As April rains fall, patients and staffers at Park Nicollet Methodist Hospital in St. Louis Park can rest a little easier this year than they have in the past.

This spring offers the first test of a 370-foot concrete flood wall between Minnehaha Creek and the lowest part of the hospital campus — even though so far, as Bob Riesselman said, "It looks like Mother Nature is being kind to us now."

Added Riesselman, director of engineering for Park Nicollet Health Services: "I think that in 2014 we were in the same position. Then, June was a tremendously rainy month and it surprised everyone."

In 2014, Methodist Hospital's operations were imperiled by flooding after sustained rains raised the creek's water levels. The encroaching water nearly cut off access to the hospital's loading docks, which would have limited supplies, food and waste removal. After volunteers helped fill nearly 30,000 sandbags, a permanent solution was sought. "Rather than sandbagging and getting the same result, we reviewed building a flood wall," Riesselman said, "but you don't just build a flood wall. There's a lot of permitting involved."

To complete the wall, the hospital partnered with the Minnehaha Creek Watershed District to help with federal, state and local regulations. The project included the excavation of nearly three acres of wetland to replace nearly 1,200 cubic yards of flood plain that were lost due to the wall's construction.

"Regulations require that, if you fill the flood plain or restrict access to water, whatever volume you take away you have to create," said James Wisker, the watershed district's planning and projects director. One option was to dig a hole in the parking lot and remove trees. But excavating the wetlands actually gave the agencies an opportunity to restore them by removing invasive plant species like cattails and planting different shrub and tree species.

"We get flood protection, and we get help with long-term maintenance of the wetlands," Riesselman said. "The district gets ongoing support for watershed reparations and improvements from us."

The wall is 5 feet at its highest point and averages 3 feet in height. Completed late last year, it cost the hospital $1 million to build; excavation and associated project costs amounted to another $1 million.

Wetlands are 'unsung heroes'

The wall was not the first collaboration between the hospital and watershed district that found mutually beneficial solutions.

They worked together in 2009 on the hospital's expansion, which resulted in realignment of 1,000 feet of Minnehaha Creek and restoration of about 10 acres of wetland. The hospital offered public access to the wetland via a 1,900-foot boardwalk.

"That project reoriented the entire hospital around what it once considered its backyard," Wisker said.

The 2009 project served as the catalyst for an urban stream restoration project called Minnehaha Creek Greenway. The project aims to restore the stream to its original state and rebuild the wetlands around it via partnerships among the watershed district, several businesses and public agencies. "In Minnesota, we're blessed with a lot of surface water," Wisker said. "We have wonderful lakes, streams and rivers. They're often the water bodies that get the most attention. But the unsung heroes are often wetlands, because they regulate the hydrology of any watershed. The quality of the lake or the quality of the stream — or the amount of water that you get in a lake or stream during a flood event — is largely the product of wetlands."

Though nearly done, certain elements of the project are still pending. "We still have, as part of our reparations, some planting that we couldn't do during the middle of the winter," Riesselman said. "You can pour concrete in winter, but you can't effectively stain it. That will be done in a couple of weeks."

Gabriel Sanchez is a University of Minnesota student on assignment for the Star Tribune.