Green-Ampt Infiltration Parameters: Difference between revisions

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== Capillary Suction Head ==
The suction head, represented in millimeters, is the capillary attraction on the soil voids. It is large for fine grain soils such as clays and smaller for sandy soils.<br>
To test the sensitivity of the simulated runoff at threea gauged locationslocation, as shown in figure 2, a low (49.5), mid representing the mean (184.4) and high (316.3) value of the suction head parameter was used with other parameters representing a clay soil (soil type 1).<br>
The larger the value the capillary suction head value, the more capillary action that is achieved and the amount of infiltration that takes place. This is shown by the increase in cumulative infiltration in the graph below with a greater cumulative infiltration for the 20% increase in the suction head.<br>
 
[[File:Fig4 sens to suction.png|600px|Figure 43: Sensitivity of cumulative infiltration in the Plynlimon Gwy catchment to the Capillary Suction Head parameter in the Green-Ampt infiltration model.]]<br>
 
'''Figure 43: Sensitivity of cumulative infiltration in the Plynlimon Gwy catchment to the Capillary Suction Head parameter in the Green-Ampt infiltration model.'''<br>
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As a consequence of this, there is a less runoff generated as shown in Figure 5. The model is not particularly sensitive to the suction head parameter and this fits with observations made within the literature.<br>
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[[File:Fig5 suctionhead.png|600px|Figure 54: Sensitivity of simulated flow at the Cefn-Brwn gauge location in the Plynlimon Gwy catchment to the Suction head parameter in the Green-Ampt infiltration model.]]<br>
 
'''Figure 54: Sensitivity of simulated flow at the Cefn-Brwn gauge location in the Plynlimon Gwy catchment to the Suction head parameter in the Green-Ampt infiltration model.'''<br>
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''<font color="red">add comment on rising lim''</font><br>
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== Saturated Hydraulic Conductivity ==
The saturated hydraulic conductivity, measured in mm per hour, represents the ease that water can travel through the soil whilst it is saturated. The saturated hydraulic conductivity is the equivalent of the limiting infiltration rate in the Horton infiltration model. The hydraulic conductivity is high for sandy soils but low for compact clays. Again, the sensitivity was conducted by varying the value for clays, which itself is relatively by low, with three scenarios, low (0.3), mid representing the mean (15.86) and high (117.8). The results shown in figure 6 show that the parameter is very