Exelon’s Share for Mitigation on the Conowingo Dam by Tom Zolper


The Conowingo Dam 20 miles north of the mouth of the Susquehanna River has been the focus of scientific scrutiny and concern since the 1990s, and public worry for the past five years. The reason is simple: the pond behind the dam that trapped dirt for decades now has filled up.

More of the dirt (also called sediment) and phosphorus clinging to the dirt are reaching downstream water. In addition, storms scour sediment and associated nutrients from the pond and flush it downstream.

These additional pollutant loads are a problem because we already have too much phosphorus and nitrogen in the Chesapeake Bay – from farms, sewage plants, and other sources. These chemicals are plant food, causing algae blooms that suck oxygen from the water when they die and decompose. The added sediment coming through the dam also is a concern for effects on downstream habitats.

When Bay states and the federal government agreed in 2010 to reduce pollution in the Chesapeake —the so-called Bay pollution diet—they thought we had more time to deal with the situation at the Conowingo. We don’t. What to do?

In 2015 the U.S. Army Corps said the most cost-effective solution was to reduce pollution reaching the dam from upstream in Pennsylvania and New York. Governor Hogan has also proposed a small $4 million pilot program to see if dredging at the pond could also be a part of the solution.

Whatever is determined to be the best solution or set of solutions, one thing is clear: it will cost more money. That’s why a new report commissioned by the Chesapeake Bay Foundation (CBF) and The Nature Conservancy (TNC) offers some good news: The owner of the dam can help chip in.

The report, “An Economic Analysis of the Conowingo Hydroelectric Generating Station,” concluded Exelon can afford to contribute $27 million to $44 million a year to help fix or mitigate the problem and still make a healthy profit. The study used publicly available finance numbers about Exelon’s operations at the dam, as well as standard industry information. It was prepared for Water Power Law Group and CBF and TNC but researched and written by Energy+Environmental Economics in California. Exelon to date has offered to contribute only $200,000.

The company shouldn’t be responsible for the whole solution. It didn’t cause pollution from upstream farms, sewage plants and other sources to discharge into the Susquehanna and flow downstream.

While it is important to hold Exelon accountable for the impact of the dam on downstream water quality and habitat, it’s important to keep the Conowingo issue in context. First, the impacts of the lost trapping capacity and scouring during storm events are significant but not catastrophic. In fact, as the situation at the dam has worsened for the past few years, the water quality in the Bay has steadily been improving.

Also, studies show that the slug of new pollution moving past the dam will cause effects primarily on the mainstem of the Chesapeake Bay. Most rivers that feed the Bay such as the Choptank, Nanticoke and others will not be impacted, nor will the thousands of fresh water streams in Maryland. Local counties and communities will remain responsible for cleaning up pollution in their backyards.

So, we can’t blame Conowingo for all our water woes. The dam is only one of many problems we face trying to clean up the Bay. But we can ask Exelon to do its share, just as we ask everyone else to pitch in. We know the company can afford it.

Tom Zolper is the assistant media director at the Chesapeake Bay Foundation.

Letters to Editor

  1. Stephen Meehan says

    Dear Editor:

    It is heartening in this season to see that the CBF is finally coming around on the Conowingo issue. This is real progress and a far cry from a few years ago when Maryland Democratic candidates were afraid to discuss policy change at the Conowingo Dam lest they be taken out to the CBF woodshed. While you can chock up the Army Corps of Engineers’ and EPA’s failure to act for decades as paralysis by analysis so common place in government, I was always troubled by the CBF’s inexplicable obstruction to making the Conowingo clean up the regional and national priority it should be. The latest demand of Exelon is a squeak compared to demands of Exelon from the CBF just a few years ago. Recognizing that the real obligations rest upstream is good news. Exelon can help by contributing ground for dewatering ponds and other support for taking on the dredging process. It needs Maryland’s help to complete its operating re-authorization. It is heartening that the CBF gives Governor Hogan a holiday cheer for his work. While the Democratic candidate refused to take up this issue on behalf of the Upper Bay, its oysters, watermen and shipping lanes, Governor Hogan embraced it in the 2014 campaign and is responsible for spearheading the forward movement towards meaningful reform. Hopefully now Maryland’s federal elected officials, the Army Corps of Engineers, the EPA, and yes the CBF will put their energies into helping Pennsylvania change its stormwater, agriculture and waste management practices so we can see the restoration of oyster beds in the northern part of the Bay and curb the estimated $1 Billion spent every decade to keep the Baltimore shipping lanes clear.

    Thank you for your own change of heart, CBF. Here’s to a New Year full of progress.

    Stephen Meehan

  2. Frederick Patt says

    Mr. Zolper perpetuates the misguided notion that the Conowingo Dam contributes to the pollution of the Chesapeake Bay. None of the pollution reaching the Bay from the Susquehanna River originated at the dam; all of it came from runoff into the river upstream, mostly from Pennsylvania, also from northern Maryland and southern New York. Since the dam was built it has trapped an enormous amount of nutrients and sediment that would have otherwise ended up in the Bay. That the basin behind the dam is full, and can no longer trap pollution, is not Exelon’s fault.

    I am no fan of Exelon generally, but it seems clear that they are being targeted to contribute to the solution of the Bay’s pollution problem because they are perceived as having deep pockets (“Exelon can afford to contribute $27 million to $44 million a year”), and are also awaiting approval for relicensing the dam. In fact, they have in no way contributed to the Bay’s current condition.

Write a Letter to the Editor on this Article

We encourage readers to offer their point of view on this article by submitting the following form. Editing is sometimes necessary and is done at the discretion of the editorial staff.
We're glad you're enjoying The Chestertown Spy.

Sign up for the the free email blast to see what's new in the Spy. It's delivered right to your inbox at 3PM sharp.

Sign up here.