Agenda

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Please log into the webinar 15 – 30 minutes before start time.


Wednesday, November 5, 2025
8:30 am – 4:00 pm CST


Agenda:
Presented by William Rahmeyer

Understanding Open Channel Flow

  • Course introduction and expectations
  • Fundamentals of open channel flow
  • Types of open channel flow
  • Design variables for open channel flow
  • Concepts of open channel flow not covered in textbooks
  • Primary applications of open channel flow
  • The three flow depths used in open channel flow
  • Open channel flow definitions
  • Steady and unsteady flow
  • Uniform and normal flow
  • Conservation of mass – Continuity
  • Hydraulic radius
  • Hydraulic efficiency
  • Effective diameter
  • Channel shapes and properties
  • Hydraulic elements chart for partially full circular pipe
  • Conservation of energy and the energy equation
  • Local energy losses
  • Froude number and its solution
  • Critical depth and its solution
  • Normal depth and Manning’s equation
  • Subcritical and supercritical flow
  • Review
  • Additional reference slides on FHWA Toolbox

Fundamentals of Open Channel Flow

  • Example of applying the energy equation
  • Energy and hydraulic grade lines
  • Where to start open channel solutions
  • Example of solving converging channels
  • Example of a diverging channel
  • Conservation of momentum
  • Channel flow resistance
  • Resistance and roughness height
  • Resistance coefficients
  • Strickler resistance equations
  • Size distribution
  • Limerinos and ASCE resistance equations
  • Turbulent flow resistance
  • Additional reference slides on using HEC-RAS

Flow Resistance in Open Channels

  • Cowan additive resistance method
  • Curved channel resistance and super elevation
  • Bed forms and bed form resistance
  • Sediment transport and flow resistance
  • Vegetative flow resistance
  • Compound channel flow resistance
  • Chow’s conveyance method for a compound channel
  • Composite or effective resistance equations for a compound channel
  • Compound channels with vertical/steep walls
  • Iterative solution of a compound channel with variable resistance
  • Open flow channel slope definitions
  • Review of using FHWA Hydraulic Toolbox software
  • Review of using HEC-RAS for open channel flow
  • Additional reference slides on using HEC-RAS with a compound channel

Principles of Open Channel Flow Design

  • Composite gradually varied flow profiles
  • Gradually varied flow GVF
  • Mild, steep, critical, horizontal, and adverse slope GVF profiles
  • Mild to steep channel and steep to mild channel GVF profiles
  • GVF summary
  • GVF of converging channels
  • Step method to find the length of a GVF profile and the end depth of a GVF
  • Solution of Manning’s n of a GVF profile given two flow depths
  • Rapidly varied flow and hydraulic jumps
  • RVF Channel transitions
  • Locations of choked flow or control points
  • Types of channel transitions
  • Channel shape and slope transition
  • Non-prismatic GVF
  • Review of calculating flow depths
  • Review of open channel flow types and examples
  • Additional reference slides on GVF slope changes, and channel transitions

Stable Channel Design

  • Composite or multiple GVF profiles
  • Analyzing and sketching multiple GVF profiles
  • Finding the location of a hydraulic jump
  • Open channel design variables
  • Channel discharge, floods, and storm runoff
  • Sedimentation, erosion, and channel deposition
  • Sediment transport
  • Channel erosion and deposition
  • Open flow channel response
  • Channel bank and bed protection
  • Stable channel design
  • Maximum tractive force method
  • Rock riprap for bed and side protection, bank protection
  • Hydraulic structures, culverts and road and railroad crossings
  • Hydraulic structures, drop structures, flow measurement
  • Hydraulic structures, flow control, gates, AOP
  • Basic considerations of open channel design
  • Additional reference slides – solving a hydraulic jump on a horizontal slope
  • Additional reference slides for channel transitions

 

Webinar Instructions 
 
All attendees must log-on through their own email – attendees may not watch together if they wish to earn continuing education credit. HalfMoon Education Inc. must be able to prove attendance if either the attendee or HalfMoon Education Inc. is audited. 

Certificates of completion can be downloaded in PDF form upon passing a short quiz. A link to the quiz will be sent to each qualifying attendee immediately after the webinar. The certificate can be downloaded from the Results page of the quiz upon scoring 80% or higher. 

