Project Description: Roughened chutes (simulating natural stream passages) are a cost effective means to provide fish passage at locations where existing culverts and bridges are structurally sound yet do not meet current fish passage rules and regulations. Currently, the construction of roughened chutes consists of using equipment and water-wash methods to place the streambed materials; compaction consists of water consolidation and use of bucket and track (using the wheels and tracks of equipment). Excessive subsurface voids can be a significant problem that settles the larger rock and allows the gravel and fines to be washed away. The loss may result in subsurface flow which may impedes passage for fish. Among the factors contributing to this loss, both hydraulic design and construction methods may play significant roles. This project is designed to investigate the role that construction technique plays in the loss of simulated streambed materials. This project may further provide background and direction for future research in simulated streambed hydraulic design
Objectives: The overall objective of this research project is to determine a list of significant construction factors affecting loss of fines in roughened chutes and develop a tool that provides better direction for the construction of roughened chutes. This research will-- 1. Utilize historic ODOT data to identify situations of unsatisfactory performance results; 2. As consistent patterns are discovered, develop a checklist of situations that lead to unsatisfactory results, providing guidelines for better construction direction in the design documents; 3. Recommend appropriate changes to reduce the likelihood of repeating design-related direction that results in predictable loss situations; and 4. Evaluate current construction methods and determine better construction and compaction methods for roughened chutes
Scope and Methodology: Task 1: Literature Review / Background investigation-- Investigate similar efforts in Northern California and in industry literature. Task 2: Identification & Data Collection-- Identify prior ODOT sites undertaken in the past 5 years; and summarize design parameters. Task 3: Field investigation and data collection-- Develop a criteria system for site evaluation. Evaluate whether the roughened chute has retained its surface design characteristics and its structural integrity. Task 4: Analyze the collected data, and propose recommended changes. Task 5: Construct a roughened chute for a pilot case study(construction to be funded by others); wait across the winter season; and study results of pilot case. Task 6: Complete final report, including areas of potential future study