Edhat Staff
By the edhat staff
San Antonio Creek overflowed through Tucker’s Grove Park on Tuesday.
“Runoff from heavy rains create a waterfall in Tucker’s Grove Park near Santa Barbara. The flowing water will find its way to San Antonio Creek and eventually drain into the ocean,” said Mike Eliason, Santa Barbara County Fire’s Public Information Officer.
Eliason captured photos of Santa Barbara County Flood Control workers as they survey the creek overflow.
Santa Barbara County Flood Control workers survey San Antonio Creek Tuesday afternoon as it overflows a crossing in Tucker’s Grove Park near Santa Barbara. pic.twitter.com/wkQsLCepra
— SBCFireInfo (@EliasonMike) March 14, 2023
If you look at the height/width of the grouted boulders in the picture you can see the extent of the design includes this amount of overflow and more. The weak point in the design implementation is the spot where the two guys in rain suits are standing. That area should have a few extra low rocks to protect that piece of asphalt but the designed flow capacity looks to be OK up to another 2-3 feet higher. This design is not for an “all weather, all conditions” crossing. The design is to allow vehicle crossing only up to a safe point and after that, the design is to be able to handle higher flows without damage. If design intended for a mini cooper to ford the stream in all weather, all conditions, it would be very very wide in a flatter place to spread out water horizontally so the water can move slower, wider and flatter. Those conditions are not often available north of Foothill/Cathedral Oaks
Engineer arguments are riveting lol!
Day of, not sure what that means but it sounds savage lol!
Jon, I think the headwaters blew the rivets out of the CMPs.
The actual problem happened back in January – take a look at the massive V shaped metal structure that the County placed IN the creek, approximately 50’ downstream of the crossing we’re looking at. It became clogged with large debris, turned into a dam, and forced the flow right into the bank, pavement got undermined and broke away. There are cones and yellow tape there now where several parking spots used to be, along w a pile of boulders the county dumped in to mitigate their mistake. Check it out.
That’s a water crossing, it’s doing what it is meant to do with heavy rain but we are used to it being dry.
Very cool. But yes I agree with SBSAND, this isn’t an overflow by any means, this is a low water crossing working as designed. Thanks for the video!
This is a vented ford structure not a weir and the depth of flow is calced to the flow over the structure area. As I said, it exceeded the “q” in which case HW is the depth of the headwater, where P is height of water over the ford, H is the upstream head, h is the water flow over the ford and D is the diameter of the CMP or the height of the vent. All you have to do is to look at the photo to see that there is an overflow over the top of the designed structure.
There’s no argument about the setup of the structure, TAG. You and I both know how it works. I still disagree that this is an “overflow,” for the same reasons stated in my last comment, overflow implies a design exceedance, which isn’t the case. A ford or low water crossing does in fact function as a broad-crested weir.
8:46AM, yes working as designed, but it is by design an “overflow” which occurs when the “q” of the 2 CSP culverts overflow what they can control.
TAGDES, in my experience, overflow implies exceeding the designed capacity. The flow is being controlled by the roadway acting as a weir, as designed. This event flow does not exceed the design storm flow, thus it is not an overflow. Overtopping is a better description.
I worked on a job where the old rusted CMP folded in on itself under pressure and then clogged. The design was fine, the materials aged out. One of the reasons the CMP was said to have aged fast was someone upstream who shall remain unnamed dumped truckloads of small cobble 4-12″ into the very steep seasonal streambed. Over the years at high water it banged its way down stream through the CMP and chipped off all the galvanization and accelerated oxidization. We replaced the headwall, outfall and installed two upsized HDPE pipes. So far so good