Stevens Creek Fish Ladder Walk – June 6th 2009 – 10 am
[I wish i could go on this walk but will be out of town. -- Judith]
Join executive director Mondy Lariz on a tour of the fish ladders of Stevens Creek. Learn about these curious structures and the importance of these and other efforts to sustain the federally threatened Steelhead trout in our creek. Please RSVP if you plan to come. execdir@spcwc.org
Meet June 6th 2009 at 10:00 AM at the picnic tables in front of Whisman Park, 400 Easy Street, Mountain View, CA. There is parking, and the location is about 15 minutes from either fish ladder. Plan to carpool to the Fremont ladder location.
Bring comfortable shoes, a camera, and water.
A document describing the walk can be downloaded from the SPCWC website and the text is below the cut.
We will view and discuss at least three of the four fish ladders on Stevens Creek – the Moffett Blvd Ladder, the Central Avenue Ladder, the Fremont Avenue Ladder, and the Evelyn Avenue Ladder.
The tour begins with a look at the Moffett Blvd Fish Ladder which is actually located closer to Highway 101 than Moffett Blvd.
All of the ladders except for the unique structure at Central Avenue are Denil Fishways, a once popular design used mostly in areas with small dams. They seem to operate fairly well in most years, but have numerous maintenance problems mostly due to sedimentation. Below is a diagram of a Denil Fishway design.The Santa Clara Valley Water District is currently conducting a study of these Denil ladders as part of the Three Creeks Habitat Conservation Plan and the Fisheries and Aquatic Habitat Colaborative Effort which began in 1991. They are also considering modifications to the Stevens Creek Dam.
The Moffett Ladder shown here is the lowest ladder in Stevens Creek. Its correct operation is of the highest importance since all fish enering Stevens Creek to spawn must pass this point to gain access to the upper reaches of the watershed. Serveral proposals are being considered for the redesign, or even removal, of this ladder and the creation of a number of scour pools and weirs.From here we will walk upstream on the Stevens Creek Trail to the Central Avenue Fish Ladder which is actually not a ladder, but rather a vortex weir fishway.
This structure is known for its habit of trapping out-migrating and resident fish. No plan to redesign or remove this ladder is currently on the table, but hopefully some improvements can be made in the immediate area where the Caltrans overpass tunnel is showing signs of wear.
In July of 2007 we succeeded in rescuing 51 steelhead from this structure when flows dropped to less than one cubic feet per second. We moved them up to the relative safety of the McClellan Ranch Preserve where the creek was cooler and would remain wet for the remainder of the summer.
The Evelyn Avenue Ladder is the next one upstream and is difficult to access so we will likely skip this one and plan to visit it at another time unless we have a very small and hardy group. The ladder is located under the VTA Light Rail and CalTrain tracks.
As with the Moffett Ladder, it is being considered for removal or modification to improve passage for steelhead. The main problems in this area are the minimal flow, access to work and property ownership.The Fremont Avenue Fish Ladder is too far to walk to so we will need to drive up to Blackberry Terrance to access it. This narrow Denil ladder gets battered by debris moving downstream each year and causes passage problems. Project proposals include removing the ladder, re-grading the stream to allow passage without a fish ladder and realignment to widen the channel slightly for greater stream stability. A series of weirs and pools would replace the ladder. The temporary loss of habitat and mature trees in this area are the main environmental concerns for the project, plus the cost will be very significant.
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Tags: fish ladders, spcwc
June 4th, 2009 at 6:48 am
Thanks for posting that! I’m going to go.
Diana
June 14th, 2009 at 4:40 pm
[...] Foss wrote an illustrated post about the tour of the fish ladders on Stevens Creek. I noticed as i was looking around her blog for information about Village Harvest* and other urban [...]