Environmental Assessment
Volume E-3.8
Tailings Facility
Hydrology
Ambatovy Project
78
January 2006
Table 3.8-8 Estimated Reductions in Streamflow in Downstream Reaches – Dry Season 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
50
6,745
202,356
94%
-
-
-
-
-
-
A1
5.9
50
9,824
294,720
64%
3,289
67%
8186
17%
8,414
14%
A2
7.6
50
12,686
380,567
50%
6,205
51%
11005
13%
11,276
11%
A3
8.7
50
14,455
433,637
44%
8,083
44%
12774
12%
13,045
10%
A4
9.5
50
15,848
475,433
40%
9,491
40%
14167
11%
14,438
9%
A5
16.1
50
26,833
805,000
34%
17,566
35%
24,040
10%
24,693
8%
A
A6
24.4
50
40,667 1,220,000
14
41%
25790
37%
36,130
11%
37,307
8%
B(tailings1)
1.7
50
2,878
86,347
100%
-
-
-
-
-
-
B(tailings2)
0.6
50
1,050
31,500
100%
-
-
-
-
-
-
B1
3.6
50
5,950
178,515
66%
2,088
65%
4843
19%
5,225
12%
B2
4.7
50
7,827
234,817
50%
4,186
47%
6720
14%
7,097
9%
B
B3
1.4
50
2,397
71,900
27
0%
2,387
0%
2392
0%
2,397
0%
C(tailings)
2.7
50
4,568
137,044
100%
-
-
-
-
-
-
C1
5
50
8,254
247,620
55%
3,350
59%
6532
21%
7,044
15%
C2
6.1
50
10,113
303,391
45%
5,235
48%
8370
17%
8,893
12%
C
C3
7.4
50
12,380
371,400
20
37%
7,502
39%
10637
14%
11,160
10%
(a)
Reduction in flow along the main stem of the stream at the downstream end of the reach.
