On-demand Webinar

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This webinar was co-sponsored by ASCE's Environmental & Water Resources Institute (EWRI) and ASCE Continuing Education

Instructor:  F. Douglas Shields, Jr, Ph.D., P.E., BC.WRE, F.EWRI, F.ASCE

Course Length: 1 Hour

Purpose and Background

Stream restoration is widely practiced in developed countries, with annual expenditures in the U.S. exceeding $1 billion. Placement of large wood (felled trees or parts of trees) in degraded rivers and streams is one of the most widely practiced river restoration measures, and its use is accelerating as scientific research yields more information on the ecological significance of wood in rivers. Large wood and structures made from large wood are used to enhance and create desirable habitat conditions and to stabilize channel beds and banks. This webinar focuses the recent research findings on ecological significance of wood in fluvial systems, the necessary levels of wood projects analyses, identification of unforeseen factors, and other topics.

Wood may be placed in streams as individual logs or pieces or formed into structures along or within the channel. However, cost-effective application of large wood introduction is difficult because natural wood decays and is transported by rivers while most restoration projects are intended to provide ecosystem services and benefits for some period of time. Reports of the efficacy of large wood restoration projects vary widely with some extremely positive reports and some reports of costly failures. Hazards posed by floating debris to downstream bridges and other infrastructure are always a concern. This situation calls for science-based design standards and criteria, and four recently-released documents address this need directly or indirectly, while a fifth, the national large wood manual, is currently under production. This webinar informs participants about these recent developments, allow them to identify key issues for planning, design and construction of large wood projects, and offer some useful principles and rules of thumb.

Primary Topics of Discussion

  • Recent findings of research on ecological significance of wood in fluvial systems
  • Criteria for screening sites (river and stream reaches) for large wood reintroduction projects
  • Appropriate levels of analysis for wood projects
  • Force and moment calculations for large wood structures
  • Identification of unknown or complicating factors

Learning Outcomes

Upon completion of this course, you will be able to:

  • Identify key roles and functions of large wood in lotic ecosystems
  • Describe several types of large wood structures
  • Select appropriate parameters and coefficients for force and moment analyses for large wood structures
  • Perform basic force and moment computations and associated sensitivity analyses
  • Identify risk factors that are beyond the current state of the art

Webinar Benefits

  • Discover key sources of design guidance for large wood introductions for river restoration
  • Learn some key findings of recent research on the ecological significance of large wood in streams and rivers
  • Find out what types of sites are not suitable for large wood introduction or placement of large wood structures
  • Avoid costly failures of river restoration projects that include large wood
  • Learn how to analyze fluid forces on large wood in rivers
  • Develop skill in quantifying uncertainty using sensitivity and Monte Carlo analyses
  • Avoid construction delays and impacts by identifying key considerations for implementation

Assessment of Learning Outcomes

Students' achievement of the learning outcomes will be assessed via a short post-assessment (true-false, multiple choice and fill in the blank questions).

Intended Audience

  • Hydraulic Engineers
  • Hydrologists
  • Planners and project managers
  • Geomorphologists
  • Biologists and Ecologists

Webinar Outline

  • Review of information resources (design handbooks) for large wood as a restoration tool
  • Is wood appropriate for your site?–criteria for screening
  • Three design approaches
  • Geomorphic analysis
  • Biological analysis
  • Site design
  • Key issues for large wood design
  • Design life for wood structures/selection of design event or condition
  • Types of wood structures
  • Hydraulic analysis/flow force computations
  • Findings of recent research on drag and lift coefficients
  • Sensitivity and Monte Carlo analyses
  • Constructability assessment

How to Earn your CEUs/PDHs and Receive Your Certificate of Completion

To receive your certificate of completion, you will need to complete a short on-line post-test and receive a passing score of 70% or higher within 1 year of purchasing the course.

How do I convert CEUs to PDHs?

1.0 CEU = 10 PDHs [Example: 0.1 CEU = 1 PDH]