C150094 Contract

• Contract/PO #: C150094
• Contractor Name: La Plata Water Conservancy District
• Contract Type: Grant
• Water District: 0
• County: La Plata
• Bill Number: HB02-1152
• Loan Projects - Doc Type: Contract Documents

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Exhibit A
Grant for Proposed Feasibility Study of Long Hollow Reservoir and Red Mesa Reservoir Enlargement

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4. Spillway and Outlet Alternatives.

Spillway and outlet alternatives will be evaluated based on the geology
and geotechnical engineering characteristics of the site, the condition and
configuration of the existing outlet works, and the ability to release water
from the reservoir as required by the regulations otthe State Engineer's
Office (SEO).

We anticipate that two spillway options and outlet options will be
evaluated. The alternatives analysis will focus on the most cost-effective
and technically feasible alignments.

5. Embankment Section, Internal Drains, and Riprap.

Alternative embankment sections will be developed based upon the
availability of borrow material. Alternatives will be evaluated for the
embankment cross sections using earth fill, rock fill and possibly roller-
compacted concrete. The embankments will be designed with internal
drainage features to control the phreatic surface in the embankment and
prevent piping of fine-grained soils through the embankment or
foundation soils by seepage forces. Riprap will be provided for slope
protection and potentially as a lining in the spillway and energy
dissipation structures.

Embankment sections will be developed to provide adequate stability for
steady-state, rapid draw down and pseudostatic earthquake loading
conditions. Embankment slopes will be determined based upon published
literature. Formal stability analysis using a limit equilibrium computer
program will be conducted during final design. -

Alternatives will be evaluated using "Factors for Planning Studies" in
Appendix B of the CWCB guideli~s. Quantities will be estimated and
unit costs will be developed to provide costs of each alternative. This
information will be combined with data on the project yields,
environmental impacts, financing, regulatory requirements, and any
special technical problems to evaluate the alternatives.

Study Report(s)

A study report or reports will be prepared summarizing the findings for items I through 9
shown on Table 2. The final report will also present an updated outline for a water
management plan on the La Plata River, and an evalua1ion of the need for a hydrologic
model(s) of the La Plata River. The fieldwork discussed herein and the study report
preparation will be conducted under the supervision of a registered professional engineer.

Estimated Costs

A breakdo'wn of all estimated costs by major category associated with work for the Red
Mesa Ward Reservoir enlargement is included in Table 1. A comprehensive breakdown
of the costs associated with each work task is included in Table 2. Total estimated costs
for work at the Red Mesa Ward Reservoir are $ I 3 5, I 14.

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