24 informal settlements in Makassar and Suva have been selected for their vulnerability to a range of water-related stressors. At all sites, intermittent water supply of varied quality and inadequate or absent sanitation systems result in high rates of exposure to environmental faecal contamination. The sites are variously characterised by combinations of: tidal inundation with occasional storm surges; riverine flooding; and, poor drainage and pluvial flooding. Testing the interventions in the two contrasting urban settings will identify generalisable conclusions and context specific considerations.

In close consultation with communities and stakeholders, RISE is revitalising settlements comprising an average of 50 dwellings per site, assuming 5–6 people per dwelling, with a total of 6,000–7,200 people. This intervention scale and sample size will ensure statistical power for primary health and environmental outcomes. Site inspections have confirmed feasibility and accessibility, with site locations and sizes determined using the UN-Habitat informal settlement selection approach.

Key site-selection criteria:

1. High risk of water-borne and -related diseases, poor drainage and vulnerability to flooding;
2. Land tenure security and resident and government consent;
3. Number of households and number of children under 5 years of age;
4. Clear settlement boundaries, which are required for the RCT design; and,
5. Households representative of the most vulnerable populations in each city.

• Households representative of the most vulnerabary relocation of residents during construction.

Selection of specific informal settlement sites in Makassar and Suva

The health assessment is focusing predominantly on children under 5 years of age. We are assessing the impact of the intervention on pathogen burden, markers of intestinal inflammation and function, and drug-resistance markers detected in faeces. Reported symptoms such as fever and diarrhoea, child anthropometric markers, and frequency of healthcare visits are also being monitored.