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1.0 Scope and Purpose <br />The purpose of this report is to document the failure of the Havana Street Dam which <br />occurred on September 12, 2013. During the extreme precipitation event in Colorado during <br />September 2013, the Colorado Dam Safety Branch (DSB) received media reports indicating <br />that dams in the general vicinity of Havana Street Dam had breached or were in danger of <br />breaching. There was some confusion from the media reports about whether a dam had <br />failed or if it was simply the impoundment of water on the Irondale Gulch drainage by the <br />abandoned railroad embankment upstream of CO Highway 2. Communication with the US Fish <br />and Wildlife Service (USFWS) indicated that the Havana Street Dam had indeed breached <br />through the spillway section and that the other dams in the area were experiencing flooding <br />but were performing well. USFWS staff also indicated that there was an abandoned railroad <br />embankment impounding water that they were monitoring. Apparently, this impoundment <br />was at least partially created by the water released from the Havana Street dam. <br />During the event, the need to perform an independent investigation of the dam failure was <br />recognized, but due to limited resources, no DSB personnel were available to mobilize to the <br />site to confirm that the dam had indeed breached. A site investigation was performed as soon <br />after the dam failure as possible to collect evidence of the failure in order to document the <br />cause and consequences of the failure and to chronicle the events so that lessons learned <br />could be gleaned for future application to dam safety regulations, policies and procedures. <br />The post failure site visit had several purposes. To confirm which dams had failed and <br />confirm no additional risks to downstream floodplain, to gather failure information for future <br />use for improvements in dam safety, and to try to estimate the damages downstream of any <br />dam failures so that impacts directly attributable to the dam failures could be delineated. It <br />was imperative to gather the information as quickly as possible following the failures to <br />reduce the chance of site degradation. The scope of work of the Dam Safety Branch was to <br />physically measure the dam breach and obtain photographic record of the dam in its post <br />breach configuration and to observe the downstream damages. <br />Authority to conduct the field investigation was given by Scott Cuthbertson, Deputy State <br />Engineer and Bill McCormick, Chief, DSB. Access to the site was secured through the USFWS <br />and Rocky Mountain Arsenal National Wildlife Refuge (RMA). <br />2.0 Methodology <br />Due to significant damage to infrastructure, RMA was closed to the general public. Access <br />was gained in coordination with Brad larossi (USFWS Dam Safety) and David Lucas (Manager - <br />RMA). A team of three Dam Safety Engineers mobilized to the site on September 23, 2013 (11 <br />days after dam failure). <br />The team surveyed four cross - sections across the channel formed by the breach of the <br />spillway. The vertical control for the survey was tied to benchmarks found on the dam. In <br />addition to the cross - sections, high water lines evidenced by debris on the upstream slope of