For example, to do a check and write the same way, ” Morena Dam is located in south-central San Diego County on Cottonwood Creek, a tributary to the Tijuana River. The dam impounds Morena Reservoir, which has a capacity of about 50,694 acre-feet. The dam and reservoir are owned and operated by the City of San Diego (City).
The dam was constructed between 1895 and 1912 with remedial improvements made to the dam and spillway in 1917, 1923, 1930, and 1946. The structure is currently over 110 years old and is considered a historical structur
Based on independent evaluations conducted by DSOD, the deficiencies associated with the dam include the spiand the outlet towers seismic instability. The seismic instability of the outlet tower affects the ability to meet DSOD requirements for lowering the reservoir in the event of a dam safety emergency. DSDO requires that the City submit a plan and schedule to address the spillway and outlet tower deficiencies by September 30, 2023.
Repair/rehabilitation improvements are needed to address identified long-standing dam safety deficiencies at Morena Dam. Thus, the necessity for performance of a comprehensive condition assessment of Morena Dam and its appurtenance structures and development of a comprehensive plan for long-term improvements to the dam to address safety issuesllways insufficient capacity to pass the design storm without overtopping the dam ———write form this information by using your own words : Sutherland Dam is a multiple arch dam with 17 bays located on the Santa Ysabel Creek near Ramona, San Diego County, California. The dam impounds Sutherland Reservoir with an approximate capacity of 29,508.1 acre-feet (AF) based on a 1998 bathymetric survey. The dam was constructed from 1952 to 1954. The spillway crest is approximately 145 feet above streambed level at Elevation 2057 (USGS NGVD29). There is an additional 13 feet of structure from the spillway to the top of the dam, including an additional 4-foot parapet wall for a total dam height of 162 feet above the streambed
The City of San Diego (City) owns and operates the Sutherland Dam and Reservoir that feeds the San
Vicente Reservoir. Water flows out of the Sutherland Dam via the Sutherland Outlet Works, which is
comprised of an upstream trash rack structure (wet side of dam) connected to dual 36-inch intake pipes
connecting to the downstream (dry side) outlet control system. The downstream outlet control system
includes a 20-inch blowoff and Sutherland pipeline that discharges to the San Vicente Creek. See
Figure 1-1 for a general flow schematic of the Sutherland Outlet Works.
For reservoirs that impound over 5,000 acre-feet of water, the outlet system should be capable of
lowering the maximum storage depth by 10 percent within 7 or 10 days and draining its full
contents within 90 or 120 days, respectively, depending on factors such as downstream and
seismic hazard, dam construction methods and age, known deficiencies, and type of dam; as
determined by the Division.
The Sutherland Dam has a capacity of 29,508.1 acre-feet and is subject to DSODs drawdown
requirements. For the purposes of this report, Kleinfelder assessed Sutherland Dams Outlet Works
relative to DSODs more restrictive time frame requirements 10 percent of maximum storage depth in 7
days and draining its full contents in 90 days.
In 2020, the City submitted a drawdown analysis to DSOD for the Sutherland Reservoir. DSOD responded
that the Sutherland Outlet Works is considered to be in substantial compliance with DSODs drawdown
criteria in the interim as an emergency plan for dewatering; however, the City must restore the floating
intake for the Ramona Pipeline, and regularly operate valves included in the Citys drawdown analysis.
The City submitted a letter in December 2022 with a plan and schedule to repair the floating intake for
the Ramona pipeline and a condition assessment of the outlet works. Preliminary recommendations were
to perform a drawdown analysis, dredging to uncover the outlet structure, and geotechnical analysis to
characterize sediment around the outlet works. In March 2023, DSOD determined the proposed plan
and schedule are acceptable. As mentioned in DSODs letter dated March 23, 2021, the Citys interim
emergency drawdown plan to use the City Pipeline as the primary means and the Ramona Pipeline only
in an emergency is acceptable pending all outlet valves associated with the emergency plan are
maintained in a dependable operation condition.