Weir Equations in HEC-RAS

HEC-RAS has the ability to simulate flow at hydraulic controls in a variety of ways. Bridges, culverts, inline structures, lateral structures, and SA/2D area connections can all act as hydraulic controls.  Effectively, they break up the conservation equations used between cross sections in a 1D reach and/or cells in a 2D area with empirically derived […]

Read More

Lateral Structure Coefficients

Lateral structures can be used in HEC-RAS to transfer flow from a river/reach to a storage area, or to another river/reach.  With the coming release of HEC-RAS with 2D capabilities (estimated beta release January/February 2014), you’ll be able to hook a river/reach to a 2-D area using a lateral structure. Although its primary function in […]

Read More

Flow spike after peak of dam breach floodwave.

Just ran into an interesting phenomenon.  I was running a dam breach model with fairly typical breach parameters and piping failure mode.  After the peak of the breach hydrograph, there appeared a mysterious “spike” as shown in the figure below. This happens to be right at the same time the flow through the developing breach […]

Read More