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2,000 fled as Manteca levees broke along rivers

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POSTED January 6, 2017 12:35 a.m.

Twenty years ago, state emergency officials were bracing for the worse.
A “boil” – so named for water that bubbles up on the wrong side of a levee meaning water is undermining it – broke on the Stanislaus River levee.
Secondary levees south of Woodward Avenue and those at the Mossdale bend on the San Joaquin River showed signs they were nearing failure.
The disaster scenario was quickly drawn up. Failure of the San Joaquin River levee where new boils seemed to be popping up every hour could send water rushing north to Weston Ranch where it would reach the first homes in that south Stockton neighborhood within seven hours.
The same break could inundate nearly a half of Lathrop.
The assessment of the potential damage from the secondary levee south of Woodward Avenue failure was somewhat better. The Office of Emergency Service envisioned a break sending water rushing toward the Highway 120 Bypass that had been designed for conversion into an emergency levee. Once there, it would pour through the McKinley Avenue undercrossing and spread out threatening the Manteca-Lathrop wastewater treatment plant, a large chuck of the Airport Way corridor and could possibly send two to three inches of water into the Sierra High neighborhood.
The orders went out: Plug the McKinley Avenue undercrossing of the Highway 120 Bypass and do the same for the Louise Avenue undercrossing of Interstate 5 in Lathrop. Caltrans crews also would be ready to close the Lathrop Road undercrossing of I-5 at a moment’s notice.

Weston Ranch residents
advised to prepare for
possible evacuation
Meanwhile, Weston Ranch residents were advised to prepare for a possible evacuation. Thousands of families did just that loading up pickup trucks, cars and rental trucks with as much of their personal belongings as possible. For several days, Weston Ranch residents were ready to flee.
Reports on CNN made the situation seem worse than it really was. The news network reported that on the dawn of Jan. 8, Manteca was an isolated community with 40 square miles flooded. Ultimately, upwards of 60 square miles would flood southwest of Manteca and east of Tracy.
That wasn’t exactly the case as commuters inched at 5 mph down the Highway 120 Bypass, to I-5 and Interstate 205 to head toward the Bay Area.
Although it had been three days since the first break occurred on the Stanislaus River levee 12 miles south of Manteca, it wasn’t until Jan. 7 that panic really set-in. Major breaks along the San Joaquin River near Wetherbee Lake and Hays Road turned dozens of square miles into inland lakes. Homes in Wetherbee Lake were under 10 feet of water.
Spreading flood water forced the evacuation of Nile Garden School where the second emergency command center had been set up.
Nearly 2,000 residents fled their rural south Manteca and rural Tracy homes. Dairy farmers either created dikes to turn dairy barns into islands or else they relied on the goodness of fellow dairy farmers from as far away as Fresno who headed to Manteca with empty trailers to help move as many as 15,000 cows. When all was said and done, 60 square miles would be underwater, 800 homes and buildings damaged, and overall losses pegged at $100 million.
FFA students from the three high schools pitched in by using pick-ups to haul out animals and personal belongings.
Telephone circuits went dead due to an overload as darkness started to descent on Manteca-Lathrop.
It was touch and go for 72 hours before thousands of California Conservation Corps workers teamed up with volunteers to sand bag boils – areas oozing mud on the land side of the land side of levees – were able to gain the extra hand.

Heavy snowpack followed
by warm rain caused it all
It had all started in November and December of late 1996. Mother Nature had dumped a near-record 180 percent of snow-fall on the San Joaquin River’s upper watershed by mid-December. The same was true on other rivers feeding into the San Joaquin including the Stanislaus. New Melones was at 95 percent of capacity since it rarely had an early run-off.
Then a series of storms dubbed “The Pacific Express” slammed Northern California on New Year’s Day dumping an inordinate amount of warm rain.
Manteca barely got wet during the storm but events to the southeast and east were set in motion as warm rain started melting snow as high as 8,000 feet that eventually set up a series of 11 down river levee failures that left some rural Manteca homes under water for nearly three months.
The first break accord on Sturgeon Bend on the Stanislaus River just south of the Airport Way bridge near the confluence of the San Joaquin River.
The initial farmland flooded was a freshly planted vineyard when the first levee failed on Jan. 5, 1997 at 1:01 p.m. as the river inched toward a 34-foot crest, some five feet above flood stage.
Crews from the CCC were sand bagging a boil on the bend when the embankment gave way and sent chocolate-colored water racing toward the gap and setting in motion a series of events that led to one levee failure after another.
In the next six days, levees would rupture in 11 places between Caswell State Park south of Manteca and the Wetherbee Lake area southwest of Manteca.
The Jan. 5 break was followed in hours by others that sent water rising toward Deuel Vocational Institute east of Tracy and Two Rivers Road south of Manteca.
The first emergency command center was set up at the Union Road fire station about 1.5 miles south of Nile Garden School.
Wetherbee Lake’s levee failed on Jan. 7 at 2:45 a.m. putting 80 homes in the Islander Mobile Home Park under 10 feet of water. More gaping holes occurred at Hays and Perrin roads. Water surrounded Nile Garden School hours after the campus was evacuated and the emergency command center moved to dry ground at the main Manteca Fire Department station on Powers Avenue.
The river-fed lake was now seven miles long.
Then came Jan. 8 when those manning the secondary levee south of Woodward Avenue and the Mossdale Bend indicated they may be losing ground.
Those levees held although OES officials say Manteca and Lathrop came perilously close to a major disaster.
The levee breaks weren’t over. On Jan. 10, a levee on Paradise Cut broke sending residents on Stewart Tract and nearby farmland fleeing.

To contact Dennis Wyatt, e-nail dwyatt@mantecabulletin.com

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