Exelon, which operates the power generating station at Conowingo, will benefit from dredging due to less wear and tear on their hydraulic turbines and improved output. Environmentalists have estimated that Exelon could afford to fund dredging at $27 to $44 million per year out of revenues from selling hydroelectricity. Yet, Exelon did not cause the problem. The dam didn't cause the sediment to flow into the river. It was allowed to run off by poor land management practices. Some silting does occur naturally, but the lack of attention to stormwater management and soil conservation is largely to blame for the rate of buildup. Maryland is taking on the job of dredging, but Pennsylvania should be the ones paying for it. Pennsylvania loses twice as much sediment to the Chesapeake Bay watershed as Maryland. They are not on track to meet their 2017 TMDL target for sediment and have not even committed to doing so.
Just the 25,000 cu. yd. dredging (representing 1% of the total targeted for removal) in the pending demonstration project entails removing 80 million lbs. of sediment. To stop the buildup in Conowingo Reservoir and carryover into the bay, removal would have to proceed at nearly 30 times that rate, i.e. the annual total sediment flow for Pennsylvania (2.4 billion lbs). Should dredging stop after reaching the target amount, the reservoir will refill in a few years.
Pennsylvania cannot be expected to eliminate all of their sediment runoff. Their target is 1.945 billion lbs. of sediment flow per year by 2025, which would equate to about a 55 million lb. per year annual reduction. This means that interstate nutrient trading would not begin to pay for the 8 billion lbs. of dredging necessary to correct the problem.
Once we dredge Conowingo Reservoir (and I'm afraid Marylanders will be stuck with the bill) , there are two other dams upstream that have the same problem. Pennsylvania should work on those, too. Exelon's bid for a new 46-year lease to run the hydroelectric station should be rejected unless they offer to foot the dredging bills (not to exceed $44 million/yr) as long as they hold the lease. If they do not, as soon as dredging is substantially complete, perhaps we should prepare to dismantle each of these dams. It would ultimately restore the lower Susquehanna River and ensure that we do not have to keep paying the piper.
