Geoscience Reference
In-Depth Information
REDUCTIONIST SCIENCE
now looking
“down the basin”
CLIMATIC CHANGE
REDUCTIONIST
RIVER MANAGEMENT
POLICY MAKING
now looking
“up the basin”
REDUCTIONIST
CONSERVATION
now looking
“beyond the channel”
GEOMORPHOLOGICAL CHANGE
(a)
CATCHMENT/BASIN
VALLEY FLOOR
FLOODPLAIN
RIVER CORRIDOR
CHANNEL
(b)
Figure 2.1
Current moves to extend sectional interests in river basin management (from Newson, 1992).
decision-making as part of adaptive management
(Newson and Clark, 2008).
Despite these perfectly valid policy-related
themes there has, in reality, been very little
supporting river science of an inter-disciplinary
nature - despite being considered essential by
those who promote catchment consciousness
(Vaughan
et al
., 2009). The key contributions
made by two component sciences, hydrology and
geomorphology, during this period demonstrate
what progress has been made during the last
20 years. It is important to realize that much
of the intellectual debate over what is 'natural'
in river systems has been qualitative (or semi-
quantitative at best), with scientists giving expert
opinions based on experience; defining 'reference
conditions' for river hydromorphology is a prime
example (Newson and Large, 2006).
The degree to which human intervention
has altered river processes and form is at the
centre of debates on near-natural and 'reference
conditions' (Boon
et al
., 2010). This debate can
be paraphrased by the question, 'When were
rivers natural?' There is now a growing consensus
on two possible historical markers for natural
conditions in the UK: (i) the Industrial Revolution
of the mid-18th century; and (ii) 1945, which
marked the beginning of the 'great acceleration'
of agricultural and urban impacts (Steffen
et al
.,
2007). Commentators agree that both hydrological
and geomorphological processes were profoundly
affected
by
changes
in
the
intensity
and
the
