This Napa County lake has a 72-foot drain built into it, and right now you can walk right up and look inside

Picture a bathtub drain scaled up to the size of a house, sitting in the middle of a lake — sound like something worth seeing up close? That’s essentially what’s built into the north end of Lake Berryessa in Napa County, and for most of the year, you can drive right up next to it.

Officially, it’s the Morning Glory Spillway. Everyone who’s ever seen a photo of it calls it the Glory Hole instead, and the second you see the shape — a 72-foot-wide concrete funnel plunging straight down — you’ll understand why.

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How this thing actually works

Monticello Dam went up between 1953 and 1957 as part of the federal Solano Project, and instead of a standard spillway running along the dam’s edge, engineers built this uncontrolled, bell-mouth funnel a short distance away. When Lake Berryessa rises above roughly 440 feet in elevation — full pool — water starts pouring over the lip and down the funnel automatically, no gates or operators involved.

At full flow, the numbers get a little absurd: about 48,400 cubic feet of water a second, or roughly 362,000 gallons a second, moving at speeds up to 53 miles an hour. That water drops through the funnel and re-emerges in Putah Creek several hundred feet downstream.

It doesn’t spill nearly as often as you’d think

The lake first filled high enough to overflow the spillway in 1963, and since then, the Glory Hole has fully spilled only around 27 times in more than 60 years. It last ran in February 2025, after a dry stretch of several years where the lake never got close.

That’s the actual draw here. This isn’t a waterfall you can pencil into a spring itinerary — it depends entirely on how wet the winter was, and most winters, it just doesn’t happen.

Which is exactly why right now is worth the drive

As of this month, Lake Berryessa sits around 432 feet — roughly eight feet below the spillway’s lip — so there’s zero chance of catching an actual spill today. What you’ll see instead is the funnel bone dry: a massive, empty concrete bowl sitting in open water.

Here’s my honestly unpopular opinion on this one: the dry version might be the better sight. There’s something genuinely strange about staring straight down a 72-foot drain in the middle of a lake and hearing nothing but wind.

It’s also just an easier trip — no mud, no crowds chasing a spill window, no refreshing a lake-level chart every hour hoping today’s the day.

The one death, and why there are buoys everywhere

In 1997, a Davis woman named Emily Schwalek was pulled into the spillway and killed after the lake crested just a few inches above the lip — the only recorded death at the Glory Hole itself in more than 60 years. It’s why officials string a line of buoys across the water well back from the funnel today, and it’s a good reminder that “empty concrete bowl” and “safe to swim up to” aren’t the same thing, spilling or not.

How to actually see it

The Glory Hole sits just off Highway 128 near the dam, with a free public pullout and parking right along the road. No permit, no hike, no boat required — just a car and a few minutes to pull over, and it’s an easy add-on if you’re already headed toward Napa or Berryessa’s marinas for the day.

So: go look at it dry and strange this week, or start tracking the lake level for next winter and try to time an actual spill. Either way, it’s one of the odder things sitting under two hours from San Francisco that most people driving Highway 128 have never actually pulled over for.

Trip tips: grab a rental car to get out here, lock in your hotel before the good rooms are gone, or skip both and book a camper van instead.

Rules and fees change — always confirm current requirements before you go.

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