Internet Explorer 11 is not supported

For optimal browsing, we recommend Chrome, Firefox or Safari browsers.

Moving Upstream to Keep Pollution Out of the Chesapeake Bay

Planting trees along small streams is a simple idea with big consequences for watersheds.

Fall 2022 Garden work day.jpg
Community members working in the pollinator garden at Overlook Community Campus in Manheim Township, Pa. Some of the 2,000 trees planted in an eight-acre streamside forest and pollinator garden can be seen in the background.
(Stroud Water Research Center)
In Brief:
  • Chesapeake Bay, the nation’s largest estuary, is a laboratory for mitigating sediment buildup and diminished water quality.
  • Eighty-five percent of the river systems that feed the bay are small streams, making them vital to its long-term resilience.
  • Planting trees and shrubs along stream beds can reduce sediment flow and improve water quality. A project in a public park in Lancaster County is bringing both environmental and educational benefits.

  • Bill Sauers, director of public works for Manheim Township, Pa., is responsible for a legacy that goes back hundreds of years. From the time of colonial settlers forward, humans have altered the system of streams and waterways in his county, clearing forests, building dams and streamside mills.

    In addition to changing the ecology in and around streams, they left something for future generations: enough accumulated sediment to harm the health of the Chesapeake Bay watershed.

    “Lancaster County is one of the largest contributors to pollution of the Chesapeake Bay,” Sauers says. “We have a strong commitment to clean water here in the township and its role in the bigger community.”
    Pollinator Garden.jpg
    The pollinator garden in bloom. One of the aims of the Overlook Community Campus is to inspire visitors to bring the native plants, trees and shrubs they see into their home gardens.
    (Rebecca Lauver, Alliance for the Chesapeake Bay)

    Sediment vs. Sunlight, and Other Problems

    Sediment that makes its way into the bay can have a range of unwanted effects. Sunlight can’t reach plants if the water is too cloudy, denying shelter to fish and shellfish. Sediment can smother species at the bottom and carry unwanted chemicals or nutrients that bind to it.

    As part of meeting the requirements for its Environmental Protection Agency (EPA) Municipal Separate Storm Sewer System (MS4) permit, Manheim Township was mandated to reduce “legacy sediments” that could be as deep as three to five feet in some stream areas. “When you get a high flow from a storm, it activates that sediment and it picks it up and carries it to our streams, to the Susquehanna River, and then eventually to the Chesapeake,” says Sauers.

    Manheim Township has completed seven stream restoration projects, reducing legacy sediment flow to the bay by an estimated half million pounds a year. It’s going beyond what EPA has mandated, with its next project planned for the summer.

    A central strategy in this work is planting “riparian buffers” of trees, shrubs and plants along streams. One of these projects, Overlook Community Campus, has added other dimensions, creating a space for ecological education and making art.

    Trees Work for Free

    Rivers might grab more attention, but the smallest streams make up 85 percent of stream and river systems, says Lamonte Garber, watershed restoration coordinator at Stroud Water Research Center. “We might fish, and we might paddle on the river, but the quality of that water and the fish in that water are going to be largely controlled by the quality of the smaller streams leading into that river.”

    Settlers arrived in Lancaster County in the early 18th century, but the Clean Water Act wasn’t passed until 1972. Early enforcement focused on the most egregious acts, such as dumping raw sewage or factory waste into water.
    Drawing 2.jpg
    Ashley Spotts of the Chesapeake Bay Foundation partnered with the owners of a local gallery for "Made in the Shade Plein Air Art Making," bringing artists from the community to Overlook across three seasons to create work as the forest and garden grew and changed.
    (Ashley Spotts)

    Over time, Garber says, more attention has been directed to how land use affects water quality. This could be a matter of pesticide and fertilizer runoff from agricultural land, or contaminated stormwater running off hardscaped urban areas, but clearing forested land around streams to make way for farming and settlements has also had significant effects.

    Decades ago, Stroud researchers noticed that the forested streams tended to be the healthiest. This was the beginning of a branch of inquiry around the importance of forests to water quality and stream health and use of riparian forest buffers as a management practice.

    Riparian plantings offer a “dizzying array” of ecosystems services, Garber says. They include wildlife habitat, pollinator support, timber value and heat island cooling in cases where streams pass through urban areas.

    Tree roots scavenge nutrients such as phosphorous and nitrogen (unwanted in the bay) out of the water. The roots stabilize stream banks and reduce soil erosion into streams. Falling leaves feed insects at the base of the aquatic food chain.

    Buffers filter runoff that brings sediment into the water in the first place. As trees shade out grasses that pull stream beds inward, streams widen, which reduces flooding potential.

    “They’re literally reshaping the stream to a wider and more natural stream channel, and they do it for free,” says Garber.
    Trees in the buffer in 2023.
    (Brian Preston)

    Thousands of New Trees

    Overlook Community Campus is a 140-acre park in Manheim Township. Its offerings include sporting fields, walking trails, a community golf course, an outdoor pool and a 250-year-old barn that has been renovated to serve as a conference center.

    It’s also the site of an eight-acre streamside forest and pollinator garden near Little Conestoga Creek. The project has multiple partners, among them the Pennsylvania Department of Conservation and Natural Resources and the Lancaster County Conservation District.

    The acres weren’t really suitable for development. When Stroud came to the township offering to lead the project at little cost to the city, “we didn’t need a lot of convincing,” Sauer says.

    Two thousand trees have been planted for the forest. As many urban foresters have learned the hard way, trees need attention during their early years. The project includes a five-year maintenance agreement to help them make it to a stage where they are self-sustaining.

    The garden and forest include signage that helps visitors learn about the native plants, trees and shrubs they are seeing, and possibly inspire them to bring them to their own gardens.

    Overlook Community Campus is part of a multiyear, multi-stakeholder effort to plant 6,000 acres of new riparian forest in Lancaster County, Garber says. The land in the county has been used intensively for farming, development and industry.

    The Chesapeake Bay watershed encompasses 64,000 square miles and part of six states, but Lancaster County is responsible for 21 percent of the nitrogen pollution reaching the Bay. (Excess nitrogen causes more algae growth, which means less oxygen and sunlight for life forms.)

    Simple, Effective, Underutilized

    Riparian buffers are a well-accepted best practice for watershed management among the scientific and regulatory communities. That doesn’t mean that farmers, municipalities and other entities with streams on their property are using them at recommended rates, Garber says.

    Allyson Gibson is director of strategic partnerships and programs for the Lancaster Clean Water Partners. Her organization works to help the diverse organizations working toward a goal of “clean and clear” water for the county by 2040.

    There’s a big need for public education about watersheds, she says. Some of that can be met if more people find out about volunteer opportunities with organizations that have shovels in the ground.

    Planting stream forests is a great way for a community to work together, she says, including the public works staff of local government. “They have a real benefit to the community from a lot of different angles, and they’re an essential part of how Lancaster is going to meet its 'clean and clear by 2040' goals,” says Gibson.

    “Few other practices offer such a rich array of benefits that are so cost-effective and long-lived,” Garber says. One of the purposes of the multi-entity partnership that came together for the Overlook project was to make this point in a public place.

    “It's a pilot project model that could be replicated in other parts of the country.”
    Carl Smith is a senior staff writer for Governing and covers a broad range of issues affecting states and localities. He can be reached at or on Twitter at @governingwriter.
    From Our Partners