HYDRAULIC GRADIENT

The gradient or slope of a water table or Piezometric Surface in the direction of the greatest slope, generally expressed in feet per mile or feet per feet. Specifically, the change in static head per unit of distance in a given direction, generally the direction of the maximum rate of decrease in head. The difference in hydraulic heads (h1 - h2), divided by the distance (L) along the flowpath, or, expressed in percentage terms: I = (h1 - h2) / L X 100 I = (h1 - h2) / L X 100; A hydraulic gradient of 100 percent means a one foot drop in head in one foot of flow distance.