Dredge Management Guidelines - the BIEAP and FREMP Website

Appendix 7
Appendix 7
Source: PWGSC
Fraser River Hydraulic Study Requirements
This section outlines requirements for conducting hydraulic studies for the purposes of assessing
Dredging Applications. These Terms of Reference are intended to establish consistent modelling
methodologies and practices when using hydraulic models to assess impacts of dredging proposals.
This should assist with expediting the review process of the study and assessment of the dredging
license application.
It is suggested that proponents or their consultants call Public Works & Government Services Canada
(PWGSC) before initiating hydraulic studies to discuss details of the study methodology. This would
ensure that the information requirements are established for the technical review of specific dredging
proposals. PWGSC is the technical reviewer (for FREMP Lead Agencies) of dredging license applications.
The following outlines details of hydraulic study requirements:
Study Methodology
The study must include an assessment of impacts to the local and downstream Fraser River hydraulic
characteristics that may occur from conducting the dredging.
Impacts to the following hydraulic characteristics to be considered:
■ Local water levels
■ Local flow velocities
■ Sandation, Deposition/Accretion Patterns (local and downstream)
■ Shoreline/Foreshore Erosion (local and downstream)
■ Undermining of existing local marine structures
Model Used
Consultants are not limited to any specific model, but the model must be capable of providing water
surface elevations, velocities, and erosion / accretion information at sufficient scale (or grid size) to
quantitatively assess the impacts of the dredging using varying flow conditions.
Calibration
Hydraulic models must be calibrated using historic prototype site information from existing records
(unless consultants are obtaining new field data for calibration purposes). Available velocity and
hydrographic survey records can be obtained from PWGSC. The model must show similarity of
hydraulic characteristics of pre and post freshet conditions to prototype records to establish reliability.
Model Extents
Model area to be sufficient for assessing local and downstream impacts. Upstream area to be sufficient
for ensuring model stability of flow.
Surveys
Hydraulic model must use current hydrographic survey data for baseline condition (e.g. Taken since
previous freshet).
55 Appendix 7