|Scott Spivey’s home on Lancaster Road in the Lakeside Heights subdivision in north Lakeport, Calif., was one of the first homes to be destroyed by a landslide. Picture taken on Saturday, May 11, 2013, by Elizabeth Larson.|
LAKEPORT, Calif. – On Tuesday morning the Board of Supervisors received an update from county staff and fielded questions from a resident of the Lakeside Heights subdivision on the work to find the cause of a landslide that has destroyed several homes and damaged county utility infrastructure.
For nearly two months, the north Lakeport subdivision of 29 homes has been the site of a landslide that has led to numerous seven red-tagged homes and voluntary evacuation notices for about 10 other homes, according to residents. However, the precise cause of the ground movement remains at issue.
Staff from several county departments were on hand to give the board an update on the situation, from studies and monitoring currently under way to safety measures for residents.
Special Districts Administrator Mark Dellinger, who oversees the county’s sewer and water facilities, said a geotechnical report and a second leak report are being finished.
A leak detection test performed last Thursday found two leaks, one on the north end of Lancaster Road, the other at the west end near Oxford Drive. “Those were repaired within 24 hours,” said Dellinger.
A March 25 leak test hadn’t found any issues with the county system but suggested a homeowners association irrigation pipe may have been at fault. Dellinger said the two companies that performed the tests are now reviewing each others’ works based on the differences in their findings.
Dellinger had received board approval to do the second test because of continued ground movement.
A design for a longterm sewer bypass has been completed, but Dellinger said no further work will be done until the county knows if it will receive state funding for a recommended supplemental geotechnical report.
A compound water meter was installed on Monday to help compare the amount of water that goes into the subdivision in the main line and how much is being used by individual homes, Dellinger said. That meter will be monitored daily to determine if new leaks are forming in the system.
The county also is moving a sewer bypass to discharge onto Downing Drive because a sewer manhole was compromised, he said. “That is an indication that the land is still moving.”
Dellinger said he and his staff are working with state officials to fulfill additional information requests necessary to be considered for state funding.
Supervisor Anthony Farrington thanked county staff and – referencing the recent national media attention the landslide has garnered – said the county and residents together have elevated the issue.
Farrington, noting his frustration with the slow movement at the state level regarding the request for help, said he was surprised about the finding of the new leaks.
Dellinger explained that the leaks were found in linear fractures that run the length of polybutylene pipe. One was estimated at less than 20 gallons a minute, the other about 10 gallons a minute. He said the second leak detection company that found the leaks said they would have put out less water when the ground was compacted around the pipes.
He said the leak found near Oxford Drive is of concern because they are seeing pavement separation well out of the area where they believed the unstable ground was, which is why getting a completed geotechnical report was so important.
“The wait is the hardest part,” Farrington noted during the discussion.
“No question,” Dellinger replied.
Dellinger’s fiscal manager, Jan Coppinger, said the superintendent who fixed the leaks noted that the polybutylene pipe is very flexible in the center. That means the leaks won’t necessarily be where the ground movement is, but will be more toward the valves and the pipes’ connections.
Supervisor Denise Rushing said the county needed two plans – one for if there was state funding and a second for if there wasn’t.
|The front window of a home on Lancaster Road in the Lakeside Heights subdivision in north Lakeport, Calif., now looks out on onto the back of the destroyed home. Picture taken on Saturday, May 11, 2013, by Elizabeth Larson.|
Public Works Director Scott De Leon, the county’s incident commander on the Lakeside Heights emergency, said county staff is still trying to get the county infrastructure out of harm’s way and continues to work on those two scenarios.
Rushing asked if it was fair to say that they didn’t really know what was going on with the underlying geology. Dellinger replied that the movement was more than originally thought.
Rushing asked when they might have answers. Dellinger said hydrological studies could take months, while geotechnical work could be done in a matter of weeks.
“So we’re still looking at weeks here,” she said.
She followed up by asking what had happened on the ground’s surface in the past week. Dellinger said water is still coming out of the ground at Downing Drive and the north end of Lancaster Road has a crack, with the ground dropping about 4 inches and another fissure opening further.
