Lago Dos Bocas at Damsite
View towards downstream
right-side of Lago Dos Bocas Spillway. Photo by
Matthew Larsen, USGS.
Bocas is located in the municipio of Utuado, and was constructed
in 1942 by the Puerto Rico Electric Power Authority (PREPA). The
dam was originally intended as hydroelectricity source.
Lago Dos Bocas has a drainage
area of 170.0 square miles (440.5 square kilometers).
Originally, the reservoir had a water-storage capacity of 30,401
acre-feet (37.5 million cubic meters), but by 1999 the capacity
had been reduced by sediment infilling to 14,625 acre-feet (18.0
million cubic meters).
Real-time Reservoir Level
resevoir level graph updated hourly with the exception of emergency transmissions
which are at 5 minute intervals. To view real-time data, follow the link below.
Dos Bocas at Damsite - 50027100
Arecibo Basin Map
Click on in the basin
map for combined real-time reservoir and rainfall information
During 1995, about 240
million gallons per day (908 million liters per day) of
in-stream fresh water were used to generate around 26 gigawatt-hours
of electricity. An in-stream water use is water that is
used within the stream channel for such purpose as
hydroelectric, power generation, navigation, fish propagation,
Lago Dos Bocas will be an
important source of potable water as part of the Superaqueduct
system. The Superaqueduct system will capture water from
Dos Bocas and Caonillas reservoirs, and transport it eastward
along the northern coast to San Juan area. The pipeline
system is expected to supply 100 million gallons per day (378.5
million liters per day) of water to the San Juan metropolitan
area, and to about fifteen communities along the pipeline
system. The Superaqueduct system will be supplying potable
water to about 1,300,000 people living in the north coast region
of Puerto Rico.
system includes the construction of a 72-inch (1.83 meters)
diameter high- pressure pipeline; a 300-million gallon (1,136
million liter) retention reservoir located between Río Grande
de Arecibo and Río Tanamá; a water filtration plant in Arecibo
that is expected to produce 100 million gallons per day (378.5
million liters per day); two 10-million gallon (37.9 million
liters per day) storage tanks in Arecibo; and two smaller
Geological Survey, in cooperation with PREPA and Puerto Rico Aqueduct
and Sewage Authority (PRASA), has produced a number of reports regarding
effects of sediment infilling on storage capacity of Lago Dos Bocas, including:
L.R., 2001, "Sedimentation survey of Lago Dos
Bocas, Puerto Rico, October 1999": U.S. Geological
Survey Water-Resources Investigations, Report 00-4234, 18 p.,
In addition, the
U.S. Geological Survey, in cooperation with local government
agencies, has produced a number of reports regarding the effects
of sediment infilling on the storage capacity of principle
water-supply reservoirs of Puerto Rico. The results of
these surveys are summarized in "Sedimentation
survey results of the principal water supply reservoirs of
reports can be purchased at a nominal cost by contacting Information Desk at the U.S.
Geological Survey, GSA Center, 651 Federal Drive, Suite 400-15, Guaynabo,
PR 00965, 787-749-4346 ext. 296. Please contact Water-Use Information, 787-749-4346
ext. 259, if you have other questions regarding water supply in Puerto
table below shows the relationship between reservoir level and
available water. This information is presented in graphical format
in the figure above. Note that an acre-foot is a volume of water
that would cover an acre (43,560 square feet) to a depth of 1
Lago Dos Bocas - 50027100
Dos Bocas. Photo by Senén Guzmán, USGS.
Dos Bocas Reservoir after Hurricane Georges. Photo
from USGS archive.