The Teesta was flowing 13 centimetres above its danger level at the Dalia point in Dimla, Nilphamari, on the morning of 5 August.
The water level was measured at 52.28 metres at 9am, while the danger mark at the gauge is 52.15 metres.
The same level was recorded at 6am.
Water Development Board Executive Engineer Amitabh Chowdhury said the river had been above the danger level from 6am and could fall during the night.
Chowdhury attributed the rise to persistent heavy rain and upstream inflow.
Water began entering low-lying areas of Purba Chhatnai, Khagakharibari, Tepakharibari, Khalisha Chapani, Jhunagach Chapani and Goyabari unions in Dimla.
Low-lying areas of Golmunda, Dowabari and Shaulmari unions in Jaldhaka were also affected by incoming water.
Tepakharibari Union Parishad Chair Rabiu lslam Shahin said rising Teesta water had started entering low-lying areas.
The evidence does not establish any damage, evacuations, casualties or a formal emergency response.