With a geographical size of 3,577 square kilometres, Lagos State is one of the smallest states in Nigeria, representing 0.4% of the entire geographical area Nigeria. Lagos State is located on the South-Western part of Nigeria on the narrow Coastal flood plain of the Bight of Benin.
Lagos State has an area of 356,861hectares, out of which 75,755 hectares are wetlands with the dominant vegetation of tropical swamp forest, comprising fresh waters and mangrove swamp forests. It shares a double rainfall pattern, with two climatic seasons – Dry (November-March) and wet (April-October). The drainage system of the State is characterized by a maze of Lagoons and waterways which constitute about 22% or 787 sq. km of the State total landmass.
The state has the highest population in the country, with over five percent 5% of the national estimate. The 1991 National Census figures put the population of the State at 5,725,116, out of a national estimate of 88,992,220. The UN Habitat Study and the UNDP assisted state Regional Master Plan estimated Lagos State population in year 2000 at 13.4million and over 15 million inhabitants in 2004.
The recent UN study (1999) expected the City of Lagos to hit the 20million population flux in Year 2010, thus progressively reaching 24.5million population in year 2015, at which time Lagos will be the third most populous city in the world. Thus Lagos population is growing ten times faster than New York and Los Angeles, with grave implication for urban sustainability.
The major water bodies in the state are the Lagos and Lekki Lagoons, Yewa and Ogun Rivers. The raw water supply is obtained by the Lagos Water Corporation (LWC) mainly from two rivers, the Iju and the Owo (170,000 and 265,000 m3 per day respectively).
The location of the state within the coastline implies that it is vulnerable to climate change, while its high urban population implies that provision of potable drinking water by the state’s water utility- the Lagos Water Corporation will be a major challenge.
The Lagos Water Corporation is in charge of supplying drinking water services to all parts of urban and semi urban areas of the state. However, the size and growth rate of Lagos means that needs are growing very rapidly.
The LWC currently has an installed water supply capacity of 160 million gallons per day (MGD) (712.9 million litres per day (MLD)), but ageing supply lines, water works and poor public electricity hamper the services of the corporation, hence it is operating at only 48% capacity, or only 36% of water demand. It supplies water to about 60% of the population. Only about 4million of the state’s 15million population have access to piped water.
The general shortage of water supply that is a result of this low capacity utilisation is then met by privately operated tankers, porters and privately owned boreholes and wells. This in turn has its own issues with regards to water purity standards, higher delivery costs and the ultimate impact on the state’s water levels from the improper tapping of ground water reserves and wastage in its collection and delivery.
The LWC believes that between 2000 and 2025 demand for potable water will grow from 200 to 1,200 million gallons per day (MGD), capital investment of US$100 million per annum will be required in order to reach 80% coverage.
Water is involved in all components of the climate system (atmosphere, hydrosphere, cryosphere, land surface and biosphere). Therefore, climate change affects water through a number of mechanisms. Water supply services are highly vulnerable to drought, extreme precipitation, and sea level rise.
Nigeria is likely to experience an increase in global warming from 1.4 °C to 5.8°C over the period 1990 to 2100. This national increase in atmospheric temperature and an increase in surface water temperature may also cause a decreased flows in Ogun/Osun River Basins caused by longer and more frequent dry seasons; and a reduction in dissolved oxygen content, mixing patterns, and self purification capacity and increase in algal blooms respectively Ogun/Osun River Basins. The Lagos Water Corporation sources it’s raw from these basins.
The changing climate is likely to exacerbate water management problems in Lagos generally through rising sea levels in the costliness, variable rainfall and extreme events like floods. Increase in inter annual Precipitation variability will evidently increase the difficulty of flood control and reservoir utilization during the flooding season.
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