Hierarchy of Controls - An Alternative Way to Look at BMPs

The goal of erosion and sediment control (ESC) practices is to keep sediments from leaving a construction site. The most cost-effective ESC practice is to not let the soil mobilize in the first place. It is much easier and cheaper to reduce erosion than to remove mobilized sediments.

Erosion control is a practical alternative to the exclusive use of erosion prevention, and should be the primary ESC practice employed on construction sites. In its simplest form, erosion control consists of preventing soils in construction areas from being mobilized. Erosion control minimizes the forces from raindrops, concentrated runoff flows, and wind, each of which detach and transport soil particles. Erosion controls treat the soil as a valued resource that must be conserved in place.

Sediment controls are used to keep sediment from leaving a construction site. Sediment control is any mechanism that removes sediment from water by filtration, gravity, chemical, or other means. Unlike erosion controls, sediment controls treat the soil as a waste product that must be continually removed and disposed of properly. Sediment control is the least cost-effective means to meet ESC objectives since removal of sediment from runoff is more costly than keeping soil in place.

A Hierarchy of Controls has been used as the fundamental method of protecting workers from exposures to occupational hazards. The controls in the hierarchy are, in order of decreasing effectiveness: elimination; substitution; engineering controls; administrative controls; and personal protective equipment. Most commonly, an inverted triangle is used to illustrate this system.

The presentation will show attendees how the Hierarchy of Controls can be adapted for selection of ESC practices and the potential advantages of risk reduction, efficiency gains, and increases in BMP selection expertise as they endeavor to address erosion and sediment discharges associated with construction activities.