Other Project Number:
7/1/2011 - 6/30/2012
- Maureen Muldoon, UW-Oshkosh
- Susan swanson, Beloit College
Wisconsin’s Driftless Area is home to thousands of springs that help support the region’s world-class trout streams. The relationship of these springs to the groundwater flow system is not well understood. Some springs appear to be supplied by a laterally-extensive perched flow system while other springs appear to be sourced by deeper flow systems. A previous project provided preliminary evidence that two tufa-depositing springs may be supplied by a perched aquifer within the Sinnipee Group. These tufa-depositing springs provide an excellent opportunity to develop a paleoclimatic record for the Driftless Area. The objectives of the project are to gain an understanding of how Sinnipee Group stratigraphy affects flow patterns in the vicinity of the tufa-depositing springs and to use the tufa-depositing springs to understand changes in Holocene climate and the effects that climate change had on groundwater flow. Correlation of detailed outcrop stratigraphy with borehole geophysical and flow logs will provide a better understanding of the flow system that is supplying the tufa-depositing springs. We will assess seasonal variations in tufa deposition by collecting monthly water samples. Continuous records of water levels in the spring pools and of fluid temperature and conductivity will be used to assess seasonal variability in spring discharge. Three existing tufa cores will be used to develop a paleoclimatic record that includes variations in stable isotopes and major and trace element molar ratios. U/Th methods will be used to date the cores. Project results will be of interest to water resources managers trying to assess how climate change might impact the springs of the Driftless Area. Better understanding of past climate variations could help inform groundwater models trying to predict future impacts to the laterally extensive perched flow system in southwestern Wisconsin. The resulting paleoclimatic record will be of interest to climate researchers.