Environmental Assessment
Volume E-4.3
Tailings Facility
Fish and Aquatic Resources
Ambatovy Project
179
January 2006
Table 4.3-5 Impact Description Criteria for Fish and Aquatic Resources
Direction
Magnitude
Geographic Extent
Duration Reversibility Frequency
positive
,
negative
or
neutral
for the
measurement
endpoints
negligible
: no
measurable effect on
the measurement
endpoint
low
: <10% change in
measurement
endpoint
moderate
: 10 to
20% change in
measurement
endpoint
high
: >20% change
in measurement
endpoint
local
: effect restricted to
the LSA
regional
: effect extends
beyond the LSA into the
RSA
beyond
regional
: effect
extends beyond the RSA
short-
term
:
<3 years
medium-
term
: 3 to
30 years
long-term
:
>30 years
reversible
or
irreversible
low
: occurs
once
medium
:
occurs
intermittently
high
: occurs
continuously
4.3.5.4 Mitigation
Mitigations that will moderate the impact of habitat loss or alterations as a result
of riparian clearing, removal of streams and wetlands, change in hydrology and
changes to water quality include the following:
Design Features
•
Staged clearing of the tailings area to minimize disturbance to
watercourses.
•
Maintain watercourse buffers within the tailings pond area as long as
feasible to maintain on-site water quality and habitat function.
•
Implementation of watercourse crossing guidelines and plans which
minimize in-water work and disturbance of aquatic /riparian habitat and
control sediment levels within specified levels to protect aquatic habitat
and biota.
•
Other mitigations related to water management in the tailings facility are
provided in the hydrogeology, hydrology and water quality assessments
(Volume E, Sections 3.7, 3.8 and 3.9).
Reclamation
•
Revegetation of all disturbed riparian habitats at road and pipeline
watercourse crossings (part of Environmental Management plans during
construction).
