Carroll County government is part of the Clean Chesapeake Coalition (CCC), which has been advocating for the past year that the Conowingo Dam be dredged in order to mitigate the negative impact of sediment, nutrients and phosphorus that flow over the dam during major storms and impact the health of the Chesapeake Bay.
The Army Corps of Engineers, in cooperation with the state of Maryland, recently released a draft Lower Susquehanna River Watershed Assessment (LSRWA). Their conclusions are reported to have thrown cold water on arguments that the Conowingo is a major cause of Chesapeake Bay pollution and a direct counter to the growing pressure to dredge the Dam.
The framework being created in the media is that the Army Corps of Engineers and the United States Geological Survey (USGS) are lining up on opposite sides of the dredging issue. But, as is often the case, one must go to the documents themselves to get the real story.
The USGS, which brought the Conowingo Dam sediment problem to public attention, reported that the massive amounts of sediment, nutrients and phosphorus normally trapped behind the dam are forced over the Conowingo and into the Chesapeake Bay during large storms. When these substances come in a huge, sudden rush into the Bay, they overwhelm the ability of the Bay to assimilate them and damage the Bay’s health.
The Executive Summary of the Army Corps’ Assessment concluded that “[t]hese additional loads, due to the loss of sediment and associated nutrient trapping capacity in the Conowingo Reservoir, are causing adverse impacts to the Chesapeake Bay ecosystem. These increased loads need to be prevented or offset to restore the health of the Chesapeake Bay ecosystem.”
Contrary to most news accounts, the Army Corps’ Assessment and the USGS report on the Conowingo Dam say essentially the same thing in regards to the sediment behind the Conowingo Dam. The Dam is nearly full; it is releasing damaging amounts of sediment, nutrients and phosphorus; and something must be done.
The Corps’ Assessment, however, states that “nutrient management and mitigation options could be more effective…than solely relying on sediment management options only” but the Army Corps’ Assessment is failing to acknowledge that sediment carries phosphorus and nutrients with it as it moves. So, dredging the Conowingo Dam is a nutrient, phosphorus and sediment management strategy and not just about the sediment.
The Army Corps cautioned against the idea of dredging because local governments, businesses, farmers and residents are already making changes to reduce sediment, nutrients, and phosphorus in a less costly manner. The question is, though, less costly to whom? When a government agency considers “cost” it talks in terms of cost to government. It does not talk in terms of cost to the taxpayer. So, if local governments, businesses, farmers and residents are making changes the costs fall on them directly. This is a saving to state and/or federal government and therefore less costly. Costs to dredge, however, fall on state and federal governments and are therefore considered more costly by state and federal agencies.
The fact is that Conowing Dam sediment is dredged out of the Bay. Bay dredging is done on a regular basis. Examples of the costs can be found in solicitations for dredging. In May, 2014, the estimated cost for a dredging contract in the Bay was $10,000,000.00 and $25,000,000.00; in 2013 $10,273,971.00; in 2012 $24.2 million to dredge in the Port of Baltimore; and in 2011 $10,0000,000 to $25,000,000 for dredging various channels in Baltimore Harbor. The question is not whether to dredge the sediment, the question is whether to dredge it before or after it does its damage in the Bay.
When the Army Corp Assessment advocates that attention be focused on nutrients and phosphorus not sediment, it is skirting the basic problem that oysters cannot survive, much less thrive, buried under inches of sediment, and it is the oysters that are the natural filter for the Bay. Perhaps the Maryland Department of the Environment has recognized this issue also, because the relicensing process for the Excelon power plant at the Conowingo Dam has just been put on hold due to sediment concerns.