Environmental Assessment
Volume E-3.1
Tailings Facility
Topography and Geomorphology
Ambatovy Project
21
January 2006
Table 3.1-1 Impact Description Criteria for Topography and Geomorphology
Direction
Magnitude
Geographic
Extent
Duration
Reversibility
Frequency
neutral: no
change in
topography
negative: a
change in
topography that
affects function
for human or
biological
services
negligible: no
measurable effect
on slopes and
landscape-level
topographic
features
low: slight changes
in slopes or overall
topographic layout
moderate: locally
prominent changes
in slopes or overall
topographic layout
high: regionally
prominent changes
in slopes or overall
topographic layout
local: effect
restricted to
the LSA
regional: effect
extends
beyond the
LSA
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
3.1.5.3 Mitigation
During construction, operations and closure, erosion control measures will be
applied as described in Volume E, Section 6 to minimize the formation of gulleys
and the removal of surface material due to water and wind erosion.
During construction, operations and the beginning of the closure phase, water
management systems will be used to catch flows along the base of disturbed
features and mitigate siltation in downstream basins. This will be particularly
important to mitigate effects on valleys downstream that are productive for rice
production and other land uses.
During the operations and closure phases, reclamation will occur. Revegetation
will reduce erosion of surface material and will help to maintain slopes and other
topographic features. Slopes will be contoured to maintain long-term stability.
Closure landforms will be designed such that there will be continuity of
landforms and watershed systems between undisturbed land and reclaimed areas.
