What Happens To Brevoy If Lake Reykal Is Drained?


Lost Omens Campaign Setting General Discussion


Hello everybody!

In my Campaign beneath Lake Reykal there was an enormous system of tunnels and caves which completely collapsed after my players fought some Neothelids there and this caused the lake to get drained completely.

What are the consequences for the nation of Brevoy? Im interessted in the obvious ones as well as in some minor consequences causing interesting alterations to the surrounding area.

I really appreciate your ideas, thanks in advance!

Grand Lodge

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A couple of hermit hierophants emerge from the woods, cast control weather and refill the lake to restore the balance of nature. They then don Raybans, high five, and return to their idyllic seclusion.


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Wasum wrote:

Hello everybody!

In my Campaign beneath Lake Reykal there was an enormous system of tunnels and caves which completely collapsed after my players fought some Neothelids there and this caused the lake to get drained completely.

What are the consequences for the nation of Brevoy? Im interessted in the obvious ones as well as in some minor consequences causing interesting alterations to the surrounding area.

I really appreciate your ideas, thanks in advance!

Well, water will likely still be running down to the lake. If one or more holes opened up in the lake, it likely would not have drained completely. I would find it more probably that there would still be a couple smaller lakes as it is likely the lake was not shaped such that a few new holes would cause all of it to drain completely. So I'd guess there would be some particularly low points of the lake that will remain as separate lakes, which won't have drained completely down into the subterranean region below. However, the land surrounding them will be full of debris and such. People will beign building buildings there, but there will be fear that they could get swallowed if the water rises again. (and those who build may fight against those wanting to restore the old life, while restorationists will try to prevent building in the areas, scared others will accept things as the new way of life, killing the support for finding a magical solution to restore things to they way they were.) If the southern river normally was a spillway, and headed south, then that river would likely dry up or even flow the opposite way for a little ways.

The even would undoubtedly wreak havoc on transportation standards. Ships used to traveling on the lake and/or rivers will have potentially become grounded/damage/destroyed. Contracts will be a mess, so those who do ground or magical transportation will suddenly be in higher demand.

Food markets will be impacted immediately due to the massive reduction of fishing capabilities. It could be that to get fish, fishermen are having to go armed into caves to try to catch fish in waters trapped in the caves, for as long as the normally aboveground fish can manage to survive.

Given the already delicate political state of the region, I'd actually suspect that three forces will quickly form and create a civil war. Three factions being the old two factions and a third wildcard that would represent opportunistic powers looking to peddle their influence to get an alliance with their preferred power, or potentially leverage themselves to be on the seemingly winning side to overtake them after the establishment has weakened themselves with all the battling.

Creatures that lived underneath may spill up onto the surface from newly created opening. These creatures may blame the surface creatures for destroying/upsetting their homes. Others may simply looking to replace destroyed space and/or resources they lost in the collapse. Some might even be looing for new allies to aide them in their continued growth.

Loss of the lake will likely reduce rainfall and generally ground saturation of water, which may have a longer term detrimental effect on agriculture some.

With collapsed ground, you can expect potential damage to strong buildings and fortified walls, that contributes to martial opportunism. It also may open up otherwise hidden historical locations for adventurers to find, which might bring an influx of adventurers and archeologists, such as Pathfinders.

Certainly, people will have had their lives destroyed, and will be looking for people to blame.

Scarab Sages

So according to Lost Omens Legends, treasure has been washing ashore and attracting treasure hunters from Numeria. A drop in water levels might reveal more treasure and prompt a major gold rush.


How big is the hole that collapsed? Lake Reykal is 90miles east to west & 45miles north to south. That's a lot of water to just disappear. Like, depending on the size of the collapse one could be talking years to decades.


Loreguard wrote:
Wasum wrote:

Hello everybody!

In my Campaign beneath Lake Reykal there was an enormous system of tunnels and caves which completely collapsed after my players fought some Neothelids there and this caused the lake to get drained completely.

