What term describes the line connecting all the piezometric surfaces along a pipeline?

The term "hydraulic grade line" refers to the line that connects all the piezometric surfaces along a pipeline. This line represents the energy head of the water, which includes the elevation head and the pressure head at various points along the pipeline. Essentially, the hydraulic grade line indicates the height to which water would rise in piezometers placed along the pipeline, reflecting the static pressure exerted by the water at those points.

This concept is vital for understanding water distribution systems, as it helps identify how water will flow under the influence of gravity and pressure, which is crucial in the design and operation of pipelines. The hydraulic grade line assists engineers in predicting potential issues related to pressure changes, flow rates, and needed elevation adjustments in a water distribution network.