E 640 Concrete Gutters

It is important to prevent dry-weather flow (the overflow of water from common domestic uses, the lawn sprinkling, etc.) from spreading over the pavement into the path of moving vehicles. The slippery surface produced by this flow may cause vehicles to skid. In addition, vehicles passing over these wet surfaces may splash water onto pedestrians,  other vehicles, and other pavement lanes. Therefore, it is important to confine the water to the area of pavement abutting the curb.

The standard pavement crown section in a level street does not adequately confine this flow to the edge of pavement. In addition, where streets have crossfall, or superelevation, any water which may be flowing on the high side of the street will cross over to the low side at the locations where cross-fall or superelevation sections reverse directions.

Where the flow is confined to the edge of pavement, experience has shown that asphaltic pavements subject to continuous water flow will rapidly deteriorate. Therefore, concrete gutter designed to the standards outlined in this section is used to confine the water. It will be found that concrete pavement can withstand this erosional force better than asphalt concrete. Moreover, concrete gutter can be constructed to a closer tolerance than asphalt concrete pavement. (This is particularly important on flat grades.) Also, concrete gutters can be provided with a smoother finished surface than asphalt concrete pavement, thus reducing the friction between pavement and water and facilitating the flow.

In urban areas, concrete gutters are generally designed in conjunction with inlets to underground water disposal systems. The spacing of these inlets is set to intercept the dry-weather flow and prevent any excess of flow from accumulating and overflowing the gutter. The design of these outlets and underground water disposal systems is a function of the Storm Drain Design Division or the Storm Drain Section.