Geography: These caverns were once part of a subterranean
lake, and were almost completely filled with water. Only the diligent
efforts of a group of pech miners has blocked off the water
flow and enabled air to fill the bulk of this area.
The reclaimed caverns are accessible only through the two
waterways flowing into them on the north side, and the continuations
of these streams flowing out from the south. The course of
the river flowing from Area 5 is made dangerous by a 500-foot
waterfall that plunges into a deep pool before resuming a more
placid journey downstream to Area 14. The latter part of this journey
is through a cavern that allows about six feet of airspace over
the surface of the river.

The easternmost of the two rivers goes underground at the
base of a huge mountain waterfall, plunging several thousand
feet from an isolated gorge to disappear through a sinkhole and
begin a hidden course. This river flows at a rapid pace from its
first moments underground until it reaches Area 14. Here, however,
the airspace over the water is a minimum of 10 feet high.
Since the sinkhole allows fairly easy access to the water below,
this river provides a navigable means of reaching Area 14.
The area itself comprises three long, narrow caves running
parallel along an east-west access. Each cave opens onto the
river, and numerous connecting passages unite the caves along
their courses. By dint of heroic applications of walls of stone, the
pech have built dikes to prevent the water from entering the three
caverns. Although small streams still flow through, they do not
constitute a menace to the area’s thriving population.

This area provides both dry and river routes that extend deeper
into the earth. Thanks to the efforts of the pech, a bridge crosses
the easternmost river at the end of the middle cavern. The bridge
connects with a, partially excavated, partially natural cavern that
descends slowly over a course of many miles. This cavern is
eight feet high and 12 feet wide.

Because these caves were filled with water until relatively
recently (geologically speaking), they are devoid of common
cave formations. In fact, their floors, walls, and ceilings are
almost uniformly smooth, since they have been polished by the
action of water through many centuries.

Denizens: The primary inhabitants of these caverns are the
pech, whose efforts have reclaimed the three caverns from their
watery origins. With their unerring instinct for potential mining
sites, they set about opening the caverns to mining. They have
profited from doing so-major deposits of iron and copper have
been discovered here. The pech have created a well-organized
community in the center of the middle cavern, from which mining
parties journey to the excavation sites and return with loads of
ore. A total of about 300 of these industrious miners live here.
Plant life now thrives here as well. All sorts of fungi grow in
remote corners of the caverns.

An assortment of monsters also roams these caverns, living off
the fungi and any prey they can catch. Their numbers include a
small group of marine trolls (scrags), several shambling mounds,
a gibbering mouther, many cave crickets, throat leeches, ropers,
an owl bear, rust monsters, and cockatrices.

The area is also subject to the depredations of the kuo-toa that
dwell in Area 15. These men-fish would like to see the entire area
filled with water again, so they regularly attempt to sabotage the
efforts of the pech by damaging the dikes or attempting to divert
the river so that it floods into the caverns. The kuo-toan war parties
generally number about 20-25 individuals. They savagely
attack any creatures they run into, but especially seek out the
pech. Thus far, the men-fish have always been defeated in these
conflicts; but they send up another war party every few months,
forcing the pech to constantly maintain their guard.

Resources: The rivers flowing into the region have enough air
space above the water level to maintain a constant supply of
fresh air. The many voracious creatures that reside here manage
to find enough to eat between the fungi and fellow creatures.
The pech operate a number of large-scale mining operations,
and have stockpiled large amounts of copper and iron ore.
Except for limited amounts needed to make their tools and weapons,
they seem to have little use for the minerals. Nonetheless,
they guard their hoard with fanatical dedication.

Unique Features: The pech have built an elaborate pumping
system to drain off excess water that flows into the caverns. The
system relies on a series of drains placed in the low spots of each
of the three main caverns, and a huge centrifugal pump used to
divert water to Area 15. The centrifugal pump is a marvel of engineering.
It is powered by a giant water wheel located where the
bridge crosses the eastern river. The water wheel spins a large
fan in one of the drainage pipes. As the blades turn, water is
pulled through the pump and hurtled on its way to Area 15. When
the water wheel is spun quickly, as is the case when the water
level of the rivers is exceptionally high, this pumping system can
move an incredible amount of water.

Simply by shifting a large lever, the pump can also be used to
activate a ventilation system over a large smelting plant and forge
operated by the pech. This plant is located in the center of their
small stone community, and can burn great quantities of coal in a
few hours. When the plant operates, the pumping system pulls
the smoke from the smelter and runs it through a vent to be
released on the surface. It eventually exits through a one-footwide
aperture into a remote mountain valley.

The pech community is well-organized and neat. The buildings
are stone, and tend to be stacked three or four deep. Narrow,
winding alleys provide access between the buildings. The pech
also have a number of large stone wagons used for pulling loads
of ore. Several of these are parked about the community at all
times, often blocking one or more important avenues.