# Problems with floods and droughts

Region 2 is north of Region 1.

River and lake description:

In region 2 there is a crater lake on what used to be a huge mountain. 2 large streams go from the crater lake and merge into a little river 100 miles away from the lake. Another stream from further north merges with the little river to form the Black Sword River that the first civilization depends on. About 50 and 75 miles from there the Black Sword River branches off and terminates at lakes. It then starts heading southeast until it reaches the mountain range in region 1. Small streams from the mountains merge with the Black Sword River once it goes completely south. Then it gets wider and wider forming a delta that leads into the ocean.

Problem:

At the crater lake it doesn't rain often, not nearly as often as it does at the Black Sword River. There are years when the lake is completely dry and there are years when it floods.

This causes there to be years when the river is much lower than usual and years when it floods. The humanoids use positive charge as waterproofing(since water is attracted towards a source of static electricity if that source is negatively charged I figured the opposite would happen for positive charge) However when it floods the waterproofing is no good and water penetrates through it.

During the years that the river is much lower than usual it almost completely freezes over and there is no choice for big fish other than to move sideways(By that I mean that the sides of the fish are at the top and bottom and the top and bottom of the fish are at the sides. In other words, a 90 degree turn)

During the years that the river floods the humanoids' civilization gets soaking wet This is perfect conditions for a marsh to form in the humanoids' civilization.

Since this is an underground civilization potentially everybody would drown in a flood and would have to swim from 1 place to another instead of climb(since climbing through water is much slower than swimming up or down).

So since fish and other aquatic animals live in the crater lake when there is water in it how should I solve the problem of a drought? Have the fish lay eggs right before the drought and the frogs dig into the soil and hibernate during the drought? But then what about the tadpoles that are still developing? Would they know to go into the streams and head towards more permanent lakes like the ones branching off of the Black Sword River? Then there would still be problems with frog eggs drying out. Since humanoids depend on all water sources would the humanoids know to carefully carry the frog eggs to more permanent lakes as fast as possible or just let them dry out?

And what about the floods afterwards? This is aimed more towards the civilization.

Since the civilization is close to the bank of the Black Sword River and some are close to the lakes how would they prevent the civilization from getting soaking wet in case the static electricity fails to keep the water at bay? In case you didn't know the humanoids have a positively charged skin surface so they won't get shocked by positive charge. I don't think coating the outside and inside of all the homes and buildings with metal will work for 2 reasons.

1) Metal is cold to the touch and could cause burns in the summer and frostbite in the winter due to it being a conductor of heat(There is no such thing as a metal insulator) and cold.

2) Most metals oxidize in water and most of those oxides are porous.

• Why don't they just build a stone wall around their city? It would corrode eventually, but they could fix sections of wall during the drought periods. – Xandar The Zenon Jan 19 '16 at 22:52

The animals are easier to answer so I'll do that one first:

# Drought Pattern

There are examples of animals on Earth that have hyper-extended hibernation periods. Take for instance the Periodical Cicada, which hibernates for 13-17 years. They do this in order to stymie potential predators. No natural predator of the cicada ever stayed around because they aren't a stable food source. I won't go into detail as it's complicated to write but fascinating nonetheless.

Anyway, the point is that, if there is a pattern to the Drought/Flood timings then animals could easily adapt to a hibernate/swarm pattern to match - as the drought years approach, aquatic life flocks to the crater to bury eggs in the mud. The mud then dries hard to protect from scavengers.

When the floods return again, the mud softens and the water triggers the hatching of the eggs. Because the animals would have evolved to match the cycle, you wouldn't have cases of tadpoles stuck on the rocks dying because the life cycles of the animals wouldn't lay new eggs until the droughts were coming.

You could have other animals working on the same timescale - it could be that there is little warning of the droughts, so there is a mad scramble to lay the eggs, and some don't make it there in time - these failures or insufficiently buried eggs would become a waking feast for other animals that become dominant in the drought season. This would help keep the aquatic/flood population down as only a small population would start the flood season each time (otherwise there is a risk of overpopulation).

Theoretically this system could occur even if there is no pattern to the drought, provided that there is a slow enough change (some trigger that gives the plant/animal life a small warning) to leave time for the rush upriver. It would also need to be reasonably regular (no random but not uncommon gaps of a decade or so) to be tenable.

# The Civilisation

This is more difficult because you've specified some details that will be hard to achieve realistically. There is an example of Earth civilisations that have worked with a drought/flood environment — The Egyptians — but they had to cope with a much shorter cycle. Some parallels can be made, but not many. I honestly can't see how an underground society could survive in a periodically flooding area, unless they have a way of sealing their tunnels that doesn't rely on standard physics. The technology that is required to properly seal would never have time to develop - everyone would die/be forced out before the civilisation became that advanced. The question you have to ask yourself is not "How do they keep it out now?" but rather "how did they keep it out before?" There has to be a simple method of keeping out enough water that everyone doesn't drown the first time it happens in order for a society to form at all.

