When do resources deplete? Tested

[Optional]

Most strategic resources can deplete. They are:

Iron 1 in 800 (each turn a 1 in 800 chance of depletion)
Saltpeter 1 in 800
Coal 1 in 400
Oil 1 in 200
Aluminium 1 in 400
Uranium 1 in 100

Strategic resources that cannot deplete:

Horses
Rubber

These figures go for Play the World and Conquests, and I assume also for Vanilla, but if somehow things are different there, I hope somebody will give a shout.

But under which conditions exactly does a depletable resource start to risk that chance of depletion? Is a road on it enough, or does it need to be available to a city? That's what I've tested.

THE TEST

The depletion chance of iron is set by a figure 800 in the editor, meaning iron will stand a chance of 1 in 800 each turn to disappear. I change that:

I'm replacing that figure of 800 with a 1, meaning that iron will now stand a chance of 1 in 1 to deplete. That's a 100% chance, so as soon as iron becomes eligible for depletion, it will deplete in my test.

For my civ I take the Ottomans, and I let them start with Iron Working. I've edited a map in which iron appears close to their start. I start the game, and let the Ottoman worker road the iron first.

Since the iron is now roaded, will it disappear in the interturn?

Spoiler :

No. Obviously that road on it is not enough to make it disappear (remember, the disappearance chance was set to 100% in the editor).

Then Istanbul expands, meaning the iron is now available to Istanbul:

Will it now disappear in the interturn?

Spoiler :

Oh yes!

The iron became available to Istanbul, and so became eligible for depletion. But Istanbul is a capital. Does the game just check capitals, or is any city good enough? Let's get that out of the way as well.

In a new start of the same game, I'm settling Edrine right next to an already roaded iron resource. The iron becomes available just to Edrine, not the capital. Will that save the iron from depletion?

Spoiler :

Obviously not!

Conclusion:
A resource that can deplete, must be available to a city to stand a chance of depletion, being roaded alone is not enough. Being available to any/town city gives the chance of exhaustion, it doesn't need to be the capital.

What about colonies?
Well, a resource available through a colony would stand a chance of depletion just like any other resource, wouldn't it? But let's check that as well. Same game, new start:

I've put Edrine a tile further now, so that I needed a colony to make the iron available. The worker has just created the colony. What will happen in the interturn?

Spoiler :

The iron and the colony are both still there! That's what I had not expected.

The iron was available to both Edrine and Istanbul, but did not deplete. So why did it not deplete?

I can think of three possible reasons:
1. Besides city boxes, the game also checks whether the resource is inside borders;
2. The colony protects the resource from depletion.
3. The game doesn't check city boxes at all, but just whether the resource is roaded and inside borders.

If it's 1 or 2, I really don't know how to check which one it would be, but I can check possibility 3. Again, a new start to the same game:

As you can see, the iron is not available to any town at all, but it's roaded and inside borders. Will it deplete?

Spoiler :

No. It clearly still needs to be available to some town to deplete.

So, wrapping it up: a resource needs to be available to a town/city to stand a chance of depletion, but it won't deplete when it's only available through a colony.

 

[Spoonwood]

quod erat demonstratum. Well done, and thank you Optional.

 

[thetrooper]

Kind of info I feel that I know already - but thanks for taking your time.

 

[CivAgamemnon]

You could possibly write this up for the War Academy, if only as a short article.

I'm sure it would be an invaluable resource to those wanting to know about the inner mechanics of the game.

 

[da3dalus]

Dude, did you read my mind??? I was just wondering about this myself the other day...

One more question though (I might test this myself. ), since the resource can only be depleted when it's within the city boundaries, can it be depleted when under a colony?

 

[thetrooper]

Probably - since a colony is regarded as en extention of your territory.

 

[EvilConqueror]

I had always thought they could deplete as long as they were roaded.

Thanks for the demonstration and info, Optional.

 

[Optional]

Kind of info I feel that I know already.

Same for me, but still I had it only from hearsay, and after in some other thread someone who knows the game well threw up he was pretty sure that only a road was enough, I just felt like doing a little test. It was fun to do, the test.
@ da3dalus: What I had heard already before doing this test, was that the game checks city boxes. That would mean it wouldn't make any difference whether a connected resource was inside borders or outside borders with a colony. To make a distinction there would seem weird to me, but yeah, if you find anything different, please post!

 

[timerover51]

Thank you for your testing, Optional. It is always nice to confirm what everyone suspects but is not totally certain about. What it tells me for my modifications to the game, that if I wish to allow resources to deplete, but do not want it to happen quickly, set the disappearance probability quite high for those I do not wish to see depleted too fast them. For those I do not wish to deplete at all, I need to set the disappearance probability to Zero.

 

[Calis]

You might want to extend that test a little bit and check what happens, if you build a colony...

 

[Bartleby]

I've seen colonised resources deplete.

 

[Bratmon]

Thank you.

 

[Optional]

I'll extend the test to include colonies. There's obviously still some doubt there, and although I have faith in Bartleby's observation, it's nice to show also what happens to a colony.

 

[Optional]

I've also tested colonies now, have yet to find time to put the pictures up now, but there was a surprise: the iron on the colony did not deplete.
So I have to adjust my earlier conclusions. It's strange, but if a resource is only available through a colony, it obviously cannot deplete. Perhaps, besides checking city boxes, the game also checks whether it's inside or outside borders.
Or perhaps it's some bug that prevents a resource from depleting once there's a colony on it. Who knows, I find it weird, at least.

 

[thetrooper]

That is unexpected - so you can all ignore post #6 in this thread now

 

[da3dalus]

Hmmm, that is very unexpected. Thanks for clarifying that Optional! You should indeed write this up for the War Acadamy.

 

[Bowsling]

do you know what happens if it is in your territory but not roaded?
btw, was the colony one tile away from your borders, or further?

 

[Optional]

do you know what happens if it is in your territory but not roaded?

Then it does not deplete. You can even have it roaded within your borders, but not connected to any town/city, and it will still not deplete. I tested this, as it became unclear after the colony test what the game is actually checking.
I'll include the extra findings in the first post, but need a bit more time to sort out the pictures.
EDIT: Okay, done by now.

 

[nick0515]

Thank you Optional. This is very interesting. Your findings are beautifully laid out. Simple, clear and aesthetically pleasing.

I actually had never considered depletion much. Had just assumed that resources could deplete from the first turn regardless of whether a civ was using them or not.

Nick

 

[Bartleby]

How many turns did you leave it go?
I swear that in one of my milkruns I had colonised all the resources and one of them did deplete.