Farrington, who said he last visited the subdivision on Monday night, said the foundations in the subdivision weren’t monolithic, and some of what was done raised issues about construction integrity.
He said some were slabs, some were perimeter foundations without rebar, still others were concrete pier post, which he said pointed to a historical knowledge of soil instability.
De Leon said a drilled pier foundation is nonstandard for general soil or foundation construction and is used in areas of weak soils or fill.
In reviewing the subdivision’s construction plans, county officials noted unique features, including a drain underneath the sewer line on Downing Drive, which also has check dams and lines that run off of it laterally, De Leon said. “Clearly subsurface water was anticipated at some point in time.”
He agreed with Farrington that it appeared there was a historic knowledge of conditions that required special construction.
De Leon told the board that the landslide continued to inch toward Hill Road, and it was being monitored daily.
He also reported that the county’s research revealed that the subdivision’s roads were dedicated for the exclusive use of residents and service vehicles – police, fire and mail. Because they’re not considered public roads, the sheriff’s office has the authority to tell people to leave.
Due to concerns from residents about people being in the area who shouldn’t be, De Leon said they’ve instituted a policy that county staff only visits the neighborhood in county vehicles. Residents are being urged to call 911 if they see people coming into the subdivision at night who don’t belong there.
Sheriff’s Capt. Chris Macedo told the board that county staff has been doing an excellent job responding to the situation, and is taking a very methodical approach to solving the problem.
He said staff are doing everything they can, working nights and weekends. “You should be proud of them.”
|Lancaster Road in the Lakeside Heights subdivision in north Lakeport, Calif., now is showing cracks. Picture taken on Saturday, May 11, 2013, by Elizabeth Larson.|
Resident asks about leak tests, size of leaks
Randall Fitzgerald, one of the last remaining homeowners still in his home on Lancaster Road, thanked Special Districts and Public Works staff on behalf of the subdivision’s residents. He said some of the efforts have been above and beyond the call of duty. “It doesn’t go unnoticed.”
Fitzgerald then asked county staff a series of questions relating to the accuracy of the March 25 leak detection test, as well as the technology used.
Dellinger said he was confident in the work done during that test. Coppinger added that different technologies are available for leak detection, and there is debate over which is best, but no technology is perfect.
She said the second leak detection firm told county staff that the leaks were less before the earth was removed from around the pipes, and the water that escaped wasn’t enough to be considered significant or to damage the subdivision.
“We are moving forward. We’re going to expect more leaks,” she said, adding they would address any new leaks as soon as possible.
When Fitzgerald asked if the March 25 test was flawed, Dellinger said he didn’t know. Coppinger added that the two leak detection companies the county has used to study the area were going to compare their tests for accuracy.
Fitzgerald asked how the county knew how much water went into the subdivision before the new meter was installed. Dellinger said they monitored home usage, but this meter was meant to increase the accuracy. In response, Fitzgerald asked if it was fair to say that they didn’t know how much water was going in before the meter’s installation, Dellinger said yes, other than assumptions for tank storage, pipe diameter, gravity and reads on individual meters.
Fitzgerald also asked about if the water found when working on a manhole on April 30 was related to a leak in the pipe 50 to 70 feet from it in the water line. Dellinger said he didn’t know but hoped to be able to answer that question.
Using the estimates of the water leaks’ volumes, Fitzgerald asked if it was possible that millions of gallons of water could have gone into the hillside since late March. Dellinger said he couldn’t speculate.
“If you’re asking for a lot of speculation, we’re going to need the data,” said Rushing.
Fitzgerald said the questions were meant to lead to the data, and Rushing suggested that compiling a list of questions would be good.
Farrington also asked questions of staff about residents’ accounts of a fire hydrant that may have been shut off improperly following a house fire on Oxford. Residents have stated to Lake County News that the fire occurred in March. Dellinger told the board he could look into the matter.
Rushing encouraged staff to capture all of the questions. “We need to get it all out on the table and find out what exactly is happening,” she said.
Email Elizabeth Larson at firstname.lastname@example.org . Follow her on Twitter, @ERLarson, or Lake County News, @LakeCoNews.