STANWOOD — A large area on the east side of Port Susan looks very different from how it appeared six months ago.

Previously diked off and dry, the 150 acres now floods at high tide with salt water from the bay and is teeming with ducks and snow geese.

“It’s a great feeling,” said Kat Morgan, manager of Port Susan programs for the Nature Conservancy, which owns the property.

The environmental preservation group breached an old earthen dike to allow salt water to rush into the site and reinforced another old dike to protect farmland.

The change is expected to restore original wildlife habitat to much of the east side of the bay north of the mouth of the Stillaguamish River, also known as Hat Slough.

A new tidegate also was installed to allow water to run out when flooding does occur. The $4 million project, by Northwest Construction of Bellevue, involved a lot of earth moving and was done between May and October. The money came from state and federal environmental programs and private donations.

First, the original, inner dike along the adjacent Twin City Foods farm was reinforced. At the dike’s north end, a new section of dike was built to connect to the original and make it longer. Dirt was skimmed off the top of the outer dike to help build the new one.

In September, the outer dike, 14 feet high, was breached in two places. Salt water crept through at high tide and now, after more than two months, the only signs of the dike are some decayed pilings and a marshy area that grew up on the dike’s outer side.

Sunny weather in August and September helped crews get the project done.

“That helped keep everything on schedule,” Morgan said.

The 1.4 mile-long outer dike near the river mouth was built in the late 1950s by farmer Menno Groeneveld, the son of a Dutch immigrant, according to the Nature Conservancy. He tried to farm the enclosed area over the years with little success. The environmental group bought the property from Groeneveld’s estate in 2001 for $2 million.

The outer dike not only dried up the tidelands in the enclosed area but blocked fresh water and river sediment from moving north in the bay. This starved that area of the water mix needed by native plants and animals, and it has slowly been losing marshland, Morgan said.

Removing the dike is expected to improve fish habitat by providing young salmon with cool, deep channels where they can hide, feed and adjust to the saltwater environment.

“They have to fatten up in that place,” said Lisa Bellefond, external affairs director for the Puget Sound Partnership, a state-funded environmental agency based in Olympia. “These are like the teenagers that are going off to college.”

The Puget Sound Partnership sets goals for restoration of each section of inland waterway, Bellefond said. In Port Susan, the target is 315 acres, meaning the Nature Conservancy project gets it half way to the goal — not counting the potential benefits to the northern part of the bay.

“This project is incredibly important for many reasons,” she said.

The area is a popular spot for birders. The Nature Conservancy has opened the outer dike to the public on a by-permission basis, but plans to keep the new and reinforced dikes closed at least until January while staff monitor the area’s progress, Morgan said.

It could take five years or more for the habitat to restore itself, but changes will be visible along the way, especially in the wet season, she said.

“Winter’s when the changes will happen,” Morgan said.

Bill Sheets: 425-339-3439; sheets@heraldnet.com.