[xr6-FTW]

The main reason why that spillway is eroding is because of what I saw on tv, it seems as though the main spillway developed a massive sink hole which forced the closure of that section to release water, so what they done was use the backup emergency spillway which they've probably never really used which is basically crumbling away. Hearing that on tv gives you a picture in your head where you can imagine the americians saying "what's the point of upgrading that section of the dam, we haven't used it in how ever long its been", so when this freak amount of rain has hit and things have gone critical, the emergency spillway is now critical of breaking apart.