Environmental Assessment
Volume E-3.8
Tailings Facility
Hydrology
Ambatovy Project
77
January 2006
Table 3.8-7 Estimated Reductions in Streamflow in Downstream Reaches – Average Month
Basin Characteristics
Baseline
Operations
Closure - End of
Pumping (Year 42)
Closure - Long-term
Basin
Reach
Name
Sub-
Basin
Area
(km
2
)
Runoff
(mm)
Flow
(m
3
/d)
Flow
(m
3
)
Year
Reduction
in Drainage
Area
Flow
(m
3
/d)
Flow
Reduction
(a)
(%)
Flow
(m
3
/d)
Flow
Reduction
(%)
Flow
(m
3
/d)
Flow
Reduction
(a)
(%)
A(tailings)
4
142
19,156
574,691
94%
-
-
-
-
-
-
A1
5.9
142
27,900
837,006
64%
9,712
65%
26262
6%
26,490
5%
A2
7.6
142
36,027 1,080,810
50%
17,893
50%
34346
5%
34,617
4%
A3
8.7
142
41,051 1,231,529
44%
23,026
44%
39370
4%
39,641
3%
A4
9.5
142
45,008 1,350,229
40%
26,998
40%
43327
4%
43,598
3%
A5
16.1
142
76,207 2,286,200
34%
49,990
34%
73,413
4%
74,067
3%
A
A6
24.4
142
115,493 3,464,800
14
41%
69,950
39%
110,957
4%
112,133
3%
B(tailings1) 1.7
142
8,174
245,226
100%
-
-
-
-
-
-
B(tailings2) 0.6
142
2,982
89,460
100%
-
-
-
-
-
-
B1
3.6
142
16,899
506,982
66%
5,809
66%
15792
7%
16,169
4%
B2
4.7
142
22,229
666,880
50%
11,360
49%
21122
5%
21,499
3%
B
B3
1.4
142
6,807
204,196
27
0%
6,797
0%
6802
0%
6,807
0%
C(tailings)
2.7
142
12,973
389,205
100%
-
-
-
-
-
-
C1
5
142
23,441
703,242
55%
10,132
57%
21719
7%
22,231
5%
C2
6.1
142
28,721
861,630
45%
15,438
46%
26978
6%
27,501
4%
C
C3
7.4
142
35,159 1,054,777
20
37%
21,876
38%
33416
5%
33,938
3%
(a)
Reduction in flow along the main stem of the stream at the downstream end of the reach.
