I posted this over at ENworld, but thought I'd attempt to tap some brains over here. I'm always impressed with the collection of fine minds that assemble here.

I'm working on a homebrew campaign setting (much like everyone else and their grandmother) and while I was sketching out some possible maps I got the idea to do a world with a surface that consisted primarily of land instead water (say somewhere around 15% to 20% water). Its hardly a "new idea", but I thought I would go with it. I want a world where different biomes still exist, and they many of them still experience seasons. I don't want another desert planet. And it is for a d20 fantasy game... although some steampunk elements may be present.

The only problem is I don't really understand the science behind it all, and I'd like to get some idea as to what would be going on, on a planet like this one, so that I can design the campaign with a shred of believability.

I originally intended for most of the surface water to be vast inland seas of freshwater, although I've since been told that to keep the weather in somewhat stable patterns I might want to go with rivers... So I've decided on a network of rivers that cover a large portion of the surface (I want some areas to be without so the weather can get a little odd). They will empty into inland seas.

A few other points have been brought up. Like the fact that trade would be more difficult unless I implement some alternate way of transporting goods long distances. Folks have suggested everything from trains and airships to complex portal systems and the simplifying of teleportation magics. I'm taking a strong look at trains (at least for relatively short distances through fairly developed lands) and possible some variation of airship for long distance travel.

Anyway... I was hoping some of you might be willing to offer some advice or assistance to help flesh out the idea some more. Thanks in advance for any given.

Some general brainstorming. No science from me...

The Wheel of Time incorporates the use of flying dragon-like beasts to carry cargo (and troops). While not ocean hopping, they were used in an environment much like you describe - many river and mountains.

Underground lakes and geysers could help supplement the water collection and evaporation cycle, though it would take a huge number of geysers to compete with an ocean.

A constant storm, like Jupitor's eye, may develope and slowly travel across the world. Inhabitants could build ships that harnesses the storm, though it would be dangerous...

Long distance, underground trains might be developed either to circumvent the rivers or storm, by using slave labor, paracrtitters, and magic to connect powerful trade centers.

Generational gypsy nomads that take years to travel around the planet selling exotic goods... Tribes that use anti aging magic to do the same... Giant land beasts - like elephants or the brontosaurus.

Dreamwalking... one could enter a dream world like a metaplane or the WoT Ways and undertake a dangerous journey that acts as a shortcut between places.

Making some of the "land" mass floating on a frozen sea would supply tundra, maybe. The icy ocean could be spreading under the land causing it to split... like a giant underground glacier...

The main setting for Heavy Gear is a "land planet"; it is mostly desert, with wide temperate zones in the poles. Most of the water on the planet is subsurface, in a vast network of underground caves. There's plenty of other "land planets" I've seen in fiction, but most of them tend to be rather inhospitable for the most part -- remember that lots of water is pretty much a requirement for any planet to sustain life (or at least, to develop life). You need a lot of water to fuel the water cycle (seas => evaporation => rain => rivers => seas) and provide enough water for the ecosystem. And, remember that water tends to pool in lowlands, so you're going to have to have some seas (or a lot of swamps) if you don't have a ton of subsurface water.

Right... I guess it comes down to how much water is needed to make it believable? I realize that I'd go insane trying to be scientifically exact, but I'd like there to be enough explanation present to allow for suspension of belief.

Some thoughts I've had on the water situation:

1.) I've mentioned rivers. The plan would be for the planet to have several very large rivers, with networks of rivers and lakes feeding off of them. The large rivers themselves would end in lowland areas where they would form inland seas. I'm hoping that the areas surrounding these rivers, and their branches, would be enough to warrant fertile grounds where vegetation could grow, and civilization could take root.

2.) I'm considering a number of wet land features. An enormous rainforest (most likely surrounding one of the larger of the big rivers), vast tracts of swampland, etc...

3.) Warmth. I plan for the overall temperature of the planet to be a bit warmer than our own. It won't be a desert planet, and their will still be areas affected by seasonal change, long winters, and so forth... but a slightly warmer/wetter atmosphere than the norm.

Still just brainstorming though...

