Table Nine
Dam Failures and Incidents

Date

Name and Location

Nature of Failure and Damage

December 1918

Masonry Dam (Boxley Burst) near North Bend

Excessive seepage through glacial moraine abutment caused mudflow about one mile from reservoir. Destroyed railroad line and village of Eastwick.

February 1932

Eastwick Railroad fill failure near North Bend

Blockage of culvert by slide caused railroad fill to back up water and fail. Water destroyed railroad line and village of Eastwick. Seven deaths.

April

1938

Loup Loup Dam near Malott

Fifty-foot high hydraulic fill dam failed when emergency spillway was undercut during a flood. Flood destroyed 1/2 mile of state highway and 25 homes and left 75 people homeless.

February 1950

Lake Dawn Dam near

Port Angeles

Heavy rains caused overtopping and failure of earthen dam. One home was destroyed plus $4,000 in property damage.

December 1967

North Star Sand and gravel dams in

Everett

Forty-foot high dam washed out by overtopping due to lack of spillway. Then a twenty-five foot high dam was rebuilt but also failed. Water washed out Great Northern railroad tracks, which derailed passing train.

January 1970

Pillar Rock Dam in Wahkiakum County

Logging road culvert blocked by debris, overtopped, and failed. This caused a twenty five-foot high concrete gravity dam to fail. Three homes and fish cannery were destroyed.

May

1971

Sid White Dam near Omak

Earthen dam failed due to seepage through animal burrows. This caused second dam to fail dumping debris into town of Riverside.

May

1974

Horseshoe Lake blowout near Chewelah

Outlet tunnel through fifty-foot high natural ridge collapsed causing ridge to fail. This drained a twenty-foot deep lake causing extensive flood damage and debris deposits on cropland in downstream valley.

July

1976

White River incident

near Auburn

Surge in water flow, caused by increased discharge from Mud Mountain Dam and removal of flashboards at PP&L Diversion Dam, killed 2 children who were playing in the White River.

December 1982

Alexander Lake Dam

near Bremerton

Spillway was undermined and failed during heavy rains. This caused damage at fish hatchery and homes in Gorst.

May

1986

Upriver Dam near     Spokane

Hydropower facility failed by overtopping. Lightning struck and turbines shut down. Water rose behind dam while trying to restart. Backup power systems failed and could not raise spillway gates in time. This caused $11 million damage to facility. Federal disaster number 769 was assigned for this event.

November 1990

Chinook Dam in

Pacific County

Heavy rains overtopped the embankment and undermined the spillway, leading to failure of dam. This caused approximately $100,000 damage to facility.

October 1991

Seminary Hill Reservoir in Centralia

Failure along weak rock zone in hillside caused massive slide, which breached reservoir. Three million gallons of water drained from reservoir in three minutes. Two homes destroyed and many damaged, $3 million in damage.

January 1993

Iowa Beef Processors Waste Pond Dam Number 1 near Wallula and Tri-Cities

Failure of 15-foot high embankment released 300 acre-feet of wastewater. Failure attributed to high reservoir levels due to snowmelt; entering animal burrows near embankment crest and eroding dam. Water washed out Union Pacific railroad tracks, which derailed five locomotives. Damages were $5 million