When you walk into Tumwater Falls Park, the Olympia Tumwater Foundation office is on your left and the WDFW hatchery facility on your right, directly ahead of you is the uppermost falls in the park. Google Maps marks it as a waterfall. Of course it does. Any water falling over a ledge looks like a waterfall, and this one photographs like one too.
It isn’t one. What you’re looking at is a dam.
The dam creates the waterfall, so in a narrow sense you’re not wrong to see falling water and call it that. But the structure underneath the water is not a natural feature. It was built, on purpose, by a company that needed it, and it’s worth remembering that before you remember anything else about this park.
The dam went up starting in July 1900, when the Olympia Light & Power Company began work on the upper falls under engineer A.J. Gillis. The goal, in the language of the time, was to “harness the falls” for a bigger hydroelectric operation, replacing an older industrial setup on the middle falls that had produced something like 400 horsepower. The new dam and its flume cost around $13,000, real money in 1900, and by October the company had built stone walls and a flume ten feet square, a wooden pipe carrying three tons of water per foot across 700 feet to the powerhouse. That first structure raised the water level four to six feet above the natural bedrock, enough to back up a slack water pool for roughly a mile upstream. In 1903 the west wing got reinforced in concrete and masonry, built specifically to survive the river’s flood stages.
When the dam reached its full and current height, it inundated flat land that is now part of the Brewery Complex, but was then called the “Chambers Place.”
Then in 1905 things got contentious. The Olympia Brewing Company and the power company both had founding claims to the Deschutes, and a legal fight broke out over who actually controlled its flow. The brewery needed water too, and the power company was starting to realize that its dry-summer turbine problem wasn’t going away on its own.
That fight is old news, but you can still feel its outcome every time you step into the river in July.
Here’s how far the dam’s reach actually extends today. The pool it creates sits at roughly 85 feet above sea level, and the dam itself only accounts for four to six feet of that artificial rise over the natural bedrock lip.
My back-of-the-napkin math says the reason its effect travels so far upstream has nothing to do with the dam’s height and everything to do with the valley above it. Between the dam and Pioneer Park, the river drops only three to four feet per mile, remarkably flat for a stream that’s about to plunge 82 feet through a gorge. A gentle gradient means a small impoundment backs up a long way, and the standard backwater math for this stretch puts the slack water influence at roughly 0.8 to 1.2 miles upstream of the dam.
Walk that distance and you pass through three distinct stretches. From the dam to about 0.3 miles up, past the old brewery complex and under the E Street and I-5 bridges, the current in summer is close to nonexistent, more pond than river, narrow and deep and still. From 0.3 to 0.8 miles, along the lower edge of the golf course, it’s still noticeably slower than a free-flowing river, the kind of water where you drift instead of ride. Past that, from 0.8 to 1.2 miles, the backwater curve finally tapers off, the water gets shallow again, gravel bars reappear, and you start to feel actual current, riffles instead of glass.
This matters most in summer, which is exactly when people are in the water. The Deschutes’ natural flow drops during peak tubing season, low enough that the dam’s slack water effect dominates the entire lower mile of the run. Instead of a current carrying you toward the takeout, you get what amounts to a long bathtub, and tubers spend the last 4,000 feet or so paddling and pushing themselves along by hand. The dam that most people don’t know is there is the reason the last leg of their float feels like work.
The 1905 fight over water didn’t stay a courtroom skirmish. The power company’s problem was simple: the river ran low every summer, right when demand for electricity was climbing, and its solution was to treat Lake Lawrence, up in the watershed, as a kind of savings account. The plan called for a canal a mile and a quarter long, dug to divert winter floodwater into the lake, dammed at its outlet to hold that water back, then metered out over the summer to keep the Tumwater powerhouse running. It required flooding land the company didn’t own and diverting water the brewery believed it had rights to, so the fight dragged through the courts for years, what one account called a monkey wrench in the gears of the whole project. To get the land, the power company pursued eminent domain, arguing in court that because it supplied both electricity and streetcar service to the growing city of Olympia, it had the legal standing to condemn private and public land in the public interest. The argument worked. Lake Lawrence fell under company control, a 25-foot concrete dam rose at its outlet, and the diversion canal got finished. The following summer, with its water supply secured, the company rebuilt the Tumwater Falls dam itself, adding four feet of height and flooding another 30 acres of condemned land along the way. By 1914 the company had what it wanted: a stable, year-round power supply for a city growing at twice its historical rate.
It didn’t get to enjoy that win for long. In 1919, Puget Sound Power & Light bought Olympia Light & Power outright, and as regional transmission grids spread across the Pacific Northwest, a small local operation like the one at Tumwater Falls stopped making much sense. Generation was phased out gradually over the following years. The physical evidence held on longer than the business did. It wasn’t until 1962 that crews finally dismantled the stone powerhouse and the penstock below the falls, clearing the lower river corridor for what came next: the Olympia Tumwater Foundation’s Brewery Park at Tumwater Falls, opened in 1962 on the site of the old plant.
