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Loudoun supervisors sign off on $3.5M sinkhole fix in downtown Leesburg

Courtesy Photo/Supervisor Kristen Umstattd (D-Leesburg)
Loudoun County supervisors threw money down a hole Tuesday night.

After the county discovered two 70-80-foot sinkholes earlier this summer under North Street’s Pennington Parking Lot being constructed in downtown Leesburg, the board signed off Tuesday on a $3.5 million to fix the problem despite little assurances from engineers that the sinkholes would go away for good and not affect neighboring properties.

Additional work on the sinkholes will add a 150-day delay to the overall project schedule. The project is now scheduled for completion in November 2018.

For years, Leesburg residents and local politicians have resisted the size and scope of the Pennington lot, which is tied to the long-awaited courthouse expansion -- a project that cannot be constructed until the parking structure is built.

“Is anything we do to remediate this situation going to increase the likelihood that any sinkholes may develop under [nearby residents'] properties?” asked Supervisor Kristen Umstattd (D-Leesburg).

Umstattd also pressed the county’s third party geotechnical engineers on whether capping the sinkhole area would push water away from it and instead toward surrounding properties, cause flooding or even more sinkholes in nearby residents’ properties.

But all of her questions were met with a slew of unknowns.

“Sinkholes are unpredictable,” Nicholas Meloy, a senior project engineer with the engineering firm ECS, responded, explaining that sinkholes develop from voids in the rock underground due to its natural weathering and, therefore, cannot be predicted.

To fix the problem, engineers have recommended cap grouting and compaction grouting at the site and in a 60-foot diameter surrounding the sinkhole. Additionally, they have recommended more cap grouting under additional pile caps that were deemed at risk, according to the county.

Cap grouting is a process by which a thick grout is injected to build a concrete cap over a distressed area. The technique prevents additional soil loss into the sinkhole. However, Tennessee-based Rembco Geotechnical Contractors, Inc. says cap grouting by itself "does not return the site to a useable condition."

“The remediation efforts that are going on are stopping at the rock surface, so we don’t believe that the remediation efforts pose a significant increase in risk for surrounding properties,” Meloy said. “They should be expected to be limited to the area that we’re remediating, as we are not puncturing the rock and affecting voids below them.”

Meloy said it was “extremely difficult to predict” what would happen to the direction of the water after the cap and grouting process. After they cap the bedrock of the area, he said the water would “find the path of least resistance” afterwards.

Meloy also said he did not anticipate groundwater would cause flooding in nearby properties because the rock was deep at some places he did not think it would happen. But again, he stressed he did not know for certain where the groundwater would travel and whether other sinkholes would occur in the area.

Altogether, the county says it needs $500,000 for sinkhole remediation; nearly $3 million for cap grouting at “at risk” pile caps; $62,315 for improvements to slab-on-grade; and $9,985 for improvements to the garage entry way.

All of the additional sinkhole improvements costs except the $3 million cap grouting work have either already been approved or will later be approved under the county's purchasing agent award.

Department of Transportation and Capital Infrastructure Director Joe Kroboth told supervisors the county likely created the sinkhole when they drilled the piles that support the lot.

“We actually have to drill down into the rock around anywhere from five to 11 or 12 feet … It’s potentially likely that we created the sinkhole and aggravated the area 60 or 70-feet below grade that most likely caused that situation,” Kroboth said, adding that his team recently wrapped up pile installation and finished with aggravating that subsurface.

Supervisors were taken aback when ECS said that after conducting tests on the structure, they knew it was expected to be on a bedrock that was known for “harsh activity and potential for sinkholes.”

Kroboth said his department budgeted for potential setbacks, but simply “did not expect the magnitude of the change that’s before us.”

Kroboth admitted his department would ask for more money in the fiscal 2019 Capital Improvement Program budget.

Other supervisors wondered if more sinkholes could develop under the area of the future courthouse construction.

Kroboth explained the Pennington lot had a different structural design than the courts building. He said the courthouse would sit on a structural slab set on piles, while the Pennington Parking Lot was not set on piles, but the concrete slabs on the first floor were laying on ground.

“We’re confident that the courts design is adequate. We are going to go back and knowing the information that we have, reevaluate the design and possibly increase the pile size so that if a large area opened up, it could structurally support the building,” Kroboth said.

But some were still wary of the engineer’s and staff’s assurances and torn on approving additional funds.

“I’m really afraid that we’re getting ourselves into an old fashion boondoggle as far as throwing our money down a hole, literally and figuratively, in this case,” said Supervisor Ron Meyer (R-Broad Run).

Meyer and other supervisors asked if other locations could be considered to move the lot or if they could go back and lower the lot of three levels to avoid the problem.

