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October
1999 Newsletter
Expressway
Threats to Fish Habitat
One
of the written submissions filed on behalf of Friends
of Red Hill Valley was prepared by our vice-chair,
Dr. Joe Minor. In the following excerpt he addresses
the impacts on fish habitat. Dr. Minor noted that
the damage will be to more than just the stream and
advised the Panel to require examination of the effects
on fish from damage to the lands around the stream.
The
proponent proposes to build a large structure straight
down a narrow river valley. This means cutting a large
swath for the footprint of the road, resulting in the
loss of 47,000 trees.
The
number of trees to be cleared for the project may be
much higher, since this figure does not take in to account
several additional sources of tree loss. Tree loss in
construction staging areas would be additional. Additional
tree loss will also occur because the bed of the creek
is to be moved to a "new" location, which will also
have to be cleared. In addition, the proponent proposes
to clear additional trees in order to prevent further
tree loss (!!) due to opening up rough forest edges.
The
proposed degree of clear-cutting appears to be a violation
of the Region's Official Plan (1.2.1, p.C4): "Tree protection
and planting should be encouraged to enhance local aesthetics
and landscape, contribute to improved air quality; reduce
erosion, sedimentation and flooding; and protect groundwater
recharge and discharge areas. To protect and enhance
the existing forests, woodlots, and tree cover, the
Region will: Adopt a tree-cutting by-law to protect
tree cover in Environmentally Significant Areas (Red
Hill Valley is a designated ESA) and limit tree removal."
The
total loss of trees and other vegetation from all of
these activities needs to be assessed because the bulk
of this clearing will occur in the floodplain/riparian
zone of the creek.
The
loss of this much vegetation from the riparian zone
will seriously disrupt fish habitat.
Quoting
from a report of a U.S. study: "Properly functioning
riparian zones along streams provide bank stability
from tree root systems and filtration of surface erosion
and agricultural nutrients as water passes through vegetation.
In fact, 80 percent of the energy for the river's food
chain comes from leaf litter and insect drop.
"Pool
depth and complexity comes from large woody debris (mature
trees falling in), and trees provide cool water temperatures
and high relative humidity (microclimates important
for amphibians) from the tree canopy, as well as long-term
undisturbed bird and animal nesting sites and migration
corridors that connect habitats."
The
study points out that riparian wooded areas provide
benefits to fish habitat in (at least) five ways:
1) climate control (shade),
2) bank stabilization,
3) sediment control,
4) organic litter, and
5) large woody debris (to provide pool structure).
The
large amount of riparian clearing the proponent proposes
needs to be considered in terms of losses to these
ecosystem functions.
The
potential for harmful alteration, disruption, or destruction
of fish habitat posed by this project is so great
that I cannot detail all of the problems here.
The
panel should refer to a recent DFO publication
(5) that outlines nine major ways that a project
can disrupt fish habitat. These are:
1)
alteration of channel shape,
2) changes to bank or bottom materials,
3) addition of sediment or mobilization of sediment,
4) alteration of bank or buffer vegetation,
5) disruption of flow,
6) changes to groundwater flows,
7) introduction of toxic materials,
8) fish kills, and
9) blockage of fish passage.
The
proposed project can best be described as "thorough":
it will result in harm to fish habitat in all
nine categories...
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©
Friends of Red Hill Valley 1991-2005
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