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(a)
(b)
viewing
platform
water
garden
retention
basin
re-engaged
meander
retention
basin
old canal
promenade
lozenge reach of future course of L'Aire
diversion
Pont des Marais
low-flow channel
high-flow channel
200 metres
Figure 18.6 The 'lozenge' approach to jump-starting channel complexity on the Aire, as illustrated (a) in a conceptual
diagram and (b) in the restoration plan. Source: ADR Architectes, Geneva, used by permission.
velocities allow deposition that is not possible in
the high-energy channelized reach.
The Aire can be located in the upper right of
Figure 18.2, in the lower left of the espace de liberte
space. The approach is clearly to give the stream a
corridor, though the surrounding urbanization set
constraints on the width and longitudinal extent
of the corridor, and provides a constituency for
restoration and a client ele to use the human
access features created. Unlike many conventional
'restoration' projects in North America, which seek
to create a stable idealized form, even where the
channel could migrate freely with infrastructure
conflicts, the restoration concept for the Aire
identified the zone within which the river could
be 'free' and removed constraints on its lateral
mobility.
Deer Creek, California:
restoring lateral and vertical
connectivity in a rural stream
In a very different context, Deer Creek, a tributary
of the Sacramento River, drains 540 km 2 of the
southern Cascades Range, flowing south west onto
the Sacramento Valley floor (Figure 18.7). Deer
Creek traverses its alluvial fan for about 17 km
before joining the Sacramento River. A rural area
in the interior of California, land use is primarily
livestock grazing and orchards. Historically, flood
flows would overtop the current channel of
Deer Creek and occupy some of the multiple
channels across the fan surface, clearly visible in
the crenulation of contour lines on the topographic
map (Figure 18.8).
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