Lepore: Gradient protecting creek from leak

The elevation of the water table below Parachute Creek is higher than at the site of a nearby hydrocarbon leak, helping protect the creek from contamination, the director of the Colorado Oil and Gas Conservation Commission said Wednesday.

“So the groundwater flow direction should be away from the creek. Put it differently, to get to the creek the contamination would have to go uphill,” Matt Lepore said in an interview.

An investigation into a leak of an unidentified liquid hydrocarbon in a pipeline corridor near the creek northwest of Parachute continues to focus on a valve box associated with a Williams natural gas liquids line coming from its nearby gas processing plant. A 30-inch-diameter gas pipeline leading to the plant also is being excavated and inspected in a process that Lepore said can’t be rushed.

Todd Hartman, a spokesman for the state Department of Natural Resources, said Wednesday that results of water samples taken by the COGCC show no signs of contamination in the creek.

Bob Arrington, a retired engineer in Battlement Mesa who is active with the Western Colorado Congress and Battlement Concerned Citizens groups, questions how groundwater wouldn’t go into a stream located at the center of a valley.

“That groundwater is seeking its way to the stream and it’s got more head (pressure) coming off the hillsides than the stream (groundwater) going up the hillsides,” he said. ” ... The whole flow profile is just going to slowly pour into that gully and go down to the (Colorado) River.”

A monitoring well has found liquid hydrocarbons on the surface of groundwater 30 feet from the creek, between the creek and a trench dug to try to intercept the contaminants. Lepore said the trench appears to be creating a vacuum pressure that draws groundwater toward it.

On Tuesday, the Grand Valley Citizens Alliance called on authorities from the COGCC and other government agencies to be more forthcoming regarding information related to the spill, saying a lack of transparency has raised fears that the extent of environmental damage is being kept hidden.

Lepore the investigation is ongoing and “very dynamic,” but the COGCC has talked about what’s being done to identify the source, about the “hot spot” at the valve box, and about monitoring wells and other developments.

“Can we do more, better, faster all the time? Always, yeah, but I’m not quite sure what we’re withholding or are perceived to be withholding,” he said.


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So now the hydrocarbons are past the trench, and Lepore agrees with me about water filling the trench.  (Response to Hartman inferring stream charging was pushing hydrocarbons away from stream - remember most hydrocarbons are “floating” on ground water through the soil others are “mixing” into the water).
From yesterday:
This latest blurb of stream recharges ground water propaganda is just that.
At any cross-section of the valley, the stream is the low point. All moisture going onto surrounding ground flows toward the stream and down valley. The stream can saturate ground in the stream bottom outward until pressure of surrounding ground water equals water level of stream. If you dig a trench in the ground bordering a stream laden with ground water, you will strike water at stream level or slightly higher depending on upstream meanders and recent moisture on ground and valley walls. The water will pour into your trench from both sides and the bottom seeking its head level (pressure balance). The flow of the water for both the stream and the ground water is down valley toward the river that stream is running to. The hydrocarbon liquids follow the path of ground waters coming from valley walls and those hydrocarbon liquids will tend to “float” on the water where it interfaces. However, depending on the hydrocarbons, the BTEXs have a more soluble nature to their molecular structure and can interface with the water. So as long as there is ground water contact with the hydrocarbons, unless a coffer dam is built to lowest level of groundwater, it is impossible to stop the flow of hydrocarbons and ground water downstream. This also involves piping upstream stream water over/past the cofferdam.
This is the same dilemma facing the Suncor clean-up on the front range.
What they are hoping and doing right now is a reduction of hydrocarbons such that dispersion will dilute below danger levels - it will not prevent some downstream contamination!

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