Environmental Engineering Reference
In-Depth Information
ally, through pinning it down on maps, in data tables and through diagrams
7
. Hy-
drological data, precipitation data and available water at any one moment in time
and for different scenarios, belong to such conceptual control. The control room in
the headquarters of the company sports 26 computer screens, presenting electricity
production targets, water levels at different places throughout the watershed, rep-
resentations of electrical circuits, highly stylised maps of the river and a host of
further data depending on the current decision to be made. There are six conven-
tional telephones on the control desk and an additional cordless phone circulates
through the room. With this level of information technology and with a watershed
broken down into numbers, graphs, tables and single-purpose maps, the Kemi
River does appear like a manageable object, a rather complex one indeed, but nev-
ertheless under control.
Leaving the control room and looking at the immense structures of the hydro-
power stations on the river, this impression remains strong: From the reservoirs on
the headwaters to the Bothnian Bay, water passes through up to 15 power stations
in a row, flowing along a total of over 35 kilometres of concrete and earthen dams
around the stations - not to mention the dozens of kilometres of embankments that
have been constructed elsewhere along the river to deal with the hydroelectricity-
related changes in the water level. At the power stations, the water falls between
seven and 30 metres, thereby turning the huge turbines to generate electricity.
Most often, the river is diverted from its former river bed into a canal downstream
of the power station, in order to increase its flow away from the dam and thereby
maintain a high falling distance ('head') at the power station. Particularly when
observed from downstream, the dams and power stations are thoroughly impres-
sive for their size and control of the water, a construction of earth, concrete and
steel towers high above, and the wide river upstream is channelled through a sin-
gle location - the power house - and released downstream sizzling and gurgling in
a rather narrow but deep canal. During the spring flood, the engineers in the con-
trol room command over 40 flood gates along the river to channel some of its flow
around the turbines working at full capacity. One can stand at a hydroelectric plant
a few hours drive away from Rovaniemi and watch stunned the opening of such a
flood gate, when suddenly a hundred or so cubic metres of water per second cas-
cade from the steel and concrete dam - knowing that this magnificent show is the
result of a mouse-click in the headquarters.
Thus, it seems that the hydropower company has achieved a considerable de-
gree of control over the river. From the control room in Rovaniemi, the river's
flow can be manipulated in large parts of the watershed and whatever happens of
importance along the river seems to be visible on the screens in the control room.
Physical and conceptual control of the Kemi River's flow allow the company to
'drive' the river as it suits their needs - mostly defined by the electricity market.
7
Of course, also salmon fishermen had their own images of the river and information
about its characteristics. In fact, they were crucial for successfully constructing and main-
taining the salmon weirs. Such 'data', however, were of a somewhat different kind; not
abstract and numerical, but grown from personal experiences with the river, the weirs and
the fish.
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