CT2017-3641 Approval Letter

• Contract/PO #: CT2017-3641
• Contractor Name: North Poudre Irrigation Company
• Contract Type: Loan
• Loan Projects - Doc Type: Approval Letter

North Poudre Irrigation Company Agenda Item 28a
March 22-23, 2017 Board Meeting(Updated March 23, 2017)
Page 3 of 6
TABLE 1: IMPACTED WATER RIGHTS
Name Amount Appropriation Adjudication Water Court
Date Date Case No.
344
MOUNTAIN SUPPLY RES 10 acre-feet 5/15/1905 4/22/1922 CA2031
(storage)
Average annual diversions of the entire Company are 88,900 acre-feet.
Project Description
The purpose of the Project is to repair the Mountain Supply Reservoir No. 10 inlet and outlet works,
removing the SEO storage restriction and repairing the reservoir in order to store its full storage rights.
Primary project elements include repair of the intake structure at the Upper 10 ditch, repair or
replacement of the pipeline leading from the ditch to the reservoir, grading across the reservoir,
construction of a new spillway control wall, and repair or replacement of the dam outlet works.
The Feasibility study evaluated alternatives for this project:
Alternate 1 - No Action: This alternate was considered unacceptable, as the Company could not store its
decreed rights, nor provide service to 48 shareholders who collectively own 81 shares of stock that
receive water from Mountain Supply Reservoir No. 10 through the Lower 10 ditch. Approximately 600
acre-feet of water is delivered annually to these shareholders.
Selected Alternate 2 - Repair inlet and outlet infrastructure: This alternate meets the goals of the
project with the following methods:
• Inlet works: Repair 500 feet of 30-inch inlet works conduit by installing cured-in-place pipe
(CIPP) lining from Upper 10 ditch to the reservoir, replacement of the inlet structure, and
construction of a new dissipation structure at the end of the inlet pipeline.
• Reservoir Site: Within reservoir, remove silt and straighten the bottom channel from the
dissipation structure to the outlet works. Construct a new spillway control wall to raise the
reservoir storage level six inches, allowing the Company to fully achieve storage of the decreed
344 acre-feet of storage rights.
• Outlet works: Repair outlet works, including construction of a new inlet gate tower and
walkway, and conduit repair by removing the temporary patch and lining the length of the outlet
conduit using a CIPP liner.
The Company considered alternatives to project elements in the cost analysis:
• An alternative to CIPP lining of the inlet works conduit was considered in the form of removal
and replacement of the existing pipe with concrete-lined steel pipe using open-cut methods.
Although this option was only slightly more expensive than CIPP lining, this option was not
utilized due to probable complications from easement acquisitions and a longer construction
period.
• An alternative to the selected gate tower and walkway would be a gate tower within the dam
embankment and a secondary gate at an inlet structure, with a grade beam supporting the gate
stem and vent extending from the structure to the dam crest. This would only be a viable
alternative if the dam were to be breached. The gate tower with walkway was selected because
the design was successfully used on the Company's nearby and very similar Reservoir No. 9, thus
reducing engineering and design costs.
• An alternative to the CIPP lining of the existing intake structure's existing CMP pipe would be an
open-cut breach of the dam to replace the outlet conduit with a new pipe. This would involve
the removal and replacement of approximately 4,000 cubic yards of dam embankment material,