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• Board Meeting Date: 11/19/2008
• Description: CF Section - Changes to Existing Loans - Bijou Irrigation District - Empire Res. East Embankment Dam Repair
• Board Meetings - Doc Type: Memo

Background

The District owns and operates Empire Reservoir located west of Fort Morgan in Weld and
Morgan Counties, between I 76 on the south and US Highway 34 on the north. The District
provides irrigation water to a 19,200 - acre service area in Morgan County, located between the
reservoir and the City of Fort Morgan. The District is a taxing district that levies a tax per acre
based on benefits received, not an ad valorem property t ax. Water stored in the reservoir is
delivere d to users through a sister company, Bijou Irrigation Company (Company), which
operates and maintains the distribution system, used for either direct ir rigation or exchanges.

Empire Reservoir is an off - stream reservoir const ructed in 1905. The dam is a Class 1 Dam with
a height of 35 feet and a crest width of 16 feet. There are essentially four separate dam
embankments that impound water, they are; t he Outlet D am of 2 , 300 feet , the Northwest Dam of
1,900 feet, the McIntyre Dam of 4,100 feet, and East Dam of 12,500 feet.

, due to the
lack of an emergency spillway . In 2006 the District obtained a CWCB loan to construct a n
emergency spillway, which was completed in spri ng of 2007, and the reservoir was allowed to
fill to it s full gauge height 30.0 . In the fall of 2007, the reservoir was restricted again to gauge
height 29.0 by the SEO, due to additional safety concerns. These concerns were the result of
s ignificant wave erosion occurring along the East Dam , resulting in sections of the existing
parapet wall failing and significant erosion occur ring along the toe of the dam embankment.

Discussion

Due to additional work not budgeted in the original cost estimate, weather conditions, project
location, and unforeseen variations in cost for specific items during construction, the overall cost
of the project has increased significantly.

To address the 2007 restriction, the District hired Applegate Group, Inc. to prepare c onstruction
plans for the rehabilitation of the East Dam. The construction plans were appro ved by the SEO in
December 2007. Given the late December 2007 approval, the District was faced with a difficult
decision of either delaying construction until the f all of 2008 o r placing temporary fill over the
east embankment with SEO approval, therefore allowing the District to fill to gauge height 30.0
and recovering an additional 2,700 acre - feet of storage. Given the economic impact of reducing
the available w ater by 2,700 acre - feet , the District elected to place temporary fill along the east
embankment, with the understanding that this material would have to be removed and placed
again in accordance with the design specifications in the fall of 2008. The cos t of placing the
temporary dam embankment was appr oximately $385,000 or about $ 143 per acre - feet of
reclaimed storage.

design engineer, re - evaluated the initial idea of just
repairing the 1,250 feet of existing con crete parapet wall. The District did not want to get into
another position of having the reservoir restricted due to the failure of any portion of the existing
parapet wall. Given the age and condition of the existing wall, the design engineer could no t
re concrete parapet wall .
o remove the
entire concrete parapet wall and replace it with a sloped rip rap section, consistent with the
configuration of the reconstructed East Dam. The cost of removing the concrete parapet wall
and reconstructing the dam embankment is estimated at $422,000 and is currently under
construction.
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