The amount of exaporation if roughly comparable to the amount of exposed surface area of water, this means that your 'dry planet' is not likely to have too much rain and stuff. The rivers idea might work (though how are the river sources fed?). Notice that the area immediatley around the Nile is pretty fertile, though not to far away is mostly desert.

You'll also have problems with large interior deserts. In general, rain won't be carried over mountains (has to do with the ability of air to hold water at temperature), most mountains are 'too tall' for the rain to get over easily. (Take a look at the deserts 'behind' California as a sample.)

The advantage of sea travel is that nothing has to be built to go somewhere. Find some people to trade with somewhere else, great! you can start directing your merchant ships there 'immediately'. The problem with an overland route (roads, rail) is that you would have to build a trade route first. If you can justify airships, that is probably the 'best' way to get around this problem.

Well... not sure if this is any help, but it might inspire.

Flight
Flight
Flight
Flight

FFXI

Craig Mullins
Craig Mullins

Anyway, another thought I had was that the planet once had oceans. Then some external force, such as the brightning of their Sun, dried up the oceans. The inhabitants somehow stopped it, but could not reverse it leaving wetlands in the ocean basins. They build some kind of giant cloud factories that use a combination of magic and machinery to draw in moisture and churn out clouds. Perhaps they dug deep wells to find the water. That could have been centuries ago, so long that many believe it myth... "Cloud Cities built at the Four Corners of the World, bah."

Quick thoughts.

1) Temperature extremes:
Little or no moderating of temperature by large bodies of water, so day/night temperatures and summer/winter temperatures will fluctuate more widely. (What is the axial tilt btw? very little in the way of seasons, or more extreme?)

2) Warmth:
"I plan for the overall temperature of the planet to be a bit warmer than our own."
Depending on how you do this, you could end up with some extremely stagnant water masses if the water never gets cold enough to reach inversion. (Water at 4 degrees C is denser than ice, which allows most large bodies of water to cycle.)

3) Land "hurricanes"?
Hurricanes are currently generated as one system to transfer heat (energy) from the tropics to the temperate regions. They directly rely both on warm water temperature and on a specific combination of upper atmosphere winds. (See hurricane Kyle from last year for an example of something really weird.) In the absence of the water element, would huge, dry windstorms develop to compensate?

4) Winds:
In any case, what with the greater temperature extremes, extremely strong wind systems are likely on a regular baiss. To some extent some might be geographically / coriolis-predictable, and some might be channelled by mountain ranges and such. Oh, which reminds me ...

5) Rain forests/swamps:
What precipitation (probably rain) you will have within this environment will mostly evaporate before it reaches ground level (verga), the rest will be sharply limited to the windward side of mountains and such (eg. midnorth-west coast of N. America). Creatures reliant on water supply will either discover some way of tapping into aerial or ground water supply, or will have elaborate catch and preserve systems set up. Depending on how far you want to take this, it's even possible that some forms of life have arisen which are not dependent upon water. (It's fantasy. Who cares about making up the detailed chemistry?)

6) Groundwater:
You had a recent change of climate. Might significant groundwater be trapped below, like oil? Might it be one of the major economic media?

Edit to add

7) Cities and population concentration:
On a planetary scale, the thinnest populated areas usually tend to be those which are most arid. (Take a glance at any population density map.) A high land-water ratio suggests that areas with sufficient water supply for mid-dense biological systems (plants & animals) will be rare, and concentrated along specific geographical markers - many of which might also have difficult approaches. The hunter-gatherer stage on such a planet might be very brief, with concentrated population centres (cities) springing up very early on. Depending on means of transportation, there might or might not be very much communication or even travel/trade between those centres: little in the way of offensive military development? If transportation is difficult, probable totalitarian rule within the cities, evolved sheerly for survival: think Pern (same issues, but due to Thread). If diseases spring up, there might also be nowhere to escape to: there might be entire ghost cities out there, perched on otherwise prime real estate.

Well....here goes...I've had thisone kicking around for quite some time...never found a use for it though...maybe you can.

Here's a world for a plotline idea if you want something to pick on.

