When dry land is submerged by overflowing water is called Flood and intense floods, ultimately result in increased flood risk as was witnessed a few days ago at Lugbe Abuja plus a common experience in many parts of the country.
According to FEMA (Federal Emergency Management Agency-USA), “Floods have been occurring throughout Earth’s history and will continue as long as the water cycle continues to run.
Overall, the water cycle is a balanced system. Sometimes the amount of water flowing into one area is greater than the capacity of the system to hold it within natural confines. The result is a flood.”
Usually, major flooding happens as a result of one or a combination of land use changes (unplanned retention and removal of wetlands}, inadequate flood controls, changes in the waterway course, and environmental impacts (climate change- increased rainfall and sea level rise).
In reference to the recent impact on Trademore Estate Lugbe and other Estates (e.g. Clobek Estate, Wisdom Estate, etc) in the neighbourhood, obvious that the flood control systems failed after being overwhelmed by environmental changes and the failure of drainage infrastructures. A review of the estate management reports, one can observe that several short-term solutions were put in place based on various investigations and recommendations without consideration for the impact of future development and reclamation activities in the neighbourhood.
FCT Abuja needs to recognise the rapid development in the area and aggressively provide the necessary infrastructures to support and protect residential and commercial properties, and private and public assets.
Recommendations/Suggestions.
FCT Abuja to review the entire Lugbe District area and immediately engage technical experts to
- Investigate the root cause of the flood, particularly with respect to all contributing factors and sources of the floods. The team to conduct Watershed Studies, develop an erosion control and stormwater management evaluation, and generate a contract execution scope of work with a 5 years storm (Assuming one big storm every 5 years) for FCT Abuja to use in advertising to competent technical bidders.
- Technical contractor to design and construct the scope of work described in item #1 above that take into consideration the entire Lugbe district area. The deliverable on completion of the construction scope should include a “Lugbe stormwater management plan”, Standard operating procedure, maintenance management plan, and emergency response plan.
The construction scope should consider and include but not limited to the: –
- Design, sizing, and sloping of the drainage channels to accommodate 150% of the largest volume of determined flow
- Areas with natural pathways of flow and adequate retaining walls to aid diversion to constructed channels
- Levees, floodplain, Stream crossings (bridges, culverts)
- Project to consider maintaining the hydrologic cycle
- Impact of the existing Dam at Aleita during low and high rise
- Future development within Lugbe and connection to the surrounding neighbourhood
- Dredging activities of the canals within the Lugbe area and their impact
- FCT Abuja to ensure all new development have in the EIA (Environmental Impact Assessment) scope, assessment, and mitigation plan for stormwater as a result of the new development. New development MUST tie into the planned Lugbe stormwater drainage system. Developers’ responsibilities must include in their EIA Report submission, the design for a tie into the nearest FCT constructed channels
- The new FCT Minister should as a matter of priority develop and implement an Integrated stormwater management system to ensure all areas of FCT beyond Lugbe with the potential of stormwater flooding are covered. Engage technical experts to evaluate, design and construct appropriate stormwater projects and management plans.
- FCT minister to ensure updates in the requirements for new development with respect to stormwater management is included with FCT and developers’ responsibilities
- FCT Minister to ensure the existing master plan which is over 10 years since last released, should be reviewed and updated with appropriate urbanisation requirements, high-rise residential with higher density based on the reality of business and population growth.
This submission is from Nigeria Engineer based in Rwanda – Engr Hammony Kun, CEO WAP