Towards a Geo-Classification of the Niger Delta for Highway Investment Costing Applications

Alolote Ibim Amadi; Amadi Kelvin Chijioke

Abstract

The study carries out a quasi-experimentation, as a basis of devising a spatial quantitative concept, delineating distinct geologic settings which would have differing cost implications for highway infrastructure development in the Niger Delta region of Nigeria. Three broad conceptual geomorphic boundaries, for the categorisation of Niger Delta soils in engineering geologic costing application, were discerned within this conceptual lens. The study further statistically explores the synthesised geo-zonation for differences in final project costs recorded on a sample of 61 completed highway projects. Using the One-way Analysis of Variance test with a further Turkey-Kramer Multiple comparison, significant differences and hierarchy in final project costs across the geo-zones were reported. The findings show that highway projects executed in the middle delta, which is predominantly composed of fresh/salt water back swamps, recorded the highest final costs. This is followed by projects located in the lower delta, which is characterised by salt water swamps and sandy coastal soils. The lowest range of project costs were evidenced in the upper deltaic zone, where dry lands are interwoven with patches of fresh water soils. The study attributes the cost disparity in final project costs between the geo-zones to the relative differences in the prevalence of highly expansive dark clayey peaty soils (chikoko clays), which require expensive specification, designs and specialized construction methods. The level of cost disparity induced by the geomorphic sub-environments of the Niger Delta, makes a case for adequate preliminary investment planning of highway projects to account for the environmental configuration of the region.Keywords: Cost,geo-zonation, highway projects, investment, Niger delta, planning; soilsCite this ArticleAloloteIbimAmadi, Amadi Kelvin Chijioke.Towards a Geo-Classification of the Niger Delta for Highway Investment Costing Applications. Trends in Transport Engineering and Applications. 2020; 7(1): 24–40p.