What are the consequences for the nation of Brevoy? Im interessted in the obvious ones as well as in some minor consequences causing interesting alterations to the surrounding area.

I really appreciate your ideas, thanks in advance!

Well, water will likely still be running down to the lake. If one or more holes opened up in the lake, it likely would not have drained completely. I would find it more probably that there would still be a couple smaller lakes as it is likely the lake was not shaped such that a few new holes would cause all of it to drain completely. So I'd guess there would be some particularly low points of the lake that will remain as separate lakes, which won't have drained completely down into the subterranean region below. However, the land surrounding them will be full of debris and such. People will beign building buildings there, but there will be fear that they could get swallowed if the water rises again. (and those who build may fight against those wanting to restore the old life, while restorationists will try to prevent building in the areas, scared others will accept things as the new way of life, killing the support for finding a magical solution to restore things to they way they were.) If the southern river normally was a spillway, and headed south, then that river would likely dry up or even flow the opposite way for a little ways.....

Thank you - those are fantastic ideas. I really like the idea that agriculture will suffer on the long run resulting in shrinkage of harvests. Huge parts of the coastal cities will be destroyed, especially the simple housings of poorer citizens.

people will quickly overfish the remaining pools of water and therefore the tension will lead to civil wars as especially the poor will have no opportunities to feed their families.

I will need to think of how exactly this will effect trade in the region - or more precise: what the consequences of no trade on rivers will be. I guess rivers will become either dried out (after mybe changing their direction of low for a while) or become torrents (those parts formerly connecting lake and river source).

@FormerFiend: Yes, the caves were enormous, their volume exceeded that of the water in the lake by far - but I see, even then it would take a while for the lake to completely drain as probably there only will be limited cross section for the water to pass through.

I also like the idea that a lot of people will be interested to restore the lake and therefore invest heavily in respective magic - but even this would probably take years I guess? Especially if they had to seal the ground first. This also might call up those profiting from this new situation, manipulating all efforts to fill up the lake again.

Thanks so far for all that advice, I guess I slowly have an idea about how this will evolve :)

Grand Lodge

FormerFiend wrote:
How big is the hole that collapsed?

The darklands are plenty big enough to absorb a few lakes


The darklands are below the level of the oceans, but somehow the sea doesn't drain into them. Some magical explanation is demanded. Presumably the same mechanism will limit the amount of the lake that drains into the hole.

Given the size of the lake, it will inevitably take a long time for it to drain. You can work it out (or at least put an upper limit on the drain rate), based on the size of the hole and the rate at which water can accelerate into it. Neglect coriolis forces, backpressure and edge effects to simplify matters.

Unless the hole itself is vast (miles across) I suspect that the current would sweep a lot of mud and detritus into the hole, blocking it up fairly soon.

Do we know how deep the lake is?

I note that Brevoy's economy seems to be based on exporting fish, grain and lumber southward down the river. That will stop dead. This has knockon effects in the River Kingdoms and Mendev.

Your PCs have made something of a misstep. I hope they appreciate how many innocent NPCs were swept to their deaths in the torrent and how many will now starve or die in the economic collapse. If not, impress it upon them. I suspect that someone will want to know who was responsible, and steps will be taken for restitution and vengeance. Murderhobos should be more careful.


TwilightKnight wrote:
FormerFiend wrote:
How big is the hole that collapsed?
The darklands are plenty big enough to absorb a few lakes

To clarify I wasn't questioning whether or not the caverns were big enough to hold the water. I was questioning the actual hole made by the collapse opening up the caverns to the lake bed, allowing water to flow. The size of that would determine the rate at which the water drained out of the lake.

Like Mudfoot said, unless the break is truly massive I'd imagine the debris would clog it up or slow the drainage.

Also I wasn't able to find a depth for the lake but I didn't perform the most exhaustive search.

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