# Hydraulics

Various types of drainage facilities are required to protect the highway against surface and subsurface water. Drainage facilities must be designed to convey the water across, along, or away from the highway in the most economical, efficient, and safe manner without damaging the highway or adjacent property. The purpose of this manual is to provide detailed information on the subjects of hydrologic and hydraulic analysis related to highway design. This manual should be used in conjunction with the Washington State Department of Transportation (WSDOT) Highway Runoff Manual and the WSDOT Design Manual, specifically Section 1210.

## Uniform Flow Calculations

The determination of the flow characteristics for uniform flow conditions can be calculated based on the continuity equation (Equation 4-1). […]

## Introduction to Open-Channel Flow

An open channel is a watercourse that allows part of the flow to be exposed to the atmosphere. This includes

## Miscellaneous Design Considerations: Siphons Culvert Design

Siphon designs require review and concurrence by the State Hydraulics Office per Table 1-1. Also, the siphon design may need

## Upstream Ponding Culvert Design

The culvert design methodology presented in Section 3-3 assumes that the headwater required to pass a given flow through a

## Horizontal and Vertical Angle Points Culvert Design

The slope of a culvert shall remain constant throughout the entire length of the culvert. This is generally easy to

## Camber Culvert Design

When a culvert is installed under moderate to high fills 30 to 60 feet or higher, greater settlement of the

## Miscellaneous Culvert Design Considerations

This section presents miscellaneous culvert design considerations, including multiple culvert openings, camber, horizontal and vertical angle points, upstream ponding, and

## Culvert Debris Culvert Design

Debris problems can cause even an adequately designed culvert to experience hydraulic capacity problems. Debris may consist of anything from

## Energy Dissipators Culvert Design

When the outlet velocities during the design-year storm event are 5 ft/s or greater, the PEO shall use an energy

## Improved Inlets Culvert Design

When the head losses in a culvert are critical, the PEO may consider the use of a hydraulically improved inlet.

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