C150308 feas study

• Contract/PO #: C150308
• Contractor Name: Parkville Water District
• Contract Type: Loan
• County: Lake
• Loan Projects - Doc Type: Feasibility Study

1.0 INTRODUCTION — BACKGROUND
1.1. PURPOSE
The Parkville Water District hereinafter referred to as "the DistricY' provides a municipal
water supply for the town of Leadville and surrounding developments in unincorporated
areas of Lake County, Colorado.
The purpose of this report is to present the results of our analysis of alternatives for
implementation of repairs to the District's Canterbury Tunnel water supply. The
Canterbury Tunnel has provided a critical source of water supply for the District over the
past 45 years. The Tunnel originally served as a mine drainage tunnel and because of
its good water quality and reliable yield of approximately 625 gallons per minute (gpm) it
was converted to a water supply source. As an important added benefit, the
temperature of the water in the tunnel was warmer than typical groundwater, which
greatly reduced the problem of wintertime freeze ups in the District's high altitude
distribution system.
Within the last 10 to 15 years, the District has encountered a gradual reduction in the
overall flow rate from the Canterbury Tunnel and large turbidity spikes have occurred
with increasing frequency at the portal of the tunnel. By the summer of 2003 the flow
rate was less than 200 gpm and the water quality was consistently unreliable, leading
the District to indefinitely discontinue the use of the supply. It is suspected that a portion
of the tunnel structure has deteriorated near its outlet, resulting in a diminished flow rate
and water quality problems. Without the Canterbury Tunnel supply, the District has
experienced an increasing number of freezing and water supply problems. During the
period from December 2009 through March 2010, over 200 service taps and at least five
service mains have frozen. Over 100 customers are currently running water on a
constant basis to prevent a frozen tap, putting the District at risk of failing to meet its
water supply demands. If repairs are not implemented to the Canterbury supply, it is
expected that the District will experience similar or more severe problems in the future.
At the request of the District, W. W. Wheeler and Associates, Inc. has prepared a
Feasibility Study to evaluate alternatives for dealing with the failing water supply, and to
__J W. W. Wheel�r ond Assoclates, Ine 5/19/2010 Final
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