Free Parking Coordinates 38 38.006, -121 13.432
TO LOG this cache stand at 38 38.119 -121 13.469 to observe
acceptible answers to the following questions sent in a separate
offline email to us. You MUST ALSO post a photo of yourselves on
YOUR LOG taken somewhere near the site or around the Fish Hatchery
area.
1. Read Plaque and tell us what is distinctive about this
bridge?
2. Judge the river width at this point.
3. Describe the geologic difference between the North and South
banks of the river.
4. What is the use of the derrick like structure a few yards
West?
5. How many operable sections in the structure ¼ mile
East?
6. Post an interesting personal photo taken anywhere near the
site.
The American River Division of the Central Valley Project
provides water for irrigation, municipal and industrial use,
hydroelectric power, and recreation. Flood control is provided
through a system of dams, canals, and power plants. The Folsom Unit
consists of Folsom Dam, Lake, and Power plant; Nimbus Dam and Power
plant; and Lake Natoma, all on the American River.
Nimbus Dam is on the American River in Sacramento County,
California, 7 miles downstream from Folsom Dam. It re-regulates the
releases for power made through the Folsom Power plant. Nimbus Dam
is a concrete gravity dam 1,093 feet long and 87 feet high.
Eighteen radial gates, each 40-feet by 24-feet, control the flows.
The total volume of material used in the dam is 121,100 cubic
yards. Reclamation operates the dam. Nimbus Dam and Power plant was
completed and accepted by the Government in July 1955. Nimbus Dam
forms Lake Natoma, with a capacity of 8,760 acre-feet and a surface
area of 540 acres.
Nimbus Power plant. Constructed and operated by Reclamation, is
located on the right abutment of Nimbus Dam, on the north side of
the river. Its two generators has a combined output of 3,500
kilowatts. It started operating in 1955.
Nimbus Fish Hatchery. Construction of Folsom and Nimbus Dams
blocked access to natural spawning grounds of salmon and steelhead
trout. To compensate for the loss of these spawning areas,
Reclamation constructed a fish hatchery about a quarter of a mile
downstream from Nimbus Dam. The hatchery is on the left bank of the
river, about 0.3 mile below the dam. It is operated by the State of
California with Reclamation funds. Work began on April 20, 1955 and
was finished and accepted on October 17, 1955.
Whether you arrive on four wheels, or follow the American River
Bike Trail on two, a visit to the Nimbus Fish Hatchery should not
be missed. Watching the spawning fish and learning about their
adventures makes learning fun. While there are no formal guided
tours, there's plenty to make a self-guided tour worth your while.
Around the first week of November the salmon make their way up a
''fish ladder'' to lay eggs in the pond at the top. The Hatchery
has a capacity of 30,000,000 eggs. That's a lot of salmon!
American River Bluffs. The Sacramento Valley is a structural trough
occupying approximately the northern third of the Great Valley
Geomorphic Province. The area is near the edge of a structural
trough associated with the bedrock formation of the Sierra Nevada
province. The trough is filled with marine, lacustrine and alluvial
deposits. The American River at Nimbus is composed of variable
topography with up to 150 feet of relief across the river. Along
the north side, the higher elevations consist of the resistant
material (bedrock) that composes the bluffs and slopes along the
American River, while on the south side the lower relief is the
result of a combination of low topographic, erodible material
located within the floodplain of the American River, and of areas
of man-made embankment fills above natural grade. The site is
generally underlain by thin veneer of colluvium derived from the
poorly to semi-consolidated sediments of the Turlock Lake
Formation, over semi-consolidated sediments of the Laguna
Formation. Quaternary and Tertiary-age alluvial deposits are
composed of medium dense to dense silts, sands and gravels. The
Laguna and Turlock Formations unconformably overlay the Mehrten
Formation, and which is exposed in rock cut on the north side of
the American River channel. The Mehrten Formation is composed of
moderately indurate andesitic conglomerates, sandstone and
breccia.
