Participatory multi-criteria evaluation of alternative options for water supply in a cyclone prone area

Abstract

The availability of fresh and safe drinking water is considered to be the most critical issue in the coastal region. The sources of drinking water have been mainly groundwater, which has limitations in that in many places groundwater has high salt concentrations at shallow depths and have high Arsenic and iron concentrations. Extraction of water from deeper aquifers also has the risk of aquifers being mined or becoming infiltrated with salt or arsenic contaminated water. On top of these, the cyclonic storm surge is a major threat to the water supply system in the coastal area. The present study was an attempt to delineate the present status of drinking water supply in a coastal area, assess feasibility of different water supply options, and evaluate the options through multi-criteria analysis. Four villages of two Upazilas of Barguna district, located in the exposed area of coastal area, were chosen as the study area. A participatory multi-criteria approach, adapted from Social Multi-Criteria Evaluation (SMCE) framework of Munda (1995) for combining participatory and scientific approaches, was used to evaluate alternative water supply options. It involved definition and characterization of the proposed problem through literature review, and in-depth unstructured interviews and group discussion, exploration of options for the case study and the definition of a set of criteria facilitated by ensuring stakeholder involvement through questionnaire survey, analysis of the feasibility of the options in the contexts of technical, social and environmental aspects, performing multi-criteria analysis (i.e. developing the impact matrix and ranking the options) using a outranking method, the NAIADE model, performing another multi-criteria evaluation based on an equity matrix (analyzes the value judgments of the stakeholders involved in the evaluation process for each option) through a stakeholders’ workshop, and finally sharing the outcome with the stakeholders in the workshop and clarifying the information obtained from the stakeholders. Five different water supply options are available in the study area, viz. manually operated deep tube wells (DTW), manually operated shallow tube wells (STW), pond sand filter (PSF), rainwater harvesting system (RWHS) and natural ponds. The important criteria for the ranking of the options were implementation cost, operation cost, impact on other uses, water availability, environmental impact, social acceptance, water quality and resilience to storm surge. Multi-criteria analysis of the options gave a ranking in which RWHS was ranked first followed by followed by Pond Sand Filter in the second position. DTWs, STWs and Pond were ranked third, fourth and fifth, respectively. Five equity issues came up from the local communities, which are: (i) distribution of maintenance cost among the users, (ii) Access to water points, (iii) Gender equity, (iv) discrimination of rich and poor in decision making and (v) influence free site selection (i.e. free from influence of powerful groups) of the facility. The ranking obtained by multi-criteria evaluation of the equity matrix is in the order: RWHS, PSF, DTW, STW and Pond. The ranking obtained from the exercise can be used by the planners and decision makers who are interested to make any interventions in the area. As the RWHS and PSF got high scores in both the impact and equity matrix evaluations it can be said that these two options have a good acceptance in the community and they are technically feasible. For the installation of other three options, technical feasibility (i.e. availability of suitable aquifer, salinity level etc.) as well as community acceptance should be verified.