ABSTRACT
Materials or substances capable of flowing cannot flow absolutely freely. Nothing flows without encountering some type of resistance. Consider electricity, the flow of free electrons in a conductor. Every type of conductor used (e.g., copper, aluminum, silver) offers some resistance. In hydraulics, the flow of water or wastewater is analogous to the flow of electricity. Within a pipe or open channel, for example, flowing water, like electron flow in a conductor, encounters resistance. However, resistance to the flow of water is generally termed friction loss or, more appropriately, head loss. The deposition of solids within flat drainage and sewerage conveyance pipes can result in problematic hydraulic restrictions, potential odor and corrosions conditions, and a flush of pollutants and solids to receiving waters (Pisano et al., 2003).
