| Roller-Compacted Concrete Projects
Water Resources Home
> Roller Compacted Concrete >
Recent
Projects >Big Cherry Dam
New RCC Dam Replaces 70-Year Old Concrete Dam
Geoffrey L. Cowan, P.E., Dewberry & Davis LLC, Keith A. Ferguson,
P.E., Kleinfelder, Inc., and Fares Y. Abdo, P.E., Portland Cement
Association
 |
| New spillway operating for the first time
in April 2006 |
The Old Big Cherry Dam is a 43-ft (1 3.1-m) high, 225-ft (68.6-m)
long cyclopean concrete dam located in Wise County, Virginia near
the Virginia/Kentucky state line. The dam impounds Big Cherry Reservoir,
the water supply for the Town of Big Stone Gap, Va. The dam which
was constructed in 1935, has been classified as a high hazard impoundment
by the Virginia Department of Conservation and Recreation (VDCR).
Dewberry & Davis LLC (Dewberry) has performed numerous engineering
studies of the dam and reservoir during the past 20 years, including
dam safety inspections, stability analyses, dam break studies, water
supply, and rehabilitation studies. Past studies have determined
that the old dam would be unstable during passage of the Probable
Maximum Flood (PMF), the required spillway design flood. In addition,
the Corps of Engineer's Phase I inspection report found the spillway
capacity to be 20 percent of the required full PMF. Because failure
during the PMF could result in loss of life, the dam had been operating
under a conditional operation and maintenance certificate from VDCR
since the inception of the Virginia Dam Safety Program.
Big Cherry Reservoir provides water supply to the town of Big Stone
Gap water treatment plant. During dry spells, such as the summers
of 1999 and 2002, reservoir levels have fallen to dangerously low
levels prompting the Town to institute conservation measures and
to examine alternatives for increasing the Town's water supply.
Water supplies in neighboring Norton and throughout the region are
also routinely stressed during dry periods, which points to a regional
water supply problem.
Before constructing the new roller-compacted concrete (RCC) dam,
the 4 million gallons (15.1 million liters) per day capacity water
treatment plant produced an average water supply of approximately
1.7 MGD (6.4 MLD) which was very near the safe yield of the old
reservoir. The water treatment plant will be able to safely treat
over 3 MGD (11 MLD) with the new dam and increased reservoir storage
in place.
Preliminary engineering studies were performed by the engineering
team of Dewberry and GEI Consultants in which the following options
for both stabilizing the old dam and increasing reservoir storage
were evaluated:
- Installation of post-tensioned anchors to stabilize the dam
during passage of the PMF
- Construction of an RCC dam overtop of the old concrete dam
- Construction of a new RCC dam just downstream of the old dam
and submerging the old dam
 |
| Big Cherry dams soon after construction of
the new dam. |
It was determined that construction of a new RCC dam downstream
of the old dam and raising the permanent lake elevation 7 ft (2.1
m) to increase water supply was the preferred alternative to stabilizing
and raising the existing dam. The New Big Cherry Dam helps reduce
the region's water supply problem and the Town has negotiated agreements
to sell treated water to neighboring municipalities once the increased
supply becomes available.
For more information about the design and construction of the dam,
highlighting the RCC mix design, cost, and core test results, click
here to download a PDF of the full case study.
|
 |
More on RCC:
Estimating RCC Costs for Dams
Performance
of RCC
Recent Projects
FAQs
RCC
Database
RCC/Soil Cement Contractor Directory
|