Geoscience Reference
In-Depth Information
until a rainfall
ushed them, and in summer time, the accumulation of organic
wastes produced foul smells to which some urban dwellers attributed diseases.
Jorgensen studied sanitation practices in late medieval England.
8
Rivers were long
seen as a convenient public good to dump wastes at will; even if some regulations
were established, like the forbidding of throwing wastes during the daytime, nightly
discharges did not suppress water pollution.
4.2.2 Water Resources, Agriculture, and Food
Mapping the
rst great civilizations rapidly provides an interesting element of their
geography and of their hydraulic environment. They generally correspond to river
basins: Indus River and Ganges in India (Indus Valley Civilization: 2500
1900
-
BC), Tiger and Euphrates in Mesopotamia, Nile in Egypt. The seasonal
oods of
these big rivers offered agriculture the opportunity to take advantage of very fertile
soils, thanks to the thin silt layer dropped on the river banks. In the twentieth
century, human societies, encouraged by their political leaders and by engineers,
have tried to gain independence from natural cycles. Dams
—
which will be treated
—
later on
were conceived for this purpose and allowed two or three annual crops.
But their disadvantages consisted in a frequent salinization of soils, enhancing a
loss of productivity. What was gained on the one hand was lost on the other after a
few years or a few decades. Other environmental damages have been produced by
the overexploitation of water resources for agricultural purposes: huge groundwater
aquifers have been pumped
—
or are still pumped
—
with much intensity in Midwest
America, in Libya, and in Saudi Arabia.
Through ponds, lakes, streams or coastal areas, water is the natural habitat of
sh, an important component of human food. Professional
shermen were already
active and powerful in Middle Ages. During the same period,
sh farming in natural
ponds or arti
cial basins was an important resource to feed cities and was one of the
many activities developed by monasteries (let us not forget that religious precepts
about food consumption were strictly observed).
9
Fish were also present in thou-
sands of natural ponds located next to rivers and in side channels, functioning as
sorts of
ood or drought. The
surface occupied by those ponds decreased drastically since at least the eighteenth
century. The urban and industrial growth entailed the drainage of many ponds and
subsequent ecological changes, both in terms of species present in the environment
and of water system regulation. In the nineteenth century took place an
“
hydraulic annexes
”
regulating water in case of
“
aquaculture
revolution
sh species in basins placed near
streams (or near coasts, when one aimed at reproducing mussels and oysters). In the
Second Empire France, Victor Coste was the man who fostered the development of
”
, consisting in the arti
cial breeding of
8
Jorgensen (
2008
).
9
Hoffmann (
1996
).
