Rain harvesting helps farmer reap cash from greenhouse

Necessity is the mother of invention and indeed it led Andrew Waweru to develop a rainwater harvesting system on his farm.
Fed up with frequent water shortages, Mr Waweru resolved to find an alternative source since the supply he was getting from the City Council of Nairobi was not enough.

And once he adopted greenhouse farming, Mr Waweru was sure that demand for water at his Miare Farm would go up significantly.
“The idea of gutters was not a new concept to me. I grew up seeing them, especially in government houses and so it was easier for me to adopt the model,” said the retired assistant police commissioner.

Eleven years down the line, Mr Waweru is a happy farmer. He has built more than three underground and five overhead tanks each holding more than 8,000 litres of water.

Won accolades

The underground tanks that measure 15 by 15 feet wide and 10 feet deep; 12 by 30 feet wide and 12 feet deep, are constructed using cement, concrete and wire mesh.

However he used more of cement than concrete for stability. He also put up breathers to ease pressure. “The breathers prevent the surface from getting wet and also protect the tank from bursting under pressure,” he says.

Mr Waweru collects rainwater from surface runoff with the help of a drainage that he built at his gate and gutters. The water drains through underground pipes to an underground storage tank.

Using an electric pump, the water is pumped up to overhead storage tanks, which supply the main house, servant quarter and the farm.
At Miare Farm no water goes to waste.

Grey water (dirty water used for washing in the house) and the one used to clean the cowshed is directed to another storage tank where it is recycled to irrigate Napier grass. The sewage system is also modified to recharge the ground water.

“We have put bricks that separate the water that comes through allowing it to sip through the ground,” said Waweru.

The concept has saved him 95 per cent in water bill.

He often has enough water for his three greenhouses, which require a lot of water, 28 dairy cattle, Napier grass and domestic use.

“We drink the water, it’s rain water,” says the farmer who has won accolades for the initiative.

Last year, President Kibaki honoured him with an award for small scale farmers at the Agricultural Society Show. He is also a recipient of certificate of recognition from Food Agriculture Organisation under the national small-scale farmer’s competition.

Although he acknowledges the attention he receives from the Ministry of Agriculture and farmers in the East African region, he says, that initially farming was not his passion. It only crossed his mind when he was preparing for retirement from the police force.