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Transport Implications of
use and management The frequency and
type of vehicle along roads is not always a function of the size of the road.
For example, in parts of CEE large roads were constructed for strategic purposes
and have low traffic flows, elsewhere, small roads may be over capacity with
high traffic flows. The latter can be problematic on account of associated air
and water pollution, and the lack of crossing facilities for wildlife. Thus, a gradual
increase in use to over capacity may be associated with negative effects by
default. Such effects may be less easy to control than with the construction of
a new road but this is a question of balance. On line widening schemes likewise
are not automatically better than a new road – on line improvements can result
in the destruction of verges associated with a diverse flora or significant
feature trees. The wider
environmental effects of highway maintenance can be overlooked with implications
for the realisation of the original design i.e. habitat creation and/ or
protection of features of value. For example, maintenance depots on strategic
routes require additional land take. Where possible these should be located with
other services, e.g. service stations. Oil interceptor tanks and balancing ponds
need clearing in order to function and assist in reducing water pollution. In cold climates,
salt is applied to the carriageway with consequential run-off into the adjacent
watercourses. The maintenance of a snow free carriageway can cause a barrier
(snow-wall) for wildlife wanting to cross. Also it can attract wildlife to the
snow free carriageway causing a hazard to road users. With heavy snowfall
wildlife underpasses and fences can become blocked diverting animals across the
road and causing a traffic hazard also. Routine verge
maintenance is required to maintain sight lines for safety and the maintenance
of firebreaks, and for access to telematics. This can be restricted to a narrow
width with the remaining verge area managed to benefit identified/particular
species of wildlife. Railways With railways
regular maintenance is required to keep the track line clear for safe use. The
passage of trains results in contamination of the track bed including
herbicides, faecal matter, metal dust and lubricants. This can cause pollution
of the ground water, streams and soil, the significance of which depends on the
level of contamination and vulnerable species but little data is available on
this aspect. Track ballast has to be replaced regularly and is difficult to
recycle creating disposal problems. Mostly a minimalist
approach is taken to bank maintenance of railways to meet operational
requirement only, for example clearance of scrub on a 5-10 year cycle. Also bank
vegetation is subject to accidental or intentional burning. As with road and
canal embankments, there may be opportunities to relate the management of the
soft estate to landscape and wildlife objectives. Waterways As previously noted,
waterways may serve several objectives in addition to transport and these affect
use. Pollution and bank erosion from the wash of boats are some of the main
effects associated with navigation. Also, pollution
includes problems relating to the importing of exotic species in ballast water
or through the mixing of waters from other ecosystems. Exotics can thrive, for
example an aggressive alien macrophytes can submerge the native flora in a
relatively short space of time leading to a significant decline in habitat
quality. Control can result in huge maintenance problems and be expensive
(Newman J 2000). Greater awareness of problems associated with exotics could
assist with their more timely removal. Regular occurrence
of water pollution from boats includes oil, antifouling paints and other
chemicals as well as domestic waste causes problems. Maintenance dredging is an
ongoing requirement of such navigations, with associated disposal problems. Maintenance of canal
bank sides may be important to retain their engineering integrity (dam
function). As with roads and railways, embankments can provide a valuable
habitat in their own right. Unlike road and rail, mostly this area is not
subject to contaminants arising from transport users.
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