Dams

Old-Time Sentiment and Sediment in Lancaster County

Legacy Sediments accumulated to 5 meters tall

Legacy Sediments accumulated to 5 meters tall

By Bonnie Turner-Lomax

I’d encourage you to take a trip through Pennsylvania’s Lancaster County to get a sense for the area’s rich culture and old-world charm, its picturesque farms, covered bridges and quaint towns and villages.  And keep an eye out for the occasional horse and buggy.

One thing you won’t be able to spot, though, is another part of the county’s past – an environmental legacy that has played out for centuries beneath area waters.

During the late 17th through 19th centuries, it was common for communities to build dams on nearby streams to provide water power for various mills that served the communities. Sediment has been accumulating behind these now defunct but still in-place dams since they were first constructed.  Centuries of sediment accumulation (referred to as legacy sediments) have resulted in numerous environmental impacts, including:

  • changes in stream structure,
  • unnaturally high stream bank walls,
  • loss of wetlands,
  • excess sediment scouring during storms,
  • and increased loading of nutrients and sediments downstream.

This historic pollution has present impacts, and affects Lancaster county as well as other communities throughout the Mid-Atlantic region.

Recently, more than 140 environmental professionals converged at Franklin & Marshall College in the heart of Lancaster County for a workshop to deal with this age-old issue.

The group, including federal, state, and local representatives, academics and environmental consultants, held discussions, considered challenges and opportunities, and did field visits to the Big Spruce Run and Banta restoration projects to highlight potential benefits of the sediment fix to water quality and wetlands.

By meeting and establishing a communication forum to share data and information, the group is taking steps to create an environmental legacy of pristine streams, waterways, and wetlands.

Find out more about legacy sediment removal and stream restoration.

About the Author: Bonnie Turner-Lomax came to EPA Region’s mid-Atlantic Region in 1987 and has held several positions throughout the Region.  She is currently the Communications Coordinator for the Environmental Assessment & Innovation Division.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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Saving Some For The Fishes And Rethinking The Future of Our Water Supply

When I first moved to Colorado, I spent my summers hiking streams and collecting aquatic insects. I visited many high mountain streams that were dammed and diverted to provide water to cities along Colorado’s Front Range. In their natural state, these rivers flowed raucously over boulders, watering streamside plants, flooding wetlands, and creating fabulous habitat for fish and other aquatic critters. Downstream of the dams, the streambeds were sometimes completely dry – other times with only a thin trickle of water.

At this very moment, there are thousands of dams in Colorado that are withdrawing water from Rocky Mountain streams. Once diverted, the water moves through networks of ditches and aqueducts, sometimes tunneling through mountains and across the Continental Divide, to distant farms and cities. But the water taken from these streams is not enough to meet growing demands. In the future, water demand will far exceed supply. In response to this need and recent drought conditions, water developers in Colorado are proposing to exercise some of the last remaining water rights – for spring snowmelt peak flows in the wettest of years.

Diverting snowmelt flows from our rivers is a controversial and complex issue, both politically and environmentally. On one hand, cities want this water to support economic growth, including new commercial and residential development. However, these flows are critical to aquatic ecosystems, rearranging sediments for fish habitat, assisting Cottonwood regeneration, recharging groundwater and flooding backwater wetland habitats. Countless plants and animals rely on these flows for their long-term survival. Many of these rivers are already anemic from water withdrawals and we are approaching a tipping point beyond which the resiliency of these ecosystems will be tested.

What are our options?

As scientists, we must apply our knowledge to better balance human needs and the needs of our rivers’ inhabitants. Various water supply and smart growth solutions are available that could maintain natural ecosystems while meeting the needs of communities. Water conservation will play an increasingly critical role in allowing for a sustainable water future. Moving forward, researching and implementing state of the art water conservation technologies is key.

Your perspective on water differs whether you live near the Great Lakes, in the arid west, or by the coast. We must all begin thinking about the sustainability of our water supplies and how we can meet our needs while also protecting our rivers, lakes and wetlands.

What do you think?

About the author: Julia McCarthy is an Environmental Scientist with the EPA Regional Office in Denver, CO. She works in the Clean Water Act regulatory program on rivers and wetlands. Her background is in aquatic ecology and freshwater conservation. She recently worked on a video titled ‘Wetlands and Wonder: Reconnecting Children With Nearby Nature.’ Check it out at http://epa.gov/wetlands/education/wetlandsvideo/

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

Please share this post. However, please don't change the title or the content. If you do make changes, don't attribute the edited title or content to EPA or the author.