Water Bodies Protection Index for assessing the sustainability status of lakes under the influence of urbanization: a case study of south Chennai, India

摘要

Vulnerability of water resources to degradation is one of the critical issues facing developing countries. Changes in population and land use associated with urbanization may alter social interdependence of water bodies in the vicinity of urban and periurban areas thereby affecting their sustainability. Preservation and proper management of lakes are urgently needed to ensure that these freshwater ecosystems continue to deliver their services to the people in the changing scenarios resulting from urbanization. In this paper, we make use of indicators, a powerful tool in decision making, and propose Water Bodies Protection Index (WBPI), which can serve as monitoring cum ranking tool to prioritize conservation efforts for periurban water bodies. Water quality, biological diversity, encroachment of the lakes, role played by the local community in lake management and preservation, and implementation of existing Acts for protection of water resources by government agencies are the five factors chosen for formulating this index. The data and information for this were obtained through socio-ecological study of six water bodies situated in the urban to rural gradient at the southern fringe of Chennai city in south India. Weightages were assigned to the above factors based on a Delphi study. A simple aggregation of weighted factors yields the index that classifies the protection status from poor (＜2.5) to sustainable (＞9). Application of the WBPI to the study lakes and comparing it with an urbanization index from the literature for the locations of the study lakes provided satisfactory classification and correlation, respectively. The WBPI is expected to help assess many such water bodies elsewhere to set targets for their revival and preservation.