Exploring Temperature Variation in Wisconsin Springs
Sophie Glaubius ’21, Wisner, Nebraska
Variation in groundwater temperature can affect the health of spring dependent ecosystems. This study aims to examine relationships between the shape of a spring source, where groundwater emerges, and the variation in water temperature across a spring pool. Seepage filtration springs and fracture springs are two types of springs. Seepage filtration springs feature groundwater emerging from many small locations in a spring pool. Fracture springs are where groundwater emerges from a crack in the bedrock.
Ten springs were included in the study. Five seepage filtration springs are located in Dane County, Wisconsin, and five fracture springs are located in Wisconsin’s unglaciated Driftless Area. Air temperature, water depth, spring discharge, and source area were recorded at each site. Dividing spring discharge by spring source area gives a spring flux value, which distinguishes highly focused spring flow from diffuse spring flow. Seepage filtration springs typically exhibit low spring flux values, and fracture springs have high spring flux values. Low spring flux is expected to correspond to a larger range of temperatures and high spring flux values are expected to correspond to a smaller range of temperatures in the spring pool. Thermal cameras can capture infrared images of the spring pool surface temperature. Temperature values were converted from each pixel of the thermal images to quantify spatial distribution. Histograms and summary statistics provide a visual and quantitative measure of the range of temperature values present in each spring. They reveal that seepage filtration springs generally have more spatial variation of temperature than fracture springs. Most of the seepage filtration histograms showed bimodal or multimodal distributions. Fracture springs generally have lower interquartile ranges and most histograms were unimodal. Generally, springs with lower spring flux values have a larger distribution of temperature across the spring pool and springs with higher spring fluxes have smaller distribution. This means that spring flux can be a useful indicator of temperature variation in springs.