Dewatering and Fish Removal at Highway 7 Bridge

posted in: WRIA 11 Nisqually | 1

On Thursday, September 3rd SPSSEG Project Manager, Kim Gridley,  ENTRIX Engineer, Chad Krofta, and Onsite Inspector Dan Blatt got down and dirty under Highway 7 in the Ohop Valley.

Highway 7 Bridge pool before dewatering
Highway 7 Bridge pool before dewatering

Their are 2 bridges that cross highway 7 in the Ohop Valley. One conveys the current Ohop Creek flow. The other currently acts as an overflow channel and conveys water from a mid-valley ditch under the highway.  By this time next year all of the flow of Ohop Creek will be directed under this bridge.  In accordance, this bridge will be getting a bit of facelift as part of the Ohop Restoration Project. This year the contractor, RV associate will be adding some armoring to the bridge footings and adjacent banks. IN preparation for that work, the deep scour pool under the bridge needed to be dewatered, and all of the living organisms needed to be collected and relocated. Below is a short description of that experience…

I had recieved a call on wednesday that we needed to get the fish out of the highway 7 scour pool the following day. During a Western Washington fish-out we usually expect to find trout species such as cutthroat, rainbow, and perhaps even a few Coho salmon. In addition, sculpin, freshwater eels, and crayfish are very common.

Under_hwy7
Under Highway 7 looking downstream during dewatering
Dan Blatt in 'The Pit'
Dan Blatt in ‘The Pit’

I showed up on Thursday morning with all of my block nets, dip nets, and bucket ready to go. I walked up to the edge of the bank and looked down about ten feet into this deep, dark mud hole. At least 5-6 feet of water had already been pumped, so I asked, “How much water is left down there in that hole?” Dan’s reply was, “Ahh, about 3-4 feet.” SO I suited up grabbed my buckets and nets and worked my way down through the muck. With each sweep of our nets we captured pollywogs, juvenile frogs (with legs and tails), Sunfish, Catfish, salamanders, Carp, Bass, Sticklebacks and large water bugs. We did, however, see a few freshwater eels but no trout, salmon, crayfish, or even sculpin. After much consideration over what to do with all of these introduced species, it was decided that we would move them to another pond in the same ditch upstream.

This is one of the Catfish that was collected during the dewatering of the pool under the highway 7 bridge.
This is one of the Catfish that was collected during the dewatering of the pool under the highway 7 bridge.
Along with thousands of immature frogs and toads, many salamanders were collected and relocated to a safer location.
Along with thousands of immature frogs and toads, many salamanders were collected and relocated to a safer location.

Your first question is probably the same as mine…”How did all of these warm water species get into a Western Washington stream?” I think a few things happened here. First, a few miles upstream is Ohop Lake. Ohop lake is (or was) very likely stocked by local residents and others. In addition, Ohop creek is listed for high temperatures which has led to part of the project which will reforest 80 acres of riparian and wetland habitat. This massive planting project will ultimately shade the stream and insulate the water from the heat of the sun, especially on those hot summer days.

unvegetated

One Response

  1. Eli Asher

    I TOLD you that we should have had an Ohop Creek bass tournament!