10 October 2006, by PowerNell. Yesterday the water level at Mtera Dam was 687.33 metres above sea level. In order to stop the current power rationing across the country, the water level should be at least 695 meters above sea level (source: The Guardian, 3 July 2006). Usually power-generation at Mtera is permitted until 690 metres, but in January, the government permitted Tanesco to continue until the level dropped to 687 metres. The decrease in the water level is mainly caused by drought. To fill the Mtera Dam, the government is studying possibilities to make articifial rain.

Available hydropower

The maximum capacity of Tanzania"s hydropower plants is 561 MW per day. The bulk power comes from the Kidatu Dam, which draws its water from Mtera Dam. This makes Mtera Dam one of the major dams relied on for power generation. When the dam is full to its capacity, its water is able to generate power through the Kidatu power plant for not less than ten months (source: The African, September 16, 2006).
The current capacity of the main hydropower plants however is much lower. Today Daily News published the current capacity of the main hydropower plants Mtera, Kidatu and Kihansi (see table). It is likely that the minor dams are also not producing at full capacity. The situation is even worse than in March this year, when the hydropower plants produced only 109 MW.
 

Hydropower plant	Maximum capacity	Capacity March 17	Current capacity
Mtera Dam	80 MW	11 MW	8 MW
New Pangani Falls	68 MW	8 MW	?
Kidatu	200 MW	50 MW	20 MW day / 40 MW night
Nyumba ya Mungu Dam	8 MW	1.8 MW	?
Kihansi Falls	180 MW	33 MW	30 MW day / 90 MW night
Hale Dam	21 MW	5 MW	?
Total	561 MW	108,8 MW	58 MW – 150 MW

 
On drought and other causes for the low water level

The decrease in the water levels is mainly caused by drought. The land is so dry that even in case of rain, all water is percolating, and the land is not saturated with water to create massive flows to the dam (source: The Citizen, March 14, 2006). Another cause is the intensivied human activities in the Great Ruaha catchment area. The Great Ruaha River used to be a streaming river all year round, but since 1993 there are increasingly long periodes in which the river dries up completely. This is caused by irrigation schemes for rice cultivation and keeping of livestock.
The Tanzanian

Future opportunities

Hydropower is still the cheapest source of electricity. Therefore some experts suggest to exploit Steigler"s Gorge in Selous National Park, which could generate 1000 MW. This would be a very costly project though, but it would make it possible to shut down inefficient and costly other methods of generation (source: The Guardian, March 28, 2006). The environmental impacts however are doubtful: the building of hydropower dams will almost certainly affect the ecosystems that are flood dependent (source: Research Master Plan for the Rufiji Floodplain and Delta 2003-2013). Research studies for hydropower stations at Steigler"s Gorge (1200 MW) and Rumakali (222 MW) have been done from the 1970s, and at the moment efforts are underway to update these studies (source: The Guardian, September 15, 2006).

Artificial rain

The Tanzanian government tries to do everything to solve the current power crisis. Obviously the easiest solution would be a lot of rain over the catchment area of Mtera Dam. The rainy season does not start before November (Mtera has only one rainy season a year). But why should we wait for the rainy season? In the recent past experts from Thailand have succeeded in making artificial rain. The Tanzanian government is already in contact with Thai experts on rain making. According to Profesor Ernest Njau of the University of Dar es Salaam, the environmental impact is minimal. In The African he gives a detailed description of the 'cloud seeding" technique, in which chemicals are injected in a moisty cloud. The chemicals then convert moisture into drops. Then entire process lasts between 20 minutes to one hour from the time when chemicals are injected to the time the rain falls. Apparently the rain making process was already carried out in the then Tanganyika in 1951 at Kongwa, in Dodoma, by the then British colonialists. It proved successful as the rain increased by six inches (source: The African, September 20, 2006).
 
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