A new dam has to be built downstream because this one is already falling apart. The problem is not that it was constructed using roller compacted concrete, the problem is that they did not use enough cement in the concrete mixture! Saving money on cement is going to cost at least $787m for the replacement dam. In 2020 they had already reduced the dam to 40% of its capacity because the original dam would not survive a 1 in 200 year flood. At 40% of it design capacity, it should survive a 1 in 5000 year flood.
9:05 video @ 8:158:15 |
I noticed that on SunWater's website, there is an "algae level" graphic so I presume the green in this photo is indeed algae. The photo was taken before 2020 when they lowered the spillway to reduce the capacity to 40%. The farmers protested the reduction of capacity because that is not a normal years supply of water. One of the primary purposes of the dam is irrigation.
WaterpowerMagazine, Credit: Erwin from Pixabay |
There have been so many problems with this 20-year dam that all of the Google search results are about problems. I could not find some basic statistics such as length and height for the dam.
Update: A video says the dam spans 600m (1/3 mile) across the Burnett River. [@1:50]
They not only didn't use enough cement, but they also had too much clay in the mix. This caused the dam wall to expand and contract when exposed to moisture. And the concrete became porous allowing cement to be leached out. This caused the concrete to deteriorate even faster. The estimate to fix the problems is now up to 1.2 billion. And the fix is to build a new dam downstream of the existing dam. [5:08] A couple of floods also demonstrated that the design inflow estimates were too low.