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Credits

Engineers
6.5 PDHs

Landscape Architects
6.5 HSW CE Hours

LACES - Landscape Architecture Continuing Education System
6.5 HSW PDHs

Floodplain Managers
6.5 ASFPM CECs

 

Continuing Education Information

This webinar is open to the public and is designed to qualify for 6.5 PDHs for professional engineers and 6.5 HSW continuing education hours for landscape architects in all states that allow this learning method. Please refer to specific state rules to determine eligibility.

HalfMoon Education is an approved continuing education sponsor for engineers in Florida (Provider License No: CEA362), Indiana (License No. CE21700059), Maryland, and New Jersey (Approval No. 24GP00049300). HalfMoon Education is deemed an approved continuing education sponsor for New York engineers and landscape architects via its registration with the Landscape Architecture Continuing Education System (LA/CES). Other states do not preapprove continuing education providers or courses.

The Landscape Architecture Continuing Education System has approved this course for 6.5 HSW PDHs. Only full participation is reportable to the LA CES.

The Association of State Floodplain Managers has approved this course for 6.5 CECs for floodplain managers.

Attendance will be monitored, and attendance certificates will be available after the webinar for those who attend the entire course and score a minimum 80% on the quiz that follows the course (multiple attempts allowed).

*On-Demand Credits*

The preceding credit information only applies to the live presentation. This course in an on-demand format is not pre-approved by any licensing boards and may not qualify for the same credits; please consult your licensing board(s) to ensure that a structured, asynchronous learning format is appropriate. The following pre-approvals may be available for the on-demand format upon request:

6.5 HSW PDHs (LA CES)

Speakers

William J. Rahmeyer

Emeritus Professor of Civil and Environmental Engineering at Utah State University (USU)

Professor Rahmeyer was on the faculty at USU for 31 years and spent 10 years as research faculty at Colorado State University. Professor Rahmeyer is the past Department Head of Civil and Environmental Engineering at USU as well as the senior professor of the Hydraulics and Fluid Mechanics program of the Utah Water Research Laboratory. He also served at USU as the director of the Hydro Composite Modeling Program, the division head of Water Engineering, the interim division head of both the Structures Division and the Transportation Division, and as the Undergraduate Curriculum division head. Professor Rahmeyer is currently working part time as a senior associate for Ayres and associates in Fort Collins Colorado, where his primary role is to conduct national workshops in hydraulics, culvert flow, and urban drainage for the National Hydraulic Institute of FWHA. He is a fellow and lifetime member in the American Society of Civil Engineers. Professor Rahmeyer has been a member of several professional societies, and serve on committees for the American Society of Engineering Educators (ASEE), the American Society of Civil Engineers (ASCE), the International Association of Hydraulic Research (IAHR), the Association of State Dam Safety Officers (ASDSO), the Instrument Society of America (ISA), the American Water Works Association (AWWA), the International Erosion Control Association (IECA), and the American Society of Heating and Refrigeration Association (ASHRAE). He has regularly attended and presented at the annual conferences of ASDSO, ASEE, ASCE, IAHR, ASCE National Department Heads, and the Transportation Research Board (TRB). In the past, he has been a member of the United States Committee on Large Dams (USCOLD) and the International Committee on Large Dams (ICOLD). Over the last several years, Professor Rahmeyer has created and presented a workshop on open channel flow for HalfMoon Education and finished serving on the Bluestone Dam UASCE IEPA and on several 100% DDR review panels for the USACE. He has been on the board of directors for the Utah Floodplain and Storm Water Management Association since 1986. Professor Rahmeyer was a member the 2008 Bettelle “Final Independent Peer Review Report for U.S. Army Corps of Engineers on the Vegetation Policy for Local Flood Damage Reduction Systems” which reviewed many of the guidelines and policies for management of levees, floodwalls, embankment dams, and appurtenant structures. Some of his recent awards include the AHRAE Technical/Symposium Paper Award, the ASHRAE Crosby Field Award for Research, and the South Pacific Division Regional Project Delivery Team Award from the U.S. Army Corps of Engineers. He has received the Idaho Transportation Department 2012 Excellence in Transportation Award and the 2011 ACEC of Idaho Engineering Excellence Grand Award for the I-84 New York Canal Modeling and Modification. Professor Rahmeyer further received an honorable mention at the 2012 National AECE award ceremonies for his work with the I-84 New York Canal.