Using multi-variable vulnerability indices in water resources management in order to prevent diseases associated with poor water and sanitation

A multivariable index, focusing on the link between water resources vulnerability on a quaternary catchment scale and potential health impact is vital in water resources planning and management. In this study a technique based on multifactor vulnerability indices is developed and applied in drawing inferences on vulnerability and susceptibility to diseases associated with poor water and sanitation. Utilising various geo-referenced datasets, four multi variable geospatial indices were generated. These are; a "Water Resources Vulnerability Index (WRVI)" by using three anthropogenic land use surrogates at quaternary catchment level, a "Microbial Water Quality Index (MWQI)" to evaluate microbial water integrity in the context of health, a "Water and Sanitation Access Index (WSAI)" according to the World Health Organisation (WHO) and United Nations and Children's Fund (UNICEF) criteria and definition of improved and unimproved water supply and sanitation, and lastly, a "Demographic Vulnerability Index (DVI)" based on three socio-economic attributes was used to evaluate factors that inhibit access to water and sanitation services and potential impact of an outbreak. In order to demonstrate the multi variable geospatial indexing technique a case study was conducted in Limpopo Province, South Africa. The technique was utilised to evaluate the relative potential impact of agriculture, settlements and waste water effluent disposal on the microbial integrity of water resources. A 3 variable 9 category Water Resources Vulnerability Index was used to classify 206 quaternary catchments. The Water and Sanitation Access Index was used to classify 2892 sub places on a 10 point scale. The Demographic Vulnerability Index was used to categorise 25 Local Municipal Districts on a 5 point scale utilising unemployment ratio, dependency ratio and population density. A 4 water use attributes 3 point Microbial Water Quality Index was used to evaluate the applicability the Water Resources Vulnerability Index. Ultimately, a 10 point water resources-health susceptibility evaluation and prioritisation index was developed. The multivariable indexing technique can be used to evaluate vulnerability in a systematic manner and aid decision making in water resources management. The practical application of the technique in water resources management can be improved by targeted water quality sampling and spatial correlation. Conception can be further enhanced by including geo-referenced data on knowledge, attitudes, behaviour and practice at sub place level. In conclusion when there is a minimum acceptable level of relevant geo-data as specified in the study geospatial indexing can be used to evaluate the vulnerability and susceptibility. This is an essential step to improve water resource management and reduce the prevalence of water and sanitation diseases in regions where water and sanitation access and demographic profiles are variable.