MOSES LAKE - The dredge used to remove sediment from Moses Lake was found partially submerged in Parker Horn in September.

Officials do not know why the 40-foot boat, owned by the Moses Lake Irrigation and Rehabilitation District, took on water and partially sank between state Route 17 and the Alder Street Fill.

How it was sunk was discovered when the district examined the boat. A hatch was opened, allowing water to fill the hull in the bow of the boat.

The sheriff's office continues an investigation to determine who sank the dredge.

There were no injuries. The craft was unoccupied.

The vessel carries diesel and synthetic oil. Irrigation district employees employed a boom after finding oil leaked into the lake, according to Grant County Emergency Services Public Information Office Kyle Foreman.

The diesel fuel was not released into the lake; only a small amount of synthetic oil escaped. It was caught in the first boom deployed by district staff, according to Foreman.

The engine of the boat remained above water, said district board president Ron Covey.

The Moses Lake Fire Department and the Grant Count Sheriff's Office Marine Unit deployed more booms as a precaution to prevent any oil from spreading from Parker Horn through the Alder Street Fill to the rest of Moses Lake.

The state Department of Ecology dispatched a spill response team to assess the situation, according to Foreman.

"The ecosystem along Parker Horn appears unaffected. Clean-up crews will work throughout (Sunday) recovering the small amount of oil which has collected along the shoreline," Foreman stated.

The district hired Spokane-based NRC Environmental Services to clean up the spill.

A Seattle-base maritime salvage company was employed to raise the dredge on Sunday, bring it closer to shore and help the district off-load the fuel and oil into trucks, Foreman stated.

The district will make a report to authorities once the cause of sinking is determined.

The state did not fine the district and commended staff for the agency's quick and thorough actions to prevent ecological damage.