Environmental Engineering Reference
In-Depth Information
glaciers. Few glaciers remain, mainly in the Mediterranean Alps and the Apen-
nines. Fluctuations in precipitation, shifts in meltseason, water abstraction for artifi-
cial snow and dam reservoirs all affect the water cycle, especially river flow. This in
turn has strong impacts on drinking water, tourism, irrigation, agriculture and indus-
trial production in downstream regions. Since existing environmental and socioeco-
nomic problems in mountain environments are complex and confined, these can be
significantly accelerated and amplified by climate change (de Jong and Schoene-
ich, 2009). For all latitudes, climate change scenarios predict severe temperature
increases with elevation in mountains (Bradley
et al.,
2004). Within the natural
environment, the 0
◦
C isotherm is critical for the persistence of snow and glacier
resources, therefore mountains are particularly susceptible to climate change (Diaz,
2004). Mountains have less buffering capacity to withstand the impacts of climate
change. Since the biota is already at the edge of tolerance in mountains, it requires
little impact to cause a major disequilibrium. The same is true for the social and eco-
nomic environment, where ski areas and snowline altitudes are highly sensitive to
the length and intensity of snowfall, especially on south-facing slopes of the moun-
tains. Increases in temperatures and decreased snowfall (but possible increases in
rainfall) as predicted in climate change scenarios can easily erode the existence of
traditional, commercialized winter tourism, as described in the recent OECD report
(Elsasser and Messerli, 2001; OECD, 2007). Means of economic subsistence, in-
cluding agricultural activities such as dairying or forest harvesting, are also highly
sensitive to changes in the physical environment. Such activities can, however, be
menaced by the increasing natural hazards and risks associated with the ongoing
decay of glaciers and permafrost.
In addition, the alteration of water flows in terms of water quantity has impor-
tant impacts on water quality through changes in concentrate mixing levels, water
velocity, temperatures and oxygenation levels. Reduced water flows generally in-
crease pollution levels by increasing pollutant concentrations, in particular during
the drier and warmer seasons. This has impacts on the health of both ecosystems and
humans, while simultaneously posing an economic burden for restoration strategies.
5.2
Climate and physical characteristics
The Mediterranean Basin is representative of a typical Mediterranean climate with
dry summers and wet winters (Rivas-Martınez
et al.,
2001). Around the Mediter-
ranean there are 16 important mountain regions influenced by the cryosphere, in
particular snow, creating important snow-fed regimes. These include both continen-
tal and island ranges, some of which are summarized in Table 5.2. There is a large
variation in: (i) altitude (from 1000 to 4800 m); (ii) climate systems affecting snow
and glacier accumulation; (iii) snow cover duration (from 2 to 10 months per year);
(iv) geology and geomorphology and therefore different surface and groundwater
discharge regimes; (v) distance from source to sea; and (vi) values of downstream
agriculture and tourism. The Platanias and Almyros rivers on the Greek island of
