Hydrological failure in culverts at coca-cola and Ajegunle-egbejila roads in Ilorin, Kwara State was investigated. Reconnaissance Survey and questionnaire methods were used to carry out the investigations. Questionnaires were administered to the residents in the affected areas where the failure of culverts occurred. Oral interview was also used to acquire information on likely causes of culvert failure from the site engineers and other qualified engineers. Rainfall data was also collected from Nigeria Meteorological Agency Ilorin, Kwara state over a period of ten years. Outcome of the investigation revealed that most failure in culverts occur as a result of blockage by accumulated debris, inadequate flow capacity and erosion of embankment. This situation often leads to lead to loss of life and properties, damage crops, and great danger to motorists and other road users. To avoid failure in culverts, it was recommended that adequate designed measures should be ensured before construction and up-stream and down-stream of culvert should permit equal discharge of flow of water.
Key words: Hydrological failure, Culvert, Reconnaissance Survey, Flood