The water level in the Ndakaini Dam has risen to 46 per cent, giving hope to many city residents who have had to contend with rationing.
The dam supplies more than 80 per cent of Nairobi's water consumption. The Nairobi City Water and Sewerage Company (NCWSC) has said rationing will persist until the volume of the dam rises.
The company said only a small amount of water had been collected at the dam despite the heavy rains.
Dam manager Job Kihamba yesterday told the star that there was no cause for worry. Water level at the dam stood at 40 per cent two weeks ago.
"The current water level is 46 percent," Kihamba told the Star on the phone.
According to Kiamba, rivers feeding the dam had dried up.
"The drought in part of 2016 and 2017 depleted the aquifers that recharge the rivers that feed the dam," Kihamba explained.
The rains had to fill the aquifers for increased river flows. "The rains have been heavy but there was no water in the rivers. It was a big dilemma," Kihamba said.
Ndakaini Dam can store 70,000,000 cubic metres at full capacity. It is 2,041 metres above sea level and 65 metres deep.
It produces 430,000 cubic metres daily, about 84 per cent of total supply to Nairobi residents.
Ndakaini's catchment area is 75 square kilometres.
It includes Kimakia and Gatare forests in the Aberdare Ranges. The main rivers draining into the dam are Thika, Githika and Kayuyu.
Last month, Athi Water Services Board acting CEO Michael Thuita said the heavy rains were pounding the lowlands and not the highlands, where Ndakaini catchment areas lie.
“The rain in Nairobi is not in Aberdare, hence little water in the dam.
The water levels in all the rivers from Aberdare have not increased,” Thuita told the Star.
The dam’s water levels had dropped to less than 30 per cent in February.
Thuita denied that the Sh6.8 billion Northern Collector Tunnel being put up in Murang’a was responsible for the declining water levels. The tunnel is only 35 per cent complete.
The project intially faced strong opposition from Murang’a residents and opposition political leaders, who said it would deplete underground water sources and cause earthquakes.
NASA leader Raila Odinga said it would turn five counties into deserts.
Kenya Meteorological Department acting director Peter Ambenje last month said the catchment areas had started receiving rains.
The government has refuted claims that Ndakaini Dam is recording low water levels due to cracks and open valves. Water CS Simon Chelugui said, two weeks ago, that they have investigated the allegations and found no evidence of “earth movement” that might have caused the low levels.
Chelugui attributed the low volume to massive deforestation of the Aberdares, which is the dam’s catchment area.