Breaklines are crucial in HEC-RAS 2D modeling because they control how the cell mesh aligns with important terrain features. This directly improves the accuracy and stability of flow simulations. This…
Breaklines are crucial in HEC-RAS 2D modeling because they control how the cell mesh aligns with important terrain features. This directly improves the accuracy and stability of flow simulations. This…
Since HEC-RAS 6.7, a more detailed 2D bridge modeling method has been introduced - 2D Pressure/Overtopping Approach. Different from the Simplified 1D Rating Curves Approach, this new physics-based "cloned mesh" approach…
A lot of things can be investigated to improve 2D HEC-RAS model stability. This post covers some of the most critical factors to investigate when a model starts to act…
Starting from Version 6.6, HEC-RAS is able to model stormwater pipe networks including conduits (pipes) and nodes (manholes or inlets). By coupling stormwater pipe networks with HEC-RAS 2D surface, modelers…
A lateral structure (LS) in HEC-RAS, parallel to the centerline of a river, is often used to connect a river reach to a 2D flow area, a storage area, or…
In HEC-RAS 2D, the terrain created from LiDAR DEM often does not have enough details for areas located within a river channel. For better modeling purpose, normally a river bathymetry…
A storm water pump station (Figure 1) is needed in low areas of a drainage system where drainage by gravity is not possible, such as a depressed roadway segment. Pump…
The SCS Curve Number (CN) is used to quantify infiltration loss during runoff calculation. As illustrated in Figure 1, a curve number should be determined by soil (Hydrologic Soil Groups, or…
To apply the HEC-18 Equation 6.2 (Figure 1) to calculate the live-bed contraction scour depth, the bed material particle D50 fall velocity needs to be determined to estimate the coefficient…
The bridge contraction scour depth and pier scour depth calculations are explained in the following three posts - Horizontal Contraction Scour, Vertical Contraction Scour (Pressure Flow Scour), and Local Pier…