In September of 2013, significant flooding along the Colorado Front Range area overwhelmed the Havana Pond, located on the Rocky Mountain Arsenal (northeast of Havana Street and East 56th Avenue). Flows down the partially riprap-lined emergency spillway locate on the left abutment of the dam resulted in head-cutting and scouring of the foundation soils and embankment fill, eventually washing out the spillway and breaching the dam.
K+A provided geotechnical engineering and design support for repair of the dam and spillway, including seepage analyses for assessing the potential for high internal and/or exit seepage gradients that could potentially result in internal erosion (piping) of the highly erodible fine sandy soil composing the dam and foundation. The design included replacement of suitable materials within the scoured extents of the dam and spillway, scour mitigation features such as a wider and longer grouted-boulder spillway, and sheetpiles at the upstream and downstream ends of the spillway and into the left abutment of the dam.
K+A also performed construction materials testing and observations for the owner’s representative during the construction, which began in March 2015 and is nearing completion.