Dry Canyon Dam and Reservoir, Santa Clarita, California
Website created and maintained by Stan Walker
Aerial view of the Dry Canyon Reservoir in 1952 taken by the US Department of Agriculture
Dry Canyon dam is located on Dry Canyon, a southern flowing tributary of Bouquet Canyon, in northeastern Los Angeles County between Haskell Canyon and San Francisquito Canyon. Construction started in December of 1910 and finished in February of 1912 at a cost of about $80,700. The dam and reservoir were, and still are, part of the Los Angeles Aqueduct system. Their purpose was to regulate the flow of water from the irregular flow discharged from the power plants in San Francisquito Canyon. The incoming water from San Francisquito came from Tunnel 77 and the outgoing water went out Tunnel 78. Today, the empty reservoir only provides flood control during storms. It also supports a mature cottonwood woodland environment. The property is still owned by the Los Angeles Department of Water and Power.
The First Annual Aqueduct Report of 1907 reports that a small reservoir would be construction in San Francisquito Canyon to regulate the flow of water leaving the power house. However, by the Third Annual Report, the reservoir was moved to Dry Canyon, east of San Francisquito Canyon. This was probably done because it would be cheaper to buy land and right-of-way in Dry Canyon then in San Francisquito Canyon.
The dam was constructed using the hydraulic fill method. The central part was pumped into position by the hydraulic pumps. The outer toes were progressively filled with earth by wagons. Steam shovels filled the wagons. See the Final Report in the Annual Reports page for a complete description of the building of the dam. Also, see Lee (1972 - see sources) for more construction information. The original height was 61 feet, but it was later heightened to 66 feet. It is 780 feet in length at an elevation of 1455 feet. The reservoir held about 1,100 acre-feet of water with a surface area of 58 acres. It is owned by the city of Los Angeles.
On October 2, 1913, the first water from the aqueduct reached the reservoir. It took 1 1/2 hours to reach the reservoir from the Owen's Valley.
In 1933, the height of the dam was increased by the Los Angeles Department of Water and Power, increasing the overall storage capacity. This was done to provide more flexibility in the operation of the San Francisquito power plants.
From the 32rd Annual Report of the Board of Water and Power Commissioners of the City of Los Angeles, 1932/1933, Department of Water and Power:
"Plans for increasing the capacity of the Dry Canyon Reservoir and enlargement of the spillway were approved by the State Engineer on November 22, 1932. Construction work was started in December, 1932 and completed in May, 1933.
On January 4, 1934, the Bakersfield Californian reported that the Los Angeles Water Bureau had denied reports that the aqueduct was broken. They said that valves in the Dry Canyon reservoir were opened for the purpose of cleansing water in storage there. Airplane pilots, flying over the reservoir, saw water streaming from the dam, leading to the erroneous report that the aqueduct was broken.
The improvement consisted of raising the height of the dam from Elevation 1510 to Elevation 1514, giving an additional capacity of the reservoir of 144 acre feet.
The spillway lip was raised from Elevation 1504.3 to Elevation 1506.9. The effective width of the spillway is 70 feet and has a capacity of 3390 second feet with high water at Elevation 1512.02 or 2.8 below the top of the parapet wall.
The additional fill in the dam was 24,250 cu. yds. and other improvements consisted of concrete parapet wall, repairs and extension of concrete facing on the dam and construction of a new road around the reservoir."
In 1941, a new outlet structure was constructed at the dam replacing the original floating weir. The old structure restricted the quantity of water which could be withdrawn from the reservoir.
Silting problems were reported in 1947.
The dam was established as a weather station on July 1, 1948.
The July 21, 1952, Kern County earthquake (7.6 - 7.7 magnatude) caused significant cracking and settlement to the dam, which was located 46 miles from the epicenter. From Hemborg (1955):
"The earthquake damage to this dam consisted of several continuous cracks parallel to the axis along the entire crest and located approximately 5 feet from the downstream edge of crest. These cracks had a maximum opening of 1 1/2 inches and were found to extend down into the hydraulic fill core. Result of check surveys of the dam showed a horizontal displacement of 0.21 foot towards the reservoir and settlement of 0.18 foot."
In response to the quake damage and recognizing its inherant weakness to quakes, the LADWP built a massive, nearly 80 feet high, buttress downstream from the dam (Babbitt, 1993). Also, a thick cap of compacted earth was added to the crest and downstream face of the dam (Keightley, 1963). In the years since the reservoir was drained, the area below the dam saw a massive build-up of homes and the buttress was removed. Dry Canyon creek was converted to a concrete enclosed culvert that drains south parallel to Seco Canyon Road.
In 1955, a mile of 9.5-foot concrete lined tunnel was started as a bypass to the Dry Canyon Reservoir. This was done to alleviate storm water loads at the reservoir. Estimated cost was $1.5 million.
In 1956-57, a new inlet control structure and a 9-foot butterfly valve was installed. The valve would control the flow of water into the reservoir, totally bypassing it if necessary. This might occur when the reservoir became muddied by storm water runoff. Bypassing the the reservoir would result in cleaner water delivered to Los Angeles.
