Environmental Engineering Reference
In-Depth Information
The changes in amounts and timing of hydrological resources converge with
enhancing levels of water demand from growing urban populations, irrigation areas
and mining activities (Reyes Carbajal 2007 ). Beyond the challenges implied by
decreasing amounts of water resources for economic inputs, increasingly dry condi-
tions in the spring and summer months would also have severe consequences for the
farmers in the agricultural belt that is situated in central Chilean areas, through
impacts in the biological productivity of ecosystems (Vicuña et al. 2011b ) . Changes
in stream flow timing and amounts already have begun to impact the different
economic sectors in the Aconcagua, and shall be further discussed in relation to the
focussing events below.
9.2.1
Focusing Events
Over the past 15 years, while there have been a few flooding events associated with
increased snow melt and heavy precipitation events, drought has been a far greater
preoccupation of water stakeholders with far reaching impacts for the SES. Andean
watersheds generally experience low precipitation in summer and rely heavily on
storage of winter precipitation within the snow pack and glaciers of the high Andes.
Climate change impacts on water quantity have already led to increased water stress,
which compounded by increasing water abstractions, has led to a reduction in surface
water recharge that tends to impact water rights in medium and lower segments of
the basin more severely (Desmadryl 2010 ). Melting glaciers and reductions in water
availability have also been observed to have exacerbated impacts on water quality,
ecosystems and overexploitation of certain aquifers in the northern and central
regions. With around three quarters of Chilean economic produce and activity seen
as water intensive, the repercussions from climate change impacts on water reserves
with far reaching potential consequences (Desmadryl 2010 ) .
In the preceding 15 years, there have been a few incidents of the river over-
flowing, such as the 2009 event in the Panquehue region, primarily from increased
flow due to ice melt in spring time. DOH has undertaken a number of remediation
works, and in the past 6-7 years, there have been no major issues from flooding, but
also no major substantial overflows either. Vulnerable areas are situated at La Calera,
Panquehue and Los Andes. Increasing variability is seen to reduce the former
predictability and the innate knowledge of precipitation volumes, snow fall and flow
behaviour. In May 2010, a combination of precipitation in the high mountains and
ice melt during summer led to increased run off and thus an overflow of the river.
The natural reservoir of the region, 'La Cordillera de los Andes' has already
been exposed to a rise in the zero-degree isotherm, reducing the capacity of snow
storage and thus further aggravating over exploitation of surface waters during the
dry summer months. Combined with the potential diminution in run off contribution
from melting glaciers, the scarcity situation of the basin has been deteriorating in
the past years. While there have been a number of droughts in recent years in the
Search WWH ::




Custom Search