A guest post by Virginia Kerslake

Sunoco has submitted a Horizontal Directional Drilling Analysis for HDD 360 in West Whiteland and Uwchlan Townships to the Department of Environmental Protection for re-evaluation. Everyone is encouraged to submit public comments, and this post will tell you how and suggest what you might say. But don’t wait: comments are due Friday, October 23.

This HDD segment has been problematic since drilling began in 2017, with two failed attempts before the most recent installation of the 16” pipeline. Residents know this segment well as Shoen Road-Devon Drive (which may explain why Sunoco has now switched to calling it “Biddle Crossing”). The problems include the loss of massive amounts of groundwater from the aquifer, inadvertent returns of drilling mud, and ongoing seeps on the north side of Shoen Road across from the worksite.

 Rather than address these concerns, Sunoco has chosen to ignore, downplay, or file false reports about them in its submission for the 20” pipeline.

Loss of Groundwater. With each drilling attempt, Sunoco has breached the aquifer within the first several days of drilling. In 2017 and 2019, this impacted homeowners with private water wells. As a result 35 families had to transfer from their private wells to public water.

In August, Sunoco again breached the aquifer and groundwater discharged into the drill pit at Shoen Road. It was estimated that about 264,000 gallons of water per day was discharged during almost two months of drilling. This estimate is based on the twenty-two 18,000-gallon frac tanks on site (these are tanks used to store this water outside of allowable construction hours until it can be hauled away as waste) and on the frequency of 5,000-gallon water trucks coming and going. This equates to 183 gallons per minute, far more than the 25 to 50 gallons per minute Sunoco falsely reported in its HDD Drill Analysis. In addition, the discharge began August 1 (if not earlier), not August 10 as falsely reported.

The drill site at Shoen Road.

Because no private wells are left to be impacted along this segment, the DEP allowed Sunoco to continue drilling despite this massive discharge of groundwater, in contradiction to the Department’s responsibility for protecting clean freshwater, a limited resource.

Sunoco has submitted no plan to ensure this does not happen again. In the comments that you submit (see instructions below), insist that the DEP require a plan to protect the freshwater aquifer.

Inadvertent Return of Drilling Mud. During drilling on August 8, grey mud began to flow out of seeps across the road from the worksite around 9:15 am and continued through the next several hours, turning orange at some point before noon.

Grey water flowing from seeps on the morning of August 8.
Orange water from seeps shortly after noon on August 8.

At 1:25pm a sandbag dam was constructed to contain the mud as per the DEP-approved Seep Monitoring Work Plan.

Sandbag dam at Shoen Road at 1:25 on August 8.

Around 3:30pm this dam failed and muddy water flowed toward the creek. The DEP finally arrived after being alerted by the property owner and Rep Danielle Friel Otten two hours earlier. Only then did Sunoco stop drilling.

In its August 17, 2020 Restart Report, signed by GES geologists, Sunoco falsely claimed that mud first appeared in the seep at 3pm and flowed for only approximately five minutes and at that time the sand bag dam was constructed.

Sunoco has submitted no plan to avoid more inadvertent returns of drilling mud and improve their plan to contain should one occur. In your comments, insist that Sunoco provide a credible plan to avoid more inadvertent returns.

Seeps at Shoen Road. When Sunoco grouted the borehole in July 2017 after the first failed HDD attempt at this location, water started seeping and flowing out of the ground on private property on the north side of Shoen Road. In a Hydrogeologic Investigation submitted to the DEP on September 1, 2017, Sunoco claimed that once the pipeline was installed and grouting was complete, the seeps would no longer occur. The 16” pipeline is now installed and grouting completed, yet the seeps continue, as this video shows.

Since Sunoco does not know how to stop the seeps, they are now attempting to falsely claim this emergence of groundwater is naturally occurring, despite acknowledging multiple times including under oath that the seeps were created by their drilling activities. Sunoco made this false claim previously in January 2020 and in response, the DEP received letters in January 2020 from West Whiteland Township, Senator Dinniman, Rep Friel Otten and the property owner refuting the claim.

This included refuting a Seep Investigation by Skelly and Loy dated July 2, 2018 (first introduced by Sunoco in January 2020) which Sunoco again references in this HDD Analysis. That investigation is inaccurate, speculative and inconclusive. Most notably it claims that soil pits were dug in the area of the seeps for the investigation. The property owner, herself a soil scientist, has stated unequivocally that no soil pits were dug and the entire Skelly and Loy report should be considered suspect.

Furthermore, the water from the seeps has had an elevated pH since grouting three weeks ago and cannot even be diverted to the creek. Instead, the water is being pumped under the road to frac tanks requiring pumps, generator, and personnel impacting the homeowners 24/7 and creating an unsightly nuisance. It has been three weeks now, and the pH remains elevated. How does Sunoco intend on handling this if the pH does not decrease to allowable levels? This has not been addressed in the submitted HDD Analysis.

Sandbag dam and pump at Shoen Road.

Sunoco has submitted no plan to stop the seeps. In your comments, insist that Sunoco provide a plan to stop the seeps that its drilling has triggered.

In addition to impacting private property, these seeps present a public safety concern because the water emerges along the path of Mariner East 1 buried just a few feet underground in soil near the transition from phyllite to karst geology. The water could be undermining Mariner East 1, risking a rupture.

In summary: before the Department can re-evaluate this segment, Sunoco must be required to submit credible plans to ensure drilling the 20” pipeline will not impact the aquifer again, discharging vast amounts of groundwater; mitigate the seeps that continue to have elevated pH; and ensure construction of the 20” does not create new seeps on this or other homeowners’ property.

This will require a thorough hydrogeologic investigation, which Sunoco must also be required to provide.

In addition to hydrogeology, further geologic investigation is required: The HDD Analysis claims that there is no known or mapped karst geology along HDD 360, but that is false. The September 1, 2017 Hydrogeologic Investigation stated that the geologic structure in the area is complex and that a drill log on the Shoen Road worksite “shows limestone where one would expect phyllite” and another boring drilled near this entry/exit pit indicated a karst formation. This change in hydrogeology can have a potentially catastrophic consequence in an area with HVL pipelines underlain by karst. And  a geophysical survey conducted by Rettew in February 2020 included in the Drill Analysis stressed the need for further geo-technical investigations at three areas of concern for subsidence or seeps on Shoen Roen and uphill from the worksite.

These investigations MUST be conducted by independent geologists not overseen by Sunoco. Recently, a whistleblower who was previously employed by GES and working on Mariner East construction in Chester County information has spoken out about falsified and editable reports among other deeply disturbing concerns. This, in conjunction with false reports already submitted to the DEP for HDD 360, should make this requirement crystal clear to the DEP.

In addition to these concerns, Sunoco has failed to perform anything but a simplistic alternate construction and reroute analysis, and has not considered the no-build option (simply leaving the second pipeline unbuilt) particularly in light of current and expected market conditions.

Here’s how to submit comments. You have only until Friday (October 23) to submit comments to the DEP. You can use the bold items above as the basis for your comments.

Write to the DEP at this address:


Tell them not to issue a permit for the HDD-360 (which Sunoco is now calling “Biddle Drive”) until these issues are resolved and the public has a chance to comment on Sunoco’s response.

While you’re at it, why not copy your elected officials? They need to know where you stand.

Time is of the essence: the deadline for you to submit comments is October 23, just two days from now.