Planned erosion and sediment spill mitigation for the
proposed $2 billion Project Hayes wind farm was questioned
during an Environment Court appeal hearing for the
development yesterday.
Technical director Graham Levy, of Christchurch, gave
evidence as a witness called by the Otago Regional Council.
Mr Levy was asked by several appellants and party lawyers
whether planned mitigation of perceived problems on the site
would actually work, as the proposed development was unique
in size, scale, and location.
Maniototo Environmental Society counsel Mike Holm asked
whether measures successful on smaller wind farms would work
on the larger Project Hayes site, which was in a more extreme
environment than other wind farms on which mitigation had
been trialled.
Mr Levy's written evidence stated some Wellington City
Council guidelines used at a wind farm at Makara could apply
in the case of Project Hayes, although when cross-examined by
Mr Holm he admitted he was not familiar with the Makara site,
whether such guidelines had been effective, or whether they
would work in the same way on the Lammermoor Range.
"The guidelines are widely used and are non-specific so I
didn't think it was necessary to apply them to particular
sites," he said.
Meridian Energy's 176-turbine wind farm would encompass 92sq
km on the Lammermoor Range if consented, and would be the
largest such development in the southern hemisphere.
Mr Levy said mitigation should work if applied "rigorously",
which would include consent authorities visiting the site at
least once a week to inspect construction effects, so long as
Meridian Energy carried out all proposed measures as planned.
In response to a question from Mr Holm, Mr Levy said he had
been near the proposed site twice, although on both visits he
did not he inspect the actual site, but drove along Old
Dunstan Rd and to the Logan Burn Reservoir, "observing the
area in general".
When cross-examined by Upland Landscape Protection Society
counsel Ewan Carr, Mr Levy admitted he did not have
experience of earthworks and potential mitigation of such
works at a site of the Project Hayes development's elevation.
He said it would be harder to stabilise certain construction
areas during winter when earthworks were exposed to snow and
frost followed by rain.
"The freeze-thaw process will make the underlying surface
more unstable but the top layer should protect it, although
it will result in an increased risk of sediment run-off.
"Sediment control ponds are designed to deal with this as
they have a certain amount of capacity to take sediment
build-up ," Mr Levy said.
During cross-examination by Judge Jon Jackson, deputy
commissioner Ken Fletcher and commissioner Heather McConachy,
Mr Levy said he had relied on the evidence of other witnesses
about revegetation and could not specifically comment on what
mitigation might be necessary to aid or allow revegetation
after construction.
Judge Jackson said he could see a problem arising if stock
were grazed in areas where revegetation of earthworks was
attempted, although Mr Levy could not specifically answer the
judge's question about the areas of land where stock should
be excluded until revegetation was complete.
He said excluding stock from areas of major earthworks and
vegetation between turbine sites could be a "helpful
alternative but not essential".
