BOARD00205

• Board Meeting Date: 3/10/1998
• Description: CF Section - Boulder and Left-Hand Irrigation Company
• Board Meetings - Doc Type: Memo

ROCKV MOUNTAIN CONSULTANTS. INC,

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February 20, 1998

Premiere Building
825 Delaware Ave,. Suite 500
Longmant. CO 80501
[phone]
Metro [phone]
FAX [phone]
E-mail [e-mail]

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Mr, John Brunner
Boulder and Left Hand Ditch Company
7437 95th Street
Longmont, Colorado 80501

Re: Twin lakes Outlet Replacement

Dear John:

To assist the Boulder and Left Hand Ditch Company in its application for a loan from the Colorado
Water Conservation Board (CWCB), we have put together a very preliminary construction cost
estimate for repair of the outlet works. The cost estimate is based on our site visit and discussions
with Ditch Company personnel. We have not surveyed existing conditions, so quantities involved
in this estimate are our best guess.

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For budget purposes, we have assumed that the existing 3Q-inch diameter corrugated metal pipe
will be removed and replaced with 65 lineal feet of concrete encased 3Q-inch diameter ductile iron
pipe. We have further assumed that the existing gate, stem, access bridge, concrete walls, and trash
rack will be replaced with a sloping stem gate. For purposes of this estimate, we have assumed the
dam height is 15 feet and the embankment slope is 3 horizontal to 1 vertical. The components
associated with the sloping stem gate include:

. A concrete beam buried in the embankment to support the stem and stem tube;
. Stem, stem tube, and gate operator;
. Two gates, one affixed to the sloping stem and a smaller gate at the end of the
structure to allow drainage of the lakes;
. Concrete structure to support the gates; and
. Miscellaneous riprap to protect the stem tube.

Also included in the cost estimate is an allowance for earthwork associated with pipe and the
sloping stem gate installation.

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We have estimated a range of construction costs for this work between $25,000 and $30,000.
Table 1 (attached) summarizes the costs. A 25 percent contingency was considered. Engineering
costs have been estimated to be $15,000 for this work as outlined in our December 18, 1997
~hus, total engineering and construction costs are estimated to range from $40,000 to

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It is our understanding that the Ditch Company would like to consider widening the dam crest at
the outlet and installing a vertical stem gate in lieu of the sloping stem gate. This alternative will be
examined and presented to the Ditch Board before we proceed to final design.

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CIVIL AND ENVIRONMENTAL ENGINEERING. PLANNING