Gehn’s 233rd Age was the first really stable age that Gehn succeeded in writing whilst in exile on Riven but even this age was not without its problems. All of his previous attempts at writing had failed either because of a lack of power for his books or his flawed writing, it took him 232 attempts to get it (almost) right which says a lot about his standard of writing and his knowledge of writing ages.
The sea in this age is particularly caustic which is why the mountains are as strangely formed as they are, over time the sea level dropped producing this rather strange landscape.
The environment is still hazardous which is why Gehn has to wear protective clothing and goggles whenever he ventures outside. The dish on top of his mountain retreat is used to collect the very small amount of rain water that falls in this age, this water is then funnelled into a sink in the bedroom on the lower level.
Whether this water is drinkable or not I suspect is open to much debate as the water would have to be drawn up from the sea by evaporation and as we know the sea is rather caustic!
The 233rd Age serves as a nexus for all of the islands of Riven as Gehn has linking books to each of the islands.