First Advisor

Kristofor Voss


Regis College

Degree Name

MS Environmental Biology

Document Type

Thesis - Open Access

Number of Pages

54 pages


Humans risk exposure to microbial pathogens when they use freshwater for recreation or as a drinking water source. In developing nations where monitoring and treatment of microbe-contaminated water is weak or unavailable, 1.8 million humans die each year from waterborne illnesses. In developed nations where public and private utilities treat drinking water, residents still remain vulnerable to these illnesses when they use recreational waters contaminated with sewage or animal feces. To assess whether streams and lakes should be closed to recreation, cities and counties closely monitor likely pathogen presence by testing for the indicator bacterium Escherichia coli (E. coli). Using E. coli concentrations to accurately portray a water body’s contamination status remains a challenge because E. coli dynamics depend on multiple interacting factors including water depth, recreation intensity, light and temperature. To tease apart the relative importance of these factors on E. coli dynamics, I measured E. coli concentrations as part of an observational field study in Denver, CO streams. Not only will this study provide a portrait of citywide compliance with E. coli water quality standards, but it will also recommend improvements to sampling protocols based on the influence of abiotic variables on E.coli population dynamics . By lowering the false positive and false negative rate, these improvements will simultaneously help prevent waterborne illnesses and limit unnecessary closures of Denver’s recreational waters.

Date of Award

Spring 2018

Location (Creation)

Colorado (state); Denver (county); Denver (inhabited place)

Rights Statement

All content in this Collection is owned by and subject to the exclusive control of Regis University and the authors of the materials. It is available only for research purposes and may not be used in violation of copyright laws or for unlawful purposes. The materials may not be downloaded in whole or in part without permission of the copyright holder or as otherwise authorized in the “fair use” standards of the U.S. copyright laws and regulations.