KANAB — The Bureau of Land Management released its final report Tuesday on an oil spill at Grand Staircase-Escalante National Monument that initially puzzled officials as to how much oil leaked and when the spill occurred.

The spill involved sections of the Little Valley Wash, a drainage about 54 miles upstream from the Escalante River, blackening soil, rocks and vegetation in the area. Land managers determined at least three events — one recent leak and two decades-old oil spills — were the cause of current conditions in the wash, according to the report.

The two older spills are estimated to have left a deposit of about 550 barrels of oil in the wash. The most recent leak, a small pipeline spill discovered by hikers on March 22, was probably less than 10 barrels of an oil-saline water mixture, according to the BLM.

A 2-mile stretch of the drainage now contains deposits of weathered oily residue, but the deposits "appear to be relatively stable and, if undisturbed, pose no immediate threat to wildlife, vegetation and water in the wash," according to a BLM news release.

Fresh water that came in contact with older oil deposits was analyzed and found to be in accordance with state surface water quality standards, according to the BLM.

The BLM plans to leave the deposits undisturbed in the drainage to prevent further resource damage, hoping the deposits will biodegrade naturally.

"We will continue to monitor natural resource conditions in Little Valley Wash, paying particular attention to the quality of water flowing from seeps and the health of the native vegetation, to determine if there is any long-term damage to natural resources," acting monument manager Cynthia Staszak said.

Citation Oil and Gas Corp., which operates the Upper Valley Unit oil field, is now required to inform the BLM within 24 hours of spills of any size. Prior to the April 1 written order, Citation was not required to report spills of less than 10 barrels.

The investigation into the Little Valley Wash spill indicates Citation followed protocols in recording the small pipeline leak and its repair in December.

Comment on this story

"We recognize the age of the field and the potential for future infrastructure failures," Utah's BLM Director Juan Palma said. "We will be working with Citation to conduct a thorough assessment of the Upper Valley oil field infrastructure … that could fail and lead to another spill event."

The report calls for increased monitoring and additional staff training to protect the spill site in the drainage, as well as a contingency plan should the oil become remobilized or threaten monument resources. The BLM will also ask Citation to prepare and implement a new surface use plan for the oil field.

Email: mjacobsen@deseretnews.com