It would probably be best if you clicked the link to the World Map picture below and referance it as you read the information below. It will make things easier to understand.
here's a map of antivion
==============================================================================
WORLD NAME: ANTIVION

WORLD INFO

General Information:
Antivion is 75% land and 25% water.
This one fact is the primary source for it's political structuring.

Si (Sirinatha)
A vast desolation of an ancient culture that has long since past. All that remains is a canyon that spans through a desert for a vast 370 miles.
The name Si is given because that is all that has ever been found of the Name of an ancient culture that once thrived in this area.
Unknown to all but a select few, Si's name is Sirinatha and it was the glorious empire of old that reigned for nearly 20, 000 years over the entire world of Antivion. The Sirinathian Empire fell nearly 10, 000 years ago at the hands of the first Talstinian Emperor, and since has faded into the void of forgotten memory as planned by Emperor Talstin I.
No one actually knows any of this, however.
Instead, Si has become the common ground for gipsi's, nomads, traveling merchants, and runaway outlaws of other nations. The mile deep canyon provides the perfect hiding place with it's pockets of leftover homes, buildings, and other cliff side structures from Sirinatha.

Muldridia
A democratic empire to the north of Talstin, this nation is in constant threat of war with the Talstinian Empire who they broke away from nearly 300 years ago.
Muldridia holds the second largest body of water in Antivion.
Muldridia is often seen on the pilitical front line attempting to keep things at peace between other nations all the while trying to aquire all the trade in Antivion so that they may take away Talstin's power by owning the majority of trade.

Talstin
Slandered as the "evil empire" by a number of other nations, Talstin is ruled by a Tirant emperor named Amosius Talstin.
Amosius Talstin XXXII is the 160th emperor of Talstin.
Talstin has been ruled by the Talstin family since it's origin nearly 10, 000 years ago.
Amosius Talstin XXXII's brother, Helius Talstin XI was actually supposed to gain controll of the thrown when their father, Helius Talstin X, died but Amosius murdered him in his sleep for the power.
Holding the largest body of water in Antivion, Talstin is the most powerful of all nations on Antivion.
Their trade is unrivaled in Antivion and their import from XS is at a stagering rate.

Paquion
A wasteland south of Talstin, Paquion is the home to the Rebeling slaves of Talstin who fled succesfully over the Valley of Death 10 years ago.
Madridia is anctious to aid the new Slave Nation of Paqion but has great difficulty do to the location of Paquion.

X.S. (Xenos the Second)
X.S. is the most technoloically advanced nation on Antivion. They remain neutral from all rivals, treaties, and alliances. Thanks to the high demand for their Science and Scientist by other nations, X.S. is able to continue this neutral stance with out contest.
X.S. is very unique in that it lacks any kind of natural ground. Instead it has been replaced with a vast covering of stuctures, roads, and stone.

Utheria
Utheria is a religious State/Nation that holds a strong symbolism in the Pyramid structure. They are a peacefull religion that emphisizes much in the study of Magica which is given from their God and Teacher, "Vi".
Vi is said to be the force of life. It is the source for all pure energy, and some claim that to achieve a Vi state of conciousness would be to find purity in all things alive.
Utheria ordaines and supports the Muldridian empire with it's Clergy and blessings.

Pendora
Pendora is another religious State/Nation that pridefully rivals Utheria. They also study Magica, but through the religion of hermeticism rather than monotheism.
They have ranks instead of a clergy and act more like a school than a religion, but none the less, they are a religion.
No other place on all of Antivion is more beautiful than Pendora since they keep their plants, tree, etc.. alive and flurishing with the power of Magica, and a direct line of water from Talstin. This direct line of water is a very large bragging right for Pendora as no other needful nation on Antivion has a direct line of water from any other nation.
Pendora ordaines The Talstinian empire and trades this blessing for the water they recieve. It is also rumored that the Magicians of Pendora are among the Ranks of the Talstinian Elite Forces, and the Emperor Talstin is under training by the Grand Master of Magica from Pendora.
==============================================================================
Hope this helps a little

i read this one book about half way through, and they used ley lines to pull vehicles, or something like that.

kind of like the magic railroad.

