HY8:AOP
Aquatic Organism Passage (AOP)
Aquatic Organism Passage defines whether aquatic organisms, such as fish and amphibians, are able to pass through a culvert from the outlet to the inlet. There are several approaches to determine aquatic organism passage, and some procedures are specific to a type of organism or a specific specie.
A few of the common barriers to fish passage are excessive velocity, culvert length, depth that is too shallow, a culvert that is perched (requiring a fish to jump) or perched too high, and excessive turbulence.
Stream Simulation
HY-8 incorporates stream simulation aquatic organism passage, as described in Hydraulic Engineering Circular No. 26 (HEC-26). The principle behind this approach is to simulate the stream throughout the culvert and make the culvert no less of a barrier to passage than the stream immediately upstream and downstream.
To begin the AOP Stream Simulation Analysis, first create a crossing (or load an existing crossing from a file) that does not have any errors. Then select AOP Stream Simulation Analysis from the menu: Culvert | AOP: Stream Simulation, or the user can click the AOP: Stream Simulation 
tool from the toolbar.
The AOP Stream Simulation dialog has four steps in a wizard format:
To learn more about this method, go to AOP Stream Simulation.
