A Hydrogeological Study of Coldwater Spring, Minneapolis, MN

Abstract

This project has monitored the water chemistry of Coldwater Spring, Minneapolis, MN to document human impacts on the spring's water quality. Temperature, dissolved oxygen, conductivity, pH and anions were monitored weekly and cations and alkalinity monitored monthly at Coldwater Spring and the adjacent Wetland A from 15 February 2013 through 18 February 2016. Dye was injected into two rain gardens in the Veteran's hospital parking lot, located northwest of Coldwater Spring. Coldwater Spring's water flows through fractures in Platteville Limestone of Ordovician age. The basic chemistry of Coldwater Spring should be the calcium magnesium bicarbonate water typical of carbonate springs. However, on an equivalent basis, Coldwater Spring's water currently contains almost as much sodium as calcium + magnesium and more chloride than bicarbonate.