good point, i think i'll keep the 50% bonus, but restrict it to increasing per civilian on or adjacent to Tundra/Snow

An interesting setup, but the UA looks overpowered. Saving 50% of food combined with the medical lab's 25% and the aqueduct's 40% adds up to 115%. Assuming the game's code allows for it, that gives you more food than you put in, making your late game population go up ridiculously quickly. Hell, even the 90% from just the UA and Aqueduct is hilariously powerful and you can have that for most of the game. This kind of boost belongs on a unique aqueduct or something. Not in a UA. It could also be good if the Civ just couldn't build aqueducts, but I don't know if that would be possible to implement since there is a social policy that gives you a free one.