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Figure 9 - Temporal Rainfall Distribution. Source: AWA As shown on the temporal rainfall distribution plot in Figure 9 above, the rain started in the early morning hours of September 11. It is important to note that the early parts of the rain likely put the basin into a high antecedent moisture condition so that Later rains were more prone to runoff. Also note that the rainfall in sub -basin 1 (S131), which is the basin directly tributary to the Havana Street Dam, had the highest depth of all basins modeled. The vast majority of the rain fell during the first half of the day on September 12th with a gradual tapering of rainfall intensities over the following 24 hours through the early morning hours of September 13th. Additional waves of rainfall added significant depth late on September 14th and again on September 15th when the storm finally stopped. Comparing this observed rainfall to NOAA Atlas 14 (NOAA, 2014) precipitation frequency events gives a better picture of the relative intensity of this storm. Figure 10 below provides a comparison of the depth- duration data provided by AWA to the estimated point rainfall estimates for various annual exceedance probabilities (AEP) for the Havana Street Dam. According to these numbers, the Havana Street Dam basin experienced a 24 -hour rainfall with an AEP of 0.1% (commonly referred to as a 1000 - year annual recurrence interval). NOAA Atlas 14 data is presented in Appendix F. ---------- pI - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - . . . . . . . . . . Figure 9 - Temporal Rainfall Distribution. Source: AWA As shown on the temporal rainfall distribution plot in Figure 9 above, the rain started in the early morning hours of September 11. It is important to note that the early parts of the rain likely put the basin into a high antecedent moisture condition so that Later rains were more prone to runoff. Also note that the rainfall in sub -basin 1 (S131), which is the basin directly tributary to the Havana Street Dam, had the highest depth of all basins modeled. The vast majority of the rain fell during the first half of the day on September 12th with a gradual tapering of rainfall intensities over the following 24 hours through the early morning hours of September 13th. Additional waves of rainfall added significant depth late on September 14th and again on September 15th when the storm finally stopped. Comparing this observed rainfall to NOAA Atlas 14 (NOAA, 2014) precipitation frequency events gives a better picture of the relative intensity of this storm. Figure 10 below provides a comparison of the depth- duration data provided by AWA to the estimated point rainfall estimates for various annual exceedance probabilities (AEP) for the Havana Street Dam. According to these numbers, the Havana Street Dam basin experienced a 24 -hour rainfall with an AEP of 0.1% (commonly referred to as a 1000 - year annual recurrence interval). NOAA Atlas 14 data is presented in Appendix F.