BOARD01808

• Board Meeting Date: 11/19/2001
• Description: CF Section - Lake Henry Reservoir Company
• Board Meetings - Doc Type: Memo

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Lake Henry Reservoir Co.
November 19-20. 2001

Agenda Item 22g,

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Water Riahts
The LHRC owns water storage rights in the Lake Henry Dam Reservoir, as shown in Table 1: It

Table 1: Water storage rights of the Lake Henry Reservoir Company

Priorit Date.
12/31/1891
9/10/1900
5/15/1909

Acre-Feet
6,355
2,000
3,561
11,916

The reservoir has a physical capacity of 9,500 ac-ft and the Company can refill until the above
storage amounts are obtained for the year. Water is delivered to the reservoir through the
Colorado Canal, which has a 756-CFS diversion right. The LHRC has consistently exercised
the Lake Henry storage right, filling the reservoir during the winter and spring and discharging
during the irrigation season. Company records indicate reservoir storage has averaged 4,279
ac-ft for the period January 1954 through December 2000.

Proiect Descriotion
Three alternatives were analyzed in the feasibility study:

1.
2.
3.

No Action
Construction of a toe drain and emergency spillway ($653,000)
Complete dam reconstruction ($3,000,000)

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Alternative 3, Complete dam reconstruction, was ruled out as it would increase the cost of the
project significantly as well as increase the time rEilquired to complete construction, with little
added benefit. Alternative 2, Construction of a toe drain and emergency spillway, consists of
economical construction techniques that are commonly employed to repair seepage and
downstream slope instability. It was the alternativlil with the least overall cost that was a
permanent solution to the problem. This alternative is !considered the preferred alternative. The
no-action alternative was considered unacceptable si6ce it would mean that the reservoir could
not be filled and the water used by the shareholdlilrs.

Selected Alternative 2 consists of construction of a toe drain and toe berm along the base of
the west dam. Drain flow will be directed to a seepage collection basin where flow can be
monitored and recorded. A new emergency spillway, :approximately 400 feet in width, will be
constructed near the right abutment of the east dam to accommodate 50% of the probable
maximum flood flow. .

The implementation schedule calls for completion of financing arrangements in spring 2002.
Final engineering design will be completed by fait 2002. Construction is scheduled to start in
fall-winter 2002-2003 and be completed by fall-winter 2003-2004.

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