Down among the rumpled, sandy hills of Millersville lies a secret stream.

The rivulet is unseen by the drivers of 112,000 cars and trucks passing every day on Interstate 97. Farmers, home builders and highway engineers carved centuries of careless decisions into it. Choking on the muck they unleashed, the stream sent a brown plume into the Severn River with every passing storm.

If it ever had a name of its own, it is forgotten. Today, it is just Jabez 3, a tributary of a tributary.

Now, that stream may represent the future — told through an $8 million project incorporating ideas about climate change, water quality and habitat into 1½ miles of restored waterway.

The project was funded through the Resilience Authority of Annapolis and Anne Arundel County, a nonprofit set up by the two local governments. It is better known for its support of the planned $100 million City Dock project a dozen miles downstream.

“The approach of restoring natural flood plains in strategic places, allowing space for rivers to flood safely, fits into my overarching view that building climate resilience requires us to rethink the systems that supply our energy, transportation, food, water and housing,” said Matt Fleming, executive director of the organization.

“So for each project, we need to take an integrated approach and work across sectors to anticipate, plan for and mitigate the risks — and seize the opportunities — associated with change.”

Fifty years ago, naturalists realized Jabez Branch was the only trout stream in Maryland’s Chesapeake Bay coastal plain. By the 1990s, highway runoff had heated the water and killed off the fish. Spawning shad and yellow perch dwindled.

Environmentalists in 1990 walked the deeply rutted streambed and recognized it as a major source of waterborne silt blocking the sun downriver, harming underwater grasses, fish, crabs and oysters. They asked the state for help, then asked again a decade later.

The prospect of bigger storms and flooding driven by a warming atmosphere didn’t bode well for Jabez Branch, which breaks into three tributaries near the spot where I-97 merges with Route 32 in Millersville.

“That system was on a downward spiral,” said Erik Michaelson, head of watershed restoration for the county. “Climate change will definitely worsen that.”

If climate change is a recent concept, stream restoration is not. Anne Arundel County has been working its way through a long list of degraded streambeds, creating a tax in 2014 to fund the work.

Maryland is investing even more resources into rivers and streams. Spurred by a 2023 report on strategies for cleaning up the Chesapeake Bay, state agencies are turning their attention from its main stem after decades of underperforming results. A new state law that takes effect next month will identify five major waterways for state-funded, five-year restoration plans.

Cities such as Annapolis are pursuing big projects to prepare for climate change. The resilience authority is helping to fund a $100 million project that will raise part of the city’s downtown waterfront by 6 feet and create a network of flood barriers and pumps.

What Jabez represents is an adaptation, incorporating the priority to address climate change into existing ideas about water quality and habitat restoration.

“I think it’s hard to isolate water quality and habitat from the climate, because it’s all interconnected too, right?” said Gabe Cohee, director of restoration and resilience at the state Department of Natural Resources. “We’re talking about inundation, like more water coming, but also heat.”

This kind of work is not without controversy. After contractors in Howard County cleared trees to rebuild two streambeds, county residents warned state lawmakers about reckless contractors. New standards were adopted that include more public engagement and professional standards.

Even at Jabez 3, concern about effectiveness is so great that DNR has agreed to monitor the site for 10 years after it is completed.

Unlike the Howard County projects, the Jabez 3 work left alone the trees and other vegetation needed to help keep the area cool and provide habitat for foxes, frogs, damselflies and fish — even if the trout never return.

“We’re going to have hotter days,” Cohee said. “We’re going to have flashier storms. We’re going to have more issues with habitat. This kind of provides all that, and it’s all related to climate and resiliency.”

Jabez 3 isn’t easy to find. The work site is entirely within the state’s Severn Run Natural Area, and there are no plans to provide park facilities.

The staging site is on a family farm bought by Underwood & Associates, once owned by Willa Brown, the first Black woman to earn a pilot’s license in the United States.

On a recent hot afternoon walk, the yellow work road matches the color of a puckered sand pit chewing its way up a nearby embankment. A few steps down, and the thick canopy over Jabez brings a rewarding drop in temperature.

There, pools of water perfectly mirror the emerald leaves above. Tadpoles dart along the clear edges of murky brown bogs, and a fox half-hidden in the brush watches a tour of people pass by.

Along a path built for people and machines, water is continually moving. It tumbles in gently from the surrounding 13-acre watershed, shifting left and right through weirs of sand and gravel anchored by verdant shoots of rye.

Holding his cellphone up against the tranquil backdrop, Kevin Smith, executive director of the Maryland Coastal Bays Program, displays a photo of what it used to look like.

“So the original floodplain and stream valley was down 8 to 10 feet,” said Smith, who as the former deputy director of stream restoration at DNR helped design the project. “Then all the sediment came in and it built up.”

Rather than clear out centuries of sediment dating back to colonial tobacco and pig farmers, Smith’s design created the weirs to lift the water on top of it.

The design at Jabez 3 is fitted to its landscape. Anne Arundel is home to steeply sloped sandy hills, and here, they form a wall along its path crowned with mature trees. The setting was perfect for brook trout, first documented in 1974 and last seen 20 years later.

“You could drink that,” Smith said.

He is adapting the same techniques to the Eastern Shore. Land and streams there have been filled and ditched for farming so thoroughly that they resemble a patchwork quilt from the air. But on the ground, stormwater flows violently through those deeply carved drains.

More stormwater restoration is coming. Michaelson is working with the State Highway Administration to fix the stormwater runoff design at I-97 and Route 32. It is collaborating with the Navy on streams around a planned solar panel installation at the old Naval Academy Dairy Farm in Gambrills.

The Whole Watershed Act, which takes effect next month, will select five watersheds and focus state resources on a holistic approach to water quality, habitat, and other factors. Michaelson predicted the winners will likely be projects that represent connecting ideas, as has happened on Jabez 3.

“We’re going to see more intense storms, bigger storms, more water flowing through these systems, OK?” Smith said. “And so these systems … would just continue to remount that incised channel and send more sediment downstream and again, not treat the water.

“The way this is designed is to address a 100-year storm so that 100-year storm passes through this system fairly easily.”

Even if that 100-year storm is now once a decade. Or once a year.