On April 7, Sunoco filed new plans for constructing the Dragonpipe (Mariner East pipeline) near Marsh Creek Lake. The plans were posted on the DEP website a week later. They involve a modified route; and all work would be done by open-cut trenching, not the horizontal directional drilling that was previously attempted.

In this blog post, I will outline Sunoco’s argument for its choice of a new route and construction method. I will also comment on why Sunoco’s choice may not be the right one.

First, a bit of history. The Department of Environmental Protection (DEP) halted construction at that location after a frac-out polluted a local wetland and stream with drilling fluid, and it flowed downstream into the lake, a popular recreation area as well as a drinking-water source.

Sunoco tried to convince the DEP that it could resume drilling at the same location, and that it would prevent any further pollution. But that was a story the DEP had heard from Sunoco one time too many, and the DEP insisted on a re-route of the construction. The DEP pointed out that Sunoco had (in its initial 2019 filing for work at that site) offered a route near the turnpike as a “technically feasible” alternative, but one that would be longer and require more work.

Sunoco took the DEP to Commonwealth Court, claiming that the DEP could not insist on the re-route. The judge did not rule on that issue, but found that the DEP had been remiss in its procedure and sent the issue back to the DEP and told the parties try to reach a settlement and to show up in court at the end of March. That appearance was postponed for a month, at the request of the parties (who apparently were still talking) and that’s the last we heard until now.

“Eleven options”. Sunoco’s revised plans are contained in two documents: a “Chapter 102” permit application (which concerns land disturbance required for construction), and a “Chapter 105” permit application (which concerns plans for crossing wetlands and waterways). These are huge documents: the “102” application is 256 pages, and the “105” application is 427 pages. I won’t pretend to have read them carefully, but I have noticed some significant points.

Near the beginning of the “105” document is a section called “Alternatives Analysis” describing how Sunoco chose the approach they are now proposing. They say that eleven options were considered. The options had to be considered in the context of a January 4, 2021 letter from the DEP to Sunoco, which tells the company it should avoid future frac-outs and it must not use wetlands as a retention area for drilling fluid if a frac-out does occur (this had been Sunoco’s proposal when it applied to restart drilling).

Routing options considered by Sunoco. See text for the details. I compiled this map from Sunoco’s descriptions of the various options, and the routes shown may be slightly off from those in Sunoco’s plans. The red “X: indicates the approximate point of the frac-out that caused pollution of Marsh Creek Lake.

Option 1: HDD plus open cut. Sunoco’s “Option 1” would use the same route as the failed horizontal directional drilling (HDD). It would still use HDD, but for a shorter distance, with open-cut making up the rest. Open-cut would be used to cross the wetland and two streams along the route (so frac-outs wouldn’t happen there), but frac-outs could still occur along the HDD sections. That seems to be the primary reason Sunoco ultimately rejected Option 1. (Sunoco also mentions the cost and the duration of the project as negatives.)

Still, in describing Option 1, Sunoco details the process it would use for crossing the wetland and the two streams. This procedure is the same one that it would use in several of the other options. In order to use trenching without water problems, Sunoco proposes to pump the stream water around the work area through a temporary culvert.

Muddy water? Although that would take care of most of the stream flow, the trench would still need to be pumped to keep ground water out. That water would be pumped to a “filtration structure”, presumably a containment area constructed of straw bales and heavy-duty plastic of the kind we have seen at many pipeline sites in the area. Water released from the filtration structure would be filtered, but still cloudy because “current feasible filtration capability … does not exceed 50 microns”. In other words, small suspended particulates will be returned to the stream. This is exactly the type of problem that is currently fouling Valley Creek in Exton, where the same procedure is being used. Sunoco labels these “temporary, minor, and less than significantly adverse impacts to streams”.

Direct pipe bore, entire distance. The next option considered is using “direct pipe bore” (commonly called “pipe jacking”) for the whole stretch. This is the approach in use at Glen Riddle Station in Delaware County. Sunoco eliminates it because the distance involved (1900 feet) is too far for this technology.

Option 2: Direct pipe bore plus open cut. In this option, Sunoco would use two sections of pipe jacking with open cut between them. The open cut part would cross the streams and wetland, as in Option 1.

The pipe jacking method involves installing a casing as part of the drilling process. The pipe itself is pulled through the casing once the casing is complete. It is a method that greatly reduces (but does not eliminate) the problem of frac-outs. Sunoco cites the long duration of construction (101-118 days) and “significant cost” as negatives for this approach. There would be significant disturbance for nearby residents during part of that time.

The company also notes the problem of “alignment drift”: this technology is not readily guided, and once off track, it is hard to get it pointed in the right direction again. That could result in “geologic binding of the rock against the pipe casing”, which would result in the casing getting stuck and failure of the procedure. (Could this be an aspect of the current work stoppage at Valley Creek, where a related method involving a casing—auger boring—is being used?)

In any case, Sunoco ultimately rejected this approach.

