Gradient and Flow Direction

The gradient, or drop in elevation, of the water along its path is a major factor in defining the water flow velocity, as defined by Darcy s law (section 

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Well Oi slanc a from Log time of number rtver along p afc water 

The gradient is expressed in meters drop of height per kilometer of horizontal flow trajectory, as shown in Fig. 4.11. The drop in water table levels between adjacent wells is computed from their water table data, and the distance between the wells is commonly read from a map on which the wells have been accurately marked. The gradient may also be extracted from a water table map by reading the drop in water table altitude between selected points, as shown in Fig. 4.12. Water flows mainly along the maximum gradient, as shown in Fig. 4.4b. 

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The Need for Complementing Data to Check Deduced Gradients and Flow Directions... 

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