Something has been happening to two of the Rift Valley's most iconic lakes, and it hasn't happened overnight. Lake Baringo and Lake Bogoria, both in Baringo County, have been growing steadily for more than a decade, and this time the evidence isn't just what people are seeing on the ground. It's coming from space.
The main gate leading to the Lake Bogoria National Reserve that was submerged in water in this photo taken in September 2024.
Photo credit: Florah Koech | Nation
Elkana Kipruto, a geospatial data engineer and remote sensing specialist, pulled satellite images of both lakes at five distinct points between 2010 and 2026, using a consistent classification method to ensure the measurements were directly comparable. The results are striking.
"Lake Baringo has grown from 138.5 square kilometres in 2010 to 229.3 square kilometres in 2026," his findings say.
That's an extra 91 square kilometres of water, a 65.6 per cent increase, or as the report states, roughly three-quarters the size of Nairobi National Park added onto the lake in just 16 years.
Lake Bogoria’s expansion has been more modest but still significant, rising from 33.7 square kilometres to 43.2 square kilometres, an increase of about 9.5 square kilometres, or 28.2 per cent, an area close to the size of Karura Forest.
Baringo and Bogoria are not the same kind of lake, and that difference shapes what their expansion means. Baringo is freshwater, a lake that supports fishing, livestock, and small-scale irrigation. According to the report, this makes it "more directly usable" for daily life than Bogoria, and it also means that as Baringo expands, it pushes into land that people actively use.
Bogoria is altogether different. It is a closed, alkaline lake, internationally known for its geothermal hot springs and geysers, and designated a Ramsar wetland in 2001. It is a flamingo habitat first and an agricultural resource a distant second. Its growth, therefore, carries more of a conservation and tourism story than a farming one.
How the researchers actually measured this
Kipruto's analysis shows water extent was classified at five separate points in time using a consistent index-based method applied uniformly across each image, specifically so the five measurements could be fairly compared against one another rather than being apples-to-oranges snapshots.
It wasn't a perfectly smooth process. For Lake Baringo, the 2014 satellite pass had to be scrapped entirely. According to the report, the Landsat scene available for that year "contained genuine sensor artifacts that would have compromised the water classification," so the nearest clean, reliable image was used instead, from 2015.
What the five snapshots show isn't a straight upward line, either. Lake Baringo's growth came in fits and starts, expanding quickly from 2010 to 2015, dipping slightly by 2018, then surging again through 2022 before easing off closer to 2026. Bogoria's growth, by contrast, has been steadier and more gradual across the same stretch of years, without those swings.
Strip away the different starting sizes of the two lakes and compare growth rates directly, and the gap is even clearer.
"Baringo has expanded more than twice as fast as Bogoria over the same 16-year period," the report states.
Not just tracking the past, but the future too
The satellite work only tells you where the water has already been. To figure out where it might go next, Kipruto's analysis turned to elevation data, a Digital Elevation Model built from SRTM terrain data, mapped around both lakes' current shorelines.
The logic is simple: water flows downhill, so the lowest land bordering each lake is the land most likely to flood first if levels keep climbing. Around Baringo, the terrain analysis found exactly that kind of vulnerability, "flat, low-gradient basins with no natural topographic barriers to hold the water back," the report states. Bogoria shows a similar, if smaller, pattern to its north.
"The maps produced in this study should not be interpreted as flood forecasts," Kipruto explains in his findings. "They do not predict rainfall, future lake levels, or the timing of flooding. What they do instead is answer a narrower, more useful question: if the lakes keep rising, where does the water go next?"
These vulnerable areas, the report states, "could have been identified using elevation data that has been publicly available for many years."
As the report states, this is "not a sudden disaster," but "the cumulative result of a slow, sustained trend" that satellite images have been recording the entire time.
Going forward, the report recommends three things: satellite monitoring of both lakes at least once a year to catch shoreline movement early, regular updates to the elevation-based risk maps as new shoreline data comes in, and, eventually, a broader catchment study to get at the underlying cause.
