Geomorphological and ecological implications of river restoration approaches in Sri Lanka

Abstract

River restoration is defined as the establishment of improved hydrologic, geomorphic and ecological processes in a degraded watershed system, returning its lost, damaged or compromised biotic, structural and functional elements to the pre-disturbance and self-regulating state. Due to the rapid urbanization and fast growth of the population and industries in Sri Lanka, most of the water bodies have been affected and continuously degraded due to direct or indirect impacts of anthropogenic interventions. At present, there exists no proper approach to monitor ongoing river degradation nor to recognize in advance, the possible extent and degrees of potential degradation in river systems, in order to implement policies and other preventive measures timely and proactively to arrest further adverse impacts. Therefore, a river classification or grading system to recognize the present level of degradation is deemed extremely useful to inventory over large regions and provide a geomorphologically stratified framework for more detailed observations. The present study was thus focused on recognizing the causes and implications of river degradation with respect to geomorphological and ecological aspects in several selected major basins in Sri Lanka.