May 22

Iowa DOT Culvert & Bridge Backwater Program Workshop – Hiawatha

Event Details

Hiawatha, Iowa


Kirkwood Regional Center – Linn County
1770 Boyson Road
Hiawatha, IA 52233
Room 216

Use the North Entrance


May 22, 2024


Sign In/Registration begins at 8:00 am
Workshop begins at 8:30 am


6 Credit Hours

Event Contact
Keith Knapp
InTrans, Iowa LTAP


This workshop will cover basic principles the Iowa Department of Transportation (DOT) uses in the selection of bridge and culvert replacement structures. The discussion will include a wide variety of concerns that are addressed during the concept stage of project development, typical deliverables that are completed during the concept phase, and the development of preliminary hydrology and hydraulics needed to appropriately specify the type and size of bridge or culvert to be constructed. During the hydraulic review for each sample problem, the workshop will cover the use of the U.S. Geological Survey (USGS) StreamStats program for estimating design discharges, the use of the Iowa DOT Annual Exceedance-Probability Discharges (AEPD) spreadsheet for calculating and comparing peak discharges using other methodologies, and the Iowa DOT Culvert and Bridge Backwater programs.

Why Attend?

This workshop will be beneficial for anyone working with the Iowa DOT AEPD spreadsheet, the Iowa DOT Bridge Backwater Program, the Iowa DOT Culvert Program, or the USGS StreamStats software.

Attendance Requirements

This workshop is computer based. Attendees are required to bring their own device capable of running the software being discussed, which can be acquired at this link or the following URL. The software will need to be pre-installed (we can’t do this on-site) and can be found at Two attendees from the same agency can also share a computer if desired. The computers should be fully charged upon arrival, but we will do our best to provide for recharging during breaks and lunch.

Note: If bringing a computer is an attendance hardship, please contact Keith Knapp ( to potentially borrow a device from Iowa LTAP.

Attendance Limitations

Due to the requirements of the workshops, we are currently, limiting each agency to 2 attendees per location (they can share a computer) in order to serve as many agencies as possible at the training. However, if you would like additional staff from your agency to attend, please email Keith Knapp (, and they can be added to a waiting list if we are not at capacity or decide to add another date.

Registration is on a first-come/first-served basis and will close when the spaces indicated on the registration page are filled. Registration is required no later than 7 days before the workshop.

Tentative Workshop Agenda

TimeEvent Details
8:00 amRegistration
8:30 am – NoonExample Problem Discussion

Basic Principles of Bridge and Culvert Structure Selection (Rules of Thumb)

Bridge and Culvert Concept Development
  • Summary Attachments (GIS References)
  • Draft T&L
  • Draft Hydraulic Modeling
  • Staging Diagrams
  • Cost Estimate
1:00 pm – 4:30 pmUse of Hydraulic Tools
  • Iowa DOT Runoff Chart
  • StreamStats
  • Iowa Culvert Program
  • Iowa DOT AEPD Spreadsheet
  • Iowa Bridge Backwater Program
Example Problems – Selecting the Proposed Structure Type

Questions and Wrap-Up
4:30 pmAdjourn

For More Information

If you have questions about workshop content, contact LTAP Director Keith Knapp at 515-­294­-8817 or