Ah.
It's important to keep in mind that beavers aren't dwarves. Not only can they all swim, they *enjoy* it. So instead of building bridges across streams, all you need to do (and all you should do) is build a stairs down into the water, a path along the riverbed, and a stairs on the other side.
This gives your citizens a mood bonus from having wet fur. Which is not, you might think, a penalty.
This also means that when you plan out engineering projects involving redirecting the flow of water, you don't have to wait until there is no water flowing so that you can do your digging/building while it's safely dry, so as to not risk drowning your citizens.
You can just order floodgates and dams built right from the get-go. They'll happily swim out there and build them, provided you've placed a path.
Left the reservoir intake gate open in the drought. Big mistake, it turned into an outflow gate.
In my complacency, I hadn't prepared emergency water stores, like I usually would. And so, literally half my 50-strong colony died of thirst, after the drought, because of how long it took for the pumps to come online and the haulers to haul the water.
Lesson learned.
Overall, I'm really enjoying myself. I'm getting stuck in, I'm pleased with what I've accomplished so far, and I'm looking forward to unlocking and completing more projects (such as more crops/food sources).
It's very close to exactly what I wanted. I also enjoy being able to rely on my experience playing other colony sims and not have to struggle to learn new stuff I'm not interested in. Laurels are comfy and nice to rest on.
Anyway, I'm reasonably sure my reservoir will stand up to any possible drought or badtide, and the only reason my food level readouts show a decline is because the warehouses are full (and when they're full, the number can only get smaller).
So, now that the colony is safe and secure, I can concentrate on making things nicer.
Oh this is VERY satisfying. I have a huge reservoir and automatic sluices, so I don't even notice droughts. I'm now growing every kind of crop and making every kind of food. My industries are powered by windmills with gravity batteries for backup. My warehouses are full of every kind of food.
VERY satisfying. It's a lovely little community. Now that they're luxuriously well-fed, it's time to move on to the social buildings and entertainments.
Len