Flooding as a major suburban problem

Suburbs are often derided for their sprawling development that chew up acres of land and significantly alters more rural settings. Within that sprawl, one problem that consistently shows up but receives less attention than it should is flooding. For example, the significant rain received in parts of the Chicago region this past Wednesday (July 12) has impacted a number of suburbs:

While some suburban communities Saturday saw water levels begin to recede in the wake of Wednesday’s downpour, others still are bracing for the worst of the fallout from flood-ravaged rivers experts expect will crest later today into next week.

In Algonquin, the Fox River reached 11.79 feet by noon Saturday, with the National Weather Service predicting it will crest nearly a foot higher, at 12.9 feet, sometime Tuesday.

As of noon Saturday, The National Weather Service reported the Des Plaines River near Gurnee had reached a record-setting 11.96 feet and was expected to crest at about 12 feet sometime in the next 24 hours. In Lincolnshire, the level had dropped to 15.5 feet, but official predictions indicate the river may rise again to crest at 16.3 feet sometime Sunday.

While Wednesday’s rain was unusual (and we could argue about how frequently such big storms do and should occur), the results highlight a common issue across suburban landscapes: what happens to all that water? Suburbs don’t just change rural or farm land into developments; they change how water flows and is absorbed into the soil.

A variety of techniques are available to deal with the water. Common in this area are retention ponds, sunken areas within developments that are often dry but serve as places where water can pool when excessive rainfall occurs. In the Chicago area, the need to deal with flooding led to one of the largest civil engineering projects in the world: Deep Tunnel. Floodplains are fairly visible during heavy rains as homes and other structures near large bodies of water, particularly rivers, are affected. Less easy to see are  formerly swampy or marshy land which have been filled in, the channeling of creeks and rivers (or even covering them up completely), and covering the ground with less permeable surfaces such as roads and driveways (this can be combated by using different kinds of surfaces).

Instead of viewing flooding within major metropolitan regions as the unfortunate result of large storms, we should see it as a regular issue within suburban settings. And if we do so, that might prompt better plans to avoid the flooding that comes when so much land is altered.

Why Canadian communities may not have an incentive to avoid flood plains

If the costs for rebuilding in flood plains is covered by the provincial and national governments, why would communities limit building on those flood plains?

As the battle to protect homes from flooding continues across the country, questions are being asked about whether it’s time to reconsider regulations that allow developers to build on flood plains.

Jason Thistlethwaite, an assistant professor at the University of Waterloo’s faculty of environment, says the problem is that municipalities set zoning regulations and collect property tax revenue but do not pay for rebuilding costs after natural disasters.

“The municipality really doesn’t have an incentive to go in and use land-use planning and building codes and communications strategies to tell people that they are at risk of flooding, particularly given that most of the revenue comes from development, it comes from property taxes.” Thistlethwaite said. “So they face a real conflict of interest…

Last February, the Parliamentary Budget Office released a report estimating that over the next five years the federal government will dole out an estimated $902 million a year in disaster-related relief to provinces and territories.

I could see at least two good arguments against building in flood plains:

  1. The financial costs in the long run. Of course, the suggestion here is that local communities don’t bear the costs. But, even if they are paid at higher levels, the costs are going to get passed down eventually. Additionally, communities might benefit from property taxes but the reconstruction times and costs also would limit the property taxes they can collect.
  2. Environmental reasons: it can’t be good to have buildings and other debris from the built environment consistently washed into waterways. Limiting development on floodplains also allows for rivers and other waterways to go through natural cycles.

Either could be a good enough reason. However, as noted above, it is very difficult for communities to pass up on allowing development on desirable properties. There are similar situations in the United States.

One of the better options I’ve seen in some suburbs is to convert these flood areas to parks. This accomplishes two purposes: (1) when flooding does occur, the damage is reduced since it affects fewer buildings and (2) having a park nearby can enhance property values and the quality of life.

Solving flooding in China with “sponge cities”

Chinese officials are providing funds for “sponge cities” to reduce the effects of flooding:

“A sponge city is one that can hold, clean, and drain water in a natural way using an ecological approach,” says Yu, who is helping to coordinate the national project.

