C150094 Application ‎(2)‎

• Contract/PO #: C150094
• Contractor Name: La Plata Water Conservancy District
• Contract Type: Grant
• County: La Plata
• Loan Projects - Doc Type: Application

Hydraulics &Hydroelectric
Hydraulics issues related to the dam construction will be evaluated. These issues will
include inlet conditions, sizing of outlet works, spillway needs, and conditions in the
receiving channel. Evaluation of each of these issues is intended to identify potential
hydraulics related fatal flaws for the site and will be incorporated into the alternatives
analysis.
In the case of the spillway, the design storm used in the evaluation will be based upon a
classification that is related to the size of reservoir, the height of the dam and the
potential for property damage or loss of life downstream in the event of a failure. The
outlet structure must be sized to draw the reservoir down quickly during an emergency.
Both the spillway and the outlet works must be sized for anticipated flows and provided
with suitable energy dissipation structures at the downgradient outlet. An outlet will
either be placed beneath the embankment or through the right or left abutment.
The feasibility study will also include limited evaluation of the potential for the enlarged
reservoir to be used for hydroelectric generation. The evaluation will focus on financial
feasibility but will also consider feasibility of construction.
Formulation and Evaluation of Alternatives
A. Interpretation of Data
The existing data, the geologic reconnaissance, and the field and laboratory test
results will be analyzed to establish strength, compressibility and permeability
characteristics of the soils and rock which are in situ or proposed as compacted
borrow materials at the dam and reservoir site.
Geologic maps, logs of test borings, laboratory test results and periodic
groundwater readings in the piezometers will be used to develop design
parameters for use in the formulation and evaluation of alternatives for both the
initial and final feasibility phases.
B. Formulation of Alternatives
Tasks:
1. Embankment Section Reservoir Geometry.
This task will consist of evaluating alternative embankment sections,
reservoir geometry and borrow area locations consistent with the existing
topography and engineering and geotechnical findings.
Phase I initial findings will be presented assuming a homogeneous
embankment with a 3:1 upstream slope and a 2.5:1 downstream slope. The
embankment height will be based on an area vs. capacity curve generated
using the new aerial topography information. Phase II efforts will be used
to confirm Phase I findings and further refine embankment section including
delineation of zones and which are compatible with available borrow
materials.
18