The "flood of record" in 2003 pinpointed a number of issues with the Squamish dike system and this week another weak link has been brought to District of Squamish council's attention - seepage.
On Tuesday (Feb. 8), district engineering manager Brian Barnett told council that $900,000 needs to be allocated to address the dike seepage problem immediately.
Like the Squamish dike's infrastructure, most of the dike's materials and geometry do not meet provincial guidelines - they are too permeable to prevent seepage over time.
"The main concern is that the dike is constructed primarily of sand and gravel," said Barnett. "This material has high permeability that allows water to seep through relatively easily."
Seepage, if not addressed, can lead to piping, an advanced stage of seepage where water creates a pipe as it removes the gravel and while seeping through the dike, eats away at it and could potentially collapse the entire structure.
"This has to be done and we're recommending this proceed immediately," Barnett said.
The warning stems from the results of study completed in November 2008. The consultant, Thurber Engineering Ltd., relayed the information and identified some tasks that were "very high priority."
The report issued a clear warning for Squamish.
"Prevent internal erosion/piping that results in boiling, which is the most critical condition that will lead to imminent dike failure," stated the report.
Thurber's report narrowed the main area of concern to the eagle viewing area of the dike on Government Road in Brackendale and recommended that remediation works be completed within one or two years of November 2008.
More than two years later, and after two Squamish geoscientists sent council a strongly worded letter and report on the seepage issue, council members this week acknowledged the situation.
"Council considers this an emergency and we should move forward on that basis," said Coun. Corinne Lonsdale.
"I look at this as emergency maintenance," agreed Coun. Paul Lalli.
There were three suggestions on how to control future dike seepage - construct a 10-metre-wide and 150-metre-long berm (an extended slope) on the land side of the dike, create the same berm on the river side, and finally, combine a smaller land-side berm with a mid-seepage diking barrier, which involves installing a sheet-pile barrier along the dike's crest.
Barnett recommended the third option as the most cost-effective, landowner and fisheries friendly. He said he was confident the project would be completed within the year.
"We could have the request for proposals out within the next week, with a turnaround of two to three weeks and then we could come back to council," he said, "followed by a few months of engineering work and then construction."
Despite council's general support for the upgrades, leaders balked at the $900,000 price tag that, according to Barnett, needed to be included in the 2011 budget.
The estimated 2008 construction cost of the 150-metre-long toe berm and the mid-dike sheet seepage barrier was $630,000, but Barnett said that after factoring in all the project costs and inflation, the total would be $900,000.
"I'm trying to understand the increase," said Coun. Patricia Heintzman. "It's almost a third more."
Barnett explained that in addition to inflation, which he calculated between eight and 10 per cent over two years, the old budget didn't include Department of Fisheries and Oceans (DFO) compensation studies.
Coun. Rob Kirkham asked why there were fisheries implications when the construction was slated for the land side of the dike.
"Even if the work is not taking place within the riverbed, DFO requires the compensation consultation because it is within the riparian area," Barnett said.
Lonsdale said she thought fisheries should cut the district some slack in this case.
"What's this compensation business - does fisheries want the river to fill the valley?" she asked.
"Do we really still have to meet all this fisheries stuff in the case of an emergency? Council considers this an emergency."
Barnett said he understood Lonsdale's frustration but didn't think it would be possible for Squamish to be exempted.
"It's the DFO's practice to require compensation in as many area as they can," he said.
Coun. Doug Race noted some of the proposed construction would affect private land and asked whether the landowner had been contacted.
Barnett said he hadn't done that yet. Mayor Greg Gardner said the district had "the right to repair and this would certainly protect said private property more than most."
Council members discussed where the nearly $1 million would come from and ultimately decided the upgrade should be included in the capital budget.
The motion to authorize $900,000 from the 2011 capital budget to fix potential seepage issues at the eagle viewing area of the dike was carried unanimously. Coun. Bryan Raiser was not present.
"This is work that should be done and must be done," Heinztman said.
