Horsetooth Reservoir Water-Quality Modeling Study

Horsetooth Reservoir is a terminal, off-stream storage reservoir for the Colorado-Big Thompson 
(C-BT) Project.  The reservoir is located in Larimer County, west of the City of Fort Collins.  
Horsetooth Reservoir serves as a resource for public water supply, agricultural water supply, 
industrial water supply, and recreation.  Water-quality concerns in the reservoir include 
metalimnetic and hypolimnetic low dissolved oxygen, as well as elevated levels of manganese and 
total organic carbon.  Development of a water-quality model was commissioned to improve 
understanding of water-quality dynamics in the reservoir, and to provide a tool for use in 
simulation of any proposed future modifications to operations or inflow water quality.  A 
two-dimensional hydrodynamic and water-quality model was developed using CE-QUAL-W2 version 
3.6.   This presentation will provide an overview of the steps taken in model development and 
testing.  Findings from that effort and potential future applications will also be discussed.
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Christine Hawley:   
B.S.  Environmental Engineering (Michigan Tech University, 1994)
M.S. Environmental Engineering (CU Boulder, 1996, – with Joe Ryan)

Christine is an Environmental Engineer with 18 years of experience, specializing in management of 
large, multi-component projects that include field investigations, data analysis, and system 
conceptualization. She has a passion for understanding natural system behavior through data 
analysis. She has worked with international and local teams of experts on high-profile projects 
evaluating contaminant transport in groundwater, surface water, transition zone water, and 
sediment. Ms. Hawley is currently working on watershed investigations, water-quality modeling, 
expert witness analyses, and serving as a technical advisor.