Environmental Assessment
Volume E-4.3
Tailings Facility
Fish and Aquatic Resources
Ambatovy Project
190
January 2006
Table 4.3-9 Potential Effects and Residual Impacts for Aquatic Species
Abundance and Survival in the Tailings Facility Area
Project
Period
Potential Effects
Mitigation
Residual Impacts
construction direct mortality and eradication of
important endemic aquatic
species
effects on downstream flow and
water quality during construction
effects on aquatic and riparian
habitat during service corridor
construction
local water management
erosion control system design
fish salvage program
high magnitude/long term
modification fish and aquatic
fauna within the disturbance area
low magnitude / short term habitat
disturbance during infrastructure
construction
operation
continued loss of aquatic biota
associated with drainages on the
tailings area
change to downstream aquatic
biota as a result of water flow and
water quality changes
water management plan
erosion and sediment control
system design
high magnitude / long-term
modification within the local
disturbance area
low magnitude / medium-term
effect on downstream
communities due to water flow
and quality change
closure
changes in the landscape and
development of revegetative
surface to support clean runoff to
downstream basins
ensure control systems are
functioning to maintain flow
and water quality to support
aquatic habitat
low magnitude / long-term
endemic species recovery
An overall residual impact classification is presented in Table 4.3-10;
environmental consequence scores used the screening system described in
Volume A, Section 7.
Table 4.3-10 Residual Impact Classification for Effects on Aquatic Species
Abundance and Survival in the Tailings Area
Phase
Direction Magnitude
Geographic
Extent
Duration Reversibility Frequency
Environmental
Consequence
Effect: Community (Habitat) Modification
construction
negative
high
local
long-
term
no
medium
high
operations
downstream negative
low
local
long-
term
no
medium
high
Effect: Change to Fish Health
construction
negative
low
local
short-
term
yes
low
negligible
operations
negative
low
local
long-
term
yes
low
negligible
Effect: Restoration and Species Re-introduction
operations
(a)
positive
n/a
n/a
n/a
n/a
n/a
n/a
closure
positive
n/a
n/a
n/a
n/a
n/a
n/a
(a)
Effect during operations assumed to be off-site.
n/a = Criteria not ranked for positive effects.
