PROJ00060

• Contract/PO #: C153721
• Contractor Name: Lyons, Town of
• Contract Type: Loan
• Water District: 5
• County: Boulder
• Bill Number: SB 96-153
• Loan Projects - Doc Type: Feasibility Study

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1. EXECUTIVE SUMMARY

With initial work commencing in December 1994, the water system of the Town of Lyons has
undergone extensive evaluation. Draft reports were circulated in February 1995 and January
1996. The work includes a feasibility analysis for the improvement of a water diversion structure
on North St. Vrain Creek at the point of the current raw water intake.

The components of the system include the raw water supply and water rights, the diversion and
intake, raw water transmission line, the water trt:atment plant, treated water transmission line, the
distribution system and storage, customer metering and system finances. Recommendations were
made concerning current and future facilities, with the exception of the treated water transmission
line which was not analyzed. Current population served is between 1350 and 1400 persons. Future
population is estimated at 2450 in the year 2015 (19 years) and about 3000 at build-out of available
land in the Lyons service area.

The current water demand level consumes approximately 333 aflyr; and approaches 1.2 million
gallons (MG) for the maximum day. The average annual supply is about 681 aflyr ifthe informal
exchange ofC-BT water upstream on North St. Vrain Creek develops the full amount of the current
C-BT inventory. This rough estimate is not to be considered a safe-yield analysis of the Town's
water rights. Future demand, using the above-stated population data is about 2.5 MG max day or
3.85 cfs for 24 hours. This is a annual supply requirement of 713 af. The Town is in the initial
stages of an analysis of water rights and estimation of safe yield of the water supply.

The diversion structure is in very poor condition. Through feasibility analysis, following guidelines
of the Colorado Water Conservation Board, reconstruction of the intake, including diversion dam,
trash screen and presedimention basin is recommended. The estimated project cost is $374,000.

Water is generally of very good quality but episodes of high turbidity occur during spring runoff
and during rain events. These conditions make the water difficult to treat, mainly due to limitations
in the flocculation/clarification process at the water treatment plant (WTP). Improvements in the
presedimentation process and operating conditions at the intake will help. The disinfection process
at the WTP does not meet current state standards; however, the residual effects of chlorine in the
distribution system has been a safeguard in the past. Major capital improvements are estimated at
$350,000. In addition, a Composite Correction Program (CCP) is recommended which will assist

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