A Discourse of Rivers
Dammed If You Do, Dammed If You Don't…
The Hazards of Dam‑Controlled Rivers —
And What You Can Do About Them
By Tamia Nelson
March 25, 2014
Back in the day, canoeing the Hudson River Gorge was a rite of passage for "serious" whitewater canoeists, and when Farwell and I came to the Gorge for the first time, we'd already apprenticed on less demanding rivers for several years. So we thought we were ready. We knew we'd find the Class III+ water challenging, to be sure, but we didn't anticipate any real difficulties. This was a big mistake. When we'd measured ourselves against the river — weighing up our strength, our skill, and our boat — and then concluded that we were ready to take on the Gorge, we'd overlooked one vitally important factor. And that single oversight cost us dear. You could say our venture was dammed from the start.
What do I mean? Just this: The flow on the upper Hudson is augmented by releases from Lake Abanakee, an impoundment on the Indian River, a Hudson River tributary. When the gates are opened on the Lake Abanakee dam, a bolus of water surges down into the Hudson, swelling that river's discharge and making the already lively rapids in the Gorge livelier still. The volume of water spilled from Lake Abanakee varies with the year and the season, of course, and nowadays it's well‑controlled, with releases scheduled according to clock and calendar, largely for the convenience of the many commercial rafting operations that operate through the Gorge. But 30‑odd years ago, when commercial rafting was in its infancy, things were less formal. And we were unlucky. Or stupid. You can take your choice.
In any case, a big bubble of water from Lake Abanakee caught up with us just as we reached the Blue Ledges. And the Class III+ drops we'd been expecting — looking forward to, really — were now a solid Class IV. To make a long story short, we were soon overmatched by the river, and instead of canoeing the rapids, we swam them. Had we not had the good fortune to come to grief just as a strong party of kayakers happened along, we'd likely have lost our boat. And I'd have lost my life.
Why do I mention this bit of debris from the distant past? Simply because it serves to illustrate the hazards that lie in wait on dam‑controlled rivers, especially for unwary or ill‑prepared boaters. As T. S. Eliot once observed, a river is "ever … implacable."Keeping his seasons and rages, destroyer, reminder
Of what men choose to forget.
And one of the things we're most likely to forget is this: The "control" in the phrase "dam‑controlled" is subject to certain terms and conditions. It is not synonymous with "safe." In fact, dam‑controlled rivers often present boaters with hazards unknown to those lucky folks who still have a truly wild river on their doorstep.
But that's not many of us, is it? So let's take a look at just what's entailed in boating on the …
Rivers of the Dammed
Wild rivers are somewhat predictable. If you keep a tally of rainfall and snowpack, chart the dates when the ice goes out on the headwaters, and acquaint yourself with the river's gradient and the configuration of its basin, you can make a pretty fair stab at forecasting water levels at any given place and time, often weeks in advance. And you can also have some confidence that conditions won't change dramatically in just a few hours. (This is not the case with flashy mountain torrents, of course.)
Unfortunately, water levels in dammed rivers aren't so amenable to amateur forecasting. They're subservient to the professional whims and fancies of engineers and water managers, not to mention the power needs of distant cities and the desires of politicians to curry favor with well‑heeled stakeholders. The upshot? Unless there's a published schedule of releases — not likely, except in the case of occasional recreational releases — the job of prediction is much more difficult. Norm Yarger, a veteran paddler whose name will be a familiar one to many regular readers of In the Same Boat, recently reminded me of this, in a letter written in response to my earlier article on flash flooding. Here's what Norm had to say:There's another source of flash floods not caused by immediate rainfall. At times the Wisconsin River can rise in the night due to a water release from a power-generating dam. We once had a bank sandbar turn into two islands — three, if you counted the tent between the two sandbars. Also, a borrowed aluminum canoe went missing. We divided up the camping gear for the father-daughter pair, and two others each took on a passenger. Eventually their canoe was located in a backwater, and we finished the trip with no loss except for a wet tent and gear. But one of the other paddlers related loading their gear into the canoe in thigh-deep water in the middle of the night after being awakened by a fish passing under their sleeping bag. That was also due to a power-dam release.
Norm's letter describes a less dramatic instance of a dam‑release‑related surge than our misadventure in the Gorge, perhaps, but the picture he paints is no less cautionary. To be wakened from a deep sleep by waves lapping around your mattress, then flounder about in the dark in thigh‑deep water to collect your scattered possessions and load your boat, fighting the ceaseless tug of the current on your body all the while… Well, that's certainly not my idea of a good time. And as it happens, I've found myself in a similar fix — in broad daylight, no less. I was taking advantage of low water conditions to explore some of The River's many undercut ledges and isolated outcrops. The River is itself one of the legion of the dammed. In fact, it was once celebrated throughout New York's Borderlands as "the best dammed little river in the country, and that's still an accurate description, even if it's been years since I last heard this particular boast given voice.
