The GloWPa (Global Waterborne Pathogen) model simulates emissions of pathogens (currently Cryptosporidium and rotavirus) to surface water. These pathogens are known to be a leading cause of diarrhoeal diseases among people that are exposed to high concentrations. GloWPa focuses on human and livestock emissions of pathogens that end up in surface water systems through various pathways (see Figure 1). Special attention is paid to the storage and removal of pathogens in manure storage facilities or wastewater treatment systems.

GloWPa performs simulations at a global scale with a spatial resolution of 0.5° × 0.5°, and at a temporal resolution and simulation time step of a year. The model can simulate pathogen emissions for the present (approximately the year 2010, see Figure 2) and for future scenarios. The future scenarios currently used consist of the Shared Socioeconomic Pathways (SSPs) combined with some assumptions about the development of sanitation and wastewater treatment.

The GloWPa model was originally developed at the Environmental Systems Analysis group at Wageningen University & Research. Current development of the GloWPa model focuses on transforming pathogen emissions into pathogen concentrations in surface water, utilising the output of the hydrological model VIC. The use of VIC stems from the need for a dynamic routing system to account for pathogen transport to surface water and for growth and inactivation rates. Further development of the model aims to convert the concentrations of pathogens into a risk indication, which depends on exposure of humans to contaminated water. Finally, efforts are made to create comprehensive future scenario analyses, using socioeconomic storylines with climate change impacts (Shared Socioeconomic Pathways (SSPs) combined with Representative Concentration Pathways (RCPs)) as well as (waste) management strategies.