This research aims to identify the key stakeholders, explain factors that influence water, sanitation, and hygiene (WASH) behaviours, determine the chance of bacterial contamination in water, and hygiene and sanitary practises in East Sumba. The interview results show that DinKes (health agency), PAMSIMAS (rural water company), and the village board are the key players that connect the upper administrative units to the local communities. The data obtained also show that the root causes that influence the WASH condition are low education level, upbringing norms, weak economy, and geography. The water quality testing results show that in terms of E. coli 14% and 12% of the respondents had a high chance of contamination in their water source and household respectively. These numbers are 25% and 29% in terms of total coliforms. Approximately 59% respondents still use poor sanitation facilities, which includes open defecation (33%) and unimproved latrines (26%). The other 14% respondents are listed under limited sanitation service, and 27% of the respondents had their own toilet, however, it is difficult to conclude if these people fall under the basic or safely managed category of sanitation services.

Fresh water resources in coastal areas are under intense pressure from groundwater consuming activities, sea level rise and extreme weather events, which effectively amplify salt water intrusion (SWI) into coastal freshwater aquifers. Literature on SWI describe the effects of SWI, model SWI scenarios and explain possible SWI mitigation strategies. To our knowledge there are, however, no studies that combine socioeconomic data with groundwater simulations to estimate SWI mitigation prevalence within an area. In this study, we demonstrate how a socioeconomic model can be combined with groundwater simulations to explore the possible role of behaviour willingness in finding suitable SWI adaptation/ mitigation strategies. The coastal province of Tra Vinh, located in the populated Vietnamese Mekong Delta, is an area affected by SWI and was used as case study area. Data collected from 313 households spread over nine communes, within the province, was used to construct a Bayesian Belief Network (BBN) model. The model integrates both socioeconomic (e.g. education, age) and psychosocial (behavioural) characteristics, to predict the willingness to change of the population; willingness to change from groundwater to a different source of water. The validated BBN model showed good model performances. The research found amongst others, using three model analysis, how the BBN model could be used on both regional (province) and local (commune) scale. The two different scales can help in defining both target groups and suitable locations for SWI mitigation/ adaptation interventions. Moreover, this study did not focus on finding suitable alternative water sources, that can serve as a substitute for groundwater abstraction. Though, the model analysis can help to more effectively define the possibilities of alternative sources and/ or water-saving interventions.