Water: the essence of life
Below is my further refined version of population growth model
- Material can be globally stockpiled, including food and prestige
- 1 pop consume 1 food, 1 prestige and water per turn. Thereby, current population of your empire = current per turn food, water and/or prestige production, whichever is the lowest.
- max population of each city is further restrained by the max capacity of local housing
- High prestige slows pop lost, hasten pop growth, but the equilibrium mentioned above will be eventually reached without player's intervention
Food and prestige is globally stockpileable (sorry Brad.. I am trying to find if there is a good way to do it, without causing internally created food crisis). Whenever there is sudden production deficit of life sustaining resource (food/water/prestige), population decline even if you have already stockpiled what is lacked.
However, there is a empirewide button that "distribute stockpiled Food/Prestige" to where it is needed. The pop drop will halt almost immediately as long as your stockpile is not depleted. It is a one button 'starvation crisis management'. This, hopefully, should not be considered as micromanagement.
Resources stockpiled can be used for trading, and especially used for supplying your army ration. Some simplistic supply mechanism should be in for EWOM, and food is essential part of it.
Ok, above is just the basis of this post. Below let's talk about water.
Water production (supply) is instantly perishable so it cannot be stockpiled locally nor globally. When you spend 5 essence, the land is imbued with water supply that is sufficient for a L3 (for example) city max. If that city is next to a river, it may reaches L4 (building aquaduct to help etc etc). Or some fraction consume less than 1 water unit per turn, so it may even reaches L4 population level.
Spending 1 essence starting a city give you only enough water supply for a L1. In case you want to develop it to a L3 (& onwards), more than 4 essence will needed to be spent. You need more essence to make the already habituated land more fertile.
Water supply is displayed in the 'local warehouse' of each city. Farming uses water, so food production consume and compete with its local population. It will be displayed as water production vs consumed per turn at the local warehouse. During siege, river can be re-routed, adding extra dimension to the game.
(Optional) The 'fertile' land eventually expands. Cities while can develop on the new land, but its water supply will not be as good, may be the water supply is only sufficient for L1 halmets.