Traditionally, Chinese cities handled water well, Yu notes. “But in modern China, we have destroyed those natural systems of ponds, rivers, and wetlands, and replaced them with dams, levees, and tunnels, and now we are suffering from floods.”…

Reverse-engineering a city to make it more spongey requires a mental rather than physical shift, he argues. “It’s a whole new philosophy of dealing with water. It is about how we plan and design our cities in an ecological way. Not about piecemeal, manmade engineering projects. So we need to avoid this kind of trap.”

Sponge-city design could also run up against China’s centralized planning system.

It sounds like this is a major work in progress. As has been found in American cities, such as Chicago, trying to solve flooding issues after the city is a certain size is quite difficult. Are cities really willing to move residents or commercial structures to better deal with water issues? Is it only possible to make changes after a major flood convinces people? The optimal way to do this would be before the development happens as planners and others can set aside space or promote greener options.

“Touring the Deep Tunnel and Thornton Quarry,” one of the largest civil engineering projects in the world

Given the recent rain and flooding in the Chicago region, this seemed apropos: one journalist describes a recent tour of the Thornton Quarry and Deep Tunnel complex south of the city.

On Saturday, I joined the Southeast Environmental Task Force (SETF) on one of its tours of Chicago’s goliath infrastructure. The tour featured the future site of the Thornton Composite Reservoir, the largest such reservoir in the world, and a Deep Tunnel pumping station 350′ below ground at the Calumet Water Reclamation Plant. Both are part of the Metropolitan Water Reclamation District (MWRD)’s gargantuan Tunnel and Reservoir Plan, the multi-decade, multi-billion dollar project designed to protect the Chicago region from the flooding and pollution caused by overflowing sewer and stormwater infrastructure…

After this brief greeting, we drove to the former Thornton Quarry in the south suburban city of Thornton. The quarry, which is one of the largest aggregate quarries in the world, is still being actively mined nearby; however, the MWRD has acquired two significant portions of the area for the Deep Tunnel project. The resulting reservoir will hold 7.9 billion gallons of water, which MWRD Principal Civil Engineer Lou Storino estimated is the equivalent of 36 Soldier Fields. While on site, staff mentioned that we would be one of the last tours to descend to the base of the quarry, which will enter into operation shortly.

Tourists may find man-made sights like Hoover Dam impressive but Chicago area residents don’t have to go far to see similarly impressive projects. Not that the public could simply walk into the Deep Tunnel complex but you can glance at the quarry from the I-80/94 corridor. The Deep Tunnel project was quite costly and time-consuming but represents an effort to more effectively drain water away from Chicago, an on-going concern that even one of the largest civil engineering projects can’t solve on its own. This is what you get when you build a 9+ million metropolitan region centered on a swampy area near Lake Michigan…

Toronto park also serves as a dyke to protect surrounding neighborhood

One Toronto park goes beyond providing recreational space by providing protection against flooding:

Corktown Common Park is a beautiful urban oasis—the 18 acre park, situated in the West Don Lands district of Toronto, boasts a wildlife-filled marsh, athletic fields, playgrounds and plenty of place to sprawl out on grass or host a bbq. But the coolest of the park’s features is the one you can’t see. Built into the sprawling greenland is a plan to protect the surrounding neighborhoods from flood waters. The landscape architects from Michael van Valkenburgh Associates partnered with engineering firm Arup to build a park that looks like nature, but works like a dyke…

Because Corktown Common was developed on a flood plain, the team began by building up the area’s natural elevation. Nearly nine meters of land was added, creating a natural barrier to rising waters. “We had to make sure that the park and the infrastructure were well integrated so that in the end it didn’t feel like a piece of pure infrastructure but felt like a welcoming park that is connected to the urban fabric,” explains Mueller De Celis. This required MVVA to add an additional six meters of topography on top of the original infrastructure. It comes in the form of rolling hills, playgrounds and open green space.

The park is split into a wet and dry side. As water falls on the dry side—whether that be from rainfall, flood waters or from the water playground—it gets collected and directed through a series of underground pipes into a cistern. This water is then reused for irrigation. MVVA says it expects the water to be used anywhere from two to four times before it evaporates. Beyond sustainability, this system also has the added benefit of relieving pressure from the mouth of the Don River by slowing the water flow that dumps into Lake Ontario.

