BOARD00105 ‎(2)‎

• Board Meeting Date: 1/23/2007
• Description: CF Section - New Project Loans - Seven Lakes Reservoir Co. - Dry Creek Railroad Crossing Rehabilitation
• Board Meetings - Doc Type: Memo

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Seven Lakes Reservoir Company
January 23-24, 2007

Agenda Item ge

Reservoir, providing about 600 AF per year. In an average year, SLRC delivers about 22.5
AF/share, or a total of 9000 AF.

Proiect Description

Four alternatives were developed to meet the project purpose of replacement of the Dry Creek
railroad crossing culvert structure. The alternatives were: .

1. No-action Alternative
2. Tunneling Alternative ($1,420,200)
3. Main Tracks Temporary Relocation Alternative ($1,151,400)
4. New Railroad Bridge Alternative ($850,210)

Alternative 1, No-action alternative - This alternative was not recommended since the
existing restriction causes significant operational problems for both SLRC and GLlC in the
diversion and storage of water. Additionally, the age and condition of the exiting culverts needs
to be addressed to avoid potential safety problems with the railroad operation and avoidance of
loss of flow capacity between Lake Loveland and Horseshoe Reservoir. The no-action
alternative in this case is more costly than appropriate rehabilitation alternatives. The no-action
alternative would result in an inability of the Company to divert water that it is legally entitled to.

Alternative 2, Tunneling Alternative - This alternative involved tunneling through the existing
culvert structure under the railroad. This alternative would require two 120" bores and additional
concrete work for new headwalls, wing walls and miscellaneous demolition of the existing
structure.

Alternative 3, Main Tracks Temporary Relocation Alternative - This alternative to
temporarily relocate the main train track and install new culverts was investigated. This would
involve the temporary construction of 1,300 feet of new track, the construction of 240 feet of
144-inch CMP, demolition of the existing culvert structure and replacement of the train track in
its original position.

Alternative 4, New Railroad Bridge Alternative - This option considers construction of
a new railroad bridge over Dry Creek with appropriate erosion protection, and demolition and
removal of the existing five-barrel culvert structure.

Selected Alternative 4, New Railroad Bridge Alternative - Based on construction cost and
the desires of the SLRC and BNSF, this was the selected alternative. Construction will occur
while the track remains in continuous service. Since trains traveling on this section of tracks
can be expected on a frequency of one about every six hours, close coordination between
personnel building the new bridge and those responsible for scheduling and running the trains is
critical. In discussions with BNSF Railroad personnel, it was determined that bridge support
pilings could be driven during the time intervals when trains are not near the site, and pile caps
could then be installed, rails, ties and ballast can then be removed and the prefabricated bridge
would be installed. The design of the new pre-fabricated railroad bridge would be based on
BNSF Railroad design requirements. All structural plans will need to be reviewed and approved
by BNSF. The primary hydraulic design consideration for the culvert structure replacement is
meeting SLRC flow requirements of 1,000 cfs with Lake Loveland full, and avoiding the creation
of flood and property damage downstream.

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