Expert: Oil would pass near water supply
Some question safety of aquifers with proposed pipeline
By Terry Woster
twoster@midco.net
October 18, 2007
PIERRE - A proposed crude-oil pipeline would pass near some shallow underground water sources in Marshall and Brown counties, an expert says.
The route proposed for a Trans-Canada Keystone Pipeline through South Dakota was altered during planning stages to limit the distance across shallow aquifer areas that the line would travel, Heidi Tillquist said in testimony filed with the state Public Utilities Commission.
She said it is "unlikely that the construction or operation of the pipeline will alter the water yield of any aquifers used for drinking water."
She also said the company doesn't anticipate spills, leaks or disposal practices during construction will hurt quality of groundwater.
A Marshall County farmer whose land is targeted in a condemnation proceeding says he doesn't trust the company to respect the importance of water supplies in the area.
"We do have these shallow aquifers and some of that is real close to us, but if you go to southern Marshall County, it's like only 20 feet underground," Jim Bush of Britton said.
This area, most of it is 80 feet to 110 feet to the aquifers, and I can tell you it's an aquifer that a lot of water is pumped for cattle.
"Nobody knows what happens once an aquifer is contaminated." The testimony by Tillquist, an environmental toxicologist with ENSR in Fort Collins, Colo., describes how the company approached routing of the proposed pipeline in areas of aquifers in South Dakota.
TransCanada wants to build the line from oil fields in Alberta to ship crude oil to Illinois and Oklahoma.
About 220 miles of the proposed line run through eastern South Dakota.
Tillquist said the proposed route crosses near a water-supply well in Marshall County and would cross an aquifer-protection area in Kingsbury County.
While it also passes through areas where shallow and surface aquifers exist, she said the company will investigate groundwater sources encountered during construction "to determine if there are any nearby livestock or domestic wells that might be affected."
Since the pipe will be buried at shallow depths, around four feet, it should not threaten underground water, she said.
About 80 percent of the pipeline would be above soils that would be difficult for crude oil to flow through, she said.
The manager of the East Dakota Water Development District said Tillquist's general descriptions of the area seem reasonable.
Jay Gilbertson said he hasn't studied the exact route of the proposed pipeline. That exact route is a critical factor for decision makers, he said.
"If it crosses over a shallow aquifer, there would be reason for extra caution," Gilbertson said in an e-mail exchange.
"A shallow aquifer in the vicinity of a public water supply well field should be avoided at all costs.
Where it traverses areas where the aquifers are at depth, caution is still appropriate, but minor spills and leaks are unlikely to cause immediate and irreversible problems."
A PUC evidentiary hearing on the Keystone request for a siting permit is scheduled to begin Dec. 3 in Pierre.
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