Wetland Water Balance Modelling Guidance and its Implementation in a Computer Modelling

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June 15, 2021 @ 10:00 am – 12:30 pm America/Toronto Timezone
Online webinar
Christy Graham

Wetlands are an essential part of ecosystems and can be sensitive to changes in water inputs resulting from development. Wetlands can naturally control flood peaks by retaining water and allowing the slow release of water to receiving bodies (e.g. lakes, streams, aquifers). Through the planning and development process, wetlands that require protection can be identified.

Under increasing urbanization, ecosystem services provided by wetlands will be affected unless their hydroperiods are protected through implementation of water balance mitigation measures. The design of effective wetland mitigation measures requires a proper understanding of the wetland hydrological system. A sound understanding of this system is a prerequisite to the assessment of the impact of any anthropogenic activities on the wetland hydrology. Also, a lack of understanding of how the wetland works can lead to the selection of invalid models, which can then result in ineffective mitigation measures. Hydrological models are tools that aid in understanding the interaction of the different components of the water balance by providing a simplified representation of these interactions. When this simplified representation is sufficiently complete, good models allow different land use and stormwater management scenarios to be explored in a way that would otherwise not be possible, thereby helping engineers and other professionals produce designs that minimize the difference between the pre- and post-development wetland hydroperiod.

TRCA established a draft Wetland Water Balance Modelling Guidance Document that outlines the methods and procedures for conducting a feature-based water balance modelling assessment for the protection of wetland hydrology. This modelling guidance document outlines accepted modeling practices, standardizes feature-based water balance analysis submissions, develops protocols for minimum standards in wetland hydrology modelling and summarizes the shortcomings of various continuous hydrology models. This document also discusses statistical methods in determining acceptable mitigation measures.

In this course, we will walk through the methods and procedures for conducting a feature-based water balance modelling assessment for the protection of wetland hydrology outlined in the modelling guidance document along with implementation of the procedures in a hands-on computer modeling exercise. The hand-on wetland modeling exercise is provided with VO6 to showcase the modelling workflow. Participants will learn how to use VO6 to create the model for existing condition, conduct model calibration, evaluate post-development condition with long-term condition and use LID measure to achieve water balance targets.

Learning Objectives

  1. Learn about approaches, methods, and procedures for a proper understanding of wetland hydrological system, assessing impacts of development on the wetland hydrology.
  2. Learn how to establish effective and acceptable mitigation measures and assess and evaluate these measures in maintenance of hydroperiod of the wetland that will satisfy requirements of regulatory agencies.
  3. Use VO6 continues hydrologic model to conduct wetland water balance analysis that includes creation of a model for existing condition, conducting model calibration, evaluating post-development condition with long-term condition, and designing LID measure to achieve water balance targets.


  • Dr. Dilnesaw Chekol, TRCA
  • Dr. Lisha Guo, Civica Infrastructure Inc.

Additional Information

  • The VO6 license and exercise data package will be provided before the session.
  • If you have any additional questions, please contact us at STEP@trca.ca
  • TRCA HST Registration number is 10808 8584 RT001