stock here: First there was the Panic Messaging, the entire Dam was going to collapse. Then calmer voices were just stating that there was no evidence of structural failure of the Dam. They were correct, but also stupid in their lack of understanding of how most earthern dams work….they don’t just “collapse” structurally, they are overtopped and then that river quickly widens at the dam body itself is ate away.
Then a female rep from Dole got on video with calming plattitudes, which to knowing observers were really insulting in their low level of knowledge but also low truthiness.
I didn’t even know there was a spillway, and there is, its just not a great spillway, and as one video shown when water way at elevation 81.5 showed that the spillway itself was being breached by water overjumping its at least right side vertical guide. We see that on video, not sure what the left side looked like. F
Directions are stated at looking from the lake to the spillway, for left and right. Let’s do the video and then some more analysis. On google earth at least, I found a place to park my truck and walk to the right side of the spillway and inspect and document the damage, I will do that on Monday or Tuesday. There is ZERO mention of this on any news or media, and I am convinced it happened. If the spillway is compromised, that could compromise the entire earthen dam, not by overtopping, but by progressive erosion from the left failed spillway into the dam body.
This video is not at peak flow, peak weir height. Guessing from the Weir look i would say 81.5 feet, they said the peak was 85.3. But the right wing wall was already breeched at 81.5!!! These things are not “linear” in terms of 1.5 feet over the weir which is at 80 feet. 85.3 is massively more flow than 81.5!
I’ll put a bunch of pictures down below, I think the more that people understand what’s going on here, the more likely that Dole and Government will be forced into effective action.
The spillway has vertical walls on both sides. The purpose is super inportant…if the wtaer can escape and start eroding the dirt right outside the spillwater, it can erode, undermine, and destroy the spillway. I am going to call them “Flow confinement wing walls”. So when I say the Flow Confinement wall was breched.I don’t mean it was destroyed, I mean the water got out….went over the top.
Hawaii has enough problems without a massively destructive dam failure wiping out some of the nicer, and important agriculture areas of Oahu.

Chute spillway (dry condition) — this view shows the full flow path when the reservoir is below the 80-ft crest, i.e., no discharge. Weir crest (control section) at top — overflow begins only once the lake exceeds this elevation; head over crest is zero here. Training (side) walls — vertical walls confine high-energy flow and protect adjacent soil from lateral escape. Long concrete chute with limited energy dissipation — supercritical flow would accelerate down this face and carry energy to the lower apron. Critical margins are geometric — wall height vs. crest elevation defines freeboard; once overtopped, flow can bypass concrete and erode the embankment.
The video does not show peak spillway flow, the max was much worse. Officials said the Wahiawā spillway begins operating at 80 ft, the reservoir later rose above 85 ft, and the dam crest is 88 ft. So a clip that looks like only modest head over the crest is very likely not the peak condition.
And this is not linear. For weirs/spillways, discharge scales approximately with head to the 3/2 power: Q∝H3/2, where H is the head above the crest. That means a rise from 1.5 ft over crest to 5.3 ft over crest is not “about 3.5 times the flow”; it is about 6.6 times the flow, before even getting into velocity, momentum, and downstream energy.
Using your numbers:
- Spillway starts at 80.0 ft.
- Your estimate for the video: about 81.5 ft reservoir elevation → 1.5 ft head over crest.
- Reported peak: about 85.3 ft → 5.3 ft head over crest. That “above 85 ft” peak condition was reported by Civil Beat, and HNN separately reported levels rose above 85 ft.
If we hold spillway width and coefficient roughly constant, then:Q81.5Q85.3≈(1.55.3)3/2≈6.6
So your core statement is right:
85.3 ft is massively more flow than 81.5 ft.
Not a little more. Not linearly more. Order-of-magnitude more severe in hydraulic stress terms when you also account for the fact that higher head means higher exit velocity and much greater erosive power.



This some kind of secondary structure about 322 meters down from the Spillway, it doesn’t look like it can move much water.