FlexBor, entire distance. FlexBor is a new variation on HDD. It has been tried at three different locations on Mariner East, and has never been completely successful. Sunoco concluded: “this technology is not perfected for larger diameter bore attempts,” and rejected it.

Conventional auger bore, entire distance. Auger bore is similar to direct pipe bore. It differs primarily in the method by which the cuttings are removed from the drill: it uses a spiral auger instead of circulating drilling fluid. Sunoco’s experience with auger bores on Mariner East suggests they should be limited to 200 feet. Previous attempts at longer distances “have at times had alignment drift and elevation deflections which have complicated installation”. In particular, “drift and deflection are concerns when boring adjacent to in-service pipelines and other utilities”. Sunoco rejects this approach as “not technically feasible.”

(Auger bore is being used at Valley Creek. Drilling there was stopped more than a month ago, after only about 25 feet. In that case, both ME1 and the “Frankenpipe” are in service in the same easement, carrying highly explosive materials. Could these problems with alignment and elevation be involved in the Valley Creek work stoppage?)

Conventional auger bore, roadways only. Sunoco next considered the combination of auger bore under roadways (presumably with open cut elsewhere). The company decided that the clusters of underground utilities and overhead wires at the points where boring would be done would cause too many problems to make this approach worthwhile, when compared with simply opening up the road for open cut, so the auger bore approach was rejected.

Option 3: Open cut, entire distance. Sunoco evaluated the option of simply doing open cut trenching along the entire right-of-way. Streams would be diverted as noted under Option 1. This approach would result in the shortest distance, and relatively low cost and duration of construction. However, the trench would come close to several homes (including within 10 feet of three of them). Sunoco decided that, although it is technically feasible, “it is not the most practicable alternative” given the “impact on environmental resources and the human environment.”

Option 4: Open cut with minor reroute. This option is similar to Option 3, except that the route is shifted to avoid residences and utilities. It heads south to skirt the residences on Little Conestoga Road, then returns to the original right-of-way (see map). There would still be requirements for cutting through roads and avoiding utilities as in Option 3, but the disturbance for residents would be reduced. It would have the shortest construction schedule (42-59 days). This is the option Sunoco is proposing.

Option 5: Open cut using roadways. Utilities are often routed along or under paved roads, and that approach could be used for this project, in large part. Sunoco evaluated a route that would follow Little Conestoga Road eastward, then follow Green Valley Road to the southeast, then turn south to rejoin the right-of-way (there is no existing road for this final segment).

Sunoco first determined that there was not space along the sides of Little Conestoga Road for the pipe to go there. Telephone poles along one side and a water line with fire hydrants along the other side would create logistical problems, so that approach was rejected. The trench would have to go right down the road, blocking a lane during construction, and that is the approach taken in Option 5.

This option would entail significant traffic disruptions during an extended construction period (60 days minimum) but it would not affect any streams or wetlands. The trench would be narrow, requiring undesirable welding conditions and techniques, and the traffic would present hazards to “equipment, materials, personnel, and vehicles”. This approach would entail “substantial and protracted impacts on residential uses, public access, emergency access, roadways, and infrastructure.” Sunoco rejected this option in favor of Option 4.

Northern reroute alternative (the “original” reroute option). Finally, Sunoco evaluated the reroute option that it had mentioned as “technically feasible” in its original proposal for HDD on this stretch. Sunoco “does not consider it practicable” because it would create a new “greenfield” utility corridor alongside the turnpike and because it would cross two small streams and wetlands, “based on desktop review”.

And yet, the pipeline runs alongside the turnpike for many miles near Mechanicsburg—why was that stretch “practicable” while this one is not? My own “desktop review”—surely less sophisticated than theirs, but still—shows only a single stream to cross, and it feeds a pond. So any spill affecting that stream could not make it to Marsh Creek Lake. Isn’t that the key environmental objective here?

I have to assume the real reason Sunoco does not like this option is that it would take longer to construct. But Sunoco eliminates it from consideration because it is “not the most practicable alternative (with regard to existing technology, logistics, and cost)” and because of its “impact on environmental resources… and the human environment”.   

So which option is the best? First, it must be stated that there is no good option here. We are left with a choice of which option does the least harm. To me, that option is clearly the “northern reroute”—the alternative that Sunoco itself laid out years ago in its original HDD permit application. Now, though, the company will not even give it more than a “desktop review”, despite the fact that it clearly poses the least threat to the lake.

Option 4, Sunoco’s choice, is a poor second. The company clearly expects its groundwater pumping operation to put mud (and anything else that finds its way into the trench) into a Marsh Creek tributary, where it will be carried to the lake. Shouldn’t Sunoco be required to at least do a serious geophysical survey of the “northern reroute”?

There will be an opportunity for public comment. On the DEP website, you will find the following notification: “After the applications are determined to be complete and a technical review of each amendment application commences, DEP will issue a notice in the Pennsylvania Bulletin about the project which will include information on public participation. That information will also be posted to this webpage.”

When I learn of an opportunity for public comments, I will post it here.