How to Make Our Cities More Like Sponges

Posted by Ecogardens


How to Make Our Cities More Like Sponges | If we can make our cities more like sponges, we can solve pollution problems and recharge our aquifers.


Our cities are plastered with impermeable surfaces that cause toxic stormwater runoff and deny water to plants, soil and aquifers that need it to maintain healthy processes. To address this, we need to make our cities more like sponges NOW.

When we found out it was Water Week, we’ll admit it caught us by surprise. Mostly because every week should be water week.

Is that just us?

But whether you were on it from the beginning or just finding out now from us, Water Week is definitely worth celebrating.

Taking our cue from Debra Shore, who is on Cook County’s Metropolitan Water Reclamation District Board, this year we’re looking at how to make our cities more like sponges.

Because we are not nearly spongy enough, and it’s time to change that with sensible green infrastructure.

Why Do Our Cities Fail to Soak Up Water?


How to Make Our Cities More Like Sponges | Today, cities are covered with impermeable surfaces that make it hard for them to absorb precipitation.

Our cities are covered with impermeable surfaces. That means when rain falls or snow melts, there’s often nowhere for it to go but somewhere else.

It collects in gutters and barrels down drainpipes. It sheets off of buildings. It runs through the streets and floods over parking lots. It overflows the sewers.

In the process, impermeable surfaces contribute to runoff, disease and pollution.

Which is not awesome, to say the least.

In addition to the above-named problems, it means that precipitation heads into streams, rivers and out to sea. Instead of soaking into the Earth to nourish local habitats and recharge aquifers, stormwater runoff instead contributes to a huge 21st-century problem: rising sea levels. We need to make our cities spongier now.

Benefits of Making a City Like a Sponge  


How to Make Our Cities More Like Sponges | There are many benefits of making cities more able to absorb water.

Pop quiz: What’s way more awesome than stormwater runoff?

Aquifer recharge.

Unless you’ve been living under a rock (and there is very limited Wi Fi under rocks, so we’re guessing if you’re reading this you haven’t been), you’ve heard about the trouble our aquifers are in. Agriculture, lawn irrigation and even running toilets all busily pump water out of aquifers, with very little getting replaced.

According to the USGS, “Water movement in aquifers is highly dependent of the permeability of the aquifer material. Permeable material contains interconnected cracks or spaces that are both numerous enough and large enough to allow water to move freely. In some permeable materials groundwater may move several meters in a day; in other places, it moves only a few centimeters in a century.”

When your best case scenario is a few meters a day, you have a problem. Paving over permeable surfaces and further limiting groundwater avenues does nothing to help.

The benefit here is, by making our cities more permeable, we can automatically improve groundwater movement and aquifer recharge. Yay!


Additionally, better overall stormwater management would:


  • Reduce the number of toxins picked up and carried into waterways by groundwater (Instead, chemicals from jet fuel, pesticides and smog would all soak into plant-covered ground for treatment.)
  • Reduce waste and disease, which can also be treated by plants effectively
  • Decrease erosion, which muddies up waterways and wears away priceless topsoil, turning valuable land into dust bowls


Suffice it to say, sponginess is a must. So how do we do that?

How to Make Cities More Like Sponges


How to Make Our Cities More Like Sponges | The best way to make cities more spongy is to increase permeable surfaces.

Luckily, the answer to making cities spongier is pretty simple in concept, if not in execution:

Create and steward more permeable surfaces. We can do that by:


  • Preserving ponds, streams and wetlands
  • Building more parks and green spaces
  • Using permeable pavers for parking lots, sidewalks, driveways and even streets
  • Enhancing curb plantings and tree pits


We can also return water to the atmosphere through evapotranspiration, the process of plants absorbing and then exhaling water. Green roofs are a particularly effective way to do this, though there are other approaches as well, including urban gardens, rain gardens and bioswales.

Even blue roofs, which have their own issues, are a good tool in the arsenal.

Want to learn more about the many possible strategies for making our cities spongier? We invite you to get in touch with us and talk about it today!



Topics: Green Infrastructure

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