Vortex weir fishway

It sounds like the name of a band. What a great phrase.

This morning, I went with Mondy Lariz, wearing his hat as Executive Director of the Stevens and Permanente Creeks Watershed Council, on a tour of fish ladders on Stevens Creek. It’s not just a long, ugly boulevard; Stevens Creek is a real waterway that goes through Cupertino and Mountain View on its way to the Bay. And it’s home to steelhead trout, who brave this concrete channel each way three or four times in their lives, spawning in freshwater and returning to saltwater to feed, as anadromous salmonids (another wonderful phrase.)

Most of the streams in the Santa Clara Valley have been channelized, lined in concrete in the 50’s, 60’s and 70’s when their role was understood to be conducting flood water as quickly as possible to the Bay. Since water flows downhill, the irregular gradients of these channels were consolidated into what are known as “drop structures.”


Steelhead trout cannot get up something like this. So we have fish ladders to help them.

fish ladder

Unfortunately, this ladder silts up pretty quickly, making it hard for the fish to find it. Yet they do, and they swim upstream to find the thing that this post is named after.

vortex weir fishway

The vortex weir fishway. To hear Mondy tell it, more like fishaway. There is a stream gauge on the bank here, which required reinforcing the bank, which led to erosion, which led to a drop structure, which led to this thing. Steelhead have got trapped in the pools left behind, when they can’t leap up over these concrete walls. Stevens Creek goes underground here, so this channel is already dry, even though we saw water flowing downstream.

I’ve mused here before about why Westerners treat their waterways so horribly. I know it’s a human thing, not just a California thing, but it’s so striking to me that our creeks and streams here are seen as dumps, drains, and inconveniences, rather than places of beauty to celebrate. On our way to the first fish ladder, we walked by an immense PG&E substation and the old County vector control facility. This last is filled with toxic chemicals, and currently undergoing an involved cleanup effort. Why locate something like that near a waterway? Highway 85 is the Stevens Creek Freeway and runs right along the creek, just as 17 runs along Los Gatos Creek. When suburban sprawl was at its highest velocity, flood control agencies paved over streambeds with no planning of oversight. Now trying to mitigate this destruction, where the natural channel meets our built environment, takes untold dollars, time and cooperation. Here is the Stevens Creek bed as it emerges from under 85 near Middlefield Rd.

useless notch

The little notch is supposed to be a place for fish to get through, but look at the much bigger step behind it. But it belongs to Caltrans, who are not interested in easing the way for anadromous salmonids. I have nothing to offer in posts like this except weary despair. Although I’m thankful to people like Mondy for doing what they can, bit by infinitesimal bit, to try to restore these waterways.

2 thoughts on “Vortex weir fishway

  1. Great post Diana.

    I spent the morning with the Water District staff touring the Coyote watershed, starting at the spillway of Andersen dam. The discussion forced the integration of water supply and flood protection. Other than detention in the reservoirs and former wetlands, there will never be an economical or politically acceptable solution to channelizing the downstream reaches of the Coyote River.

    Read more on my blog.

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