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such as willow trees limits flood discharge capacity,
in which case the trees are removed sometimes
with adverse effects on the habitat values of rivers.
Since 1990 there has been increasing pressure
on the remaining point-source waste discharges to
water from industries such as dairy factories, meat
works and sewage treatment works, and this has
resulted in improvements with many discharges
now completely removed from rivers (Ministry for
the Environment, 2007).
Recognition of non-point-source pollution as a
tangible water quality problem grew through the
1980s (Wilcock, 1986) and 1990s (Smith et al. ,
1993) and links were made between agricultural
land-use and adverse fisheries impacts (Harding
et al ., 1999; Young and Hayes, 1999). Despite
recognition in policy documents, acceptance of
non-point-source pollution as a significant problem
by land users and regional councils was slow in
coming because of the dispersed nature of the
problem and the lack of benchmark water quality
data.
Intensification of agriculture from the mid-1990s
onwards was led by a progressive change to
dairying and away from more extensive sheep
and beef grazing, increasing the non-point-source
pollution problem and public awareness of it.
As dairying began to be established in non-
traditional locations, particularly on the South
Island's Canterbury Plains, increases in irrigation,
stock densities and disposal of effluent to land
hastened water quality declines at a time when
communities were expecting improvements.
So a decade on, researchers drew similar
conclusions to those drawn before - that lowland
rivers in agriculturally developed areas were in
poor condition owing to high nutrient, sediment
and faecal contamination. The dairy boom was
identified as the main but not the only culprit
(Parkyn et al ., 2002), a conclusion corroborated by
angler perceptions of long-term changes in lowland
river fisheries (Jellyman et al ., 2003).
A major report on intensive farming
(Parliamentary Commissioner for the
Environment, 2004) questioned the sustainability
of current farming systems and the implications
for the environment. It noted that New Zealand's
limited and fragile freshwater resource was coming
under increasing pressure from farming activities.
The report identified non-point-source pollution
from farming systems as a significant risk to the
New Zealand environment and to the future of
farming itself, concluding that a fundamental
redesign of farming systems was required to deliver
economic wealth and environmental sustainability.
However, no such redesign has yet occurred and
dairy farming has continued to expand with the
national dairy herd growing from 3.8 million in
1994 to 5.8 million in 2009.
There was a lull in pressure for new hydro-
development from the early 1990s but the quiet
period has now ended as power companies
pursue 'renewable' energy sources in response to
new climate change policies. Many rivers have
already been modified (Young et al ., 2004) or
flooded through hydro-dam construction with
approximately 60% of the country's electricity
coming from hydro-electricity schemes. The rush
to develop renewable electricity potential using
geothermal, wind and river resources poses a clear
risk to rivers with 65 potential hydro-schemes
being identified as 'high to medium confidence
hydropower development opportunities' across
New Zealand (East Harbor Management Services,
2004). Some new hydro-dam proposals on rivers
with important conservation and recreation values
such as the Wairau, Lower Waitaki and the
Arnold Rivers have recently been granted resource
consents. Others are tracking through the resource
consent approvals process including the Mokihinui
River on the South Island's West Coast. Much of
the Mokihinui catchment is sub-tropical rainforest
and the valley is home to threatened wildlife but
the proposed 85 m high dam would destroy an
unspoilt wilderness river (Martin, 2008). Still other
rivers, such as the Nevis and Clutha, are under
active investigation by power companies.
A Proposed National Policy Statement on
Renewable Electricity Generation has been
prepared to address issues arising from the
new focus on renewable energy including
adverse environmental effects (Ministry for
the Environment, undated). One policy proposal
is to require decision-makers to have regard to
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