Panola Mountain Research Watershed

Location

The Panola Mountain Research Watershed (PMRW) is located within the Panola Mountain State Conservation Park, about 25 km southeast of Atlanta, Georgia, USA (84°10’W, 33°37’N).

Catchment size

• 41 ha main catchment
• 10 ha sub-catchment located in the western part of the main catchment
• 0.1 ha trenched hillslope

Climate

Humid continental to subtropical.

The mean annual precipitation is ~1240 mm, which on average is distributed uniformly throughout the year. Rainfall typically has a long duration and low intensity associated with the passage of fronts in the winter and a short duration and high intensity associated with convective rainstorms in the summer. Less than 1% of the precipitation falls as snow or sleet. A long growing season, warm temperatures, and many sunny days result in a high evapotranspiration demand, particularly during the summer. Air temperature averages 15.2°C and the average monthly temperatures range from 5.5°C in January to 25.2°C in July.

Geology

The bedrock is predominantly the Panola Granite (granodiorite composition), a biotite–oligioclase– quartz–microcline granite of Mississippian to Pennsylvanian age. The Panola granite contains pods of amphibolitic gneiss, particularly at lower elevations.

Soils are predominantly ultisols developed in colluvium and residuum, which intergrades to inceptisols developed in colluvium, recent alluvium, or in highly eroded landscape positions. Typical soil profiles on the hillslopes are typically <1.6 m thick, grading into saprolite of variable thickness. The riparian zone has the deepest soils (>5 m).

Topography

The basin relief is 56 m and slopes average 18%.

Vegetation/Land use

The watershed contains a naturally regenerated second-growth forest on abandoned agricultural land, typical of the Piedmont physiographic province. The watershed is 90% forested, dominated by hickory, oak, tulip poplar, and loblolly pine, and 10% partially vegetated (lichens and mosses) bedrock outcrops. The forested area varies from 100% deciduous to 100% coniferous.

Context of investigation

The PMRW was established in 1985 as part of the USGS Acid Rain Thrust Program. In 1991, the 41-ha forested watershed became one of five Water, Energy and Biogeochemical Budgets (WEBB) sites focusing research on the movement of water and solutes within a small forested watershed and the effects of anthropogenic and environmental change. The experimental hillslope study site was established in 1995 with the excavation of a 20-m-long trench.

Measurements/Equipment

41 ha main catchment and 10 ha subcatchment:

• Precipitation
• Climate
• Streamflow
• Several transects with recording wells
• Water quality (weekly and event sampling)
• Soil moisture

0.1 ha hillslope study site:

• Lateral subsurface flow (trench)
• Soil moisture
• Groundwater
• Sapflow (Summer of 2002)
• Sprinkling experiments (Summer of 2002 and Fall of 2006)
• Tracer experiments (Summer of 2002 and Fall of 2006)

Links to project webpages

http://ga.water.usgs.gov/projects/panola/

References

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