SS3.09 Climate-Lake Interactions
Date: Wednesday, June 12, 2002
Time: 11:45:00 AM
Location: Colwood
RosenberryDO, U.S. Geological Survey, Lakewood, USA,
Lake stage as an indicator of climate change: ground-water interaction complicates the linkage
Long-term trends in lake stage frequently are linked to climate change. If a lake has no surface-water connection, the stage often reflects the balance between seasonal precipitation and seasonal evaporation. However, fluxes to or from ground water are significant for many lakes and the degree of interaction can vary with climate, and not necessarily in phase with surface-water stage. Although ground water was a small component of the water budget at a pond in the prairie-pothole region of North Dakota, processes related to ground water enhanced pond stage changes in response to decadal-scale climate change. During extreme drought, water-table troughs formed next to the pond, causing flow reversals that accelerated the drying of the pond. During extremely wet periods, the ground-water table rose to near land surface, which enhanced overland flow to the pond. At a pond in Minnesota, ground water interaction minimized stage change during decadal-scale climate change. During extremely high stage, the shoreline moved beyond the low permeability organic deposits; pond water flowed freely into the adjacent porous sand, minimizing the potential for additional rise in pond stage.