TID hopes to prolong spillway releases; Tuolumne River over flood stage

The Tuolumne River in Modesto, struck by a surge of water from the Don Pedro Reservoir’s spillway, rose above the flood stage Tuesday, though it did not result in major flooding.

The situation remained precarious, with a full reservoir and swollen rivers downstream. The Turlock Irrigation District is trying to get approval for a plan to lower the reservoir to a more manageable level in the next week.

At a briefing Tuesday afternoon, officials said TID has submitted a plan to the U.S. Army Corps of Engineers to maintain releases from Don Pedro at 16,000 to 17,000 cubic feet per second for eight or nine days to reduce the reservoir to 815 feet. The dam’s maximum level is 830 feet.

That would keep the Tuolumne River in Modesto around 59 feet and maintain the threat of flooding. By lowering the reservoir, however, the district hopes to keep from using the spillway multiple times in the next couple of months, said Jason Hicks, incident commander for TID, which operates the reservoir under guidelines from the Corps of Engineers.

Hick said the success of the plan depends on the weather cooperating. So far, the Corps of Engineers has been receptive to the proposal, Hicks said. No rain is in the forecast until a chance of showers Saturday night and showers Sunday.

Agencies in Stanislaus County remained on alert for flooding and possible evacuations.

The TID decided Monday night to reduce the flow from the Don Pedro floodgate to 16,000 cubic feet per second, down from the initial 18,000 cfs when the controlled spillway was activated Monday afternoon for the first time since the 1997 floods. The spillway releases are expected to continue at least until Friday afternoon and possibly until next week if the Corps of Engineers approves.

TID spokesman Calvin Curtin said the heavy storm Monday skirted around the river canyons east of Don Pedro, which feed into the reservoir, so the storm did not impact the reservoir as much as anticipated.

TID was glad it was able to reduce the flow, Curtin said. “For folks still impacted, it will help some but not all,” he said. The district expects the controlled spillway will remain open at least until Friday afternoon and perhaps longer if the Corps of Engineers approves.

Don Pedro’s level crept up to 828 1/2 feet as of Tuesday at 11 a.m., not far from the maximum 830-foot mark. The Tuolumne River in Modesto was flowing at 13,735 cfs at 2 p.m. Tuesday, pushing the river level to 57 1/2 feet, or 2 1/2 feet above flood stage. The river is projected to crest at 59.2 feet and 16,328 cfs at 9 p.m. Wednesday.

The rising water prompted the city of Modesto to advise homeless people camping near the Tuolumne to relocate. The city said the homeless were welcome at Modesto Gospel Mission, at 1400 Yosemite Blvd; the Salvation Army Berberian Shelter, 320 Ninth St. in Modesto; and a shelter at the Stanislaus County Fairground, 900 N. Broadway, in Turlock.

Floodwater was impacting areas of Modesto, including the airport neighborhood, mobile home parks in south Modesto, and Kewin Park on Dry Creek in the La Loma area.

On Tuesday, nine people had taken refuge in the American Red Cross shelter at the Turlock fairground, most of them from flooded areas near Newman and Patterson.

“We are getting a lot of calls today for information regarding the center,” said Nancy Reeves, shelter manager for the Red Cross. “We don’t know how many may show up.”

Because of the releases from Don Pedro, the TID disconnected 975 customers and electrical hookups near the Tuolumne River for safety reasons. Hicks said personnel were surveying properties to determine where they could safely restore power. Hicks said power had been restored for about a dozen customers and the process will continue.

Modesto officials huddled Tuesday morning to consider whether flood issues could affect the city wastewater plant on Sutter Avenue.

“Right now, we think we’re in good shape and we’re watching conditions closely and are in frequent contact with OES and Don Pedro,” said Tom Sinclair, regulatory compliance manager for Modesto.

A small stream and urban flood warning from the National Weather Service will remain in effect for Stanislaus and San Joaquin counties until Thursday.

Road closures remained in effect, including the Waterford-Hickman Road bridge; Shiloh Road between Grayson Road and Paradise Road; Grayson Road from Cox Road to Shiloh; and River Road from Hills Ferry Road to Villa Manucha Road.

The plan for keeping the Don Pedro spillway open would most likely keep the Waterford-Hickman bridge off limits for a week or more.

County Public Works Director Matt Machado said the span built in the 1960s is not designed for high river flows. “We really can’t risk having people use the bridge,” Machado said. “If it’s not designed for it, there is a lot of risk involved if people use it.”

Machado said the county will open the bridge to traffic when the river flow is less than 15,000 cfs.

Pat Bates of Hickman said she worries that emergency vehicles can’t use the bridge and have to take a much longer route to respond to emergencies. She said her husband has a heart defibrillator and is on oxygen. He goes to Memorial Medical Center in Modesto in an emergency.

In San Joaquin County, crews worked through Monday night and Tuesday morning shoring up a San Joaquin River levee near Manteca. The Department of Water Resources were evaluating the levee to determine if an evacuation order affecting 500 residents and 300 homes could be changed. On Tuesday afternoon, the evacuation area was reduced to south of Woodward Avenue, west of Airport Way and north of Airport Court.

When the levee started to breach Monday afternoon, farmers responded with tractors to prevent a full rupture of the levee, said Jenny Rich, a public information officer for the San Joaquin County Office of Emergency Services.

The San Joaquin River is at dangerously high levels southwest of Manteca, between Highway 120 and the Airport Way bridge, where numerous levees broke in 1997, inundating homes and forcing evacuations.

Since the reservoirs upstream are full, San Joaquin County officials are worried the river will remain swollen for weeks and weaken the levees. “They have not seen this much water in such a long period of time,” Rich said. “We will have more storms and there’s a heavy (Sierra) snowpack above the reservoirs.”

This story was originally published February 21, 2017 at 6:32 PM with the headline "TID hopes to prolong spillway releases; Tuolumne River over flood stage."