EDMONDS — One of the city’s landmarks is its 28-acre fresh- and saltwater marsh.

Visitors can spot up to 225 species of birds there. Its cattails and wetlands are remnants of what was once a 100-acre marsh, stretching from what is now Marina Beach Park north to Brackett’s Landing.

Now the city wants to know more about the marsh’s health, analyzing issues such as the impacts of stormwater, how the marsh could be affected by different buffer requirements, and how plans to daylight Willow Creek, which flows into the marsh, will impact it, City Council member Mike Nelson said.

“We’ll have people go out there and test the water, look at the wildlife habitat, and how much of an impact pollution is playing on its functioning,” he said.

The study also would take a look at how different sizes of buffers could boost the ecological effects of the daylighting project.

Plans call for freeing about 1,000 feet of Willow Creek from pipes in which it has been encased since the 1960s, allowing it to meander toward the beach.

Juvenile salmon, once they migrate out of streams, look for salt marshes to rear in. The Willow Creek project “is about bringing back juvenile salmon,” Nelson said.

Work on the marsh study could begin early next year. The City Council is scheduled to hear from two prospective firms that have submitted proposals for the work at its Nov. 14 meeting.

The study’s cost will depend on how many topics the council wants the firm to explore, but could range from $200,000 to $400,000, Nelson said.

“We’ve read other folks’ studies,” he said. “The City Council felt like we wanted our own objective assessment, especially the science behind it as we move forward.”

Information from the study could guide future development and restoration projects in areas surrounding the marsh, he said.

For a long time, the marsh might have been a little overlooked, Nelson said. “You have to kind of go a little out of your way to find it.”

But as one of the last remaining saltwater estuaries in the Puget Sound region, “it’s clear that it’s an important resource,” he said.

Sharon Salyer: 425-339-3486; salyer @heraldnet.com.