Environmental Assessment
Volume B-3.1
Mine
Topography and Geomorphology
Ambatovy Project
17
January 2006
3.1.5
Impact Assessment
3.1.5.1 Assessment Methods
Existing topography was studied using literature and topographic maps. The
relative uniqueness of topographic features was assessed by comparing the
features to be affected by the project with other features in the LSA. The
characteristics of pre-mine topography was compared qualitatively with post-
mine topography.
3.1.5.2 Assessment Criteria
The assessment criteria used for topography and geomorphology are presented in
Table 3.1-1.
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
Project design will allow direct impacts of the mine development to avoid the
Torotorofotsy Wetlands.
During construction, operations and closure, erosion control measures will be
applied as described in Volume B, Section 6 to minimize the formation of gulleys
and the removal of surface material due to water and wind erosion.
