A rainstorm flushed the oil two miles to the San Juan, said Walt Baker, director of the Utah Division of Water Quality.
The company deployed booms on the wash and captured oil before it reached the river, a major tributary to the Colorado and an important water source, according to David Ariotti, a DEQ district engineer.
"They had equipment on site and were already 60 percent done with the cleanup when I got there," Ariotti said. "I didn't observe any impact on the river or near the river."
As a precaution, company crews also used absorbents and a containment booms several miles downstream at Sand Island, but no oil was captured there, although the DEQ spill report said a "rainbow sheen" was observed on the water.
Ariotti gathered water samples from the river to test for the presence of hydrocarbon pollution. Those results are not yet back.
The day before the Montezuma Creek spill, Aug. 13, another pipeline rupture near Bluff discharged 200 barrels of oil about 1,000 feet from the river, according to an earlier report posted on the DEQ database. Running Horse Pipeline Co., a firm belonging to the Navajo Nation, operates the 16-inch line. Contractors vacuumed most of the crude, which migrated toward the San Juan, but did not enter the water, the report said.