CHARACTERIZING HYDROGEOLOGICAL CONDITIONS IN ADVANCE OF ECOSYSTEM RESTORATION IN THE MANISTEE NATIONAL FOREST, MICHIGAN

Field-based characterization of hydrogeological conditions at an ecosystem restoration site in the Manistee National Forest, Michigan provides baseline data in advance of prescribed forest canopy reduction. The Pines Point study area was historically a natural savanna that currently includes plantation pine forests created during depression era efforts of the Civilian Conservation Corps, and oak forests resulting from fire suppression efforts during the 1900’s. The forest service will reduce canopy cover on nearly 3000 acres of red pine and oak forest to restore savannah habitat, in part to re-establish appropriate habitat for the endangered Karner Blue Butterfly. We hypothesize that this forest cover reduction will generate an increase in groundwater recharge and a resultant increase in discharge to the adjacent White River. Three drilled groundwater-monitoring wells equipped with transducers and data loggers were installed in the upland restoration site between the North and South branches of the White River. Pre-restoration monitoring sites include red pine plantation, oak, and pine/oak transition forests, all of which overlie a permeable sand and gravel aquifer that discharges directly to the adjacent White River. Groundwater fluctuations and seasonal water table response vary across the Pines Point restoration site. Initial hydrograph records show variable groundwater level fluctuations and growing season declines at all sites. The depth to water table ranges from 10 to 18m, and all sites display responses to precipitation events. Between May and August 2010, water-table declines ranged from 0.12m at PPW3 and 0.05m at PPW2. Sediment samples from the screened intervals, recovered during drilling, are variably sorted, dominantly quartz sands. Continuing and future work includes sedimentological analyses of drilling samples, further hydrographic analyses of water-table behavior, and potential installation of on-site meteorological instrumentation and additional wells to further quantify hypothesized changes to groundwater levels.