Environmental Assessment
Volume E-4.3
Tailings Facility
Fish and Aquatic Resources
Ambatovy Project
177
January 2006
4.3.5
Key Question FA-1: What Effect Will the Project Have
on Aquatic Habitat?
4.3.5.1 Impact Pathways
Aquatic habitat can be affected by activities in the study area during construction,
operation and closure phases. These habitats can also be affected by ancillary
facilities and services such as watercourse crossings by access roads. Changes in
the availability, quality or quantity of aquatic habitat will result from:
•
removal or disturbance of aquatic (riparian and instream) habitat;
•
changes in water flow downstream; and
•
changes in surface water quality.
Removal and Disturbance of Aquatic Habitat
Clearing of riparian vegetation and disturbance of the riparian zone results in an
indirect loss of aquatic habitat through alteration and loss of terrestrial food
sources for aquatic biota, and changes to physical limnology (e.g., water
temperatures) and water quality (e.g., sedimentation) affecting the ability of biota
to survive or complete critical life history functions. Riparian clearing will occur
during construction of the tailings area and the service corridors.
Removal and drainage of existing stream channels and wetlands (either
permanent or ephemeral) permanently eliminates the instream habitats by
directly removing water flows and channel geometry, and eliminates the
capability of the local watersheds to support fish and other aquatic biota. Loss
and disturbance of these habitats will occur during the tailings facility
construction. Creation of the tailing facility berms also block access to upstream
habitat which may be critical to life history function of some fish. Disturbance
will also occur during watercourse crossings associated with access road
construction, pipeline construction, and the water intake construction.
Changes in Water Flow Downstream
Change in water flow (surface water or groundwater) will occur, as during
construction and operation, headwater streams will be disturbed and a portion of
the water collected or diverted, or the drainage area eliminated. These changes
can affect the use of downstream habitats by aquatic biota.
