Description

Thomas/Wright, Inc. was retained by Clark County, Washington on a flexible services contract to analyze fish barriers on Breeze Creek. A federal grant and matching funds by the County are being used to complete the study. The project includes a preliminary site reconnaissance, field surveys, fish barrier analysis, an alternatives analysis, project management, and preliminary design. Breeze Creek is a tributary of the East Fork of the Lewis River. Several endangered species of fish have been identified in the Lewis River basin. Four sites were examined in the three square mile watershed for Breeze Creek.

The primary site is near the mouth of the creek. The fish barrier consists of a 150-foot long, 48-inch diameter corrugated metal pipe culvert. The culvert conveys the creek beneath Lockwood Creek Road. The culvert is undersized, too steep, and is hanging at the outlet. In addition, Lockwood Creek Road is approximately 35 feet above the culvert and is a major arterial for east-west traffic through the City of LaCenter and northern Clark County. A detour is not possible. The alternatives analysis examined replacing the culvert with a bored culvert, a cut-and-cover culvert, and a bridge. During the construction of the new culvert, Lockwood Creek Road will be widened to allow safer pedestrian movement and traffic flow. The new Lockwood Creek Road cross-section will have sidewalks, bike lanes, and two lanes of traffic. The alternative analysis included different widening alignments in conjunction with the culvert replacement options. T/WI completed a hydraulic analysis examining the flows necessary for fish passage and the 100-year flood flows through the culvert. Planning level cost estimates were prepared for use as an evaluation tool. Construction methods, scheduling, and staging were major factors used to recommend the selected alternative.

The secondary site is a berm across the creek approximately 800 feet upstream of Lockwood Creek Road. The berm has created a fish barrier by downcutting at the downstream end and siltation at the upstream end. The siltation clogged the culvert through the berm and caused the creek to cut a channel around the berm. This resulted in a waterfall over the berm. T/WI examined removing the berm, regrading the stream, and constructing a fish ladder to allow passage upstream of the berm. The selected alternative included regrading the stream with a pool-weir configuration. Log weirs are proposed to minimize impacts to the sensitive creek corridor.

Two additional culverts were analyzed for fish migration. Recommendations included stream regrading, adding weirs, and complete culvert replacement. Cost estimates and hydraulic analysis were prepared.

The alternatives analysis report was prepared and submitted to the County. The review team included Clark County Public Works Department, the County's construction Division, Washington State Department of Fish and Wildlife, the Lewis River Fisheries Board, an independent consultant retained by the County, and the City of LaCenter. Preliminary plans of the selected alternatives will be prepared. The plans will be used by the City of LaCenter to obtain necessary permits for construction.