This memo was superseded the 08/18/09 memo Distribution of HY-8 Culvert Hydraulic Analysis Program, version 7.2

	Memorandum
U.S. Department of Transportation
Federal Highway Administration

The Office of Bridge Technology is pleased to announce the release of version 7.1 of the HY-8 Culvert Hydraulic Analysis Program (HY-8 7.1). The HY-8 7.1 represents the second phase of the FHWA’s multi-phase upgrade of its culvert hydraulics software approaches and protocols. Notable new features completed during this phase include:

• Incorporates energy dissipater module;
• Performs hydraulic analyses of embedded culverts;
• Allows use of modified outlet loss coefficients;
• Incorporates dynamic culvert shape database with new materials; and
• Implements various improvements, technical updates, and bug corrections.

The HY-8 7.1 has on-line Help that assists users in understanding software operations and features. The technical methods applied in HY-8 are based on the FHWA publications: “Hydraulic Design Series 5: Hydraulic Design of Highway Culverts” (HDS-5), May 2005 and “Hydraulic Engineering Circular 14: Hydraulic Design of Energy Dissipaters for Culverts and Channels” (HEC-14), Third Edition, July 2006.

Attached to this memorandum is a copy of a “HY-8 Quick Start” document that provides information on background; program downloading and installation; some important differences between older versions and HY-8 7.1; and ways to report bugs or other problems.

A copy of this memorandum and attachment is being e-mailed directly to the hydraulics unit in each State department of transportation.

If you have any questions, please contact Mr. Joe Krolak of my staff at (202) 366-4611.