CT2015-073 Contract

• Contract/PO #: CT2015-073
• Contractor Name: San Luis Irrigation District
• Contract Type: Grant
• Loan Projects - Doc Type: Contract Documents

The dam safety and operational issues described above combined with the value of the reservoir for
optimizing water use for multiple stakeholders in the basin have driven the District to move
forward with the rehabilitation of the Rio Grande Dam and Reservoir.The District is a proponent of
the Rio Grande Cooperative Project where the District works with multiple stakeholders in the
State,primarily the Colorado Water Conservation Board and the Colorado Division of Parks and
Wildlife to restore the full use of the reservoir. The project is made up of final design,
program/project management and three primary construction components that address structural
and/or operational deficiencies of the Reservoir,as described below:
Final Design
The rehabilitation of Rio Grande Reservoir requires that the proposed improvements be designed,
managed,and inspected by a professional registered engineer in the State of Colorado. The
engineering firm selected to conduct this work will provide overall project management,surveying,
geotechnical exploration,geotechnical and hydraulic analysis,and the final design of the spillway,
clay blanket liner,bypass tunnel and outlet works. The engineering firm will also provide cost
estimating,QA/QC for the project,respond to State Engineer comments and assist will bidding and
award for the project. This work is currently being conducted by SLVID under Contract
C154210 at a cost of$1,256,134,under its sub-consultant-Deer and Ault Consultants.
Program/Project Management
The Rio Grande Cooperative Project involves the coordination and management of many different
project components. Some of key project management issues that need to be addressed prior to
the SLVID proceeding forward with construction,are 1)successful negotiation,feasibility analysis
and exchange of land between the Forest Service and the SLVID, 2)storage accounts and operation
modeling,3)execution of storage agreements,and 4)overall stakeholder coordination and program
management. The successful management of these key issues is vital to the overall success of the
Project.
Primary Construction Components
1.)Upstream Clay Blanket-In order to reduce seepage through the rock slide formation at the left
dam abutment,a clay blanket slope liner will be installed on the upstream side of the dam at the left
abutment.The clay blanket,shown on Figure 1 in plan and Figure 2 in cross-section,will be a
zoned fill placed over the rock slide and extending across the west abutment of the dam
approximately 100 feet.The zones include a filter layer,low permeability clay core,and cover zone.
This improvement is expected to substantially reduce seepage and allow full storage capability of
the reservoir to be achieved. Clay liner materials will be obtained by borrowing and processing
approximately 20,000 cubic yards of soil and rock material from reservoir property.These areas
are described in Figure 1. Processing shall consist of screening various gradations from the existing
landslide deposit,as described in Exhibit 1. The clay liner material for the construction
component described above is currently being conducted under Contract C154213,under its
sub-consultant-Brad Moore,at a cost of$295,699.66.
2.)Low Level Outlet-The existing low level outlet will be replaced with a hollow jet valve
discharge structure at the downstream side of the dam.The existing low level outlet tunnel will
continue to be used to provide conveyance between the upstream and downstream portals.The
existing sluice gate control structure will either be demolished or abandoned in-place with a bypass
tunnel providing conveyance around the structure;this is shown on Figure 1.Schedule constraints
for the work and the uncertainty of the demolition costs (for removal of existing sluice gate control
structure)suggest that the construction bidding process may be the best way to determine the
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