Nigeria’s Response to the Impacts of Climate Change: Developing Resilient and Ethical Adaptation Options

Global climate change will have a strong impact on Nigeria, particularly on agricultural production and associated livelihoods. Although there is a growing scientific consensus about the impact of climate change, efforts so far in Nigeria to deal with these impacts are still rudimentary and not properly coordinated. There is little evidence of any pragmatic approach towards tracking climate change in order to develop an evidence base on which to formulate national adaptation strategies. Although Nigeria is not alone in this regard, the paper asserts that National Climate Change Adaptation Strategy could help address this situation by guiding the integration of climate change adaptation into government policies, strategies, and programs, with particular focus on the most vulnerable groups and the agricultural sectors. There is an urgent need to adopt abatement strategies that will provide economic incentives to reduce the risk from disasters, such as developing agricultural practices that are more resilient to a changing climate.     

Assessment of Ground Water Vulnerability and its Application to the Development of Protection Strategy for the Water Supply Aquifer in Owerri, Southeastern Nigeria

Pollution vulnerability of theOwerri regional water supply aquifer wasevaluated as a basis for developing appropriateprotection strategy for the groundwaterresource. The assessment was accomplished usingLegrand, GOD, Siga and DRASTIC models.Techniques of the models generally involvedparameters rating and point count systems, whichare based on the evaluation of various parameterin relation to their capacity for enhancing orattenuating contaminants in the groundwatersystem. Field and laboratory evaluations of theparameters indicate that the Owerri areagenerally occupies a nearly, flat topographywith a relatively high groundwater recharge. Thearea is underlain by predominantly sandyfacies in the Northern area which grades intogravelly sequences towards the southwest. TheSoutheastern area is distinguished by thickclayey facies that thin westwards towards theOwerri metropolis. Effective hydraulicconductivity (Kz) in the downward directionranges from 1.44 × 10^-3 to 5.6 × 10^-9 m s^-1; with the upper limits reflecting coarsesands and gravelly units. The amount of clay andclay-size particles in the sandy and gravellyunits is negligible, suggesting that thesorptive capacity of the units is low. Depth towater table decreases southwards while hydraulichead gradients vary between 0.09 and 0.22.Groundwater occurs in unconfined conditions inmost places except in the southeastern zonewhere it is semi-confined due to the presence ofa clayey unit. The groundwater vulnerabilitymap developed on the basis of the models andseveral other thematic maps shows that theOwerri metropolis and the southwest area ofOwerri have high vulnerability, indicatinggroundwater pollution. The existing wastedisposal sites in these sub-areas should beabandoned and rehabilitated to forstall furtherpollution of the groundwater system. Areas tothe North and Southeast of Owerri have moderateand low vulnerabilities, respectively,indicating the relatively lower sensitivity ofthe groundwater system in the sub-areas tocontamination. The lower sensitivity couldfurther be matched with properly engineeredsanitary landfills in the event of choice ofsites, as an additional protective strategy forthe groundwater system.     

基于Verhulst模型的新建隧道顶板下沉预测研究

隧道顶板下沉量预测对隧道安全施工十分重要.通过分析隧道下沉过程,指出其具有"S"型曲线特征,探讨了采用Verhulst模型进行隧道顶板下沉预测的适用性和可行性,并运用MATLAB软件开发相关程序,模拟遵赤高速公路中枢隧道YK39+134.6断面沉降过程,获得相应的预测方程.通过对比其预测结果、回归分析预测结果和实测值,发现该模型的顶板沉降预测值与实测值最接近,证实运用灰色Verhulst模型预测隧道顶板沉降量是合理、可行的.