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shown in the false color aerial photograph captured on September 14`" in Figure 13 <br />below and released slowly through a 36 in diameter culvert under the embankment <br />and later with supplemental pumps deployed by RMA staff. A stage storage <br />relationship of this impoundment provided by RMA staff indicates that it has a capacity <br />of approximately 293 ac -ft (stage - storage relationship provided in Appendix G). As a <br />point of comparison, approximately 493 ac -ft was released when the Havana Street <br />Dam failed, and over the course of the modeled storm, approximately 1692 ac -ft of <br />runoff entered Havana Street Pond. The embankment reportedly never overtopped <br />during the flood, which indicates that there was significant depression and floodplain <br />storage between the Havana Street Pond Dam and this impoundment. The HMS <br />model was not able to account for this storage, and consequently shows the <br />embankment overtopping. Further effort in calibrating the model to more closely <br />simulate the performance of the railroad embankment was not performed for this <br />study, but could be done to get a better picture of what happened downstream of the <br />railroad. This was not performed because there were no reports of damage <br />downstream of the railroad embankment. Figure 13 clearly shows significant <br />depression storage in the downstream floodplain in addition to the impoundment <br />created by the abandoned railroad embankment. It is suspected that once the <br />railroad embankment caught the peak from the spillway breach, flows downstream <br />would have rapidly returned to pre- breach levels. There was little infrastructure in <br />the path of the flood wave as it traveled north and west towards the CO Highway 2 <br />embankment. Downstream of Highway 2, Irondale gulch travels through Commerce <br />City developments before entering the South Platte River. <br />1, <br />Railroad Embankment <br />' Impoundment <br />MHavanaStreet Dam <br />Figure 13 - False Color Aerial Photograph - 14 SEP 2013. Source: DigitalGlobe <br />