The authority on Saturday announced that the Tana River had burst its banks.
Kenha said the river burst its banks between Madogo Total Station, Mororo and Tana River Bridge.
It said it led to the flooding of the section between Madogo Town and Tana River Bridge.
The authority said the road in the section is rapidly eroding potentially leading to dangerous washouts.
"Motorists and pedestrians are advised to avoid the road section. Similarly, area residents are advised to avoid idling near flooding waters, as there are risks of stray crocodile attacks," the statement read.
"The Kenha team is on the ground closely monitoring the situation and will update on progress."
This comes at a time the country is experiencing El Nino rains that have caused flooding in some counties.
A section of roads have been rendered impassable; some roads have been totally cut off and residents forced to seek alternative routes.
On Saturday, the Mombasa-Malindi highway was rendered impassable after a section of the Mbogolo bridge was washed away by raging floods.
Kenha later said it had commenced repairs works with normal traffic flow expected in 24 hours.
Garissa and Tana River are among the most affected counties by floods as detailed in needs assessments conducted in the two counties by the Flood Command Centre managed by the National Disaster Operations Centre (NDOC) as of November 23, 2023.
