The government has re-established a rainfall isotope monitoring station in Kericho County, under the Global Network of Isotopes in Precipitation (GNIP).
This marks the first collection of such scientific data in the area since 1968, significantly strengthening Kenya’s capacity to manage water resources using modern climate science.
The newly installed GNIP station, located at the Tea Research Institute in Kericho, will systematically collect and analyse rainwater to determine its isotopic composition, helping scientists trace how rainfall contributes to groundwater recharge, river flows and soil moisture essential for agriculture and domestic use.
Speaking to the Kenya News Agency (KNA) during the installation, Regional Centre on Groundwater Resources Chief Executive Officer Patrick Murunga said the revival of the Kericho station fills a 58-year scientific data gap and restores the region’s position in a globally recognised rainfall monitoring network.
“This station gives us an opportunity to begin collecting data again and compare what was observed in the 1960s with what is happening now, which is extremely important in understanding changes in our water resources,” he explained.
Murunga noted that historical data from the original Kericho station, which operated between 1967 and 1968, remains archived under the World Meteorological Organization system, making the renewed monitoring effort a direct continuation of internationally referenced scientific records.
At the same time, the CEO emphasised that the GNIP programme strengthens research in groundwater, agriculture and environmental management while boosting Kenya’s laboratory credibility through quality control partnerships with the International Atomic Energy Agency (IAEA).
Murunga pointed out that the station will benefit tea farmers, households, water managers and county planners by providing accurate rainfall source data that supports irrigation planning, drought preparedness and sustainable allocation of water resources.
Meanwhile, the Regional Centre on Groundwater Resources hydrologist, Cynthia Wachuka, said the Kericho GNIP station will analyse rainwater for stable isotopes such as Oxygen-18 and Deuterium to help scientists understand the origin and movement of water within the hydrological cycle.
“This station allows us to understand our water resources from the source, which is rainfall, and this information is critical for long-term water planning and climate studies,” she explained.
Wachuka emphasised that rainfall samples will be collected monthly and analysed over a four-to-seven-year period to generate dependable average values that eliminate distortions from extreme rainfall seasons and enable scientists to establish a Local Meteoric Water Line for Kericho.
The Hydrologist pointed out that a Local Meteoric Water Line is essential because rainfall characteristics differ from one region to another and localised isotope data helps accurately link rainwater to groundwater, springs and rivers relied upon by communities and farms.
Wachuka further said that the new monitoring station in Kericho has been engineered to protect the integrity of rainfall samples, featuring a white-painted exterior to reflect heat, an elevated base to reduce ground radiation and a specially designed funnel fitted with deterrent spikes to prevent birds from contaminating the collection system.
Equally, she explained that trained staff from the Tea Research Institute will oversee monthly sample collection using standard rainfall measuring equipment and specialised isotope sampling bottles that minimise evaporation before the samples are transported to laboratories for analysis.
Wachuka further mentioned that duplicate samples will be analysed at the Regional Centre on Groundwater Resources laboratory and a second set sent to the International Atomic Energy Agency for inter-laboratory comparison, a process that ensures accuracy, builds confidence in Kenya’s scientific results and strengthens the country’s contribution to global water research.
Kenya now has ten active GNIP stations spread across different ecological zones including Lodwar, Marsabit, Mombasa, Kilifi, Chyulu hills, Oloitokitok, Muguga, West Pokot and now Kericho, a distribution that allows scientists to compare rainfall characteristics across arid, coastal, highland and semi-arid regions.
In the long term, the data will guide national and county governments in designing evidence-based water policies, enhancing drought resilience, protecting ecosystems and ensuring sustainable water supply for households and industries, thus reinforcing the government’s commitment to science-led development and resource security.
By Dominic Cheres and Kibe Mburu
