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TO: All Design Section Staff
FROM: J. Kapur 
Phone: 705-7209
DATE: June 4, 2001
SUBJECT: Bridge Drain Types 7 and 8

Sheet 8.4-A3, Bridge Drain Types 7 and 8, is to be deleted from the Bridge Design Manual.

If a designer has a need for a Bridge Drain to be used as a catch basin type, instead of a drop drain, they should contact OSC Hydraulics Office at 705-7278, and request a Neenah Drain model, or similar recommendation to be specified for their application.


The WSDOT Bridge Standard Drains Type 7 and 8 have come under review lately. Consulting with Jay Christianson, OSC Hydraulics, about the Bridge Drains led to the following information: normally we try to keep inlets off of bridges; when Bridge Drains are required, OSC Hydraulics prefers drop drains, otherwise they will spec out a Neenah Drain or similar; and WSDOT Bridge Standard Drain Type 7 is no longer available while Type 8 is no longer used. Therefore, WSDOT Bridge Drain Type 7 and 8 are not to be used in contracts henceforth.

If you have any questions regarding these issues, please contact Gary Battin at




cc: J. Weigel, Bridge and Structures - 47340
        F. Higgins, Bridge and Structures - 47340