Introduction to Water Crossings
This chapter covers the design requirements for water crossings on state highways over fish-bearing waters, in addition to HEC-18, HEC-20, […]
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.
Subsurface Drainage
Subsurface drainage is provided for control of groundwater encountered at highway locations. Groundwater, as distinguished from capillary water, is free
Pipe Materials for Storm Sewers
When designing a storm sewer network, the PEO shall review Chapter 8 (for pipe materials) and the list of acceptable
Hydraulic Grade Line
The HGL shall be designed so there is air space between the top of water and the inside of the
Design Criteria of Storm Sewer
Along with determining the required pipe sizes for flow conveyance and the HGL, storm sewer system design should consider the
Introduction to Storm Sewer
A storm sewer is a pipe network that conveys surface drainage from a surface inlet or through a manhole to
Scupper Barrier
Scuppers in median barriers shall not be used in the following situations: • Passing runoff from one side of a
Grate Types
Grate Types Grates are an essential component in ensuring the efficiency of a drainage system. The following grates (except the
Inlet Structure Types
WSDOT uses grate inlets, catch basins, and manholes to capture runoff for WSDOT projects. Each inlet structure type has different