C150242 Feasibility Study

• Contract/PO #: C150242
• Contractor Name: Seven Lakes Reservoir Company
• Contract Type: Loan
• Water District: 0
• County: Larimer
• County: Weld
• Loan Projects - Doc Type: Feasibility Study

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The section of canal and natural drainage channel that carries water from the
north end of Lake Loveland to Horseshoe Reservoir is known as Dry Creek and
is approximately 7,512-feet in length. Features along the canal include the
existing 30-foot wide hinged crest gate, the railroad crossing culvert structure
(shown in detail on Sheet 1 of 2 in the Map Pocket), the culvert under Hwy 287,
the culvert under 29th Street and the double arched culverts under the Monroe
Avenue Bridge just upstream from Dry Creek's discharge point at the west edge
of Horseshoe Lake. The railroad crossing culvert structure presently limits the
SLRC and GLlC's ability to start the runoff season with Lake Loveland in a full
condition. Many times the irrigation company has lowered Lake Loveland by
moving water to the lower reservoirs in order to accept spring runoff and found
that the runoff did not occur as anticipated. This leaves the water level in Lake
Loveland lower than desired and results in the need to run pumps out of Boyd
Lake to deliver water that could have been delivered by gravity from Lake
Loveland. With the capacity of the Dry Creek railroad culvert structure matching
the inlet capacity of The Big Barnes Canal, Lake Loveland can start the runoff
season full and can safely pass legally decreed and diverted water on to its lower
elevation reservoirs without unnecessarily lowering the water surface in Lake
Loveland prior to receiving runoff. This will result in resource conservation by
eliminating the need to pump water from Boyd Lake that had in the past been
repositioned from Lake Loveland prior to runoff seasons.

While considering the capacity of the Dry Creek railroad culvert structure, some
discussion should be made regarding the storm capacity of Dry Creek. The
main channel of Dry Creek consists of a sandy clean bottom with steep side,
eroding side slopes. The channel top width varies between 50-feet to 90-feet.
Channel banks vary from 9-feet to 25-feet. The average channel slope is
approximately 10.5 ft.lmile or slightly less than 0.002 ft.lft. Storm flows through
this section of canal (as identified in the Ayers Dry Creek Study) range up to
2,720 cfs during a 100-year storm event with an average depth of 13.6 feet and
average velocity of approximately 2.8 ftIsec. During the 1 OO-year storm event,
the Monroe Avenue Bridge is overtopped by approximately 662 cfs with a

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