The landscape of dam lake Gadouras by Michaelis Chondros

Dam Lake Gadouras

The Environmental impacts of hyraulic projects

Dams

Natural phenomenon

Anthropogenic phenomenon

There construction can be out of concrete, but also, as the case on Rhodes, made out of an 'arch gravity rock-fill'

WHY??? building a dam is such a huge topic?

…There are 3 main purposes for storing water:

Generation of electrical power from the momentum of water
Supply of drinking water
Irrigation (water for fields)
and for navigation of small tankers to distribute materials inland

Criteria for right location of a dam:

Narrow part of the river (the valley sides can then act as natural walls)
Earthquake faults
Hydrological basin
Permeability
Slope stability
Enviromental impactson river fisheries, forests and wildlife
Impacts on human habitationsplenty others…

The dam of Gadouras

construction of the dam @ 2005 (first part) and 2007 (second part)
project of multiple goals??? No!!!
main goal: potable water
secondary-side goal: none

Basic construction: Rock-fill dam with clay at the core

Characteristics

Crest: height 125 m, length 550m, width 10 m
Maximum capacity of water tank / reservoir: 67.5 million m3
Mean annual discharge: 32.5 million m³
Water drawing per year: 18 million m3 (not yet)

Variation of the water level

Overflow level (HWL): 122.10 m

Mean water level (MWL): ~ 110 m

Lowest level of water intake (LWL): maybe 94.30 m

Spill water running down the water chute

(Note by editor: since Feb. 2011 Rhodes had experienced a lot of rain and still at the beginning of June 2011, there was to be observed this overflow of water. This is necessary in order to avoid overt pressure being exerted on the dam's construction.)

Mean annual water equilibrum:

Predicted needs of water in whole island by 2039 would be 26.5 million m³

Those will be covered by:

Gadouras’ reservoir18 million m3
From underground (drilling)7.5 million m3
Other local springs (mainly Salakos) 1 million m³

The artificial lake Gadouras

Hydrological basin148 km2= 11% whole island area !!!

Impacts of such a project

Constant impacts

Due to the phase of construction
Due to the phase of operation

Consequences that can be reverted

After the phase of construction

Impacts due to the phase of construction

Disturbance of flora and fauna
Noise
Dust
Building secondary/auxiliary works
Excavation / materials deposition

And more ……

Impacts due to the phase of operation

Erosion of land
Disturbance of water/land flora and fauna in the general area
Break of the communication of the two sides of the dam
Underground water body enrichment or disturbance???

Impacts due to the phase of operation

Change of the micro-climate (greater water surface bigger evaporation increase of humidity)
Signs of “ignition” of earthquakes
Break of sediment accretion in downstreams erosion
Removal of population (in Gadouras there was no relocation of people)
Explicit and huge aesthetic change of the landscape Of course every culture (equals to each one of us) has his own perception-opinion-view for beauty.
Explicit and huge aesthetic change of the landscape

Of course every culture (equals to each one of us) has his own perception-opinion-view for beauty..

Statement of one future problem (among others)

As the water level of the lake falls, a dead zone is revealed leads to a lack of beauty.. How much can the level fall in order to this dead zone doesn’t occur??? And so the lake remains attractive…

Theoretical background to assess the impacts

Objective method