The only way I can think of is if the land around the flood plains is very hilly. The society started in the caves that are high up and remain relatively dry, but as the population grew they had to start trying to waterproof wetter and wetter areas, with the poorest occupying the wettest areas. That way, your waterproofing method doesn't have to be perfect. In fact, it's likely to be made up of things like hastily built dams and constantly dripping sandbag walls, occasionally flooding catastrophically, depending on how much your society cares about the poor.

if you're willing to scrap the underground approach, there are some other societies you might have:

## 1) No building on the flood plains

The Egyptians dealt with the Nile by not using the flood plains to build on - they used them as farms. All of the actual permanent structures were on land that never actually flooded. Depending on the contours of the land this could be viable - if there is a significant rise in the land limiting the size of the flood plain, then civilisation would naturally form there, if anywhere. During the floods the marshlands could be used as growing areas, like paddy fields. During the droughts... be creative! There could be some special mineral in the water (a by-product of whatever caused that crater, for instance) that can be harvested from the mud during the droughts. This would certainly explain why civilisation formed in such a hard environment in the first place.

The culture doesn't deal with the changing landscape because they don't have to. When the landscape starts changing, they up and leave, or even just move to the edge of the flood plain for the duration. None of their buildings are permanent, or the important once are movable (buildings on wheels!). Alternatively, Boats! During the drought season the tribes are scattered across the waterways, with only a small few chosen watchers left behind. As the floods come and a large water-filled basic forms, the tribes all flock back along the waterways to form a central civilisation for the extend of the flood period, sharing advances and discoveries in that time. In theory you could combine the two, or have two nomadic tribes, one water based, one land, that swap control of the same area.

## 3) Floating Buildings

Every building in this budding metropolis floats on a raft of sort anchored in place by... something of your choice. As the water level rises, the buildings rise with it. As the level falls to nothing, the buildings drop and slowly settle on the drying ground. This drought time allows the people there to tend to the anchors and deal with any decay, potentially replacing any that have rotted through. During flood time sometimes shoddy work comes loose, sending buildings crashing downstream and causing mayhem in the poorer areas of the city.

## 4) Hybrid Culture

Combine any of the previous 3! Rich people living on hills in a stable environment, poor people having to live on floating rafts in the valleys. The variations are multiple.

## 5) An Aquatic Civilisation

If we're departing from reality enough that everyone has electric skin, why not make them have gills? Rather than being a land-based society, it's a water-based one. They live underground in water-filled caverns that are filled during the flood season, and slowly dry out during the drought. For them, the problem is the drought season, not the flood, as they struggle to preserve enough water during their flood to last out the dry season.##

## Technology

There are certain things that any permanent civilisation would have to get a quick handle of. A stable human civilisation requires stable supply of water, so they would have to learn to make reservoirs (big ones) that filled during the floods and would last through the drought. They would have to have a consistent source of food throughout the drought period. Even if it is less bountiful, it would still have to be present. Again, rich people might keep reservoirs/aquariums filled with flood-time delicacies that the poor have to do without.

## Corrections

Finally, just a couple of things that I feel I should point out. First of all, water is attracted to charge, full stop. Water itself is electrically neutral, but this is because it is made up of electrical dipoles - sets of positively and negatively charged particles that cancel each other out. Because of the way water is structured, if you introduce any charge nearby, it will pull the oppositely charged parts towards it, and they pull the whole stream with them in a chain reaction - basically, the static charge unbalances the system in one direction, rather than the water being naturally charged in the first place.

The result of this is that an electrical barrier wouldn't work, but you could still use the concept, by using a giant electrical beacon on the other side of the river to try and bend all the water away from the populated area. That said, it would need to be one MASSIVE charge - one that would potentially electrocute anything in the water, depending on how salty the water is.

Secondly, positively charged skin would be a nightmare due to other properties of physics. Everyone would generate a significant magnetic field, for one. I believe this means that everyone would be repelled by everyone else, something that would make procreation quite difficult! If you want them to not be shocked by electricity, a more convenient approach would be to give their skin the highly insulating properties of rubber. You get shocked because the electricity uses you as a faster conduit to the ground - if your skin is insulating, you won't be chosen as an alternate route when you touch the charged object.

Neither of these things matter if you don't care so much about the accuracy of your physics, just thought they might be worth pointing out! I hope some of that helps.

I would say, do what the Netherlands do. Make earth and stone walls around the civilization. This way they would not have to move in the drought/flood seasons. If they make their buildings underground, they could make stone structures whose roofs would be at ground level. That way they would not have seepage into their homes. They could rebuild damaged sections of wall during the drought periods.

As for the animals, well, they'd better learn to move or die. These animals likely wouldn't need the humanoids' help because they have survival instincts. If it's uncomfortably dry, go somewhere wetter.