1910
 
 Elwha Dam
 
 Constructed
 
 First dam on the Elwha River constructed
 
 in 1910. This dam blew out in 1912 and was
 
 replaced with a stronger structure by 1913.
 
 Thereafter the river was no longer
 
 free-flowing and anadromous fish were
 
 blocked from the upper reaches of the
 
 river and its tributaries. 
Submitted by @Ritterton