From the mid 1940s to the mid 1960s, the Calhoun Experimental Forest in upstate South Carolina was the site of intensive research by the US Forest Service focused on what we would now term restoration ecology. After the collapse of cotton farming in the Southern Piedmont of the US in the 1930’s, the region including Calhoun was left largely cutover; heavily cultivated, eroded, and gullied; and socioeconomically depressed. Among other work, USFS research focused on restoring forests and other groundcover, mitigating ongoing erosion, and monitoring the effects of their restoration experiments on sediment and hydrologic outputs of headwater watersheds within the experimental forest. Although active research was mothballed by the mid 1960s, they left behind a ~15 year dataset of hydrology and precipitation from the early days of the Calhoun’s forest recovery. The creation of the Calhoun Critical Zone Observatory (CZO) in 2013, provided an opportunity to reinstrument and upinstrument the hydrology monitoring network to align with the transdisciplinary goals of the CZO network. A ~5 year record of streamflow in three watersheds (two adjacent headwaters nested in a larger watershed) is complemented by hydrometeorologic data, shallow and deep groundwater levels, soil moisture time series’, and high resolution LiDAR terrain data. In conjunction with an ongoing, critical zone-focused, satellite site at the Duke Forest in the Piedmont of North Carolina, the Calhoun is elucidating both fundamental hydrologic questions and is well-positioned to inform multi-disciplinary studies via concurrent measurements of everything from deep geochemistry and geophysics to forest ecohydrology.
Mallard, John McDevitt, Margaret A Zimmer, Daniel deB. Richter, Brian L McGlynn (2019): The Calhoun Critical Zone Observatory: historic hydrologic research in a complex socio-environmental context reinvigorated and expanded by critical zone science. American Geophysical Union Fall Meeting, San Francisco, CA, December 9-13, 2019.
This Paper/Book acknowledges NSF CZO grant support.