Mission Public Works crews sandbag the harbourfront last Friday in the event of unanticipated flooding.

Flood risk remains as weekend looms

Flood response plan kicks in once water levels reach six metres

Waterfront homeowners and businesses should still remain watchful despite falling Fraser River levels, said Mission’s emergency preparedness coordinator.

Ian Fitzpatrick said Wednesday that although the river level at the Mission gauge is sitting at around 6.1 metres, that level is expected to rise to 6.4 metres or higher this weekend, which is potentially high enough to flood some homes around Silvermere Lake, as well as businesses on the water side of the Silverdale dike at the foot of Nelson and Duncan Streets.

“We are expecting something similar to last weekend,” he said, when water levels peaked at 6.38 metres and caused municipal crews to begin sandbagging on the harbourfront.

Fitzpatrick said areas outside of the diking system are particularly vulnerable to flooding, such as Nicomen Island Road in Deroche where one house began sandbagging Wednesday.

He said flood monitors also found a “boil” in Lane Creek Park at Mission Way and London Avenue and the provincial diking authority was inspecting it Tuesday evening. A boil is usually a hole in the ground beyond a levee where flooding comes from underground seepage. They’re usually sandbagged around the perimeter and then filled with sand.

Dikes along the Fraser River are regulated to handle about 8.5 metres at the Mission gauge, except for the Silverdale dike which is constructed to a lesser agricultural standard and remains at pre-2007 flood protection levels for its entire length.

According to the 2012 District of Mission Flood Response Plan, the emergency preparedness planning committee takes several actions at six metres:

• Potentially opening the district’s Emergency Operations Centre.

• Emergency Social Services and Fraser Health Authority are engaged regarding possible evacuations.

• Daily dike patrols.

• Some isolated low-lying areas not protected by dikes may need sandbagging or evacuation.

• Flood response supplies, such as sandbags, and Mission Search and Rescue equipment are moved from permanent housing on floodplain to temporary housing at Public Works yard.

• Temporary sewage pump is installed on North Railway Avenue.

• Low sections of Mission Dike will be prepared for the installation of temporary dikes or other temporary measures.

• Coordinating with volunteer organizations.

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