Each and every Dam in the world is an individually designed and built boondoggle which will fail eventually, earth and spoil dams first, stone and concrete after years to a century.

Boondoggle in that all Dams are built on a budget where the funds are diverted elsewhere, the folks downstream get all the benefits and cities get built on the floodplain guaranteed to be washed away the moment the dam fails or needs to be emptied simply because the reservoir enables all year round water for industry, population and agriculture and the population rushes in to the now fertile area.

Once the cheap and cheerful Dam is built the electorate ceases to place a priority on the important thing which is replacement and maintenance of this life giving structure and put incredible priority to tat.(Yes webbot was on to a dead certain thing when it(the site) claims dam failures causing flooding and 100,000′s to flee without giving out the location and dates beforehand(prophecies of impending doom issued each year). i.e the number of Dams in the world -Circa 515,000 and since the 12th C over 2000 Dams have failed and 200 Reservoirs have failed we can largely discount anything between 1900 and 1200 simply because the majority of all Dams have been built since 1900. we will give the odds of failure at 117/2200 *100/1 or 5% per year but we start with 5% at 1900 we add these percentages together in probability in the specific rule formulae i.e (5/1)*(5/2)=12.5% where 5 is the percentage of dam failures over a 117 year period divided by years from 1900 as the first event probability times the next event probability. SUM[(5/1)*(5/n-1)]=
to be more realistic we have the (5/117) probability set as year 1900 because new dams which are maintained rarely fail. i.e SUM[(5/117)*(5/n-1)]=total probability of a dam failure which is about 24% by 2017)

For a dam to fail we do not need sabotage, just neglect and a design flaw.

A good and free to view source is found here where I got the statistics: (http://www.assakkaf.com/Courses/ENCE620/Lectures/Chapter5b.pdf). The equation there used to calculate failures is far more complex and I am not even going to attempt it