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Engineering Components
Lesotho Highlands Water Project
Phased Development of the main features of the Project
PHASED DEVELOPMENT OF THE MAIN FEATURES OF LESOTHO HIGHLANDS WATER PROJECT
| Phase
Main Reservoirs |
Katse |
1B
Matsoku
|
1B
Mohale
|
II
Mashai
|
III
Tsoelike
|
IV
Ntoahae
|
| Cumulative catchment area (km2)
Cumulative mean annual runoff (hm3)
Total storage (hm3)
Active storage (hm3)
Full supply level (masl)
Minimum operating level )masl)
Type of dam
Height of dam(m)
Crest length (m)
Volume of dam (hm3)
|
1 866
622
1 950
1 519
2 035
1 989
Arch
180
710
2,2
|
2063
Diversion weir
|
945
314,7
810
720
2 075
2 005
Embankment
140
564
8,5
|
7 978
1 615
3 430
2 430
1 887
1835
Embankment
170
680
14,4
|
10 376
1 971,7
2 170
1 250
1 757
1 725
Embankment
160
490
11,7
|
11 345
2 133,1
1 370
650
1 634
1 610
Arch
125
180
0.5
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| Pumping stations
Name |
|
|
Mashai-Katse |
Tsoelike- Mashai |
Ntoahae-Tsoelike |
|
| Design discharge(m3/s)
Design static head (m)
Total tunnel length (km)
Pumping tunnel diameter (m)
|
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|
50
218
19
5,45
|
25
160
4,4
4 |
8
148
1,3
3
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| TRANSFER TUNNELS
Name |
Katse-'Muela 1 |
Matsoku-Katse |
Mohale-Katse |
Katse-'Muela II |
|
|
| Length (km)
Excavated diameter (m)
Lined diameter (m) |
45
4,95
4,35 |
6,4
4,0
3,4 |
32,0
4,0
3,4 |
45
5,5
4,9 |
|
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| Hydropower Plants
Name |
'Muela 1 |
'Muela II |
|
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|
| Rated plant discharge (m3/s)
Rated net head (m)
Number of units
Installed capacity (MW) |
35,7
236
3
72
|
53,6
246
3
110 |
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| TAILPOND
Name |
'Muela |
|
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| Total storage (hm3)
Active storage (hm3)
Full supply level (masl)
Minimum operating level
Type of dam
Height of dam (m)
Crest length (m)
Volume of dam (m3) |
5,9
3,9
1775
1760
Arch gravity
55
180
85 000
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| DELIVERY TUNNELS
Name |
Delivery Tunnel I |
Delivery Tunnel II |
|
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|
| Length (km)
Excavated diameter (m)
Lined diameter (m)
Outfall water level (masl) |
37
5,1
4,5
1 735,5 |
37
5,1
4,5
1 735,5 |
|
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| ACCESS ROADS |
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| New access roads (km) |
172 |
|
69 |
39 |
8 |
|
| Upgraded existing roads |
170 |
|
93 |
92 |
8 |
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| WATER DELIVERY |
|
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| Incremental (m3/s)
Total (m3/s)
|
18,2
18,2
|
2,2
20,4
|
9,6
30,0
|
25,4
55,4
|
9,6
65,0
|
5,4
71,4
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| Year of Commissioning |
1996 |
2003 |
2004 |
2008 |
2017 |
2020 |
Legend
hm3 = cubic hectometre = 1 million cubic metres,
masl = metres above sea level , m3/s =cubic metres per
second
km = kilometres, m = metres, m3 = cubic metres
(Need pics of Katse dam, Matsoku and Mohale and 'Muela)
OTHER DAM CHARACTERISTICS
| Dam
Name |
Katse |
Mohale |
'Muela |
Matsoku weir |
| Type of dam structure |
Double curvature concrete arch dam |
Conrcete face rockfill embankment |
double curvature concrete arch dam |
concrete 12-stepped o'give |
| Maximum height (m) |
185 |
145 |
55 |
19 |
| Crest length (m) |
710 |
620 |
|
180 |
| Volume of concrete(m3) |
2,300,000 |
7,500,000 |
|
21, 000 |
| Spillway discharge(m3/s) |
6,252 |
2,600 |
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| Volume of reservoir (milliom m3) |
1, 950 |
947 |
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