Inspection of a 700 ft long, 48 inch diameter, vertical, brick & concrete siphon, charged with storm and sewer wastewater, built in 1909, running under the Lake Washington Ship Canal. The project was undertaken to asses the condition of this 96 year old pipe. The flow had been reduced to less than 20% and heavy rains caused countless polluting overflows. Plans had been drawn to replace the entire siphon ...more.

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Inspection of a 1360 ft long 36 inch diameter double wood stave siphon constructed in 1935 of Redwood timbers fully charged with storm and sewer wastewater. Because of low flow capacities and overflows into the canal in recent years, SSI was asked to survey the siphons.

There had been no inspections of this twin wooden pipe system in 70 years. SSI found several problems including a massive failure to the mainline and large amounts sediment build up in both pipes. The sonar inspection findings resulted in long term plans to replace the lines. SSI’s documentation prevented a 7 million dollar holding tank project from being undertaken as originally planned. The funding is now being allocated to replacing both failing pipes with larger ones solving a problem the holding tanks would not fix ...more.