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Green-Ampt Infiltration Parameters: Difference between revisions

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The initial moisture value represents the fraction of the soil that is initially wet. As both initial moisture and porosity are expressed as fractions, the soil capacity is defined as the difference between them both. As such, the initial moisture should not exceed the porosity otherwise soil capacity will be set to zero with no infiltration occurring for that soil type. A [[TUFLOW Message 2508 |2508 WARNING]] is issued if this is the case.<br>
 
The three initial moisture sensitivity tests have been undertaken with the Green-Ampt method using both a pre-2023 release of TUFLOW and a post-2023 release of TUFLOW. Figure 911 shows how variations in the initial moisture affect the simulated cumulative infiltration, whereas Figures 1012 and 1113 show the effects of varying the initial moisture on flows at the catchment outlet when using the pre-2023 and post-2023 releases of TUFLOW. As the initial moisture is increased at the beginning of your simulation, there is less infiltration (as you are closer to soil capacity) and more runoff, causing the catchment outflows to exhibit a faster response to rainfall upstream. As the event progresses, soils become more saturated and the influence of the initial moisture parameter becomes less significant. In the examples shown here, the catchment outflows, as visible in Figures 1012 and 1113, show a higher responsiveness to variations in initial moisture at the beginning of the simulations, and attain higher peak values, when using the post-2023 TUFLOW releases.
 
[[File:Init moisture F10.png|600px|Figure 11: Sensitivity of cumulative infiltration in the Plynlimon Gwy catchment to the initial moisture parameter in the Green-Ampt infiltration model.|border]]<br>
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