Compared to coastal areas, river deltas which are located in coastal zone, have complex morphologies, because river waters and sediments are transported through the deltas into the sea. A delta can have many elements included, such as barrier islands, multiple estuaries, sand beaches, or mud coasts. It can be crisscrossed by rivers emanating from different sources and carrying different types of sediments; which differentiate the segments of the coast. Generally, deltas are fertile and highly productive, attracting agricultural activities and trade and thus densely populated. The physical properties of deltas and anthropogenic activities make them vulnerable to the effects of the changing climate; however when evaluation of vulnerabilities is important many coastal deltas lack even the most basic necessary data (e.g water level) for performing such a task. Data availability is one of the most important factors for analysis, assessment and modeling of physical and other phenomena related to river and coastal systems. Although lower Niger delta is classified as one of the deltas of the world vulnerable to the effects of climate change, it has little availability of data for hydrologic and hydraulic modeling. Present paper will show how to model the possible effect of a rise in sea levels on the lower Niger delta, by dividing its coastline into 54 segments based on slope, elevation and presence of large estuaries. The segments are analyzed for vulnerability to flooding, erosion and inundation. The parts identified as the most vulnerable are modeled using Deltares' DFlow modelling methodology, using a flexible mesh for discretization of the modeled area. Satellite derived DEM is used to calculate an upstream rating curve for the Bonny River, and to provide topographic data. Sea level rise is represented by changes in the tidal level to reflect IPCC predictions of sea levels by 2050 and 2100. The results are analyzed for flooding and inundation, increase in land loss, water depth and flood extent as compared with no sea level rise scenarios. Also, dry and wet land losses are mapped and quantified within a GIS environment.@en

Accelerated sea level rise (SLR) is the most important climate change impact for coastal areas. However many coastal deltas lack necessary data for evaluation of the vulnerabilities. The Niger delta is one of the coastal areas with little data for coastal planning and management. Use of satellite data helps bridge the data gap by providing ancillary data - imagery, elevation, altimetry etc. This thesis therefore uses satellite data as the main sources of data for hydrodynamic modelling and GIS analysis to assess the impact of SLR on the Niger delta land area, coastline, and surface water. The thesis results show that because of high subsidence levels, a rise in sea levels of 0.14m already inundates Niger delta areas. Consequently, 4.6–5.2% (1119.3–1254km2) of the Niger delta land area can be lost to inundation by 2030, and 4.9–6.8% (1175.9–1633km2) by 2050. From the thesis, major mitigation/adaptation measures that can be used for the Niger delta include:dykes, by–pass channels, storm surge barriers, coastline shortening and legislation to ensure compliance by all. Furthermore, some of the existing sustainable local practices in the Niger delta should be included in SLR mitigation/adaptation planning. Such practices include: planting of Bamboo trees for erosion control, use of sandbags as bridges and dykes (flood control), and use of flood receptor pits as temporary flood water reservoirs. @en

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 1119.3 km2 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 km2 which is 5.2% of the surface area. Results for 2050 show that a rise of 0.29 m (subsidence = 7 mm/year) will cause an inundation extent of 1175.9 km2 which is 4.9% of the total surface area, and RSLR of 0.96 m (subsidence = 25 mm/year) inundates 1633.0 km2 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.@en

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 1119.3 km2 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 km2 which is 5.2% of the surface area. Results for 2050 show that a rise of 0.29 m (subsidence = 7 mm/year) will cause an inundation extent of 1175.9 km2 which is 4.9% of the total surface area, and RSLR of 0.96 m (subsidence = 25 mm/year) inundates 1633.0 km2 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.@en

Hydrological data collection requires deployment of physical infrastructure like rain gauges, water level gauges, as well as use of expensive equipment like echo sounders. Many countries around the world have recorded a decrease in deployment of physical infrastructure for hydrological measurements; developing countries especially have less of this infrastructure and, where it exists, it is poorly maintained. Satellite remote sensing can bridge this gap, and has been applied by hydrologists over the years, with the earliest applications in water body and flood mapping. With the availability of more optical satellites with relatively low temporal resolutions globally, satellite data are commonly used for mapping of water bodies, testing of inundation models, precipitation monitoring, and mapping of flood extent. Use of satellite data to estimate hydrological parameters continues to increase due to use of better sensors, improvement in knowledge of and utilization of satellite data, and expansion of research topics. A review of applications of satellite remote sensing in surface water modelling, mapping and parameter estimation is presented, and its limitations for surface water applications are also discussed.@en