In any case, I had pulled my canoe up on the bank and ventured out onto a rocky isthmus. My destination was a bedrock outcrop, an island that low water had transformed into a headland. And all went well until I was on my way back. I stopped for a moment to shoot some photos, only to feel my ankles suddenly awash in a fast‑moving flood. I knew immediately what had happened. The engineers had opened one or more gates in the dam upstream. Needless to say, I didn't stay around to see how high the water would rise. I scurried back to the shore (and my little canoe) immediately, slipping and sliding on the moss‑slick surface of the newly submerged isthmus. I was in no real danger: I was only a few yards from shore and safety when the water rose. But the experience was still a salutary reminder that low water is a temporary condition on any dam‑controlled river — and that when the water rises, it can do so with astonishing speed. Just as Norm had said.
~ ~ ~
OK. Nobody likes unpleasant surprises. And dam‑controlled rivers have plenty of scope for putting a damper on any outing. That being the case, what can you do to keep the odds on your side? Quite a lot, as it happens. Begin at the beginning, by …
Doing the Due‑Diligence Dance
First, determine if the river you hope to paddle is dammed, how many dams there are, and where they're located. It also helps if you can find out the purpose of the dams. After the seasonal snowpack has melted away, flood control dams are less likely to give you a surprise soaking than the dams which drive power‑generating turbines, and whose releases therefore fluctuate day in and day out, according to the demands of the grid.
One remote hazard worth mentioning, if only to dismiss it, is the possibility of dam failure. The likelihood is small — very small — but if you'll be paddling below a large impoundment held back by an earthen dam during a period of record rainfall or runoff, the possibility of a partial failure is worth considering when you camp for the night. You may decide to eschew the convenience of a riverside camp, choosing a site located higher up, instead. Just in case.
And how do you find out whether or not a river is dammed? Here are some ways:
Unroll a Map. Every river trip should be run on a topographic map before you dip a paddle in the water. Don't rely on a digital map gleaned from the Web or preloaded on your GPS. Good as these are for helping you stay found while driving, they're pretty haphazard when it comes to documenting dams. Paper still has its place in the paddler's library. (By the way, you can download free PDFs of USGS quads. But don't put it off. I doubt that this happy state of affairs will last much longer.)
Now lay out your map(s) on the floor and follow your chosen river(s) from source to mouth. Look for heavy black lines inked across the river. Some will be labeled as dams ("barrage" on many Canadian quads). But others will be nameless, as in the case of the Lake Abanakee dam:
The red arrow marks the location of the short black line that's the only indication of the dam's existence. There's a lesson to be learned here: Take your time when you follow your river's paper trail, and keep your reading glasses or a magnifier handy. Sometimes, however, you'll get lucky and find a dam properly signposted, as in this instance — the Conklingville Dam holding back the Great Sacandaga Lake in the southern Adirondacks:
At least the Conklingville Dam is identified by name, but the Stewart's Bridge dam immediately below it is not, though the spillway is clearly visible (its location is marked by the red arrow on the lower right).
Now here's another example, this one a double barrage associated with a long‑derelict mill, a legacy of an earlier time when even little rivers were expected to earn their keep:
A word to the wise: Any rural hamlet with "Falls" in its name is likely to have a dam or two. Or even three. And sure enough, the map above shows a third dam where the highway crosses the river. Can you see it?
So far, so good. You can learn a lot from maps. But even good maps have their limitations. They're already out of date on the day they're printed, for one thing. And while they usually permit you to distinguish power dams from mill dams and flood control dams (the electric transmission lines which you can see radiating away from the Conklingville Dam are just such a giveaway), they tell you nothing about the frequency or magnitude of releases. So it's time to consider other resources, including …
Government Agencies and Quangos. Dams are highly regulated, and their operation and maintenance are overseen by both government agencies and quasi‑autonomous nongovernmental organizations (or "quangos," to use an acronym that originated in the States but is now heard mostly in the UK, usually in a pejorative context), many of which are also in the tourism promotion business. Not surprisingly, then, agency and organization websites sometimes offer useful information about access points, portages, boating regulations, scheduled releases, and the like. You might even learn where the fish are biting. On the other hand, security concerns — some genuine, others specious — are often invoked in limiting public information and restricting waterway access. Still, you never know what you'll find till you look for it. Don't hesitate to Duck, Duck, Go. (Or Google. Or Bing.) This might be your lucky day.
Of course, you can always …
Turn to Paddling.net. And you should. I'd like to think it's the closest thing to a one‑stop shop for paddling information on the Web, and it probably is. The Message Boards, in particular, allow you to tap an almost infinite reservoir of local knowledge. (Yes, I know. "Almost infinite" is mathematically meaningless. But you get my drift, I'm sure.) You'll also find links on Paddling.net's pages to paddling clubs and associations. Use them. And don't overlook the guidebooks that have been written for waterways around the world, many of which can be found in Paddling.net's online store.
You'll also want to make use of the …
American Whitewater Association Website. Their National Whitewater Inventory is a good starting point for river‑specific information. From there, jump to the lists of rivers, cataloged by state. Find the river you're going to paddle, and then click on it to see gage readings, discharge summaries, scheduled releases, and other information of interest to paddlers. You'll even find a comments section for each river, though — as is the case in any collaborative venture — not all those who participate are both coherent and reliable. American Whitewater provides information about a smattering of international (i.e., non‑US) rivers, too.
