A control measure that you might run across on a construction site, typically during the land development phase, are diversions that come in the form of berms and swales. These are generally installed along the perimeter of the project and will act as an earthen perimeter control measure that will intercept run-off from sloped land. They will then divert the sediment-laden water to a sediment basin. These diversions consist of a channel or dike-like channel that are constructed with either ridges, excavated channels, or a combination of both. Diversions and their supporting infrastructure should be installed prior to the commencement of land disturbing activities. 

Diversion channels can also be utilized to prevent stormwater run-on from entering a project by diverting the water around the project before being discharged at a stabilized outlet. Channels are typically constructed using trapezoidal or parabolic cross sections. It is common practice for diversion channels to be lined in order to minimize erosion within the channel. They are normally lined with one or a combination of the following materials: erosion control blankets, plastic lining, turf reinforced mats, rip-rap, vegetation, or concrete. Just like with any other control measure on a construction site, it is important that diversions are properly constructed, maintained, and designed to perform for their life span. Always refer to the local jurisdiction for specific temporary diversion requirements.