## 2 Methods  
This study was conducted on Turkey Creek, a 2 nd-order stream in central Louisiana, USA (latitude 32\({}^{\circ}\)6\({}^{\prime}\)26.46\" N, longitude 92\({}^{\circ}\)27\({}^{\prime}\)35.20\" W), that drains an area of approximately 3400 ha within the Flat Creek watershed (Figure 1). The area has a flat topography with a slope gradient \(<0.5\%\), and the stream has organic-rich substrates. Land use is mainly forestry (61% of the total watershed area) and rangeland (21%) in the Flat Creek Watershed. Forest type is a mix of hardwood and evergreen, with loblolly pines (_Pinus taeda_) comprising the majority of the evergreens. The region is characterized by a warm, humid, subtropical climate, with an annual mean temperature of 18.2 \({}^{\circ}\)C (ranging from 8.0 \({}^{\circ}\)C in January to 27.4 \({}^{\circ}\)C in July) and an annual mean precipitation of 1508 mm (ranging from 91 mm in September to 158 mm in December) (data from 1971 to 2000; obtained from the National Climatic Data Center's Winnfield 2W Coop Station, located 23 km southwest of the study area). As part of a related hydrological study in the Flat Creek watershed, [PERSON] [34] estimated annual evapotranspiration to be around 80%-90% of annual precipitation. Two YSI 6920 V2 water quality monitoring probes (Yellow Springs Instruments, Yellow Springs, OH, USA) were deployed in June 2006 at an upstream and a downstream location (N1 and N2, respectively), approximately 500 m apart along Turkey Creek, to record stream DO concentrations, temperature, and depth at 15-min intervals. The elevations of N1 and N2 were 43.8 m and 42.6 m, respectively, creating a gradient of about 0.2%. The drainage areas of N1 and N2 were 33.8 km\({}^{2}\) and 34.2 km\({}^{2}\). Mean wetted widths (and standard deviations) of the stream were 3.3 \(\pm\) 0.6 m at N1, 4.4 \(\pm\) 2.2 m at N2, and mean depths were between 0.5 \(\pm\) 0.2 m and 0.6 \(\pm\) 0.2 m at both sites. Stream data were continuously recorded until September 2010, during which time monthly site visits were made for probe calibration and cleaning. Monthly water samples were taken at both sites for field turbidity measurements (Turbidimeter 2100Q, Hach Company, Loveland, CO, USA) and analyzed for concentration of total suspended solids (TSS) at the Louisiana State University Agriculture Chemistry Laboratory. A HOBO weather station (Onset Computer Corporation, Bourne, MA, USA) was installed in the watershed (Figure 1) to record continuous meteorological data including rainfall and air temperature at 15-min intervals. A 45 ha commercial tract of loblolly pines was clear cut harvested in late summer-early fall of 2007 between the N1 and N2 sites. All of Louisiana's current timber harvest BMPs [30] were implemented for the harvest, including maintaining streamside management zones (SMZs) with a basal area of 11.4 m\({}^{2}\) ha\({}^{-1}\) along perennial  
Figure 1: Geographical location of the Flat Creek watershed in Winn Parish, Louisiana, USA, and the study sites (labeled N1 and N2). A closer image of N1 and N2 is also shown (taken from Google Map), with the sites above (N1) and below (N2) the harvested pine stand (outlined in black). Also pictured is the weather station (WS). stream channels (keeping a minimum of 15.2 m distance from the stream, as per BMP guidelines for perennial streams \(<\)6.1 m wetted width), minimizing stream crossings, limiting equipment within SMZs, constructing water bars and lateral ditches, reconstructing haul roads, restoring stream crossings, and removing slash and logging debris from stream channels. To prevent damage caused by the timber harvest from occurring to the water quality probes, they were removed from 15 September to 17 October 2007. As part of related research [35], post-harvest canopy cover (%) was measured using a convex densiometer at eight random points between 8 and 150 m upstream of N1, and also at eight random points between 8 and 150 m upstream of N2.