But staff said lowering the lot would not fix the problem and moving it would cost significantly more.

“This is one of the more unsettling staff reports I’ve heard in a long time,” Chairwoman Phyllis Randall (D-At Large) said. “It feels like half of Loudoun County is about to fall into a sinkhole because they’re unpredictable.”

The board ultimately voted 7-2, with Supervisors Meyer and Umstattd opposed, to award Howard Shockey & Sons, the project’s contractor, $2,973,520 million more to fix the sinkholes, bringing the total of its contract for the parking lot from $12.7 million $15.9 million.

Supervisors also voted to authorize staff to transfer $5.4 million from the $56 million in funds in the Courts Complex Phase III project account to the Courts Complex Phase III Structured Parking Facility project account.


Contact the writer at .(JavaScript must be enabled to view this email address) or on Twitter at @SydneyKashiwagi.

Comments


As Robert_Q_Smith commented, the “karst geology” of the region is not a surprise.  I would have thought that there was some radiographic or other methods of determining what lies underground before construction starts, similar to methods the petroleum industry uses to determine where to drill for oil and gas,


The usual brilliance here along with transparency—and let’s not forget they gave themselves a raise.


David - is this were a Walmart, and the same ECS geo-tech analysis had been done, and then the sinkhole circumstance had occurred, would this be an example of how badly the private sector screws up?

ECS is a private sector firm, and their report/findings is their report/findings. The owner of the project for which the report/findings are for is immaterial.

The decision makers (the BOS, the Walmart Corp board), if they throw good money after bad, without getting better information, that is totally on them.


This was the wrong location all along, a peaceful residential neighborhood with small side streets? Perhaps it’s karma. Stop the bleeding now and pull the plug . Throwing millions at the problem will not solve it and unfortunately there will be more “unforeseen” problems ahead.


Good for Supervisor Umstattd for asking the hard questions, and showing us the problems with this project.  I do not know of any other elected official who would have had the courage to do that.  The typical politician would have tried to cover it up (no pun intended) and keep the public from finding out about the problem.  As far as effectiveness, clearly over two-thirds of the Board was going to support the extra money spent plan, and only a game player or a fool would claim that Supervisor Umstattd caused the vote to go the way it did.  Supervisor Umstattd has, as anyone who has followed this project knows, made a real effort to have the neighbors concerns addressed.  The only other solution would have been the entire courts complex, and probably all of County government, move out of Leesburg, and I have no doubt if that had happened, the screams and cries would have been deafening.  So, thanks Supervisor Umstattd, for doing your job, and being honest about it.


Same comment, different topic:  Why is it that no matter how badly government screws up, nobody ever gets fired?


This thing should be put on the former Times Mirror land, not on North Street, but Umstattd is such an ineffective supervisor that all she can do is vote NO on the extra money. All show, no results


I resisted commenting on this article, but the fact that Kristen made her comments and provided the previous (scare tactic) photo have struck a nerve or two. Somebody missed something in the original evaluation (design) of the soil analysis performed by ECS, thus resulting in the low bid by Shockey. Perhaps something occurred between points A and B with the deficient soil conditions, but with the limited amounts of months, and the type of soil, it is very unlikely. Someone in the LC, and Town of Leesburg Engineering Divisions, and Government (BOS/Mayor/Town Council - although this is ultimately a County project), needs to be more technically aware of what is going on, which it seems nobody has a clue and the taxpayers are subject to getting gouged as there are no checks and balances on change orders. What are the requirements to substantiate a change order for 3 million dollars?!? How do we know it couldn’t be done for 2 million?!? Why wasn’t a 3rd party engineer brought in to review the ECS design work to see what might have been missed?!? I can think of about 10 other easy questions for Kristen and the BOS as they have no utter clue about large contracts, construction, change orders, etc. then they are trying to use politics to act like they are protecting citizen homes, which I knew from the previous article. Is ECS to blame for this is our government? Some of it was probably going to happen either way, but it should have been known in advance and you need to substantiate change order costs and ensure no hanky Panay is happening. It’s a huge sum of money, construction is affecting some good folks, we need that parking for the extended Holiday season, etc.


If Supervisors are unaware of the presence, and nature, of the karst geology underneath their feet as they sit/stand in Leesburg, that is an indictment upon them as being fairly out of touch.

If fact, their own website has a very informative page about this - loudoun.gov / limestone


Another reason to vote them all out. When is enough, enough. You have the garbage from Shockey and Sons who should not get another contract for 10 year then look at the Silver Line 100 million dollar increase with a delay also. If the contractors are not accountable we need new supervisors. Paying more for crummy work is poor politics. The Jackson Five, the 4 Tops…and the supervisors the Boondoggle 9!

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