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Engineering Components <<..back
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
|
| 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) |
50 218 19 5,45
|
25
160 4,4 4 |
8 148 1,3 3
|
|||
| 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 |
||
| Hydropower Plants
Name |
'Muela 1 | 'Muela II | ||||
| 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 |
||||
| TAILPOND
Name |
'Muela | |||||
| 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
|
|||||
| DELIVERY TUNNELS
Name |
Delivery Tunnel I | Delivery Tunnel II | ||||
| 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 |
||||
| ACCESS ROADS | ||||||
| New access roads (km) | 172 | 69 | 39 | 8 | ||
| Upgraded existing roads | 170 | 93 | 92 | 8 | ||
| WATER DELIVERY | ||||||
| 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 |
| 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 | ||
| Volume of reservoir (milliom m3) | 1, 950 | 947 |