Foothills Sentry October 2020

Foothills Sentry Page 20 October 2020 Family. Friends. Community. We’re all in this together. State Farm, Bloomington, IL 1801073 Ron Esparza, Agent Insurance Lic#: 0C79663 827 S. Tustin Ave Orange, CA 92866 Bus: 714-505-3400 ron@ronesparza.com Heart of Shadowland Residential Care Facility for The Elderly Administrators & Licensee Facility #306001441 Karen Fields & Jan Soule’ (714) 710-9020 (714) 724-5186 klsfields@yahoo.com Modjeska Canyon 28342 Shadowland, Silverado, CA 92676 1. Reinvest in another 6%WFS alternative 2. Invest elsewhere 6% Alternative 36-Month Term • $50,000 Minimum Investment • 3-Year Commitment • 6% Per Year Return (Paid Monthly) • Security: Secured Promissory Note • Exit Strategy: After 3 years, when your money is liquid, you will have the option to: RETIREMENT I WEALTH MANAGEMENT Since 1968 12419 Lewis Street, Suite 101 Garden Grove, CA 92840 714-705-1900 www.wilson-financial.com Santiago Creek safety valve should not be overlooked By Douglas Westfall, National Historian The watershed of the Santiago Creek encompasses over 100 square miles of the Santa Ana Mountains and has 10 major trib- utaries throughout its course. The creek is harnessed by two upstream dams, but is still sub- ject to periodic flooding. Until recently, there was an additional safety valve, an open flood plane bordering Santiago Canyon Road and Cannon Street. For years, that property was a sand and gravel mine, some 500 feet across and one mile long. Undeveloped, it gave Santiago Creek a place to spread out and slow down when it overflowed its banks. Now it is piled high with con- struction waste that would effec- tively block any overflow from the creek. Without that buffer, a raging Santiago Creek would threaten Villa Park and Orange. The last catastrophic Santiago Creek flood was in 1969. What are the chances it could happen again? There are three factors to consider: rainfall, heavy rain fre- quency and water storage. Over the last 140 years, the av- erage rainfall in Orange County has been 14½ inches. Since then, every quarter-century shows av- erages of 14 to 16 inches, and the area has cracked 30 inches of sea- sonal rainfall five times since re- cord-taking began. The last time was in the 2004-05 season, when we received 31 inches of rain be- tween November and February. We’ve had 125 percent above average rainfall, 40 times in the 140 years with an average span of just three years in between. Dur- ing the flood of 1969, we had 16 to 27 inches for three years — all back-to-back. Through our recent drought starting in 2012, we had four con- secutive years ranging from 5 to 9 inches ending in 2015 — all back-to-back again, and all way below average. Yet in the fifth year ending with 2016, we hit almost 21 inches, then had two low years of 4 inches each but re- bounded the next year with near 21 inches again. The Santiago Reservoir, known as Irvine Lake, is often full. The dam, opened in 1931, is compact- ed earth with a rock fill. It holds up to 38,800 acre-feet of water, or more than 12 billion gallons. This represents two-thirds of the watershed — with but one foot of rain. The Villa Park Dam is usually kept low to allow a back-up sys- tem for the Irvine Lake. It holds 15,600 acre-feet, or 40 percent of the total volume of Irvine Lake. Together, the dams are there to contain 84 square miles of runoff. At even one-foot depth of wa- ter, that represents nearly 54,000 acre-feet — or exactly what the two reservoirs hold together. When the two reservoirs over- flowed in 1969, they could not contain the 84 square miles of water surface — which was far above the one foot level. The sand and gravel mine site helped con- tain the Santiago water flow by allowing the creek to spread out. And there is one more thing. There is a 1¼-mile-long earth- quake fault directly under the Santiago earth-filled dam. No one could have known it was there when the dam was constructed, and for over 40 years, it went undetected. If a large earthquake should ever happen in the area — especially in winter — all 12 billion gallons of Irvine Lake will immediately fill the Villa Park Reservoir. The remaining 60 per- cent of that water will bypass the former floodplain relief valve and flood Orange Park Acres, Villa Park and Orange until it reaches the SantaAna River. If the rainfall is that heavy, the Santa Ana River will already be overflowing. Santiago Creek is a great re- source to the northern Orange County area, in the way of pres- ervation, recreation and history. Yet it can be a raging torrent, tak- ing out roads, homes and bridges. We should really consider just staying out of its way. A FEMA map shows the flood plain (blue and red stripes) where Santiago Creek overruns its banks. A torrent of Santiago Creek floodwater took out a road in 1969. An earthquake fault, discovered in 1973, runs directly beneath the earthen Santiago Dam. Creek flood waters invade Hart Park. Douglas Westfall has authored numerous books on Orange his- tory. His latest, Santiago Creek, is available at specialbooks.com