Orange County Branch Newsletter

August 2012

History and Heritage

Back to the Sixties Again


By Carl Nelson

In the mid-sixties I was assigned the role of lead engineer for production of the Orange County Flood Control District's (OCFCD) comprehensive report entitled “A Survey of Flood Control and Water Conservation deficiencies in Orange County, California.”  The report was completed in 1964 and fellow contributors to the report included Al Nestlinger, Don Talley, Bob Rende, Jim Brennan, and the late Fred Singer.  Orange County’s population had surged to more than 1 million residents.

The Orange County Flood Control District (OCFCD) was completing their backbone network of earthen flood channels authorized by the successful $43 million countywide bond election of 1956.  Many of the new channels followed or improved upon existing natural watercourses across Orange County.  Prior to the approval of the bond, the merged alluvial plain of the San Gabriel and Santa Ana Rivers provided little or no incised flow patterns.  Infrequent major floods would follow the sandy washes of Brea Creek, Fullerton Creek, Carbon Creek, Moody Creek, and the agricultural drainage ditches of the area as sheet flow through the incorporated cities of  Buena Park, Anaheim, Garden Grove, Stanton, Westminster, Fountain Valley and Huntington Beach, rather than in defined watercourses.  The excavation of bond issue flood channels required acquisition of relatively flat, otherwise developable land, at costs greater than estimated by the bond report engineers.  Growth of OCFCD’s property tax revenue from new subdivisions was used to supplement the shortage of bond funds.  With the availability of new outlets for underground storm drains, private land development accelerated.  However, increasing urban runoff proved more damaging to the earthen channels than anticipated.

The 1964 deficiency report mapped a system of flood control dams, basins, channels and storm drains that would be needed for future buildout of the county’s remaining undeveloped land.  The report estimated a total cost of  more than $300 million for 700 individual project improvements.  Interestingly, I could not convince Chief Engineer Osborne to call the report a “Master Plan of Flood Control and Drainage,” perhaps because the financing was not the sole responsibility of OCFCD.  Another issue was awareness of cost escalation with time.  At the time it was known that there was no immediate need for all of the project, and changing conditions might render some of the work unnecessary or impracticable.  Further, similar with the 1956 bond issue, many of the facilities could be staged with interim improvements, leaving final improvement to sometime later.  Also, it was not expected that any one agency or organization would be responsible for financing, construction, and operation of the facilities proposed.

The known agencies available for funding the work were described as follows:

  • Federal Government; if the project was found by the Army Corps of Engineers analysis to have a favorable benefit/cost ratio, funding was authorized by Congress, and construction funds were appropriated.  Upon authorization, the local sponsoring agency had to enter into an agreement for cost-sharing.  Ironically, at the time of the deficiency report no one realized that the 1941 Prado Dam project would later be found deficient in capacity for national hydrologic goals.  Eventually, after lengthy studies, the Congress in 1988 authorized the $1+ billion Santa Ana River Mainstem Project including reconstruction of Prado Dam, Seven Oaks Dam and other Santa Ana River elements.
  • State Government; in 1945 a California Water Code amendment authorized assistance to local sponsors for costs of lands, easements, and right of way for federally funded projects.  This assistance was subject to annual budget appropriations by the legislature, a budgetary factor now affecting cash flow for completion of the Mainstem Project.
  • Local Government; incorporated cities and the unincorporated county government were empowered to construct flood control and drainage facilities using property taxes or the sale of various assessment district bonds.  Also, a provision of the subdivision map act afforded municipalities the power to adopt Local Drainage Master Plans by which subdividers would be required to contribute fees for construction of flood control and drainage facilities.  Alternatively the municipalities also have authority to require (at subdividers sole expense) the construction of  flood control and drainage facilities where necessary to protect future residents from flooding.  Since the 1970s this has been the primary methodology providing flood-safe developments for the cities and county of Orange.
  • OCFCD; The boundaries of OCFCD are the same as the external boundaries of the county, thus including all of the cities and the unincorporated areas.  The district, prior to Proposition 13 in 1978, was empowered to levy an ad valorem property tax not to exceed 20 cents per $100 assessed value.  Since 1978, the district’s annual property tax revenue is based on a small proration of the county’s Proposition 13 limit on revenue ($1 per $100 AV).  From it’s 1927 founding, the district has been empowered to issue bonds for construction only after approval of at least two thirds of the votes cast in countywide election.  The two bond elections in 1966 & 1967 failed to receive 2/3rds voter  approval.  The 1956 (forty year term) bond funds were long ago expended, and paid off.  Now 34 years after Proposition 13, inflation, property value escalation, and changed allocation formulas make it difficult to describe OCFCD revenue in simple terms.

Responding to the deficiency report, and request of the Board of Supervisors, the Army Corps of Engineers commenced review of earlier reports on the Santa Ana River (and Orange County).  The Corps review work was accelerated by the floods of January and February 1969.  Extremely intense and cumulative rainfall in the San Bernardino and Santa Ana Mountains resulted in flood releases from Prado Dam that were damaging to unprotected downstream locations.  Prado Dam experienced the highest peak flow and cumulative volume since completion in 1941.  The lower Santa Ana River levees threatened to breakout across Fountain Valley and Huntington Beach.  The volume of January runoff from Santa Ana Mountains filled Santiago Reservoir (a water supply reservoir) to spillway level.  Hence, the February storm passed unretarded through Santiago to Villa Park Dam (OCFCD’s 1956 Bond Project).  By February 25, 1969, the Villa Park reservoir spillway was overtopped with an estimated flow rate of 4,500 cubic feet per second (CFS) to lower Santiago Creek through Orange and Santa Ana.  Hart Park in Orange remained relatively unscathed, even though Santiago Creek peak flow overtopped the masonry walls of (1930s WPA Project).  Previously it had been presumed the lower natural watercourse could withstand the Villa Park Dam's gated discharge rate (3,500 CFS).  Although OCFCD’s flood hazard reports advised against unprotected development, numerous residential structures along the unimproved portions of the creek were badly damaged.

Realizing the weakness in the lower Santa Ana River levees, OCFCD dedicated most of the early 1970s revenue to concrete lining of the sand bottom channel from Coast Highway to 17th Street in Santa Ana.  From I-5 Freeway to Weir Canyon Road in Anaheim several drop structures were constructed to reduce velocity and enhance groundwater replenishment.  The sand bottom channel sideslopes were revetted with quarry rock.

The federal Survey Report for Santa Ana River was completed in 1975 under supervision of  Los Angeles District Commander, Col. Jack Foley (now in retirement and currently Chairman of the Metropolitan Water district’s Board of Directors).  The Survey Report revealed that, contrary to the 1964 assumptions, Prado Dam was incapable of controlling a future 100 year storm.

Preliminary design studies led to Congressional authorization of the Santa Ana River Mainstem Project.  Federal appropriations commenced in 1989 for a $1.4 Billion project that would include the now completed Seven Oaks Dam  (at the foot of  San Bernardino Mountains), reconstruction of lower Santa Ana River within Orange County,  increased height and storage capacity for  Prado Dam (nearly completed), and Santiago Creek improvements (not yet started).

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