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• Board Meeting Date: 11/19/2008
• Description: CF Section - Changes to Existing Loans - Bijou Irrigation District - Diversion Structure Rehabilitation
• 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. It provides
irr igation water to a 19,177 - acre service area in Morgan County, located between the reservoir
and the City of Fort Morgan. The District levies an annual assessment per acre based on
benefits received. In addition to the Reservoir, the District owns and operates the diversion
structure/headgate on the South Platte River for the Empire Intake Canal as well as a reservoir
outlet canal. Annual District headgate diversions are 50,970 acre - feet, and delivery from Empire
Reservoir is about 15,900 AF (0.83 AF/a cre).

which consists of a structure with 5 steel radial gates to adjust flows into the Empire Intake
Canal, and 2) the river diversion structure, used to dive rt flow into the ditch intake structure. The
diversion structure had suffered extreme damage in times of high flow in the river. It previously
used a removable board system to control water levels in the river, which had lost its
effectiveness due to lar ge sand build - up on the upstream side. The diversion also had problems
with debris, mainly tree s getting caught in the structure , requiring continual maintenance. The
original intent of this project was to make repairs to the river diversion portion of t he structure
only, by constructing a 100 foot l ong Bladder Gate, located immediately adjacent to the ditch
intake structure.

Discussion

Due to additional work not programmed in the original cost estimate, due to unforeseen site
conditions encountered in the field, the overall cost of the project has increased significantly.

Upon removal of the 100 - foot section of diversion structure located adjacent to the intake
structure it was discovered that the remaining 180 - feet of structure had been severel y
undermined. The extent of the void was unknown and given the cost of replacing the entire
structure , the District first elected to fill the void with concrete. After the placement of 100
cubic yards of concrete and no visible improvement to the probl em, the District realized that full
replacement of the struct ure would be required. The replacement structure consists of 1 00 - feet
of 5 foot high Bladder Gates and 180 feet of concrete rollover dam. Additionally, it was
decided in order to adequately addr ess the sand and debris problem , the intake structure would
need to be reconstructed and realigned. Currently , the structure does not align perpendicular to
the river and creates a sediment trap next to the intake s tructure. Therefore, to allow th e gates in
the river to function as designed, the location and con figuration of the intake need s to be
modified. The new intake structure will be modified to align with the river and the five existing
steel radial gates will be rep laced with two 25 - foot wide Bladder Gates. The total cost for the
improvements des cribed above is $ 1,206 ,760 . These improvements were not included in the
original cost estimate
.

A comparison of the total cost of the project with that originally estimated is summarized bel ow in
Table 1. Nation Engineering , Fort Morgan, Color ado, completed the cost est imate for the p roject in
August of 2007 . The estimated total cost of the project at the t ime of loan approval wa s $720,000 .

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