Assessing the sustainability of local resilience practices against sea level rise impacts on the lower Niger delta

Response strategies determine the resilience of an area to effects of sea level rise. Strategies that are sustainable are those that do not negatively affect the environment, biodiversity and community life of the people. The paper discusses response strategies practiced in the Niger delta to combat effects of sea level rise like: flooding, erosion, inundation, storm surge, and intrusion of sea salt. Local responses to these natural hazards and the degree of effectiveness of the methods in enabling the people return to their normal lives are reviewed for their suitability as future adaptation strategies. GIS and remote sensing analysis of slope and topography show the Niger delta is vulnerable to further flooding, inundation, and erosion as a result of sea level rise. Based on a 'business as usual' scenario, the GIS based bathtub approach is used to calculate and map possible inundation extents for the Niger delta under sea level rise conditions. As the Niger delta is subsiding due to oil and gas exploitation, relative sea level rise (RSLR) values for the Niger delta are obtained by adding measured subsidence values (7 mm and 25 mm) to predicted eustatic sea level rise values (19 mm by 2030 and 35 mm by 2050); resulting in RSLR of 0.14 0.96 m by 2030 and 2050. With subsidence at 7 mm/year and a RSLR of 0.14 m, results for 2030 shows an inundation extent of 11193 km(2) which is 4.6% of the total surface area; subsidence of 25 mm/year (SLR = 0.44 m) gives an inundation extent of 1254.0 km(2) which is 5.2% of the surface area. Results for 2050 show that a rise of 0.29 rn (subsidence = 7 mm/year) will cause an inundation extent of 1175.9 km(2) which is 4.9% of the total surface area, and RSLR of 0.96 m (subsidence = 25 mm/year) inundates 1633.0 km(2) which is 6.8% of the surface area. Although the literature shows local practices have helped people to cope with the challenges posed by flooding, erosion, inundation, and inland intrusion of sea salts, however some of the practices have disadvantages that make them undesirable for inclusion in future planning. Sustainable local practices in the Niger delta include: planting of Bamboo trees for erosion control, use of sandbags as bridges and dikes (flood control), use of flood receptor pits as temporary flood water reservoirs, and community legislation against sand mining and indiscriminate tree felling. Further studies on the limitations of the local resilience practices in the Niger delta is recommended. (C) 2016 Elsevier Ltd. All rights reserved.