Importance of effective drainage systems (2)

In the last few weeks, as it is during the rainy season, Lagos was completely flooded, causing untold damage and inconvenience to millions of its residents. There was the usual lamentation from citizens about lack of government care and neglect that makes them suffer during this period. Government responded with the usual platitudes about all they are doing to ensure floods are contained in the future.

So what actually is ‘flood’ or ‘flooding’?  The immediate answer is one described as a temporary condition when surface water (sea, river, canals, lake) overflows its banks and confines to flood surrounding areas, or a situation where there is heavy accumulation of water, usually rain water, and there are not enough and adequate drainage systems to ensure discharge of such water.

Lagos represents all of these factors. As we know, Lagos is below sea level and so as a natural factor will almost always be prone to flooding when there are heavy rains.  On the other hand, it is also a fact that there are inadequate drainage systems to deal with the problem and the heavy nature of the rainy season.  This is further compounded by the day to day habits of its inhabitants – indiscriminate throwing of garbage on the streets and the peculiar nature of using drains and gutters as refuse bins during the dry season.

Lagos continues to be characterized by poor waste management systems which expectedly lead to a situation where, for weeks in a year, floods take over the city, causing untold misery to individuals and costing businesses billions of naira revenue. There’s also the damage done to our collective emotional and mental stability.

While drainage and focusing on longer term solutions remain the responsibility of government at both local and state levels, there are still ways in which habits can be changed to reduce flood and mitigate the impact of floods in our lives and businesses. One of which ways is to have a long term forecasting and planning approach to flood management.

How can information and knowledge about the area using reliable weather forecasting, water levels be used when planning for houses and businesses in those areas?  A good facilities management system will be required in the planning and designing of built environment to review what is needed to manage floods. This will include an analysis and inventory of all structural and non-structural measures needed to prevent, control and reduce floods and also provide a risk assessment of how human activities in the areas can lead to floods. Identifying inadequacies in the drainage systems and all other structures will be useful in providing short to long term preventive measures.

A facilities management plan will also include drainage maintenance, especially for businesses. This will focus on the prioritization of the individual drainage systems of each location, how frequently each will require maintenance and establish a risk assessment record that documents incidents of drainage issues, the causes including how rainfall affects the drainage, estimate damage done or projection of damage based on the analysis and frequency of such incidents.

The engagement of people is also critical to managing floods and keeping drainage flowing.  This can be done by training individuals to manage waste better, installing systems to enable the harvesting of rain water for other uses, for example gardening, putting in place landscaping that absorbs water in areas prone to flooding, ensuring that all buildings have adequate drainage systems, and that all users have understanding of management and effective reporting systems.

Tunde Obileye