Environmental Assessment
Volume C-3.2
Slurry Pipeline
Soils
Ambatovy Project
26
January 2006
Soil compaction results in a reduction in porosity and an increase in soil bulk
density. It is caused by external pressure resulting from construction related
equipment and vehicle traffic. The potential loss of soil structure from soil
compaction can affect vegetation growth, especially root development, aeration
and drainage. The slurry pipeline will involve equipment traffic and activity on
soils with potential compaction.
Spills and leaks during operation can result in the alteration of soil chemistry and
physical properties, which in turn can affect vegetation, surface water and
groundwater quality.
Assessment Methods
Soil and terrain units directly affected by the slurry pipeline were quantified by
Geographic Information System (GIS) analysis using the following process:
•
the areas of soils to be disturbed within the slurry pipeline footprint was
GIS quantified;
•
the areas of reclaimed soils following pipeline RoW reclamation were
calculated; and
•
impact ratings were determined based on the net permanent loss of soils
and the expected changes in soil quality.
3.2.3.2 Assessment Criteria
The criteria used to rate soil residual impacts are outlined in Table 3.2-3.
Table 3.2-3 Assessment Criteria for Soils
Resource
Direction
Magnitude
Geographic Extent
Duration
Reversibility
Frequency
Soils
positive
,
negative
or
neutral
for the
measurement
endpoints
negligible
: no
measurable effect
(<1%)
low
: <10% loss
moderate
: 10 to
20% loss
high
: >20% loss
local
: effect restricted
to the LSA
regional
: effect
extends beyond the
LSA into the region
beyond
regional
:
effect extends beyond
the region
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
