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In most studies on flood risk in Nigeria, priority is given to urban flood risk than rural flood risk. Smallholder farmers who mostly inhabit rural areas and flood plains are known to be at great risk of flooding, but to date, there have been no studies on the impacts they experience and how they cope with these impacts.
To establish the existence of significant change in precipitation in the study area, statistical analysis of precipitation data was conducted using linear regression and non-parametric Mann Kendall test. Landsat satellite images for 1986, 2003 and 2016 were obtained from the United States Geological Survey’s (USGS) website and used to collect and analyze data related to land use.
To determine flood risk in the context of land use change, the HEC-HMS model version 3.5 was used. Land use maps corresponding to 1986, 2003, and 2016 LULC conditions were analysed and prepared for the calculation of CN values using Soil Conservation Service (SCS-CN) method. CN map was prepared by integrating the maps of hydrologic soil groups and land use in ArcGIS software.
Based on selected morphological parameters, a flood risk map was developed for the study area. The morphologic flood risk showed that most parts of the basin face moderate flood risk. Higher runoff values were observed under 2016 LULC conditions mainly due to intense deforestation relative to those of 1986 and 2003. The results indicated that runoff and peak discharge are significantly affected by deforestation instead of changes in the rainfall pattern. Flood inundation maps of the study area were prepared for the flood events of 2012 and 2015. Maximum depth for the 2012 and 2015 flood events was calculated as 10.58m and 7.39m, respectively.
The socioeconomic aspects of the research were conducted using household survey method. Using snowball sampling techniques, 400 flood-affected households were selected. The results show that the adaptive capacity of smallholder farmers in the study area remains very low and hampered by several factors such as poverty and weakened social networks. The synopsis of the examined variables leads to the following conclusion: Instead of climatic factors – as one indicator of vulnerability – it is social inequality and poverty in the region as well as the structural economic differences between various groups that mainly drives vulnerability in the study area.
The existence of large deposit of crude oil in the Nigerian Niger-Delta accords the region a strategic position in the country’s economy. However, activities associated with the oil and gas industry have resulted in extensive and in some instances indelible damages on the ecosystems. The destructive effect of hydrocarbon on bionetwork necessitated this study that aimed at evaluating the potential of adopting microbial and biosurfactant technology as tools for bioremediation. The research involved gas chromatography monitoring of hydrocarbon degradation in polluted soil, microbiological/molecular identification of hydrocarbon degraders and the evaluation of biosurfactant production by indigenous bacteria. The performance of four treatments involving; co-treatment with mixed bacterial consortium and close-to-nature surfactants (Bioversal QF and Bioversal UK), treatments with mixed bacteria culture, single bacteria culture and treatment with close-to-nature surfactants only were evaluated for the mineralization of hydrocarbons contained in 500g of 2% crude oil contaminated soil supplemented with Na2HPO4*2H2O, KH2PO4 and NH4Cl as nutrient sources over a period of 20 weeks. Six indigenous biosurfactant producing and/or hydrocarbon degrading bacteria strains were isolated namely: Pseudomonas aeruginosa, Bacillus sp, Achromobacter sp, Stenotrophonas sp, Lysinibacillus sp. and Delftia sp. Molecular characterization of sequenced polymerase chain reaction products of these cultured bacteria using Nucleotide Basic Local Alignment Search Tool confirmed close relationships ranging from 98.83% to 100% with those on the NCBI databank. Co-treatment with mixed bacteria culture and Bioversal UK/Bioversal QF yielded synergetic impact that enhanced 73.35% and 71.52% degradation of total petroleum hydrocarbon respectively. Treatments with close-to-nature surfactants and with mix bacterial culture recorded 53.61% and 54.58%. The use of single bacteria strains resulted in the mineralization of 46% - 62.26% total petroleum hydrocarbon while their use as a consortium yielded 54%. Liquid chromatography-Mass spectrometry assessment of extracellular polymeric substances produced by cultured bacteria strains indicated the presence of rhamnolipids (L-rhamnosyl-3-hydroxydecanoyl-3-hydroxydecanoic acid with a mass of 504.654 Da) and lipopeptides (2-(Hydroxymethyl) phenyl 6-O-palmitoyl-β-D-glucopyranoside with a mass of 524.687 Da). Extracellular polymeric substances produced yielded emulsion index ranging from 70.70% to 75% and 39% to 65% with crude oil and heptane respectively. EPS yields ranging from 1.34 g/ml to 1.5 g/ml were recorded.
This study closely examined how oil exploration has caused environmental degradation and untold hardship to the local communities in the Niger Delta region of Nigeria. Nigeria is known to be the sixth largest producer of crude oil among the Organization of Petroleum Exporting Countries (OPEC), and thelargest in the African continent. The crude oil that puts Nigeria in this position is being produced in the Niger Delta region of the country. Nigeria’s economy is based on crude oil exports. Despite this enormous wealth coming from the Niger Delta, there is pervasive poverty and despicable environmental damage as a result of crude oil mining activities going on in this region. Suffice it to say that, there is total neglect of the region in terms of infrastructural development and economic empowerment of its local populace by the government and oil companies operating in the region. This has led to youth restiveness and hostage taking in the area. A sound methodological research approach was developed and utilized in this study. Both primary and secondary data were collected from questionnaires, structured interviews, personal observations, relevant literature, documentation from government agencies and oil companies. These data were analyzed, and they synthesized the discussions contained in this study. This study is all about charting a new course in the way the oil companies operating in the Niger Delta region carry out their activities in order to ensure the environmental sustainability of the region, and improve the economy of the rural communities in the region at the same time. It identifies the constraints to effective implementation of Nigeria’s environmental laws and policies especially the Environmental Impact Assessment (EIA) as it concerns oil prospecting, which has hitherto contributed in hindering her environmental sustainability. It also unveils the critical issues concerning the deplorable state of the economy of the local populace of the region. After identifying the various problems contributing to the environmental woes, and the poor economic growth of the region, this research proffers recommendations that should be conscientiously and vigorously implemented to reverse the trend. Although, the oil companies have made some efforts towards providing the necessary infrastructures needed in the region, they need to do more in the area of capacity building, and use of green technologies to ensure healthy environment of their host communities. The government on her part should strengthen the various Ministries and Agencies vested with the responsibility of protecting the Nigerian environment, by providing them with the necessary incentives for maximum efficiency. This study therefore emphasizes a concerted approach from all the stakeholders in the Niger Delta region for the successful implementation of the recommendations herein to ensure the sustainable development of the region, and Nigeria in general.