This infrastructure is masked by more than 700 trees, and more than 120 species of plants (95 percent of which are native to the area). Mueller De Celis says that as soon as the marsh was implemented, wildlife bloomed in what used to be a browned-out, post-industrialized area. She recalls one day when she was giving a tour of the park. There was construction happening in the neighborhood, as usual. “The people who were touring couldn’t hear me, not because of the construction but because of the frogs,” she recalls. In the process of building development-enabling infrastructure, Toronto has found itself with a real ecosystem in the middle of the city (no wildlife was reintroduced). As Mueller De Celis puts it: “It might be a constructed landscape, but the wildlife don’t know that.”

Building parks in floodplains is not a new idea – it can be a good use for that space and flooding then does not damage as much. But, this sounds more unique in protecting a surrounding urban area and providing space for development. And, it sounds like all of this is hidden out of sight from people in the park, making it yet another piece of important infrastructure that works best when no one notices it in the background.

Connecting McMansions to water runoff problems

Echoing a post from a few days ago, a editor to the letter suggests the construction of McMansions has led to more flooding problems in Needham, Massachusetts:

The recent Times article on flooding after our “hundred year storm” didn’t mention one likely contributor to the storm water runoff problem — McMansions. Teardowns surely contributed to the recent flooding, because each new McMansion’s large footprint eliminated a big chunk of drainage land from Needham’s overall water absorption capacity. And building large homes on previously open lots is an even more direct “drain” on our Town’s total runoff capacity.

I’m sure someone could go through the records and calculate exactly how many acres have been lost to big houses (and driveways) over the past 10 years of heightened development. Though we haven’t exactly “paved Paradise and put up a parking lot,” I’m guessing this is enough of a factor that it should be taken into account as Needham considers its longer range development future.

At face value, this seems to make sense. However, I would still have a few questions:

1. What if the new teardown McMansions actually include more efficient drainage systems? This might occur because of updated building codes. I’m not quite sure how this might balance out against having a larger footprint.

2. Is the problem really McMansions, large houses on smaller lots, or is this more of a problem of sprawl in general? Perhaps bigger suburban houses are worse than smaller suburban houses when it comes to water issues but it seems like the underlying problem might be suburban development in the first place.

3. Are there better ways for homebuilders to limit water runoff with new homes? If so, why not require these options for new homes? Local municipalities could make such decisions if they are unwilling to limit more sprawl. Why not require permeable driveways and roadways in new developments?

Considering a new utility tax in DuPage County to help address flooding

These are the sorts of issues sprawl brings: the DuPage County Chairman discussed a new power available to the county to collect tax monies to address flooding.

Cronin told the audience at a Naperville Area Chamber of Commerce luncheon that flooding has long been a serious problem in DuPage.

In order to address it, he said, infrastructure improvements are needed. Right now, money for those projects comes from property taxes.

The proposed utility fee would charge property owners based on use. Those who have more stormwater leaving their land would pay a higher fee. Anyone with land producing less stormwater runoff would pay a lower fee.

Enacting a utility fee would make it possible to have charges for stormwater projects removed from the property tax bill, he said…

However, some residents already are opposing the idea. Last month, protesters demonstrated before a county board meeting and called the proposal a “rain tax.” Objections also are expected to come from schools, churches and other tax-exempt entities that would be required to pay the fee.

At this point, DuPage County is largely built-out (or the land is tied up in Forest Preserves) so dealing with flooding is largely taking place after the development has already happened. Thus, remediation can be quite expensive. I imagine residents and organizations would not like the idea of a new tax but flooding is a serious recurring issue.

On a related note about the cost and length of projects intended to combat flooding: here is a story about progress being made at constructing the world’s “largest reservoir of its kind in the world” in the south suburbs as part of the impressive Deep Tunnel.

A small crowd gathered Monday at the lip of the mammoth Thornton Quarry, all eyes fixed on an outcropping of dolomite nearly 300 feet below the shoulder of the westbound lanes of Interstate 80.

A ripple shot through the two-story rock formation, and it collapsed amid a small, dusty landslide. And so construction of the largest portion to date of the decades-in-the-making Deep Tunnel floodwater control system began with a bang…

When it goes online in 2015, the Thornton Composite Reservoir will hold 7.9 billion gallons of stormwater and sanitary sewer water from more than a dozen south suburban towns…

The 30-story-deep reservoir will fill like a regional bathtub during massive storms that threaten to overwhelm local sewer systems, a problem that has grown worse with more frequent and intense downpours in recent years and as development has replaced open, absorbent land with rooftops and pavement.

Dealing with flooding is not easy