Modeling Water Table Response to Climate Change in a Norther Minnesota Peatland

McAdams, Toby V.; Brooks, Kenneth N.; Verry, Elon S.; ,

Modeling Water Table Response to Climate Change in a Norther Minnesota Peatland

by Toby V. McAdams, Univ of Minnesota,
Kenneth N. Brooks, Univ of Minnesota,
Elon S. Verry, Univ of Minnesota,

Document Type: Proceeding Paper

Part of: Management of Irrigation and Drainage Systems: Integrated Perspectives

Abstract:

Projections of global warming raise questions concerning the fate of wetlands in many parts of the world. In northern Minnesota, there is concern that the nearly 3 million hectares of peatland could be affected by increases in temperature, increased evapotranspiration, and changes in precipitation. In this study, the Peatland Hydrologic Impact Model (PHIM) was used to simulate the water table and streamflow changes in a small peatland in northern Minnesota associated with possible climatic changes. Projected temperature and precipitation increases output from the Goddard Institute of Space Studies (GISS) global climate model were entered as input to the PHIM model. The results suggests earlier snowmelt and higher initial water tables in the early spring. Water tables dropped 0.5 to 1.5 cm during the growing season. Overwinter water tables remained high. Increased temperature caused precipitation to occur as rain rather than snow. These results suggest that the primary effects on northern peatlands from global warming will be on the winter 'freeze down' period, and spring snowmelt timing, which may have significant downstream effects. Since there is little effect on growing season water tables, no net increase in carbon release to the atmosphere is indicated.

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