2019-10-28-minutes-public-works-study-session

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Lick Creek Hydraulic Design Decislor: Memorandum 32 North 3rd Street 3 tte 32D Yeldma, WA 9=1 Subject: Lick Creek Hydraulic Design Decision Memorandum,- Teanaway Road Hydraulic Impravements Attention: Mark Cook, Kittitas County Director Public Works From: Jacobs Project Manager Date: September 8, 2019 Introduction and History Kittitas County Public Works received Federal highway Administration (FFIWA) funding through their FLAP Grant program to replace fish passage barriers on Teanaway Road. In 2016, Washington Department of Fish and Wildlife (WDFW) requested the County consider reassigning the funding allocation to replace the Lick Creek fish passage barrier, which wasn't part of this origlnal funding package. Lick Creek Is a top -priority watershed for WDFW, DNR, USFS, and Yakama Nation for salmon recovery. In partnership with WDFW, the County coordinated with FHWA to transfer funding and added Lick Creek as a priority replacement, understanding the importance of the watershed. Since that time, collaborative efforts have continued throughout the Lick Creek watershed, including habitat enhancement and bridge replacement projects. The Lick Creek Fish Passage Enhancement Project includes replacing two total barrier culverts under North Fork Teanaway Road, Including a 54 -Inch diameter reinforced concrete pipe, and a corrugated metal pipe with a 36 -inch Inlet diameter and a 494nch outlet diameter. The project will replace these culverts with a 40 -foot span bridge located approximately 175 feet north of the existing crossing on the natural Lick Creek alignment meeting FHWA and WDFW hydraulic design criteria and restoring natural stream processes. Downstream of NF Teanaway Road, Lick Creek is highly altered from historic flow paths. This Includes an approximate 1,000 -foot length that has been straightened where it flows through private driveways. The creek in this section is entrained between NF Teanaway Road and private properties preventing natural hydraulic processes to occur. in addition, during higher flows the existing culverts under NF Teanaway Road cannot convey flood capacity, causing the Forest Service Road to the south to overtop and send water south down the NF Teanaway Road Ditch. This water then overlaps NF Teanaway Road, causing repeated damage to the roadway. Flood waters that stay in the existing Lick Creek channel also leave the channel and cause damage to private properties.