This winter, when the pond at Singer Farm tops its banks, the excess water will cascade over a sinuous trail of boulders and rocks, passing by native shrubs and trees before spilling into Judd Creek some 50 yards away.

It didn’t used to be this way. The pond used to service cattle, animals that would wander through this sloping pasture adjacent to Judd Creek, trammeling creekside vegetation in the process. The nitrogen in their waste would seep into the water, pollutants that would make it all the way to Quartermaster Harbor.

Now, thanks to a set of agreements and property transactions between the Singer family and the Vashon-Maury Island Land Trust, as well as support from King County, a transformation is taking place in this once-barren cow pasture — part of a bigger effort by the land trust to restore Vashon’s largest watershed.

Over the last several months, a small county crew — part of the Small Habitat Restoration Program — brought in a backhoe and created the stream bed that now snakes from the pond to the creek. They planted hundreds of native trees and shrubs — cedar and cottonwoods, ninebark and dogwood — that will eventually provide a swath of riparian habitat along the new stream. Bullrushes and sedges now line the pond, the beginnings of what land trust staff call an emergent wetland.

Tom Dean, the director of the land trust, Abel Eckhardt, the land trust’s steward, and Beth Bordner, its operations manager, walked the former pasture on a clear day last week, taking in the scene and discussing its importance. The land trust owns the 16-acre pasture; another nine acres of pastureland — still owned by George Singer — have been fenced to keep cattle out of sensitive areas.

“We’ve really made a commitment to this entire watershed,” Dean said. “And this is the right place to do it. Not just because of chum and coho, but also because of a host of other species.”

The willow flycatcher, an imperiled songbird, for instance, needs large swaths of stream-side habitat to thrive. Judd Creek flows into Quartermaster, where grebes, scoters and terns are in a steep decline, in part, some believe, because of the bay’s poor water quality.

“Judd Creek is small and may seem inconsequential,” Dean added. “But it ties into the rest of central Puget Sound.”

The restoration at Singer Farm in Paradise Valley is just one piece of a far-reaching and ambitious effort by the land trust. All told, Dean said, the land trust has invested around $500,000 and worked with the county to purchase 80 acres of various sizes and shapes along the main branch of Judd Creek over the last six years.

The organization’s latest purchase, slated to close next month, is small — a 2.5 acre parcel. But like other acquisitions along the creek, it holds some significance to the land trust: The parcel harbors a history of illegal uses, including a pump that was taking water out of the creek without a water right, an un-permitted septic system that was putting nitrogen into the stream and a barn-like structure that had become a year-round home.

“Judd Creek is really a puzzle,” Dean said. “We’re putting the pieces together.”

The west fork of Judd Creek — the only fork that flows year-round — originates in Island Center Forest, wending its way south through Paradise Valley where the east and west forks converge. Soggy wetlands and dozens of springs, including 14 seeps at Singer Farm alone, feed it before it empties into Quartermaster Harbor.

The creek and its watershed are important not only for their size. Judd Creek hosts Vashon’s largest concentration of coho and chum salmon, as well as cutthroat trout and the native Western pearlshell mussel.

What’s more, Dean said, the soils in the watershed provide the highest level of recharge to Vashon’s aquifer, the source of the Island’s drinking water.

Last week, as the three land trust staffers made their way across various parcels now owned by the organization, they noted some of the transformations currently under way.

The former Doretha Park — a five-acre parcel between the Singer Farm and the Sportsmen’s Club that for a while was the site of a clandestine marijuana operation — is now dotted with up to 1,000 small cedars, firs and shrubs, part of an ambitious reforestation project by the land trust.

Another parcel, this one off of 111th Avenue S.W., also shows the land trust’s handiwork. A jungle of Himalayan blackberry vines has been removed, and the bare ground is now sprouting a sea of spindly willows, dogwood, vine maples, Douglas firs and cedars.

Dean looked at an adjacent property not owned by the land trust — impenetrable because of the blackberries. “That’s what this used to look like,” he said.

The restoration projects along Judd Creek reflect not only the organization’s commitment to the watershed, but also its maturation as an organization, Dean said. The land trust undertook its first restoration project in 2000, when it saw restoration as “reforesting a former meadow,” Dean said. Now, at the Singer Farm as well as elsewhere, “we’re creating habitat assemblages,” Eckhardt said — a suite of habitats, from forest to riparian to emergent wetlands, that more fully replicates natural systems.

With diversity of habitat, Eckhardt noted, comes a diversity of species. “We’ve gotten much more sophisticated,” Dean added.

But replicating nature takes time, and as Eckhardt made his way along Judd Creek, pointing out habitat features of note, he added that this work will have to continue long after he’s gone.

“These aren’t 10-year projects,” he said. “They’re 100-year projects.”