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 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:

1. Input Reach Data
2. Gradations
3. Align and Size Culvert
4. Results Table

To learn more about this method, go to AOP Stream Simulation.