I had been rolling around the idea of a 75% land 25% water world for a few days now. (Funny how ideas seem to hit several people at once...) I was planning on using huge underground aquifers to keep things going. Even with those most civilizations will be centered near springs and wells as the inner areas of the world will be deserts. I took geography as an elective in college and actually remember one lecture where the prof told us that large land masses away from water always become deserts due to the limited influence from water.

One way around this is to have the underground aquifers supplying massive amounts of water in essentially a pattern that covers the whole world (though not necessarily evenly). The free surface water could acount for 25% as seen from space but there could actually be much more water underground.

[edit]
As far as transportation, I have always been a fan of a steam railroad in a fantasy campaign. Mostly for humor: "That guys is nuts if he thinks I'll ride his metal horse when I have a perfectly good natural one right here." Perhaps this could be overcome by the king, priest, elder, whatever, deciding that a rail-line to an important trading partner is worth the risks.

High Fantasy? I prefer portals. Big huge portals that instantly transport people and goods to a receiver on the other end. Could use crystals as a way of dialing the receiver address. For the record, yes, Stargate gave me this idea.
[/edit]

Anyway, thats my two cents.

- theartthief

Alright if you want the scientific side of things to add abit more realism to this world I'll try to help a bit - I do teach meteorology after all, Its not critisism just take what you like and add it in.

The large oceans on the planet earth act as large heat sinks as you will in that they can hold a great deal of heat energy to offset the loss of incoming solar energy at night. Also because they are fluid they help transfer heat energy to the higher latitudes to increase the temperate zone of a planet. Keep in mind the availability of H2O in the atmosphere is the principal factor affecting weather. Clouds of H2O protect us both from harmful solar radiation as well as insulate in heat energy. Often ignored is the fact that large areas of vegetation also contribute to the amount of H2O in the atmosphere through the process of transpiration - but not nearly as effective as large bodies of water - and don't confer the ability to transfer heat throughout the atmosphere. Large areas of vegetation are also dependant on rainfall in an area which usually requires large bodies of water nearby.

Hurricanes (and tornadoes and other disturbances) form from intense areas of low pressure. Remember water has heat energy hence only oceans can provide hurricane like energy. The factors for a thunderstorm to form - and an associated tornado also require a great deal of heat energy.

Winds are driven by differences in atmospheric pressure and directed by the coriolis force. They can also be altered by orographic details to have wide ranging local phenomenom. The two primaries here are mountains and coastlines. Case in point - the planet Venus has a relatively homogenous surface in other words the wind is always from the same direction.

As for how the rise of civilization might be affected by climate and geography I urge you to read a book called Guns, Germs and Steel...

Of course things like magic and ultra tech might have unforseen influences on a planet's climate.

This made me think of one passage in Hyperion by Dan Simmons, where they need to cross the Sea of Grass or something like that. It's well, a huge plain with incredibly tall grass. The grass is filled with various dangerous creatures, so they need a vehicle to pass it.

Said vehicle is a sort of boat with a single large wheel in the middle. It uses the planets magnetism to keep its balance and a sail to move.

That part always stuck with me: a simple sail boat on a wheel in a high-tech sci fi novel.

rivers come out in giant inland sea's, where water coulde sink into the ground and eventually end up in larg underground reservoirs, which (due to the constant inflow of water) are under some enormous pressure, constantly pushing the water out and up, causing several enourmous mile high geisers, thus creating vast lands, where it constantly rains?

transportation, dunno, airballons or zeppelins are always nice, but strange maner of creatures are too...

briann Aldiss wrote a trilogy called Helliconia, about a planet with 2 suns, and thus 2 season cycles, one is about 480 days long, and the second lasts about 1800 years, thus creating a very strange biology...
one of the human-like species are the madi, who just travel all over the planet, seeingly without purpose, and have done this for several millenia. this his caused giant "wilderness tracks, just covered in all sorts of plants that normally only are found in other regions, and even some that can onlyu be found in these tracks. perhaps something you could use??

Also you could think about throwin in an ancient technologically advanced race, tha has terraformed the planet but has eventually disappeared, and now a whole new kind of "concious animal" has risen to power?

Considering you wrote this: