3.2.3 Intercomparisons of flood magnitude and dynamics
The intercomparison of flood magnitude and dynamics helps to understand the effects of re-infiltration in a real 500-year event. Figure 8, similar to Figure 5, depicts the basin-integrated differences. For flood dynamics, the initial inundation timing (Tinit) and total inundation duration (D) could vary from -2 (delayed) to 4 (earlier) hours and 0 to 15 hours, respectively. For the temporal evolution of the Harvey event, it is featured by two subsequent events. The first event from 2017-08-26 to 2017-08-27 saturates the soils immediately, during which the large differences of surface water volume and soil moisture are present between the two schemes. The soil moisture content for the re-infiltration scheme is about 10% more than without the re-infiltration scheme; the surface water volume, however, is 40% less. The second event does not produce a large difference because of the saturated soils over the domain (Figure 8d). As indicated by the sensitivity analysis, this effect is highly dependent on soil condition, soil types, and rainfall characteristics. The extreme rainfall from Harvey leaves less room for water to infiltrate, compared to other less intense events. It is therefore expected to have more pronounced improvements for less intense rainfall or other regions with high soil infiltration capacity.
[INSERT FIGURE 8 HERE]