My suggestions are having rainfall and droughts have a bigger impact on your colony. If it rains hard areas like lakes could possibly overflow and spill out, if the water was to flood your electrical systems it would cause them to short out or explode much like the random event. It could wash away your stockpile and destroy crops.
To counter this sandbags can be used to protect areas from flooding. I also suggest digging, the game already recognize a few elevations such as deep water, shallow water, normal elevation and mountain. So if we could dig, for instance "Dig shallow" when it rained it would fill up to the shallow level, or "Dig Deep" It would then fill up to the impassible water level. As well as filling the lower elevations to normal elevation. You could use this to help manage rainfall, or build a moat around your base or something.
Water sources could also attract animals instead of having them just randomly around the map. You could fill natural lakes and and build your own closer to your base luring animals to an easier area to hunt.
Droughts would work like you would imagine, dry up lakes, causing higher fire risks, killing crops, discouraging certain animals from visiting.
Water could be transported using buckets or something similar, so you could re-locate bodies of water to prepare for droughts. An example would be having a cooled indoor area with water that is not affected by weather as long as the temperature is controlled. Then during a drought you could transport that water to irrigate your crops to protect them. A pipe block sort of like the power conduit could transport the water under your crops (a colonist with growing task selected would open/close the valve where the water is fed into the pipes as needed) or colonists can transport by bucket manually.
This would all fit in nicely if thirst became a need of the colonists, or water for cooking.
Thank you for reading!
moats for castles :3