Research was performed under NCHRP Project 24-40 by Colorado State University to develop guidance based on a scientifically supported method for determining the design hydrology for stream restoration and channel stability at stream crossings and for understanding how that design hydrology might change over time. Several decision support/analysis tools were developed to improve and facilitate design hydrology analyses. The tools include: (1) a decision tree to be used with web-based hydrologic analysis tools (eRAMS) for generating design hydrology metrics under existing and future land use scenarios, (2) guidance on relating channel response potential to an appropriate level of design analysis, (3) guidance on selection of analog reaches and performing rapid geomorphic assessments of channel instability in the field, and (4) a spreadsheet-based Capacity Supply Ratio Tool (CSR Tool) for computing analytical channel designs that account for the full spectrum of sediment transporting events. The resultant report is NCHRP Research Report 853 - Design Hydrology for Stream Restoration and Channel Stability at Stream Crossings.
A 90-minute TRB webinar was conducted on April 30, 2018, and an estimated 496 people attended. Based on the post-webinar survey, 96% said they were satisfied or very satisfied. Participants stated they plan to use the information presented (including the CRS design tool) for stream restoration design and review, bridge widening and culvert replacement projects, evaluating streambank erosion situations and potential stabilization measures, having more effective discussions with regulators and designers regarding stream restoration projects, reviewing specifications, and enhancing current practices. A desire was also expressed for more examples from urban, eastern US. Several participants indicated that it would be helpful if regional short courses were developed to provide a walk-through and live demo using the spreadsheet, identification of key metrics for field investigations and ranges of expected values, and class exercises working through several examples for each region.
NCHRP has contracted a consultant to implement the research results from NCHRP Project 24-40 / NCHRP Report 853. The consultant will organize and present the information in a manner that facilitates timely comprehension and understanding of the material.
This effort will take 22 months and will include the following tasks:
· Three regional, two-day workshops conducted to provide participants with firsthand experience using the information from NCHRP Report 853, including the Capacity Supply Ratio (CSR) tool and flow duration curves (FDC).
o Additional examples from each region to be developed for use in these short courses.
· Site visits to demonstrate field techniques close to each training facility.
· Identification of regional points of contact (i.e., subject matter experts) to provide ongoing, supplemental technical support.
· Follow-up surveys following each workshop as well as six months later, after participants have had the opportunity to apply research findings.
· Documentation to agency-specific resources developed to support implementation along with specific examples of projects completed using the design analysis tools
Participating agencies may provide the use of training facilities and equipment, reproduction of training materials, and necessary travel costs for staff. Agencies will provide assistance with identifying potential bridge or culvert replacement projects for example applications of research findings. The will also post links to NCHRP Report 853 along with example project applications on agency website for general use.