Mirror Lake, New Hampshire: Watershed Research

Mirror Lake has been the focus of limnological studies since the mid 1960s. Mirror Lake is located within Hubbard Brook Experimental Forest (HBEF), an area selected by the National Science Foundation for Long Term Ecological Research (LTER*). Although some hydrological work was done in support of the earlier studies, extensive hydrologic instrumentation of the lake and its watershed was initiated in 1979 to focus research on the interaction of the lake with atmospheric water, surface water, and ground water. As part of these studies, (1) stream-gaging flumes were constructed on the three streams that flow into the lake and on the stream that flows from the lake, (2) numerous water-table wells and piezometer nests were constructed within the lake's watershed, and (3) climate instruments were placed on a raft and at a land station.

Research at the site has focused on extensive studies of (1) evaporation, including determination of energy budgets and evaluation of commonly used empirical methods for determining evaporation, (2) ground-water interaction with Mirror Lake as well as with each of the streams that enter the lake, (3) hydrochemistry of the Mirror Lake drainage basin, (4) hillslope hydrology of the two largest drainage basins associated with Mirror Lake, (5) evaluation of long-term trends in stream and lake water chemistry, (6) evaluation of the source and flow paths of chloride contamination of Mirror Lake related to highway deicing, and (7) hydrogeochemistry of a ground-water fen wetland downgradient of Mirror Lake.

Because of the extensive instrumentation and understanding of the hydrologic system in the Mirror Lake drainage basin, the site was selected by the USGS Toxic Substances Hydrology Program for research on flow and transport in fractured crystalline rocks. This research on the fractured crystalline bedrock underlying the Mirror Lake drainage basin was initiated in 1990.

* The LTER program was established by the National Science Foundation in 1980 to support research on long-term ecological phenomena in the United States.