Landscape – Great Idea! X-LArch III - Department für Raum ...

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Fig. 1: Ponte di Piave (PP) and Ronco all‘Adige (RA), 1955-2003.
A diachronic comparison analysis (1955-2003) in two
areas of a few square kilometres, Ponte di Piave (PP)
and Ronco all’Adige (RA), situated in the middle-lower
plain, illustrates four series of spatial transformations
[Fig. 1]. Densification of buildings and up scaling of both
fields and settlement plots go with a shift from a decentralized
system of homogenously distributed farms and
related fields towards a concentration and separation of
the activities and cultivations in specialized areas. As a
result the mosaic changed from a fine grain of land parcelling
and farm units where the buildings hardly emerge
from the agricultural matrix, to a middle-coarse grain of
differentiated patches where defined solids stand out
against the background with a juxtaposition of residential,
industrial (PP) and clay pits (RA) patches within the
matrix of extensive farming.
The processes of concentration and separation
have had consequences on the irrigation and drainage
systems. In 1950 the agricultural matrix of the fine grain
was supported only by the surface water system. A
few spring rivers cross the matrix. Plots were arranged
according to the ferrarese agronomic type of field setting
(CSXP). The main features were: fields with a convex
section (baulatura), ditches (cavini), mainly performing
a drainage role and strips of land (capezzagne) for
accessibility free from cultivation. Flood irrigation was the
main irrigation practice. Wells played a minor role. The
cultivations were organized in a specific mixed farming
system (piantata veneta), and corridors of hedgerows
were planted along the close net of ditches playing a
multifunctional role (timber and firewood production,
wind break effect). In 2003 the minor surface network
of irrigation and drainage supported a different matrix
of a middle coarse grain. The rivers crossing the matrix
exhibit channelized features (straightening). The former
convex terrain sections are flattened. The open air
ditches on the fields and along the roads are filled and
substituted by a subsurface pipe system in higher but invisible
density. Drainage and irrigation performances are
improved. The size of fields is no longer depending on
the irrigation technique. Wells are playing an important
role (Boscolo & Mion 2008). Wide uniform farming field
patches dominate the matrix. An extensive reduction of
hedgerow and riparian woodland is visible. The shift from
mixed agriculture to monoculture and the consolidation of
manufacturing is the driver of this rationalization process
of water infrastructures resulting in a different landscape
(Bevilacqua 1991: 30). The water system is turned in to
a hydraulic system; storage capacity decreases, physical
elements that gave the area its legibility and ecological
diversity disappear.
The de-layering at the level of the two water boards
(about 50x50 km) illustrates the main contemporary
system. On the dry plain a diverting system of irrigation
stretches out. It is composed of small concrete canals
arranged in tree form structures. This system is superimposed
on the former system composed of open ditches
arranged in mesh structures (CSXP). Below in the middle
plain numerous spring rivers join the mountain river
network enriching the surface water network. They form,
over the low plain, a converting drainage structure with a
higher density (CVG). In recent decades, in some basins,
the tree-structures of the stream network were turned
into a mesh-structure by the water board, connecting
water bodies for flow control (CSXP).
The supply system for irrigation performs well, but is
often unable to cope with the higher agricultural requirements
(CSXP, CVG) and water shortages occur frequently
in summer periods (PP, RA) leading to abstraction
from unconfined (PP) and confined groundwater (RA).
Dwellings and industries also make use of groundwater
abstraction for non-potable uses. The huge amount of
abstraction has led to its depletion (PP, RA). The drainage
system rationalized to drain agricultural fields is under
stress because of the growth of impervious surfaces.
Increasing sources of contaminant production especially
from farmland threatens the quality of the water supply.
The technocratic rationality of optimizing flows for quicker
supply and discharge by means of the processes of
centralization and separation, and their related infrastructures,
result in a paradox. The requirements for water
resources with respect to water quantity, quality and
security for flooding are the strongest. At the same time
hazards such as droughts, pollution, floods, depletion
of groundwater and conflicts among different users of
the water are of high importance, often at the cost of the
neighbours upstream or downstream. Climate change
also threatens the Region (Chiaudani 2008:151).
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