January 7, 2013 The Lake Huron Primary Water Supply System is undertaking a critical repair of the transmission pipeline at two locations in the Mt. Carmel area. In order to limit the impact to the area municipalities and consumers, the repair is planned for Wednesday January 9th and will be undertaken simultaneously at both locations.

The quality of the water supplied to area municipalities and consumers is not affected and most consumers should not experience any change from their normal water supply.

Municipalities supplied by the Lake Huron Primary Water Supply System include Bluewater, South Huron, Lambton Shores, Lucan Biddulph, North Middlesex, Middlesex Centre, Strathroy Caradoc and the City of London.

Damaged Pipe Detected

A recently completed condition assessment undertaken on the transmission pipeline between the water treatment plant located in South Huron near Grand Bend and the terminal reservoir in Middlesex Centre near Arva detected two pipes that are damaged beyond acceptable tolerances and require immediate replacement. The replacements of the two damaged pipes are being undertaken simultaneously on Wednesday January 9th starting at 4:30 a.m. Although the replacement of the two pipes themselves is anticipated to take approximately 20 hours to complete, it will take another 24 hours for the water supply system to refill depleted reservoirs throughout the region before operations return to a more normal condition.

The supply of treated drinking water to the City of London from the Elgin Area water supply system will be increased, however the majority of the water supplied to the consumers by the Lake Huron Primary Water Supply System will be provided from storage reservoirs while the pipe repairs are being undertaken. Some communities in the region may experience lower than normal water pressures, including Ailsa Craig and Ilderton. Consumers are encouraged to contact their municipality if they experience discoloured water or have no water.

Background Information

Condition Assessment: The Lake Huron Primary Water Supply System recently completed a $1.5 million condition assessment of the high pressure reinforced concrete pipe between the water treatment plant located in the Municipality of South Huron near Grand Bend, and the terminal reservoir in the Municipality of Middlesex Centre near the village of Arva. The condition assessment utilized the Smart Ball® leak detection and the Pipe Diver® electro-magnetic inspection technologies by Pure Technologies Ltd. The equipment was deployed within the transmission pipeline between October 2nd and October 5th 2012.

Until recently, electro-magnetic inspection of reinforced concrete pressure pipe required the complete isolation and draining of the transmission pipeline for extended periods of time to allow the equipment to be "driven" through the length of the pipeline. In the case of the Lake Huron Primary Water Supply System, this would not be feasible as several segments cannot be fully drained nor can the supply of water to the area municipalities be interrupted for extended periods of time (weeks or months). The Pipe Diver® inspection equipment is relatively new technology, and can be deployed within the pipeline while in operation and supplying water to the area municipalities. This allows for a complete and comprehensive assessment of the pipeline with limited impacts to area municipalities and the consumers.

Although the majority of the 1200mm (48 inch) transmission pipeline constructed in the 1960's was found to be in excellent condition, two pipe segments of significant concern have been identified in the Mt. Carmel Drive area which require immediate replacement.

Pipe Repair: The two pipe segments will be replaced simultaneously, starting on Wednesday January 9th, allowing for both areas of concern to be repaired during the same shutdown of the water supply system. It is anticipated that the complete replacement of the two pipe segments will take approximately 20 hours to complete at an estimated cost of $125,000.

During the replacement of the two pipe segments, area municipalities will be relying on water which is stored in reservoirs throughout the various water distribution systems. Typically low consumption during the month of January should ensure that most consumers would not be impacted by the repair operation; however some communities in the region may experience lower than normal water pressure particularly in the Ailsa Craig area.

Following the completion of the pipe replacement, it could take up to an additional 24 hours to replenish all area reservoirs and return to normal operation.

The Numbers

Lake Huron Water Treatment Plant:

• Originally constructed in 1967
• Utilizes "conventional treatment" processes consisting of chemically assisted sedimentation and dual-media filtration
• Current rated capacity = 340 million litres per day (3,935 litres per second)
• Current average day supply = 135 million litres per day (1,563 litres per second)
• Current peak day supply = 239 million litres per day (2,766 litres per second)
• Consumes approximately $4.5 million in electricity per year in treating and pumping drinking water to area municipalities

Lake Huron Transmission Pipeline:

• 47 kilometres of 1200mm (48 inch) diameter concrete pressure pipe constructed in 1967:
•    :9,729 pipes
•    :2 pipes found to be deteriorated below acceptable standards and require immediate replacement
•    :56 pipes found to be mildly distressed but within acceptable standards
• 21 kilometres of 1200mm diameter "twinned" in 1996 in high pressure "failure prone areas":
•    :7 kilometres of steel pipe
•    :Two sections of 7 kilometers each using reinforced concrete pressure pipe
• Treated drinking water takes approximately 12 hours (on average) to travel from the water treatment plant to the terminal reservoir near Arva
• Currently supplies eight municipalities in southwestern Ontario; Bluewater, South Huron, Lambton Shores, Lucan Biddulph, North Middlesex, Middlesex Centre, Strathroy Caradoc and the City of London.

Additional Information: Lake Huron Primary Water Supply: www.watersupply.london.ca