By Doug Curlee | Editor at Large

Engineers unsure what caused sinking roadway

When a major thoroughfare through north Grantville started to sink quickly this summer, it got the attention of city public works experts. They quickly moved to close down the median and the two inner lanes of the four-lane road, and started trying to figure out why it was happening.

As of this writing, there is a problem: They still don’t know why it happened.

Engineers and repair crews started in on trying to figure it out on June 7, and they’re still going at it today.

That means the roadway between Greenbrier Avenue and Old Cliffs Road is still down to one narrow lane each way, north and south, and it’s likely to remain that way for a while. It could be as long as October or even longer.

Area residents, and those who use the road daily, are somewhat less than pleased about it — some are considerably less than pleased.

Frank didn’t want his last name used, but he was willing to share his feelings about the condition of the road he’s used for more than 20 years to get to work.

“Just call me ‘Frank Highly P.O.’d,’” he said as his truck idled at the Old Cliffs stoplight, part of a long single file of cars that stretched back out of sight on southbound Mission Gorge. “This is how I avoid both the 52 and Interstate 8, and now it’s not working.”

The traffic problem has really affected Adele Puckingham, who lives on Greenbrier Avenue. She’s had to scramble to find ways out of the area so she can get to her business.

“You can do it, if you look for a way,” she said. “I’ve been able to take the back streets around the neighborhood and wind up on Zion Avenue, which is south of the problem. It’s either that or turn right and go north on Mission Gorge until you can turn around and get in the long line with everyone else.”

Her problem is compounded by the fact that she can no longer turn left onto Mission Gorge and go south, because that part of the Greenbrier intersection is shut down, and will be until the problem is finally fixed.

But back to the problem. What is causing the street to sink?

There is general agreement that, when something like this happens — a sinkhole or the start of one — the problem is almost always water being, and going, somewhere it isn’t supposed to go.

The city just doesn’t know where that water is coming from.

“We just don’t know yet,” city information officer Scott Robinson said. “We’re testing everything we can think of, and there are possibilities, but we’re still doing test drilling and anything else that might help.”

The best Robinson can say right now is that the city hopes to have the problems, and the road, fixed this fall, with no firm date on the books yet.

Where could the water be coming from?

It could be that a 600-foot-long deep sewer line underneath the roadway could be damaged and leaking. If that’s it, it will mean going down 25 feet beneath the surface to dig it up and fix it.

The cause could also be a higher water table in the area — it is very close to the San Diego River channel.

It could be underground springs that no one really knew about.

It could be any of those. It could be a combination of any two factors. It could be all of them. It could be something totally different.

Robinson says the cause will be found, and it will be fixed. He just can’t say when.

In the meantime, it is important to remember that the city has closed turn lanes at the intersection of Greenbriar Avenue and Mission Gorge Road and that the closures will impact the following turns:

• Northbound Mission Gorge Road to Greenbriar Avenue will remain open
• Southbound Mission Gorge Road to Greenbriar Avenue will be closed
• Greenbriar to northbound Mission Gorge will remain open
• Greenbriar to southbound Mission Gorge will be closed
• U-turns on Mission Gorge at Greenbriar Avenue will not be allowed

After the work at the intersection is complete, these additional traffic control measures will be removed but the lane closures will remain in place. You’ll notice the controls by the barriers blocking access to the impacted lanes until this mess is over. Until then, be advised to travel cautiously near the work areas and keep an eye out for closed lanes and posted signs. Construction will take place 7 a.m. to 7 p.m. Mondays through Sundays.

The city is advising people in area to count on adding time to their commutes and to use alternate routes when possible, but if Mission Gorge is your preferred route, be patient — you don’t have any choice.

—Reach Doug Curlee at [email protected].