Hydraulic and Sediment Modeling of Reference Reaches
Matthew Johnson, PE, CFM
WaterVation
Colorado Springs, Colorado
Hydraulic and Sediment Transport modeling is often used during the design process for stream restoration and channel designs. These simulations are typically applied to the proposed conditions to confirm if the design is operating within a required set of criteria. These analysis tools and techniques are often prepared without calibration or even confirmation. They are used as a check and can influence and modify the proposed design depending on the results.
Hydraulic modeling is often used to determine parameters for the design such as shear stress and velocity. These parameters are compared against typical published values to check if the design is in conformance of the owner’s criteria. Sediment transport modeling is used in a variety of ways, but one method is to apply a sediment transport equation over a given flow condition to assess whether sediment continuity is reached or whether degradational or aggradation trends are present within the proposed design.
This presentation explores a comparison of hydraulic and sediment modeling for a healthy functioning reference reach compared to a proposed design reach. This study begins the conversation whether the results of these models are providing accurate or adequate design guidance. Key comparisons between the reference reach and design reach are shear stresses, velocities, and predicted sediment transport capacity. The purpose of this study is to calculate these parameters for the reference reach in order to develop “criteria” for the project reach.
The goal of the presentation is to present a framework for comparing hydraulic and sediment transport modeling between reference reaches and proposed designs, to share findings, and to engage the stream restoration community on this topic.
A stream restoration project to improve aquatic habitat resources located on Flat Creek in Jackson, Wyoming will provide the primary test case for this comparative study.
About Matthew Johnson, PE, CFM
Matthew Johnson has over 7 years of experience in hydrologic and hydraulic planning, analysis, and design primarily focused in stream systems. He has managed smaller stream stabilization projects and served as design lead / assistant project manager on stream restoration projects up to 2 miles in length with construction budgets of $3M. This experience includes construction oversight and implementation of stream restoration/stabilization designs.
Matthew is experienced in hydrologic modeling, 1D, 2D, and 3D hydraulic modeling, sediment transport modeling, stream stabilization and restoration design, scour analysis, and erosion countermeasure design. This includes major drainage analysis including FEMA floodplain modeling, mapping, and permitting. His modeling experience includes GIS, HEC-2, HEC-RAS, HEC-HMS, SRH-2D, HY-8, Flow3D, EPASWMM, InfoSWMM, and XPSWMM.
Matthew has prepared and lead trainings for SRH-2D and HEC-RAS 2D as well as other hydraulic topics. He has presented his work at ASFPM, EWRI, NHEC, CASFM, and the Rocky Mountain Stream Restoration Conferences.