Looking at the data for lake that goes through the dam, it seems like they keep it at the same level. So it probably CAN make 7MW with more flow, but generally only flows at a state that puts out 2.
There is no way it’s max is 7MW. They likely meant 7GW.
7MW is the amount of power you can get from a couple of diesel gensets, waaaay smaller than even a small power plant
[https://www.cat.com/en_US/products/new/power-systems/electri...]
I looked into this more, and there is quite a bit of seasonal variability to contend with as well.