Commentary: We’ve been successful in combining floodplains and greenways; now we need an urban counterpart.

It’s hip to be (a water) square

What if we could engineer urban public spaces to play in while simultaneously helping our storm drain systems and storm water capacity? How would our city look different?

This time of year in the Carolinas the sky opens, streets flood and parks become ponds.This photo shows Frazier Park flooding last Aug. 5 – the worst flooding in three years in Mecklenburg County. Around the country, a June flooding disaster in Duluth, Minn., and the drenching Florida experienced from slowly spinning tropical storm Debby were just the most recent examples of the danger to property and lives from too much water in too short a time.

However, during a recent research trip through Europe I encountered creative urban water management solutions that go beyond protecting lives and property, by creating attractive places for people, too.

Rotterdam is in over its head in water challenges. Architect Florian Boer of De Urbanisten (The Urbanists) has added something new to the well-known repertoire of water management tools, such as green roofs, rain gardens, storm drain systems and pervious pavement. He has designed “water squares,” which act to hold the heavy runoff from storms. During sunny days, the plaza invites people to sit, lunch, read, watch and play. But as it rains, the water square begins to fill with water, and the deeper the rain, the more water will cover the square, creating new patterns. The squares spread the water-holding capacity throughout the city, easing the rush on the storm drains.

After all, why not design places so they can be useful to the public – even beautiful – for the 90 percent of the time they aren’t needed as part of the storm water system?

One way to integrate water catchment into the existing city is to build underground catchments. But they are expensive. So, instead of spending a lot of money on one underground system, why not spread out the money, and put it into making more quality public space at the same time, combining the needs of the storage surface space and people space? Can solutions to our local issues be solved in ways that have similar overlapping benefits?

Making room for the river

Rotterdam’s strategy is to make more room for water. The city has predicted it will need to accommodate for 600 million liters of extra water over the next five years. [1] That’s enough water to fill 200 Olympic-sized pools. Because creating a huge lake in the city is out of the question, enter the concept of the water squares – spreading water capacity throughout the city. In a project that parks cars and water, Rotterdam has built a parking deck in Museumpark that accounts for 10,000 cubic meters of water storage[2]. The parking deck not only holds water within it, but also contains water above it and sits next to and under a public space.

Softening the city

Boer speaks of “softening the city.” During flooding, infiltration – the ground’s ability to absorb water – is key. In a hard-surfaced city, this capacity is limited.

Rotterdam, which is below sea level in a low-lying delta region, has recognized that climate change will increase peak rainfall and cause fluctuation in the water coming from rivers. With shallow ground water, plus heavier and more frequent rainfalls as well as water from the North Sea and the Maas River, the water has fewer places to go, except to flood. Because the frequency of heavy rainstorms is increasing, the storm water system can’t handle the volume. Sewers overflow, and it’s a mess.

Charlotte also must deal with rivers, although in the Queen City they’re called creeks. According to Jennifer Frost of the City of Charlotte Storm Water Services, there are 34 major creeks and 3,000 miles of open-air creeks in Mecklenburg County, a comparatively large system in North Carolina.

Soak-store-release

Perhaps we can think about our parking lots as rain catchment surfaces, implementing artful ways to capture the flowing water, temporarily relieving our storm pipes. Looking out across the parking lot across from ImaginOn on Seventh Street, I can envision a low wall on the lowest point to capture and hold water temporarily to give the storm pipes a chance to recover. What about the empty corner lot at Sixth and Tryon streets where the derelict Carolina Theatre has awaited restoration for decades? Could a park there act to collect the rain from surrounding buildings and retain water rushing off the pavement, while doubling as a park on the sunny days? 

As I talked with a few staff at the Mecklenburg Storm Water services department, I learned they have developed a series of innovative programs like the Future Conditions Floodplains mappings, private-public partnerships, pond retrofitting, low-impact development manuals, a flood notification system and property buy-out programs. They have taken ownership of the Future Floodplain mapping process and have developed it into one of the best floodplain maps in the country, says Tim Trautman of Mecklenburg County Storm Water Services. Starting in 1999-2000, the county instituted 100-foot creek buffers (undevelopable areas next to the creek) which have changed development, improved water quality and have helped create today’s greenways, while preventing property damage.

Have you ever walked along the Little Sugar Creek Greenway behind the Park Road Shopping Center along Westfield Drive? There used to be close to 50 homes along the street. Charlotte-Mecklenburg Storm Water Services purchased these homes in 2002-2003. Doral/Cavalier apartment buildings off Monroe Road along Briar Creek have been the latest site to see demolition in favor of a floodplain. Twenty-four acres of open space are now available to give more room to the creek. In 12 years the acquisition program has removed 250 buildings, displacing 350 families.[3]

While these projects are helping improve safety for residents and reducing property damage, what about measures that can be used in more urban areas upstream of the creeks that catch the runoff? In less dense neighborhoods along the creeks we’ve combined the benefits of having the buffer of a floodplain with greenways that provide added health, recreation and connectivity benefits. With water squares, we can develop a similar multi-beneficial approach to our urban waters.

Views expressed in this commentary are those of the author and do not necessarily represent the views of the UNC Charlotte Urban Institute, its staff or the University of North Carolina at Charlotte.


[1] De Urbanisten and the Wondrous Water Square,  page 10.

[2] http://www.waterworld.com/articles/wwi/articles/print/volume-25/issue-5/editorial-focus/rainwater-harvesting/rotterdam-the-water-city-of-the-future.html

[3] Author interview with Dave Canaan. July 3, 2012