The Second Los Angeles Aqueduct also made use of Dry Canyon. A 210 foot pipe span between Tunnel No. 2 and Tunnel No. 3 of the Saugus Pipeline Part I section of the aqueduct was laid in upper Dry Canyon in February and March of 1966. 2860 foot long Tunnel No. 2 sloped downhill toward Dry Canyon and 2730 foot long Tunnel No. 3 sloped uphill to the next canyon (Pettinger). Among other advantages, this would allow ground water in the tunnels to drain into Dry Canyon. The pipe was 96 3/4 inches in diameter and was placed on two piers above the creek bed.
Part of the original plans for the Second Aqueduct were also to build a new Upper Dry Canyon reservoir as a pump-storage facility and make it the starting point of the Saugus pipeline. The reservoir would be positioned at a point higher than the Drinkwater Reservoir, the current starting point of the Saugus Pipeline. This would have made it easier for pushing the water southward and allow the pipe to be reduced in size and length, decreasing the cost. However, the additional costs involved proved to be more than the estimated benefits, so the plan was scrapped.
Also in 1966, the reservoir was drained. Studies were done to determine the feasibility of a partial or complete reconstruction of the dam and reservoir (Lee, 1972) along with a seismic evaluation (Taylor, 1998). The reservoir taken out of commission and never filled again, although it was nearly rebuilt in 1971.
In 1969, DWP financial statements budgeted about $810,000 for the reconstruction of the reservoir. And in 1970, the budget for the fiscal year for the City of Los Angeles included $814,000 for reconstruction of the reservoir. By 1971, the work was scheduled to begin in the spring and the project would cost $5,300,000. It would include storm drain water control facilities and rebuilding of the dam. A contract was advertised and bids were received but the project was cancelled before an award was made due to the February, 1971, Sylmar earthquake. Other quake related projects were required. The reservoir reconstruction project was never revived.
There was no significant damage to the dam from the February, 9, 1971, 6.6 Sylmar earthquake probably because the reservoir had been drained in 1966. However, there was damage to the aqueduct system (especially the Lower Van Norman Dam in the San Fernando Valley) that required the flow of water to be stopped. This was done at the Fairmont Reservoir (located west of Lancaster in the Antelope Valley). Personnel at the Dry Canyon Reservoir were instructed to trap the remaining water flow in transit from Fairmont and discharge it through the dam's blowoff valves.
I have found no mention of damage to the dam from the Northridge quake of 1994, but by then the dam and reservoir had been virtually out of service for nearly 30 years.
On February 26, 2001, the Santa Monica Mountains Conservancy adapted resolution No. 01-39 authorizing them to exercise the first right of refusal on the Dry Canyon Reservoir property owned by, and declared excess by, the City of Los Angeles Department of Water and Power. The first right of refusal is a contractual right that gives the SMMC the option to buy the property from the LADWP before the LADWP sells it to someone else.
Today, the reservoir acts more like a nature preserve, sort of like the Chatsworth Reservoir in the San Fernando Valley. The aquaduct now passed through the east end of the reservoir property south on its way to Elsmere Canyon and the Cascades. At the north end of the reservoir, some water from the aqueduct overflows slightly into the reservoir. It may be possible to divert the water from the aqueduct into the reservoir in case of some emergency, but this is only a guess.
Dry Canyon Dam is in the red ellipse. The reservoir is the green area above it. Seco Canyon Road is the blue line and its northern end points to the dam (from google maps).
This cross section of the dam shows the original dam (1912) and the part that was added in 1953 in response to the 1952 earthquake (from Keightly, 1963). You can also see the original cross section on Plate 18 on the Annual Reports page.
Keightley did some vibration tests on the dam in 1963 for his CIT thesis. Here are the "shaking machines" from the above diagram.
Here is another cross section of the dam (from Lee, 1972)
Some of the 1952 earthquake damage (from Lee, 1972)
Water starting to flow to the reservoir. From the Los Angeles Herald of September 27, 1913
Water reaches the reservoir. From the Oakland Tribune of October 3, 1913
From the Municipal Journal of October 23, 1913
Drivers encouraged to drive to the reservoir. From the Los Angeles Herald of October 11, 1913
Drivers reach the reservoir. Driving into any reservoir would obviously not be allowed today. From the Los Angeles Herald of October 25, 1913
From the Bakersfield Californian of January 4, 1934
This map is from 1968. It shows the routes of both the first aqueduct and the second aqueduct (still under construction then - completed in 1970).
Legend: A = Owens River, B = Independence, C = Mt. Whitney, D = Second LA aqueduct intakes, E = Tehachapi, F = San Francisquito Power Plant No. 2, G = Dry Canyon Reservoir, H = Cascades, I = Susana Trunk Line, J = Tujunga trunk line, K = Cascades, L = San Fransciquito Power Plant No. 1, M = Bouquet Reservoir, N = power plant, O = Waiweee Reservoir, P = Owens Dry Lake, Q = Lone Pine, R = First LA aqueduct intakes.