HYDROLOGIC MONITORING AND MANAGEMENT OF GROUNDWATER-FED WETLANDS IN THE SOUTHERN APPALACHIANS

The Mountain Bogs National Wildlife Refuge was established in April 2015 to conserve rare wetland habitats in the Southern Appalachians. These wetlands typically occur at the base of slopes, have been impacted by previous land use, and are still vulnerable to the effects of upslope land use. They are fed primarily by groundwater discharge and lose large quantities of water through evapotranspiration (ET). This presentation will describe how monitoring, management, and restoration at three wetlands have been tailored to the hydrologic regime at each site.

Garland Seep can be classified for most of the year as a hypocrene wetland, where groundwater flow doesn’t reach the surface due to low discharge rates and high evapotranspiration. The site has been subject to controlled burns since the early 1900s, however, and the Nature Conservancy has continued the practice to combat woody vegetation and open the canopy. The burns reduce evapotranspiration (at least initially), cause a rapid rise in water levels (up to 0.3m), and have helped maintain a thriving population of federally-endangered green pitcher plants (Sarracenia oreophila).

Butt Pasture was an unsightly, overgrown agricultural field along a railroad track that nonetheless supported a population of the endangered Bunched Arrowhead (Sagittaria fasciculata) in spring-fed ditches. A restoration project in 2015 lowered the overall elevation of the pasture and created a series of channels and swales. New seeps along each of these features provide continuous and consistent water flow, and the bunched arrowhead are thriving.

Finally, Riverbend Bog (actually a fen) features standing water where the water table intersects channels or depressions and a large population of endangered mountain sweet pitcher plants (Sarracenia rubra ssp. Jonesii). It is frequently subjected to large volumes of nutrient-rich stormflow from upgradient residential development and pastureland. In addition to stimulating the growth of invasive and woody vegetation, the stormflow has also led to sediment deposition and/or scouring in various parts of the site. A hydrologic restoration planned for next year will attempt to retain or reroute stormwater, maintain the groundwater-fed features, and ultimately protect the Sarracenia.