Back in April, I wrote about the problems Sunoco was already having with trying to bore under Valley Creek, near the library in Exton. Those problems have only gotten worse. I recently wrote about a sinkhole that formed and then swallowed a small tree while observers were filming it. That post featured a link to a video of the event. Now the DEP, after failing to take action for months in spite of obvious violations, has finally shut down construction at the site.

In this post, I will outline what has been happening there, and then describe what the DEP is asking Sunoco to do, and how you can help.

The sinkholes. As of that April post, there were three sinkholes at the bore location. Now, there is a continuous line of about 10 of them (the exact number is no longer clear). With each new sinkhole, Sunoco quickly orders in cement trucks full of grout and fills the sinkholes, before the DEP can arrive (to check whether grouting in that location is permitted) and before the PUC can arrive (to see whether the active pipelines immediately adjacent to the bore path are endangered or actually damaged).

Because the geology in the area is karst (limestone), riddled with fissures and voids, more sinkholes can be expected. It is also possible that grouted areas lie on top of weak rock, which could give way under the weight of the grout and carry the pipelines downward. That type of earth movement is often the cause of pipeline ruptures, like the one in Beaver County two years ago that caused the Revolution pipeline to explode. There is no indication that the possibility of a rupture is being taken seriously.  

This is a still from the July 14 video that showed the sinkhole opening up. A few seconds later, it swallowed the tree.

The wetlands. Between the Exton library and Lincoln Highway (Business Route 30), there are extensive wetlands. This is the only remaining large wetland area in Exton, and the pipeline route goes right through it. Sunoco’s construction plans called for boring under the wetlands, leaving them untouched. It hasn’t worked that way.

Some of the sinkholes mentioned above are in the wetland area. Grouting there is illegal, but Sunoco is doing it anyway, and the DEP has cast a blind eye. Sunoco has also deliberately moved wetland markers, sometimes claiming that they had been put in the wrong spot.  

Mud from Sunoco’s construction site flowing into the wetlands.

Water problems. The wetlands are an indication of the very high water table in the area. Auger boring, which Sunoco is using, requires placing the boring equipment in a deep pit. The pit is clearly below the water table. It has to be continuously pumped out, at the rate of approximately a million gallons a day.

At first, Sunoco was trying to filter the pumped water and release it into the wetland (and from there to Valley Creek), but the filtration system soon failed and Sunoco was releasing huge volumes of mud into the wetlands, which violates the law and Sunoco’s construction permits. It took 11 days of resident complaints before the DEP finally stepped in and made Sunoco change its approach. The company cut a deal with local townships and is now dumping that water into the sanitary sewer system.

And still, Sunoco has struggled to keep the bore pit dry enough for work to proceed.

It is worth mentioning that removal of all that ground water can be a factor in encouraging sinkholes. In some locations, the underground water plays a role in supporting the soil and rock above.

Hiding from observation. Sunoco, knowing that it is violating the rules, has gone to great lengths to avoid being watched. When neighbors started noticing some of the problems, Sunoco put up plywood barriers. When the neighbors watched from stepladders, Sunoco made the barriers higher. When one neighbor put a camera on a tall pole, Sunoco put up black plastic on poles 18 feet high to hide its work. (That wall, which violated local fence ordinances, blew down in a windstorm.) Now, when grouting is occurring, Sunoco moves heavy equipment into position to try to block the view, or positions groups of workers such that detailed observation is prevented.

What the DEP wants now. On July 17, West Whiteland Township announced that the DEP had asked, and Sunoco had agreed “to voluntarily shut down pipeline construction” at the location. (There is, as of this writing, no official announcement yet from the DEP.) Sunoco is supposed to submit a plan in which it will “lay out the steps they will take to mitigate or prevent future subsidences [sinkholes] at this location.”

The West Whiteland announcement continues:

“DEP expects Sunoco to submit an emergency permit request to:

  • outline the previously conducted grouting operations that have been in response to the recent subsidences,
  • outline the required restoration for those sites, and
  • submit a plan to prevent future subsidences from occurring on site during the completion of the pipeline installation.”

The second bullet point, in particular, will be challenging. It is hard to see how Sunoco can actually “restore” the grouted areas. The grout will have spread into the cracks and crevices of the karst. There is no way to extract the grout.

The grout may well be forming an impervious underground barrier that prevents normal groundwater flow through this flood-prone area, making the likelihood of flooding even higher than it already was. The flood threat is serious: in the past, three homes at this location had to be abandoned and torn down because of repeated flooding.

Ask the DEP for a public comment period. The public needs to be able to review and comment on the emergency permit request that Sunoco submits to the DEP. Too often, the DEP has simply accepted as sufficient whatever plan Sunoco comes up with. That cannot continue.

Please write to the DEP at:

Let them know that they have done the right thing by requiring Sunoco to halt construction, and now they must let the public have the opportunity to weigh in on Sunoco’s plans.