Ibadan is the third largest metropolitan area in Nigeria after Lagos and Kano. With a population of 3.1 million and a land area of 3,850 square kilometers (2013), Ibadan city is the largest metropolitan geographical area in West Africa, housing almost half of Oyo state’s population (45 percent). From around 60,000 in the early 1800s Ibadan’s population grew to 200,000 in 1890, and to a million by 1930, the population is projected to reach 5.6 million by 2033. The city’s urban footprint also grew considerably to its current extent of more than 3,850 square kilometers. This sprawl is primarily due to weak land use planning practices, leading to low population densities (800 people per square kilometer) especially when compared to other large cities (with densities reaching 30,000 to 40,000 people per square kilometer). This sprawl increases the cost of infrastructure development and operations, and maintenance, reduces the urban efficiency and potential quality of life, and accelerates the loss of agriculture lands.
The city of Ibadan has 11 Local Government Areas:
- Ibadan North
- Ibadan North East
- Ibadan North West
- Ibadan South East
- Ibadan South West
The rapid urban growth in Ibadan has led to both positive and negative externalities. On the positive side, this growth attracted diverse industries, improved access to technologies, developed the socio-cultural infrastructure of the city, improved health standards, increased literacy and education rates, and boosted entrepreneurship, creativity, investments and wealth generation. On the negative side, this rapid growth weakened the prospect of good governance and effectiveness of government policies mostly visible in (i) the proliferation of slums; (ii) increased health hazards due to poor solid waste and wastewater management, resulting for example in the 2013 cholera break-outs in parts of the city; (iii) deteriorated air quality due to energy over consumption; and (iv) the unplanned expansion of the city into high risk areas such as wetlands and flood plains.
Ibadan is highly exposed to frequent flooding. The city has been experiencing an increasing number of flood events during the last 50 years (16 major events recorded). The most recent floods of August 26, 2011 caused significant human and economic losses in the city, primarily in the housing, education, agriculture and transport sectors. Settlements located in unstable and risky locations such as along Ogunpa, Kudeti, Ogbere and Orogun floodplains and the hillsides of Oke-Are, Oke-Aremo, Sapati and Mokola were seriously affected with over 120 fatalities reported. Land use within the city is primarily residential and a majority of Ibadan’s urban poor live in crowded slums within the core residential areas of Ayeye, Agbeni, and Bere and are at increased risk from flood events due to their location in low lying areas. Ibadan city setting is characterized by rugged terrain with wide valley plains. The city is drained by three North-South flowing river systems, namely, Ona River (Western), Ogunpa River (Central) and Ogbere River (Eastern) that flow through the city. These rivers are main drainage channels that cause flooding when not properly regulated. The network of rivers and streams is extensive throughout the city as a result of a combination of the geology of the area and the tropical monsoon climate.
The flood event of August 26, 2011 took place after a downpour rainfall of 187.5 mm (about 7.38”) that occurred in about 4-5 hours accentuated by the overflow from Eleyele reservoir causing the death of more than 120 people and serious damages to infrastructure (many bridges collapsed, roads washed away, and substantial property losses).