costs. In December 2010, an independent panel of engineers published a study that determined the cause of the failure "was internal erosion in the embankment coupled with overtopping flow". The study believes that a malfunctioning spillway gate and increase reservoir size may have exacerbated an existing problem with the dam's design. The embankment was constructed in such a way that its fill did not settle correctly. Within the embankment section, a concrete wall, designed to reinforce it, was not constructed up to the height of the dam's crest. That sped up internal erosion and allowed the water to over-top the dam. Reconstruction By March 2012, $1.7 million in donations was collected to replace the dam and $9 million in local and county bonds was approved. $5 million in state funding was then requested for repairs as well. The cost at that time was estimated around $12 million. In April, 2014, ground was broken on a $16 million project to replace the failed Delhi Dam embankment and spillway. Completion of the project was scheduled for October, 2015. Of the cost, the state contributed $5 million, the county $3 million and the balance from assessments against the local property owners. In September 2016 the river level was back to pre-flood stage levels. See also Dam failure Hope Mills Dam References External links Lake Delhi Recreation Association Overhead video of Delhi Dam before full breach Overhead video of Delhi Dam after full breach Reservoirs in Iowa Dams in Iowa Dam failures in the United States Disasters in Iowa Buildings and structures in Delaware County, Iowa 1929 establishments in Iowa 2010 disestablishments in Iowa