The power company’s old foe for control of the river, the Olympia Brewing Company, ended up owning the old dam site a few decades after the Puget Power sale.
Notice what got removed in that demolition and what didn’t. The powerhouse and the penstock, the parts of the complex that unmistakably read as industrial machinery, came down. The dam, the part that produces a waterfall people like to photograph, stayed exactly where it was. Whether or not that was the intent, the 1962 clearing erased the site’s industrial past and preserved its scenic present in one move.
And here’s a theory worth taking seriously: that clearing is probably what started the Deschutes’ recreational floating culture in the first place. The newspaper record doesn’t show organized river floating before the park existed. It shows up within less than a decade of Brewery Park opening, when a group called the Rough Riders started promoting floats down the Deschutes in the early 1970s. That timing reads like cause and effect more than coincidence. People don’t float for fun through a demolished industrial corridor with no public access and no destination. They float through a park with parking, a takeout, and a name.
The Rough Riders called floating “quite relaxing,” while warning newcomers about log jams and waterfalls, a warning that carried real weight given the still-recent memory of five people drowning after being swept over an unmarked falls sometime in the 1960s. They noted that a float from the East Olympia railroad bridge down to the brewery could take about eight hours during high spring flows. In June 1972, police searched for a group of missing juveniles and found them safe, floating on a raft near the brewery. By 1978 the activity had become fully organized, with the Deschutes River Float & Picnic drawing crowds for a run from the Henderson Boulevard bridge down to Tumwater Falls Park. The early 1980s brought a surge in inner tubing specifically, and with it came friction. A 1983 article described complaints from riverfront residents about trespassing and safety, and tubers who ran into trouble often ended up “bedraggled” on someone’s back lawn, looking for help. Thurston County considered putting up warning signs at the popular entry points.
In 1988, the city of Tumwater bought a stretch of pasture along Henderson Boulevard and built Pioneer Park. On paper it’s a sports and nature park, all ballfields and trails. In practice it became the unofficial starting line for the float, several miles downstream of the old East Olympia entry point, with enough parking to make the whole thing genuinely accessible for the first time. What it didn’t do was settle the question the dam raises a mile downstream. Pioneer Park sits at the edge of the slack water zone, near it or inside it depending on the flow that year and depending on exactly where within the park you put in. The 1988 purchase moved the uncertainty upstream rather than resolving it, handing the question to individual people choosing a launch spot, most of whom have no idea the choice even matters.
The dam itself is now well past a century old, built in phases between 1900 and 1913, a concrete gravity structure that at this age almost certainly carries no steel reinforcement inside it. Washington State classifies it as a Category 3, low hazard dam, meaning that if it failed, nobody’s life would be at risk and the resulting damage would be minor. That classification is its own quiet form of forgetting, a bureaucratic note that says this structure doesn’t need anyone’s attention. Structurally, though, it’s in better shape than its age suggests. Because it’s keyed directly into bedrock, it’s largely immune to the foundation scour that kills most aging dams during overtopping. Predating rebar reinforcement by decades, it’s also immune to the internal rusting and spalling that eventually destroys modern concrete. And our mild, wet climate spares it the freeze-thaw cycling that cracks concrete apart in harsher places.
It isn’t invulnerable. Vegetation works its way into old construction joints and slowly wedges them wider. Water percolating through the structure leaches calcium hydroxide out of the cement over time, weakening it. A century of silt has built up behind the dam, adding a steady load against the upstream face. None of that adds up to sudden failure. Left alone, this dam is likely good for another 100 to 200 years, wearing away slowly at its joints and spillways rather than going all at once.
I emailed the Olympia Tumwater Foundation to ask about the dam’s structural condition. That’s the organization that turned the demolished powerhouse site into a park in the first place, the one that, whether they meant to or not, decided sixty years ago which parts of this history would stay visible and which would get hauled away. They’re looking into what they might have and get back to me later. I’ll update this post if they have anything.
So the next time you’re standing in Falls Park facing that uppermost falls, know what you’re actually looking at.
It’s a dam built in 1900 to solve a hydroelectric company’s dry summer problem, expanded in 1913 after a legal war over a lake most people have never heard of, stripped of its machinery in 1962, and left standing, quietly, as the scenic backdrop for a park built on top of its own demolition.
The float culture that treats this river as a summer playground likely exists because that park got built, not despite the dam’s industrial history but because a foundation cleared away the parts of that history that looked too much like a factory. And the ambiguity never really left. Somebody launching a tube from Pioneer Park on an ordinary August afternoon has no way of knowing, without doing the math we just did, whether they’re floating on a free river or drifting through a captured pool behind a hundred-and-twenty-year-old dam. Most of them will never think to ask. The current under them, either way, carries the settled residue of a legal fight, a corporate merger, a demolition crew, and a social structure built on a slack pool and two parks.
