Thalassicus
Bytes and Nibblers
Most of us intuitively think the Aqueduct sets stored food of grown cities to 40%. A city reaching size 2 would always 0.4*30 = 12.
This is not how it works. Firaxis chose a more complicated design, which I believe improves gameplay. The aqueduct copies surplus food into itself each turn. If the city has +3 food surplus, then the aqueduct copies 3 food into its personal storage each turn. It copies the food... it does not move the food. The food is duplicated so the city and aqueduct both get the food.
Say we have a 1 city with +3 surplus per turn. We purchase an aqueduct 8 turns after founding the city. This happens:
Turn|City|Aqueduct|
0|0||
1|3||
2|6||
3|9||
4|12||
5|15||
6|18||
7|21||
8|24|0|Aqueduct purchased
9|27|3|
10|30|6|City reaches 30 food, cap increases to 34.
| 0 |6|City removes 30 food, grows to 2 .
| 6 ← |0|6 food moved from aqueduct to city.
11|9|3|
12|12|6|
13|15|9|
14|18|12|
15|21|14|
16|24|14|
17|27|14|
18|30|14|
19|33|14|
20|36|14|City reaches 34 food, cap increases to 39.
| 2 |14|City removes 34 food, grows to 3 .
| 16 ← |0|14 food moved from aqueduct to city.
21|19|3|
22|22|6|
23|25|9|
24|28|12|
25|31|15|
26|34|16|
27|37|16|
28|40|16|City reaches 39 food, cap increases to 46.
| 1 |16|City removes 39 food, grows to 4 .
| 17 ← |0|16 food moved from aqueduct to city.
29|20|3|
30|23|6|
Note: some details of what happens the moment the city grows might vary slightly. Firaxis might add food to the aqueduct after moving it to the city, instead of adding food to the city and aqueduct at the same time, though this is unlikely.
The first time the city grows, the aqueduct adds 20% of the total food required for growth, not 40%, because we purchased the aqueduct late in the growth cycle. Every later cycle adds 40% of maximum food because the aqueduct is present for a full cycle. I think they did it this way to reward purchasing an aqueduct as soon as possible, instead of 1 turn before city growth. Purchasing earlier than the turn before growth would otherwise waste maintenance.
This is not how it works. Firaxis chose a more complicated design, which I believe improves gameplay. The aqueduct copies surplus food into itself each turn. If the city has +3 food surplus, then the aqueduct copies 3 food into its personal storage each turn. It copies the food... it does not move the food. The food is duplicated so the city and aqueduct both get the food.
Say we have a 1 city with +3 surplus per turn. We purchase an aqueduct 8 turns after founding the city. This happens:
Spoiler :
0|0||
1|3||
2|6||
3|9||
4|12||
5|15||
6|18||
7|21||
8|24|0|Aqueduct purchased
9|27|3|
10|30|6|City reaches 30 food, cap increases to 34.
| 0 |6|City removes 30 food, grows to 2 .
| 6 ← |0|6 food moved from aqueduct to city.
11|9|3|
12|12|6|
13|15|9|
14|18|12|
15|21|14|
16|24|14|
17|27|14|
18|30|14|
19|33|14|
20|36|14|City reaches 34 food, cap increases to 39.
| 2 |14|City removes 34 food, grows to 3 .
| 16 ← |0|14 food moved from aqueduct to city.
21|19|3|
22|22|6|
23|25|9|
24|28|12|
25|31|15|
26|34|16|
27|37|16|
28|40|16|City reaches 39 food, cap increases to 46.
| 1 |16|City removes 39 food, grows to 4 .
| 17 ← |0|16 food moved from aqueduct to city.
29|20|3|
30|23|6|
Note: some details of what happens the moment the city grows might vary slightly. Firaxis might add food to the aqueduct after moving it to the city, instead of adding food to the city and aqueduct at the same time, though this is unlikely.
The first time the city grows, the aqueduct adds 20% of the total food required for growth, not 40%, because we purchased the aqueduct late in the growth cycle. Every later cycle adds 40% of maximum food because the aqueduct is present for a full cycle. I think they did it this way to reward purchasing an aqueduct as soon as possible, instead of 1 turn before city growth. Purchasing earlier than the turn before growth would otherwise waste maintenance.