Comment by u1hcw9nx

It can be hard to recognize the heaps of dirt on the riverbanks. The internet claims the Hoover Dam could last 10,000 years, but I don't believe that for a second.

Dams are not permanent structures without maintenance. If they are holding back water or if water is flowing through them, they will eventually erode and their foundations will collapse.

Because the main structure lacks rebar , it will last longer than most modern structures, but it won't last nearly as long as 2,000-year-old Roman structures made with volcanic ash and lime because it uses Portland cement.

There is bigger and more immediate problem. Hoover Dam ends with siltation long before concrete erodes. The Colorado River carries massive amounts of sediment. Eventually, the lake behind the dam will fill with mud, turning the dam into a giant waterfall. Once water starts flowing over the top of a arch-gravity dam rather than through controlled pipes, scouring at the base will undermine the foundation.