When they got to the river, Serena asked, "Do the river flood often?"
She wanted to have the city close to the river so there was a constant supply of water, one of the most important things they needed, but river flooding would cause a problem.
Especially when they had heavy rains. Because at best it could do some serious damage or at worst could completely destroy the city. Something she did not want happening.
If it did tend to flood then she was going to need to build some kind of barrier on the river bank as well as create more canals to divert the waters. Perhaps a dam too?
That would allow them to keep more water for the drier season, but her worry was how it would affect others within the area. They were likely not the only ones that relied on this river for water.
And she didn't want to accidentally cut off the supply of some other place's water. She'd need to recheck the map and see if she could get any hint of where this river came from and where it went.
