Environmental Assessment
Volume E-3.8
Tailings Facility
Hydrology
Ambatovy Project
81
January 2006
Table 3.8-9 Estimated Changes in Flow Characteristics
(a)
– Operation
Baseline
Operations
Operations- Percentage Change
Scenario Sub-
Basin
Station
Flow
(m
3
/s)
Flow
Area
(m
2
)
Average
Depth
(m)
Max
Depth
(m)
Average
Velocity
(m/s)
Flow
(m
3
/s)
Flow
Area
(m
2
)
Average
Depth
(m)
Max
Depth
(m)
Average
Velocity
(m/s)
Flow
(m
3
/s)
Flow
Area
(m
2
)
Average
Depth
(m)
Max
Depth
(m)
Average
Velocity
(m/s)
A4
QESF-203
0.52
7.4
0.9
1.24
0.07
0.31
5.5
0.67
1.05
0.06
-40% -26%
-26%
-15%
-14%
A5
QESF-207
0.88
11.9
1.7
2.58
0.07
0.58
11.2
1.59
2.47
0.05
-34%
-6%
-6%
-4%
-29%
average
month
A6
QESF-201
1.34
14.3
0.64
1.3
0.09
0.79
9.8
0.44
1.10
0.08
-41% -31%
-31%
-15%
-15%
A4
QESF-203
0.18
4.4
0.54
0.94
0.04
0.11
4
0.49
0.88
0.03
-39%
-9%
-9%
-6%
-25%
A5
QESF-207
0.31
10.2
1.45
2.33
0.03
0.21
9.7
1.38
2.26
0.02
-32%
-5%
-5%
-3%
-33%
dry
month
A6
QESF-201
0.47
6.3
0.49
0.92
0.07
0.28
4.8
0.37
0.80
0.06
-40% -24%
-25%
-13%
-19%
(a)
Flow characteristics at hydrometric monitoring locations (located at bridge crossings).
Table 3.8-10 Estimated Changes in Flow Characteristics
(a)
– Post-Closure
Baseline
Post-Closure
Post-Closure - Percentage Change
Scenario Sub-
Basin
Station
Flow
(m
3
/s)
Flow
Area
(m
2
)
Average
Depth
(m)
Max
Depth
(m)
Average
Velocity
(m/s)
Flow
(m
3
/s)
Flow
Area
(m
2
)
Average
Depth
(m)
Max
Depth
(m)
Average
Velocity
(m/s)
Flow
(m
3
/s)
Flow
Area
(m
2
)
Average
Depth
(m)
Max
Depth
(m)
Average
Velocity
(m/s)
A4
QESF-203
0.52
7.4
0.9
1.24
0.07
0.5
7.2
0.88
1.22
0.07
-4%
-3%
-2%
-2%
0%
A5
QESF-207
0.88
11.9
1.7
2.58
0.07
0.87
11.9
1.7
2.58
0.07
-1%
0%
0%
0%
0%
average
month
A6
QESF-201
1.34
14.3
0.64
1.3
0.09
1.32
14
0.63
1.29
0.09
-1%
-2%
-1%
-1%
-4%
A4
QESF-203
0.18
4.4
0.54
0.94
0.04
0.17
4.4
0.53
0.93
0.04
-6%
0%
-2%
-1%
0%
A5
QESF-207
0.31
10.2
1.45
2.33
0.03
0.3
10.1
1.44
2.32
0.03
-3%
-1%
-1%
0%
0%
dry
month
A6
QESF-201
0.47
6.3
0.49
0.92
0.07
0.46
6.1
0.48
0.91
0.07
-2%
-4%
-2%
-1%
-6%
(a)
Flow characteristics at hydrometric monitoring locations (located at bridge crossings.