And speaking of discharge summaries, there's a handy desktop app for users of Macintosh computers, offering real‑time stream discharge information for a long list of US rivers. It's the …
RiverLevels Widget. Best of all, it's free. Developed by Adam Franco and available from SourceForge, this clever app presents USGS river discharge data in an accessible form. You can also toggle between gage readings and discharge at various points, allowing you to get some idea of the timing of releases, even on rivers without a public recreational schedule. I keep a number of RiverLevels Widgets open on my Dock at any one time. That way I can track flows in several dam‑controlled rivers simultaneously.
Here's a screenshot from RiverLevels, giving gage heights at Lee's Ferry on the Colorado:
You don't use a Mac? No problem. You'll find the same information and graphical displays — and a good deal more, besides — on the USGS Current Water Data pages. Users of older browsers may encounter some difficulties, though.
Finally, don't overlook the oldest source of all:
Local Knowledge. Talk to people who have day‑to‑day contact with "your" river. Paddling clubs can often give you useful leads, as can the folks on Paddling.net's forums. You might even learn a thing or two from the habitués of local diners and ser‑sta‑gros. But keep your critical antennae twitching. Remember Deliverance.
~ ~ ~
So much for planning. But what about those times when you're on a dam‑controlled river, with no cell phone coverage and no Wi‑Fi hotspot nearby? Can you learn anything about the river's ups and downs just by looking? Sure you can. It's at times like these when you realize the value of …
The Mark I Eyeball
Your ears can help, too. More and more dams on recreational waterways sound a siren or whistle when they open the gates. But you can't count on it. Nor can you count on sussing out a bolus by the seat of your pants. Our first clue that a release was upon us in the Gorge came when the bow of our 17‑foot Tripper suddenly pointed skyward, dumping us unceremoniously into the maelstrom. Admittedly, we'd ignored a few earlier hints and a lot of common‑sense precautions, but you can put that down to the impetuous nature of youth, if you like. It's not something you'll want to emulate.
Now, let's see what can be learned by eyeballing. The picture below was taken on that day on The River when I got my feet wet. Can you see the slight dip in the water's surface where it meets the rock? That's a sign of a (very) rapid rise in water level. When I noticed this in my camera's viewfinder, I knew it was time to go. And I was right. Seconds later, the water had risen over my ankles.
It's a subtle sign, to be sure, and it doesn't give you much time to act. Luckily, such extremely rapid rises are rare. And it's much easier to spot the evidence of a recent, sudden drop in discharge. A wet "bathtub ring" around mid‑river rocks is one such sign:
Consider this to be a warning, as well. Not only will shallow rock gardens grow even bonier, challenging your water‑reading skills to the utmost, but sudden drops are often followed by equally sudden rises. That said, the bathtub ring is easily obscured by wave splash, so if it's a breezy day, or if you're in the middle of a lively rapid, you're not likely to spot it.
That's when it pays to turn your eyes shoreward. Wrack lines, fresh cutbanks, scoured beaches, odd bits of trash hanging from the lower limbs of trees or tangled in riverside grasses… All these tell of recent episodes of high water. It could be a flash flood, of course, but if the river you're on is dam‑controlled, it's a fairly safe bet that the flooding is a regular thing. Be on your guard. What does this entail, exactly? Other than taking likely releases into consideration when you decide whether or not to run a long, difficult rapids, it means you'll want to avoid camping on low‑lying islands. And you should probably give that beautiful site at the water's edge on the sandy cove a miss, as well. Its charms will fade if your tent floats away in the small hours — especially if you're still in it when it ups anchor and sets sail.
Is there any other way that dammed rivers can surprise unwary paddlers? Yes. And it involves the water on the other side of the dam: the upriver side. Impoundments, too, are subject to fluctuating water levels. This is particularly true in fall, when annual maintenance inspections are often conducted and reservoirs are partially (or even totally) "dewatered" to accommodate projected spring runoff. It's possible to wake on a beautiful autumn day, only to find your boat high and dry and your idyllic island camp surrounded by mudflats, with the nearest navigable channel now several hundred squelchy, smelly yards away. That's enough to make anyone say "Dam!"
In a perfect world, all rivers would flow wild and free. But dams are a fact of life. And though damming rivers makes it possible to offer on‑demand whitewater, it also creates problems for touring paddlers. With Norm Yarger's help, I've tried to highlight the dangers and suggest ways to minimize the risks. Now you, too, will have the tools you'll need to put an end to all those "dammed if I do, dammed if I don't" moments.
Related Articles From In the Same Boat
- "A Discourse of Rivers: It's a Matter of Scale"
- "A Discourse of Rivers: Current Affairs"
- "The Dynamics of Moving Water: Theme and Variation"
- "The Dynamics of Moving Water: Rhythm and Tempo"
- "Alongshore: Down in the Mouth"
- Air, Earth, and Water — Natural History for Paddlers
A collection of related articles from In the Same Boat.
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