C153642 Contract

• Contract/PO #: C153642
• Contractor Name: Colorado River Water Conservation District
• Contract Type: MOU
• County: Garfield
• Loan Projects - Doc Type: Contract Documents

Scope of Work
Sub-task 4F. Geophysical Survey
Perform and document findings of a mic refraction survey of the area of the
downstream toe. proposed right abutment way crest. and spillway channel of the enlarged
dam.
Sub-task 4G. Surveying
Perform surveying to obtain locations and elevations of dam and appurtenances. spillway
channel features. test holes/pits, and needed supplementary topography with ties to controls
used in and shown on topographic mapping.
Subtask 4H. Elkhead Creek Channel Stability
Estimate the existing bank-full hydraulic capacity of Elkhead Creek between Elkhead
Dam and the Yampa River using mapping of Sub-task 3A, field reconnaissance, and other
existing information. Describe vertical and horizontal stability of existing channel. Describe
potential for downstream channel changes under altered sediment loading conditions both
baseflow and flow conditions of anticipated reservoir operation. In particular, address the
stability of the high bluff downstream of the reservoir on the west bank.
Sub-task 41. Meetings
Prepare for, participate in. and document discussions of necessary TSG meetings to
carry out Task 4 up to a total of 32 man-hours.
Sub-task 4J. Task Memo
Prepare a summary memorandum describing activities and findings of Task 4 for review
by the study TSG.
TASK 5: DAM AND RESERVOIR ENGINEERING
The objective of this task is to develop preliminary and final recommendations regarding
project configuration and construction methods. Optimization of project components, size and
dam type will permit decisions to be made and a single well-defined project to be suggested for
implementation. Information from tasks addressing operations. ecological issues. functional
purpose and need. institutional considerations and other criteria will affect the project
composition. This task will provide the basic information for developing cost estimates and
development schedules in Task 9.
Sub-task 5A. Preliminary Type and Configuration
Enough information exists trom previous studies and the knowledge of site conditions to
conclude that an earthtill embankment is the most suitable structure for this site.
Documentation of this conclusion will be provided with mention being made of other
alternative dam types for comparison purposes. The work in this study will emphasize
earthwork-based alternatives including external geometry, internal geometry, maximum use of
available materials. embankment/spillway configurations. the possible remove and rebuild
option, upstream versus downstream raise. and related physical issues. In the process,