Spatio-temporal analysis of wetland change in Port Harcourt Metropolis

Abstract

The study assessed changes of wetland in Port Harcourt Metropolis using geo-information techniques between 1984 and 2015. Landsat images of 1984, 2000 and 2015 of 30m x 30m resolution were used. Supervised classification was used for image classification using Maximum Likelihood Algorithm in Erdas Imagine 9.1 whereby five major landuse classes were identified namely thick vegetation, built up area, farmland/sparse vegetation, wetlands and waterbodies. Areas in squared kilometers of each landuse were calculated in ArcGIS 9.3 and simple arithmetic was used to compute the percentage change. Probability of landuse change in the next 10, 20 and 30 years was determined in Idrisi Selva 17.0 using Markovian Transition Estimator. Descriptive statistics were employed for data analysis. Finding shows that wetlands decreased from 150.17km²  to 42.70km²  (-87.5%) between 1984 and 2015. Thick vegetation and waterbodies decreased by 35.6% and 41.48% respectively while built up area increased from 81.63km²  to 205.89km²  between 1984 and 2015. Wetland had 13.51%, 23.75% and 32.88% chance of changing to built up area in the next 10, 20 and 30 years respectively. The study recommended that farming and construction activities diminishing the wetland should be carefully done.

Keywords:  Geo-information, Landsat Imagery, Landuse, Farming, Construction