courtesy Bethany Brewer

How to stop a flood

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World Water Month was in March, a time to learn about and celebrate the management, sanitation and preservation of water. Water is both a resource and a risk, as the June flooding of Southern Alberta illustrated.

The 2013 flood was deemed the worst in Alberta’s history and has spurred a number of initiatives including a proposed dry dam and water-diverting tunnel to reduce our vulnerability to future disaster.

“We create [the flood hazard] ourselves. It is not a fluke of a nature — it’s the most expectable thing there is. The flood wasn’t a hazard until we developed on a flood plain,” says Jerry Osborn, geoscience professor and expert in surficial geology and geomorphology.

Why do we continue to implement residential zoning in areas along the riverfront? It seems like a good way to put private property and homeowners at risk. The City of Calgary could rezone these areas as recreational areas or public space. There is a cost to rezoning, however, because if residential areas were replaced by recreational areas, the City loses a substantial portion of property tax revenue.

Downtown homeowners could alternatively be protected by the Alberta government through adequate headwater protection along the south-eastern slopes of the Rockies, where potential floodwater is diffused or slowed. This would mean preserving and maintaining forest growth in those areas. The government has not yet implemented such policy, possibly because timber harvesting companies in Hidden Creek Valley don’t like the idea. Neither do the motorized recreation community who often rip through unofficial trails in protected areas.

Undoubtedly there are a number of stakeholders involved including residential owners and businesses such as timber harvesting companies, and they must be consulted before flood mitigation policy is implemented. Trade-offs are necessary for successful planning.

Who should pay the costs of flood mitigation — the public, the government, industry or all three? Various groups have criticized the government for not doing enough to balance interests.

A proposed dry dam in the headwaters of the Elbow River is currently entering the environmental screening and community consultation phase in Alberta. A dry dam is specifically designed for flood control and would collect some floodwater when river levels are high in the Elbow River. However, key experts including Osborn, question the success of such a strategy.

“This dam will be too far upstream to do any significant mitigation for some storms,” says Osborn.

Others, such as Kevin Van Tighem, a wildlife author who has studied landscape ecology and conservation biology for almost 40 years, believes that such a dam would require massive storage capacity to hold back the volume of water that comes down during floods.

“A dry dam, at first glance, seems a clever idea. It’s essentially a dam with a permanent hole in it. The river runs through the hole. The hole is big enough to let a moderate flood through, but during extreme floods, the extra water can’t get through. Instead, the water backs up into a temporary reservoir,” he writes in the Calgary Herald in January.

Van Tighem believes the problem with a dry dam on the Elbow River is that massive amount of gravel, sediment and trees would impact the dam’s wall.

The impacts of building a dam will likely fall upon the ecological environment in that area, including fisheries and recreational users of the Elbow. Dam construction can block or delay fish migration and endanger species.

The most controversial project proposed is a tunnel that would carry water from the Glenmore Reservoir underground to the Bow River, further downstream. It would run right through Calgary and help control Elbow River overflows.

Osborn thinks it’s important to look at the beneficiaries of Elbow River engineering structures.

“Floodplain residents should assume the cost of their own risk, which is presently not the case. The general taxpayer pays for the risk, either in flood bailouts or they pay for it with dams and tunnels,” he says.

Oftentimes talk of this tunnel includes rhetoric about protecting the downtown, but experts assert that Bow River floodwaters will endanger downtown infrastructure, not the Elbow.

“Turns out that for the 100-year flood, downtown flooding comes from the Bow. My colleague and I are pretty convinced of that. The beneficiaries of the dam and the tunnel would be mainly homeowners on the Elbow and the Stampede Grounds,” says Osborn.

Using the downtown as a leverage point is effective because the downtown is not only the heart of Calgary, it’s symbolic of economic status and strength. And yet the Elbow dam isn’t really about saving the downtown, it’s about protecting the property values of residences along the riverfront.

A $300-million tunnel diverting water from the Glenmore Reservoir into the Bow would effectively excuse the provincial and municipal governments from rezoning and it would protect the interests of those who value their riverfront property.

The loss of electoral support aside, what costs more: the tax-payer funded tunnel or the loss in property tax revenue? The fact the City is entirely dependent upon property tax revenue is instituted by the provincial government. Fiscal issues that plague municipal government relate to the inability to manage water. The $300 million would be better spent if at least a portion were granted to the municipal government to buy riverfront properties and discourage further development.

“For the good of the city in general, it makes sense to buy up the houses closest to the channels and put in a strip of park that people could walk along. The money for the tunnels and dams could be spent on that instead. Politically that’s very difficult,” says Osborn.

