No small task to install stormwater detention tanks

When designing a new hospital, it’s easy to get caught up in the “shiny and new” aspects of the building and grounds. It’s exciting to see pretty pictures depicting wide open green space and light filled rooms that offer promises of good health and renewal.

What you don’t hear much about are the more mundane projects, like the installation of a new stormwater detention system, which begins the week of March 4, 2019.

Are you still reading? OK good. 

Admittedly, there’s nothing spellbinding about stormwater detention tanks in and of themselves. The cool factor is how these tanks will help our community.

When fully operational, the tanks will divert hundreds of thousands of gallons of stormwater off MetroHealth's campus every year for decades to come. This will prevent flooding, erosion, street damage and raw sewage from entering the Cuyahoga River and eventually Lake Erie.

That’s right, raw sewage.

Cleveland has century-old combined sewer pipes that carry stormwater and sewage water together, taking it to treatment plants. During heavy rains, these pipes may get overwhelmed. To prevent sewage back-ups in homes, the pipes are emptied into area waterways using a combined sewer overflow system (CSO). The sewage and stormwater then makes its way to Lake Erie.

The Northeast Ohio Regional Sewer District’s (NEORSD) Project Clean Lake will separate sewer and stormwater pipes in the region going forward and remove approximately 98 percent of raw sewage and polluted stormwater from entering waterways.

MetroHealth’s new stormwater detention system will do something similar, as it diverts stormwater from the combined sewer system; here’s how it works:

1) When it rains, the stormwater that runs off our campus surfaces is diverted to the detention system, where mud, muck and other debris are able to settle out before exiting the system and entering the downstream sewer. The settling of debris increases the water quality of the released stormwater to meet Ohio Environmental Protection Agency regulations.

2) The water then slowly drains into an 84-inch ODOT storm sewer at a controlled rate to reduce erosion and flooding. This sewer is beneath I-71.

3) The water continues to flow underground through a series of pipes, eventually emptying into the Cuyahoga River.

According to Sarah O’Keeffe, Director of Sustainability, these stormwater detention tanks make MetroHealth more resilient to handle and recover from the increasingly fierce and frequent storms we are experiencing due to climate change.

The series of tanks not only avoids the city’s combined sewers, decreasing the likelihood of sewage going into the lake, but they also slow the rate of stormwater run-off, preventing erosion.

The tanks will also be a welcome relief for staff of the Emergency Department and ambulance bays. This area is prone to flooding due to its location, which is one of the lowest points on campus. The configuration of the new hospital, coupled with the capacity of the tanks, will change this dynamic.

While the tanks are the first step in a “greener” campus, Sarah says there are many other ways we can keep stormwater at bay including the materials we use for sidewalks and parking lots and how, where and what we plant on campus.