AN EXPLORATION OF SPRING FLUXES TO CLASSIFY WISCONSIN’S SPRINGS

Data from nearly 400 springs in Wisconsin show that the spring flux, or the ratio of spring discharge to spring area, may be a useful metric to classify and understand springs. The Wisconsin Geological and Natural History Survey is currently conducting a springs inventory in which they are collecting discharge measurements, drafting maps of spring sites, and measuring spring orifice areas. Most springs have discharges less than 100 L/sec and orifice areas less than 100 m². A scatter plot shows that there is no proportional relationship between orifice area and discharge. Large orifice areas do not necessarily correspond to the highest discharges. Bar graphs of the spring flux by source type and orifice geometry reveal that low fluxes are typically the result of more diffuse groundwater discharge, whereas high fluxes are typically the result of more discrete groundwater discharge. The magnitudes of the fluxes also agree with known geological controls on springs throughout the region. This suggests that spring flux may be a meaningful way to categorize springs and distinguish between those dominated by more discrete versus more diffuse groundwater flow.