Logarithm of Head Ratio Graph

View | Log Head Ratio

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This selection displays a graph of logarithm of Head Ratio (Ht/Ho or Head at adjusted time = t, divided by Head at adjusted time = 0) on the vertical axis vs. arithmetic Adjusted Time on the horizontal axis. The graph should theoretically be a straight line. However, the slope of the graph typically starts steeply negative and becomes more gentle because of compressibility of the aquifer.

The head ratio graph is the basis for the Bouwer and Rice graphical method, and the Hvorslev graphical method.

Negative head values can not be graphed because the log of a negative value will cause an error.

The following options are available for graphs:

Units for the drawdown axes are set from Options | Units.
The font can be changed from Options | Graph Font.
The graph can be printed by selecting File | Print with print option specified from File | Page Setup.
The colors can be changed with Options | Graph Colors.
Symbols can be selected from Options | Graph Symbols.
The default axis scaling can be changed from Options | Graph Axes.
Graph text can be changed from Options | Language.
The graph can be copied to the clipboard from Edit | Copy Graph.
The graph can be saved as a bitmap from File | Save Graph As.

This graph should not be confused with the data plotted for the Cooper type curve method. The Cooper method plots arithmetic Ht/Ho on the vertical axis and logarithm of time on the horizontal axis. This graph is logarithm of Ht/Ho on the vertical axis and arithmetic time on the horizontal axis.