Case Study of Groundwater Control in a Power Plant in a Marginal land in the Niger Delta

Abstract

The paper describes challenges posed by rising groundwater level in a construction site, apriori sandfilled, with installations that are sensitive to the presence of water. The geotechnical investigations, leading up to the design of a network of shallow abstraction well points are described. The permeability of the soil, which was shown to be the single most important parameter, was insensitive to the method of determinations (whether by in-situ or by empirical computations). By combining information on the radius of influence of the pumped well and the drawdown at the well point a network of dewatering wells were designed and constructed. The selection and operation of suitable pumps in these wells ensured that ground water level was maintained below the threshold level across the site, throughout the period of construction. The operation of pumps has ensured effective and satisfactory operation of the power plant more than 10 years after commissioning.