Drainage Structures
Many variables are involved in determining the hydraulic capacity of an inlet structure including depth of flow, grade, superelevation, and […]
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.
Capacity of Inlets at Sag Locations
By definition, a sag is any portion of the roadway where the profile changes from a negative grade to a
Capacity of Inlets on a Continuous Grade
The flow that is not intercepted by an inlet on a continuous grade and continuous run of curb and gutter
Gutter Flow and Inlet Spacing
When stormwater is collected and carried along the roadside in a gutter, or next to a curb or barrier, the
Bridge Deck and Downstream End Drainage
The drainage design for the bridge deck requires the coordination of the bridge designer, the State Hydraulics Office, and the
Introduction to Drainage of Highway Pavements
Roadway and structure pavement drainage should be considered early in a project design, while the roadway geometry is still being
Placement of Rock Bank Protection
Once the type of rock has been selected from Table 4-2, the next step is to determine the appropriate installation.
Countermeasures for Stream Instability
Because of the abundance of watercourses in Washington State, and the legacy of highway placement along and across their corridors,
Manning’s Roughness Coefficients (n)
Table 4-1 presents references for Manning’s roughness coefficients. Table 4-2 presents estimated Manning’s roughness coefficients (n) for quarry spalls and