Athi Water Service Board Chief Executive Officer Malaquen Milgo says the northern collector tunnel is being built to increase water supply to Nairobi having capacity to deliver to Nairobi 140 million litres of water per day.
The Sh6.8 billion water project is designed to draw flood flows from Irati, Gikigie and Maragua rivers in Murang’a County and then channel the raw water to Thika dam.
The flood water diversion structures will be constructed on these rivers and will divert the water to the collector tunnel.
Milgo said that scientific impact assessment study was done to ensure it will not affect underground water.
“We contracted GIBB Africa Ltd to undertake an Environmental and Social Impact Assessment to ensure that only flood water is channelled into the tunnel and that downstream demand is not impacted by the project,” he said.
He said that a resettlement action plan has been prepared to ascertain the extent of land acquisition and to ensure that any persons affected by the project are adequately compensated.
An environmental plan has also been put in place which requires monitoring to ensure that adequate protection measures will be inserted into the design of the weirs to allow for the safe passage of fish, replanting and nurturing of saplings that will be done in conjunction with the Kenya Forest Services.
He said that the board has been in consultations with the local leaders of Murang’a County who are behind the project.
Pipelines will be constructed so that the Thika-Kigoro pipeline will be for raw water and the Kigoro-Ngethu pipeline will have treated water.
Nairobi will require 1.2 billion litres of water daily by 2035 according to the Nairobi Water master plan study.