Rather than private space along that riverfront, we could provide greater public accessibility to an enjoyable area. Osborn believes that parks and recreational space is easier to evacuate and can be cleaned up without as much cost.

Homeowners along the riverfront, such as Beth Brewer, disagree.

“I don’t want to move because I love my house. The river is a great amenity and it’s just a risk you take,” says Brewer, when asked about the reality of moving to another part of the city in case of another flood.

“That sense of community is rare,” says Brewer, of her Bowness neighbourhood. While residents were devastated by the destruction the flood inflicted on Bowness, she thinks it would be difficult to make people who lived there for generations leave.

“Rezoning is not an option. It’s a terrible idea,” she says.

“It’s the responsibility of the homeowner as well as the government,” says Brewer when asked who is responsible for flood mitigation.

While it’s difficult for residents such as Brewer to consider leaving their homes, re-zoning seems to be the best solution available. The reality is that Bowness and other communities near the riverfront will flood again. It’s just a matter of when.

If residents like Brewer already feel as though their sense of community was jeopardized by the 2013 flood, it’s frightening to imagine how liveable those places will be in the event of another, potentially more devastating event.

The government of Alberta recognized that the status quo of land management isn’t working and endeavoured towards a comprehensive regional planning framework in 2008.

The South Saskatchewan Regional Plan has been in the works since 2008 and is being drafted by the Government of Alberta and it will directly affect flood mitigation. The success of such a plan, especially after the flood, remains a contentious issue. The SSRP creates new conservation areas, establishes environmental limits, protects our water supply and provides clarity about land use and access. However, there are some major shortcomings in the plan.

Conservation director Kate Morrison of the Canadian Parks and Wilderness Society (CPAWS) explains the regional planning framework “aims to balance economy, communities, and environment by looking at how we manage our land.” Ultimately it has failed to achieve this goal.

Headwater areas are the source from which a river originates — the area furthest upstream in a river from its estuary. Maintaining intact forests in these areas helps retain some of the water that might otherwise flow downstream, and further reduces the rapid pace of that flow. Despite numerous public concerns regarding the protection of headwater areas, the Alberta government has not provided any substantial action in the SSRP to explicitly protect headwater areas.

“It’s less of a planning document and more of a political or policy document,” says Morrison. The draft proposed after public consultation introduced little change to current measures. Morrison points out that the newly proposed protected headwater areas in Calgary, Lethbridge and Medicine Hat have actually been protected since 1984 under a different piece of legislation. The plan does not outline any new areas to protect.

Forest in headwater areas has a number of roles: to soaks up, slows down and spreads water out. Cutting down forest to build road networks, for example, decrease the ability of forest to hold back water.

Some point out that severe floods have been a reality in this province long before our inadequate headwater management plan came along. Destroying trees in headwater areas, however, would make the problem worse.

“If we logged 50 per cent of headwaters we’re going to get more runoff and higher floods,” contends Osborn.

Protecting forest in headwater areas is therefore the best way to prevent massive flooding. Once an area is deforested it takes decades if not centuries to regrow and gain back its same capacity to contain water.

“I think what people find hard to understand is when we talk about headwater protection as a way of mitigating floods, we’re not saying it’s going to stop all floods. The difference between an intact and a fragmented or cleared forest is its ability to help mitigate those larger water flows,” says Morrison.

Planning should focus on longterm sustainability. Unregulated ATV activity and unofficial routes through headwater areas are a huge issue right now, and Morrison points out that violators are rarely prosecuted.

In addition to intensive logging, oil wells, factories, roads and pipelines are all culprits of deforestation. Economic development is a necessity, yes, but there are areas feasible for development, and areas that aren’t. Exploiting the natural environment doesn’t make much sense if it means compromising water quality and making houses and government buildings in the downtown more vulnerable to floods.

Headwater protection is inexpensive compared to flood diversion projects, and therefore should be considered part and parcel of reducing flood vulnerability. Diverting floodwater is just one, very reactive, solution to this problem. Headwater management is proactive; it accounts for climate change and the need to harness the environment’s ability to manage water. There is often an ideology that nature should be engineered to our own requirements rather than working with nature.

While there is merit to dry dams and diversion tunnels, there are obvious limitations. Planning departments must face this reality. A diversion tunnel or dry dam may not have the capacity to hold back another flood because we just don’t know how big the next one will be — nature is unpredictable, and any engineered solution will have a breaking point. Rezoning and better headwater protection may not look good on a politician’s track record, but it’s vital nonetheless. It’s important to consider the short and long-term perspectives and impacts of flood mitigation. Southern Alberta communities will be better for it in the end.