BLM releases new water monitoring plan

by Stephen Crane

In mid-December, the Bureau of Land Management released the Interim Groundwater/Aquifer Pollution Prevention, Mitigation and Monitoring Plan, which will be an important step in characterizing and understanding the water systems of Sublette County.

“It is a direct result of the Record of Decision (ROD),” said Merry Gamper, supervisory natural resource specialist with the BLM. “And there’s three tasks, as specified by the ROD.”

The three tasks of the ROD, according to the new monitoring plan, include the “characterizing the groundwater system, augmenting the existing monitoring program as necessary and identifying mitigation for all potential sources of contamination.”

The ROD was released in September 2008, and since that time, regulatory agencies and operators have been working on producing this interim plan.

“Initially, the (regulatory) agencies met without the operators and without the public,” said Jim Sewell, environmental engineer for Shell. “And then they brought us in, Geomatrix and the operators, in late October. So it was quite a streamlined process.”

Geomatrix is a consulting and engineering firm that was contracted by the operators to perform water studies in the Pinedale Anticline Project Area, and the company also produced the recent water-monitoring plan. Water monitoring in Sublette County has been ongoing since 2004, when the Sublette County Conservation District first began testing water wells in the area. Since that time, the SCCD has been testing hundreds of wells each year, and currently tests about 260.

The results of the 2008 testing showed that eight wells tested positive for hydrocarbons above the water quality standard. With so much energy development in the area, the need for a comprehensive grasp of the underground water systems is vital, and this interim plan is important in achieving that goal.

The first goal of aquifer characterization will provide the framework for all the actions that follow, including future monitoring and mitigation.

“Our goal is that one year from now, we will have all of the data from characterization and assessment,” said Gamper. “And then we will redesign (the plan) to better monitor the different hydrostratigraphic units (HSUs).”

In the PAPA, there are three primary HSUs, which include the alluvium HSU, the Shallow Wasatch Formation HSU and the Regional Wasatch Formation HSU, which hosts “the majority of private, domestic and stock wells, and industrial water supply wells.”

Many questions concerning the water systems of Sublette County persist, and the task of characterization will be to understand if and how these water systems interact, not only with each other but also with the groundwater flows in the area.

“We have a lot of wells, a lot of water wells right now,” said Sewell. “And they go into the Wasatch formation, but there are other aquifers out there that have not really been investigated. So that’s one of the data gaps to fill.

“We have a good idea of which way the groundwater is flowing, but how fast is it flowing, the volumes that we’re dealing with, how fast the aquifers recharge with water, what is the aquifer’s contribution to the New Fork River, and to a lesser extent the Green River…”

Another product of this aquifer characterization will be the development of a “source list of credible wells,” according to the plan. Once the aquifer is better understood, all the wells currently being tested may not be pertinent to the improved monitoring program.

“We may be gathering data that isn’t really telling us anything,” said Gamper. “In order to gain the data that we need, the wells that we use for the study have to meet certain criteria, basic scientific standards.

“It’s likely we’re going to have to put in a lot of new, dedicated wells just for the characterization effort. I don’t think we envision a future water monitoring program that involves 260 wells.”

According to a previous report produced by Geomatrix, the current theory of the local aquifer system is that the aquifer may flow in pockets, or lenses, within the area, similar to the gas reserves currently being developed. Another possibility is that the aquifer might also be a continuous body.

This speculation, coupled with the possibility that tested wells may be reduced, is problematic for Linda Baker, coordinator for the Upper Green River Valley Coalition. “The nature of the aquifer is key,” said Baker. “By cutting down on the number of monitoring wells, and I’m speculating, is it possible that they could be monitoring on one of those discontinuous sand lenses while contamination is occurring on another discontinuous sand lenses?

“If it is continuous, would it be wise to place monitoring sites down the slope from the development?”

The bottom line, for Baker, the BLM and the operators, is that the water systems be clearly defined, thereby allowing far more precision for monitoring and, if need be, mitigation efforts.

“The existing monitoring program has been pretty good, but I think it can be improved,” said Sewell. “And to me, that’s the whole purpose of this (interim plan) that we’ve been working on…a more comprehensive study of the water and aquifers.”