Flow nets isopotentials

Flow nets consist of two types of lines streamlines and isopotentials. Streamlines are lines that follow the path of representative parcels of water water always flows parallel to streamlines. Isopotentials, drawn perpendicular to streamlines, are lines along which the hydraulic head, h, is constant. Therefore, water always flows perpendicular to isopotentials. Flow nets are often drawn to represent the horizontal movement of groundwater and associated chemicals in an aquifer the plane of the flow net then represents the horizontal aquifer surface, and it is assumed that underneath each point on the surface, flow is essentially the same at all depths in the aquifer. An example of such a flow net is shown in Fig. 3-8. 

The groundwater flow into a well also can be analyzed by using a flow net. Because the well is symmetrical, lines of constant drawdown (isopotentials) are circles centered at the center of the well (Fig. 3-11). Streamlines are arranged radially around the well if there is no regional flow in the aquifer. 

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