Hydraulics & Waterways


397902 - 1-D Hydraulic Model Data, Calibration, and Validation Guidelines

Tuesday, June 5
2:00 PM - 3:30 PM
Location: Regency Room

Succinct guidelines are being developed by an American Society of Civil Engineers Task Committee on the data needs, and calibration and validation of hydraulic models. The primary types of data needed to build, calibrate, and validate a 1-D hydraulic model are stream channel geometry, water surface elevations, discharge, velocity, and roughness. The amount of data will depend upon the precision needed for the study, the water body size, and whether the model is built for a structure, river reach, or watershed scale. Consideration needs to be given to the accuracy and uncertainty of every input data used to build and calibrate the model. The various data types and uncertainty considerations will be discussed in the presentation.

Once a 1-D hydraulic model is built with the available geometry and input data, the model can be calibrated to observed data and then validated to a separate set(s) of data. Calibration is the process of adjusting model parameters to minimize the difference between predicted and observed values for a given time period. Validation is the process of comparing predicted and observed values for a time period independent of the calibration period. Ideally, the validation time period is a similar length and during the same seasons as the calibration period. While calibrating, there should be an assessment of uncertainty and sensitivity. Uncertainty of the data and parameters combined with sensitivity of the modeling results to changes in these data or parameters indicates whether there is a need for extra data collection and a new calibration and validation process. The primary parameters and options available for calibration for 1-D hydraulic models are roughness coefficients, structure coefficients, ineffective flow areas, time step, and cross section spacing. The parameters, parameter adjustments, and the quantification of errors between predicted and observed data will be discussed in the presentation.

Send Email for Tim Straub

Chad Ballard, MS, PE

Civil Engineer
Michael Baker International

Chad Ballard is a licensed civil engineer holding a Bachelor’s and Master’s degree in Civil and Environmental Engineering and has experience using a variety of hydrologic and hydrodynamic solvers and modeling platforms. In both an advisory and consulting role, Chad has helped hundreds of engineering firms around the world apply different numerical modeling solutions to their specific projects. Currently, he is consultant at Michael Baker International as well as an adjunct faculty at the California State Polytechnic University, Pomona. Chad is a past board member of the Orange County Chapter of the Environmental and Water Resources Institute (EWRI) and is involved with EWRI at the national level as part of the Calibration/Validation of Free-Surface Hydraulic Models Task Committee. Chad currently serves as the Treasurer of the Orange County Professional Chapter of Engineering without Boards (EWB) as well as being involved with other non-profit flood modeling work. Chad currently lives in Southern California with his wife and four daughters.


Send Email for Chad Ballard


397902 - 1-D Hydraulic Model Data, Calibration, and Validation Guidelines

Attendees who have favorited this

Please enter your access key

The asset you are trying to access is locked. Please enter your access key to unlock.

Send Email for 1-D Hydraulic Model Data, Calibration, and Validation Guidelines