Construction of Subuiga Dam in Buuri sub-county, Meru County started on Wednesday, 15 years after the idea was discussed.
The dam is expected to benefit over 25,000 residents by helping irrigate 4,000 acres.
John Kinoti, the chief programmes and partnerships officer at Lewa Conservancy said the dam, which will have the capacity to trap 15 million litres of rainwater, is a partnership between the Kisima Farm and Ngare Nything Water Resources Users Association and the county and national government agencies.
Kisima Farm Ltd, a mixed-working farm in the Timau area, donated nearly 12 acres where the dam will be located.
Lewa has pumped in Sh40 million for the first phase of the project while the second phase will cost about Sh12 million.
Mr Kinoti said they were committed to assisting residents get water for domestic, livestock, and agricultural use, tapping from Ngare Nything river whose volumes had reduced due to drought.
"Once the rains come, we will trap rainwater to address an acute shortage of water in this region. In view of the persistent drought ravaging our country, it is advisable to harvest water whenever it rains,"' said Kinoti.
He said residents would access water from the reservoir during the dry spell, adding that the project was set for completion around April next year.
Residents of Subuiga, Matunda, Ntumbori, and the environs will benefit from the reservoir.
"Residents, livestock, schools, and other institutions in the area will be able to get an alternative water source when it is completed and it is also going to serve the purpose of sensitizing the community on the need for them to be harvesting rainwater," he said.
Martin Dyer, the chairman of the Ngare Nything Water Users Association, said the idea of a dam in the area was mooted sometime back, and they were happy construction had eventually started.
"It has been our idea for a long time to build this dam because we feel there is plenty of water in this country. We are not just storing it and using it well enough; we are letting it all flow away,"' said Mr Dyer.
He said water users' associations in Kenya should build dams to increase water volumes in rivers.
Speaking during the groundbreaking ceremony, Meru Governor Kawira Mwangaza expressed willingness by her administration to allocate resources for water.