Chicago had better get ready for bigger storms

What would happen if a disastrous storm hit Chicago, like a hometown version of Hurricane Maria?

Chicago has had its share of big storms, but thanks to our Midwestern location, we have avoided the kinds of disasters our neighbors on the coasts experience all too often.

But what if ? The world’s weather is in flux and far less predictable. At a time when we are rapidly approaching the daunting intersection of environmental responsibility, scientific evidence and economic investment decisions, the question needs to be asked sooner than later.

The Metropolitan Water Reclamation District of Greater Chicago is constantly monitoring weather patterns. Our engineers have multiple tools to prepare for intense rainfall.

First, they begin drawing the river system down to the absolute minimum elevation, which is 4 feet below lake level. This allows for maximum water retention in our waterways. Next, our seven treatment plants go into maximum production. Pumps 30 feet below ground drain sewers throughout the county, providing space to hold and convey water.

This includes emptying our Deep Tunnel, which holds 2 billion gallons, and our three reservoirs, which combined hold approximately 10 billion more gallons.

When a large storm hits, the system fills quickly. In addition to maximizing the capacity of our plants, tunnels and reservoirs, MWRD begins pumping storm water into the Ship and Sanitary Canal. In extreme cases, locks are opened to relieve water into Lake Michigan and save downtown Chicago from being under water.

The largest issue is conveyance. Local sewers simply cannot carry water fast enough to move it into the MWRD system. Imagine draining a swimming pool with a straw. The analogy shows the difference between the amounts of water we would receive in a 500- year storm and the pipes used to drain it.

In addition to sewer back- ups and slow- draining water, much of Cook County — particularly the suburban areas — would experience significant overbank flooding in a 500- year storm. Such a storm would cause $ 200 million worth of damage in Cook County, with economic loss in the billions. It would be a devastating event with long- reaching consequences.

MWRD has done a lot to prepare for extreme rain events, but every year, the county suffers flooding due to intense rainfall. There is more we can do.

We need to look at our outdated infrastructure. Sewers built 100 years ago cannot convey large amounts of water fast enough.

It is important to find creative ways to capture storm water before it enters our system. Rain gardens, permeable pavement, rain barrels — when implemented on a large scale, they can act as additional means of water detention and drainage.

Development is essential to our economic growth, but paving over our green space with concrete eliminates the porous ground that absorbs rain water. The district enacted the Water Management Ordinance in 2013. It mandates developers to account for runoff and detention when building. We need to engage the business community to do their part to protect against intense flooding.

Finally, we must accept that climate change is real, and that we have the responsibility to operate in a manner that reduces its effects. That means being smarter about how we create and consume energy and enacting policies and regulations that protect our environment.

It is no longer a question of “if ” a 500- year storm is coming to Chicago, but rather “when.” Will we be ready?