Environmental Assessment
Volume C-3.6
Slurry Pipeline
Hydrology
Ambatovy Project
52
January 2006
Table 3.6-3 Reach Characteristics and Discharges Along the Pipeline Route
Pipeline Kilometre
Post
Stream Name
Drainage
Area (km
2
)
Survey Date
Wetted Width
(a)
(m)
Discharge
(m
3
/s)
XR2+000
Vondronina (upper reaches of the
Torotorofotsy River)
4.7
Sep. 30, 2004
3.5
0.58
XR7+510
Unnamed
~1
Oct. 18, 2004
1.2
0.04
XR16+100
Sahatany
(Tributary to Sahatandra)
38
Oct. 03, 2004
7.2
1.10
X42+300
(b)
Volove
28
Oct. 19, 2004
15.0
1.14
X107+200
Rianila (Tributary to Vohitra)
~1,860
Sep. 25, 2004
126
57.4
X136+200
Sahanavo
n/a
Sep. 22,2004
77.0
18.4
X145+700
Morongolo
~1,000
Oct. 16, 2004
51.4
9.81
X157+700
Berohondry
n/a
Oct. 12, 2004
3.2
0.08
X175+200
Sandranentana
(Tributary to Fanandrana)
n/a
Oct. 13, 2004
3.0
0.08
X178+900
Ivondro
~2,560
Oct .14, 2004
183
50.0
E3 007+000
(c)(d)
Vohimana
6.5
Sep. 30, 2004
5.45
0.22
E3 011+950
(d)
Sahatandra
~7
Oct. 01, 2004
26.5
9.66
(a)
Wetted width at discharge measurement location.
(b)
Recorded as 041+600 (same river within 1 km).
(c)
Recorded as E3 005+150.
(d)
Alternate watercourse crossing location.
n/a = Not available.
~ = Indicates approximate drainage area.
3.6.3
Issue Scoping
Hydrology issues related to the project were identified through consultation with
stakeholders and by reviewing previous environmental assessments for resource
developments in Madagascar and elsewhere. As described in Volume A, the
issues were identified, tracked and summarized at a high level for consideration
in the impact assessment. The following hydrology issues were identified:
•
changes in flows, water levels and sediment loads that could alter
channel morphology and sediment concentrations; and
•
changes in water availability for various uses (human and animal
consumption, irrigation and aquatic habitat).
For both issue areas, there was strong concern that the pipeline not affect water
quantity or quality in the Torotorofotsy Wetlands. The key indicators of change
due to the project are flows, water levels, sediment concentrations and channel
morphology. These changes may also have an effect on water quality, fish
health, vegetation (wetlands), and socioeconomic components of the project.
