
Clean Water Act
||Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy.
||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 located in the Wabbaseka Bayou watershed in central Arkansas. The study area is part of the Arkansas Department of Environmental Quality (ADEQ) Planning Segment 3A and is located within the Delta ecoregion. The predominant land uses in the study area are cropland (78%) and forest (19%). Wabbaseka Bayou is included on the draft 2004 Arkansas 303(d) list as not supporting the aquatic life use due to exceedances of numeric criteria for turbidity. For this TMDL, Wabbaseka Bayou was considered to be a least-altered stream rather than a channel-altered stream. The applicable numeric criteria for turbidity for least-altered streams in the Delta ecoregion are 45 NTU (primary value) and 84 NTU (storm-flow value). ADEQ historical water quality data were available for one location along Wabbaseka Bayou. 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). The seasonal analysis showed that values of turbidity and TSS tend to be higher in the winter and spring and lower in the late summer and fall. The plots of concentration versus flow showed some correlation, with the high stream flows tending to result in higher TSS and turbidity values. This TMDL was expressed using TSS as a surrogate for turbidity because turbidity cannot be expressed as a mass load. Two regressions between TSS and turbidity were developed using the ADEQ data. Using the base flow regression equation with the turbidity criterion.
||Sponsored by Environmental Protection Agency, Dallas, TX. Region VI.
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|PUB Date Free Form
||6 Jan 2006
||68D; 68G; 48G; 91; 43F