[Op-ed] Let the [Susquehanna] River Run Wild

[cpzilliacus]

N.Y. Times: Let the River Run Wild

IF the Chesapeake Bay is America's Estuary, then its largest tributary, the Susquehanna River, could arguably be called America's River. But we certainly don't treat it as a national treasure: This once magnificent watercourse, which runs through New York, Pennsylvania and Maryland toward the coast, is today an ecological disaster – largely thanks to four hydroelectric dams, built along its lower reaches between 1904 and 1931.

An impending license renewal by the Federal Energy Regulatory Commission for two of these dams will lock in another half-century of measures woefully inadequate to remediating the dams' environmental consequences. Instead, all four should be removed.

The Susquehanna's 27,000-square-mile watershed was once home to remarkable runs of migratory fishes – and none more so than the American shad, a type of herring. In 1827, one net hauled in was said to have contained an astounding 15 million shad and river herring. A commercial fishing operation on the river stationed a sentry on a hillside to watch for the moving bulge in the waters that signaled another huge school approaching. Shad were such a mainstay of regional diets that traveling fishmongers would blow horns and shout "shad-o"  to announce the availability of this delicacy.

[Laura]

I've always fantasized about what the Susquehanna would be like without the Conowingo Dam. I always imagined how the fish populations would come back, and how we'd gain back all of the islands north of the dam that were flooded.

If they think that the power from hydroelectricity can be generated without the dam, then I support and would push for its removal.

[cpzilliacus]

I've always fantasized about what the Susquehanna would be like without the Conowingo Dam. I always imagined how the fish populations would come back, and how we'd gain back all of the islands north of the dam that were flooded.

If they think that the power from hydroelectricity can be generated without the dam, then I support and would push for its removal.

There are a few practical issues with removing the Conowingo Dam (not impossible to deal with, IMO):

(1) What to do with the massive slug of sediment and mud that is trapped behind the dam structure (and has reduced the effectiveness of the dam as a source of hydropower (I would have it pumped and barged downstream to Smith Island, Maryland and Tangier Island, Virginia, both very threatened by sea level rise);

(2) Maryland taxpayers (or tollpayers) would have to build a new structure to carry U.S. 1 over the Susquehanna River if the dam were to be removed; and

(3) The pool that backs-up behind the dam is a source of reactor cooling water for the reactor cores of the Peach Bottom Nuclear Generating Station in Delta, York County, Pennsylvania.  There would need to be something figured out to keep a large amount of water available for the reactors (currently there are 2 General Electric boiling water reactors in service there).

I do think that low-head hydroelectric generation (piping part of the river's flow into large pipes upstream and then through turbines further down the river) does have merit.

[Duke87]

By our calculations, a solar park built on the drained floor of the empty Conowingo Reservoir could allow the river to run beside it and replace the 575 megawatts the dam generates.

*when the sun is shining

VERY important point that cannot be understated. Hydroelectric is baseload power, it generates 24/7. Solar is intermittent and generates only weather permitting. No amount of solar panels can "replace" a hydroelectric dam in the real world, the two are very different things.

These hacks need to go back to physics class and learn what a megawatt actually is before they spout more bullshit like this.

If they think that the power from hydroelectricity can be generated without the dam, then I support and would push for its removal.

It is possible to generate power from flowing water without having a dam, but because of the reduced head you won't get nearly as much of it. And if you read the article you will note that even they (correctly!) don't say this will replace the dam in full. It's only supposed to supplement the magic solar panels that generate the same power at night and in cloudy weather.

[cpzilliacus]

By our calculations, a solar park built on the drained floor of the empty Conowingo Reservoir could allow the river to run beside it and replace the 575 megawatts the dam generates.

*when the sun is shining

VERY important point that cannot be understated. Hydroelectric is baseload power, it generates 24/7. Solar is intermittent and generates only weather permitting. No amount of solar panels can "replace" a hydroelectric dam in the real world, the two are very different things.

These hacks need to go back to physics class and learn what a megawatt actually is before they spout more bullshit like this.

Could we teach them some transportation engineering at the same time?

Regarding space for solar energy panels, I am not so sure there is much room for same, even if the dam at Conowingo goes away.  The river is in something of a gorge (which extends downstream from the dam site nearly to the Susquehanna Flats at the mouth of the river (where it drains into the upper Chesapeake Bay)). So removing the dam means there gorge will re-appear (page here gives an idea what the area looked like before the dam was built).

If they think that the power from hydroelectricity can be generated without the dam, then I support and would push for its removal.

It is possible to generate power from flowing water without having a dam, but because of the reduced head you won't get nearly as much of it. And if you read the article you will note that even they (correctly!) don't say this will replace the dam in full. It's only supposed to supplement the magic solar panels that generate the same power at night and in cloudy weather.

Absolutely correct about baseload power, though I recall reading someplace that at least the Cononwingo dam was (at the time) only used as a peaking plant, perhaps because there is not so much water stored behind the dam (all that silt and mud trapped there) any longer.

Baseload operation may indeed not be possible with run-of-the-river hydroelectric generation, though I suppose they may still be useful in providing blackstart capacity (if correctly designed).

[sbeaver44]

I'm assuming we're also discussing the possibility of opening up the other dams -- Safe Harbor generates, in addition to regular 60hz electricity, 25hz phase electricity that powers Amtrak's Northeast Corridor.  That would need to be replaced.  There's a lot of hydro power off the Susquehanna.

By the four dams, which are not explicitly stated in the article, I know for sure we are talking about Conowingo, Holtwood, and Safe Harbor.  Is the fourth one York Haven?  That's a much smaller dam than the other three.  It's also right below Three Mile Island, so I'm not sure how taking that out would impact the amount of water available to TMI.

Either way, the Susquehanna is a very beautiful river.

[SteveG1988]

I know newer dams are designed to remove the silt (the yellow river dam in china can do it and it is spectacular) via just blowing it out, is there any option here?

[cpzilliacus]

I know newer dams are designed to remove the silt (the yellow river dam in china can do it and it is spectacular) via just blowing it out, is there any option here?

I think (but am not certain and am not an expert on dam engineering) that you would have to tear the old dam down and build a new one with that feature.