Modifying the dam isn’t the issue, you need to make sure the upstream area can be flooded. Not all rivers are in a canyon. You need a sizeable lake and consider how catastrophic an overflow would be. Then you also have to consider the effect downstream because you will likely cause a minor drought persistently since not all dams will dump into the ocean. So yes, I understand that “hydro” is both a source and a battery, but they are really 2 entirely different systems based on your other categorizations.
Same thing with the biomass. One system makes trees, one system burns wood.
The graphic isn’t particularly wrong, it’s just splitting some items and combining others inconsistently.