- The dam will mitigate against persistent droughts being experienced countrywide and ensure rice farmers farm through-out the year.
- It will see the irrigated acreage at Mwea Irrigation scheme increased by 10,000 acres and double rice production.
Image: Alice Waithera
The persistent droughts experienced through-out the country have affected most farming activities.
With the dwindling flows in rivers, the worse hit are rice farmers who require large amounts of water to do their farming.
However, the government has come to the farmers’ aid by establishing the Sh7.8 billion Thiba dam that has the capacity to hold 15.6 million cubic metres of water.
The dam was allocated Sh8.2 billion but the contractor was able to save Sh400 million by using locally available construction materials.
The dam is 40 metres deep and 1 kilometre long and will provide a consistent supply of water to the farmers and boost their farming activities.
In Kirinyaga county, thousands of farmers depend on rice farming as their main economic activity.
They have had their returns decreased due to reduced farming activities occasioned by insufficient irrigation water.
Mwea Irrigation Scheme covers 25,000 acres with more than 7,022 farmers.
Image: Alice Waithera
According to the scheme’s manager Innocent Aremba, the dam will help channel water from Thiba river to rice farms.
The harnessed water will, however, only be released from the dam when it is needed.
The dam constructed at Rukenya area will work by releasing water back to Thiba river through which it will flow for 24 kilometres to the scheme’s intake.
Its construction started in 2018 and is now complete and awaiting the rains to start filling up. It is expected to take between two and three months to get filled.
Aremba said the dam will see an extra 10,000 acres of land irrigated.
Project manager Stephen Mutinda said engineers will control the release of water from the dam through an outlet that flows back into the river.
The outlet will have a pipe that will be fitted with automatic valves and will have a flow metre to measure the amount of water being released.
“The dam’s operations manager in co-operation with the scheme manager will know when to release a certain amount of water depending on their cropping patterns,” Mutinda said.
The outlet has another pipe that has been specifically designed to ensure the amount of water flowing through the river is not affected to interfere with the flow downstream.
Mwea Irrigation Scheme’s intake has gates that channel the water into the canal. The gates help to regulate the amount of flow allowed into the canal.
Image: Alice Waithera
The scheme releases 3.35 cubic metres of water per second from Thiba river though the intake and has the capacity to abstract 12.2 cubic metres of water per second.
This is mainly because of the low water levels in the river. The scheme’s irrigation water requirements are eight cubic metres of water per second.
The intake also has a flash gate that will be used to clean the system by flashing the silt accumulated from upstream.
“The main canal then discharges the water into four branch canals that then deliver the water to rice farms,” Aremba said.
Sometimes, Aremba said, water levels in the river get too low, necessitating rotational irrigation in the different farming blocks.
Joy Nyambura, a rice farmer, said the constant droughts make it impossible for them to have two seasons of farming each year, reducing their earnings.
She said Thiba dam will boost their living standards by improving their earnings.
She said she cannot wait for the dam to become operational saying their lives are set to be turned around.
According to the National Irrigation Authority head of communication Daniel Nzonzo, the project is one of the efforts the government is making to make the country food secure.
Irrigation, he said, is at the centre of the President Uhuru Kenyatta Big Four agenda.
“Once you provide water for irrigation, you capacitate farmers to grow their own food and make an income,” he said.