Modelling of THM formation potential and DOM removal based on drinking water catchment characteristics

Highlights: • Vegetation cover extracted from satellite imagery using spectral mixture analysis. • Models of DOM in runoff waters, based on catchment characteristics were developed. • Models of treatability of DOM and THMFP, based on catchment parameters were developed. • Catchment management decision support tool to estimate water quality was developed. Catchment properties influence the character and concentration of dissolved organic matter (DOM). Surface and subsurface runoff from discrete catchments were collected and DOM was measured and assessed in terms of its treatability by Enhanced Coagulation and potential for disinfection by-product (trihalomethane, THMFP) formation potential. Models were developed of [1] DOM character [i.e. SUVA and SpCoL] and concentration (measured as dissolved organic carbon), [2] treatability of DOM by coagulation/flocculation processes and [3] specific THMFP based on the catchment features including: (a) surface and sub-surface soil texture (% clay: 5–25%), (b) topography (% slope: 5–15%) and (c) vegetation cover [i.e. high photosynthetic vegetation, low photosynthetic vegetation and bare soil] extracted from RapidEye satellite imagery using spectral mixture analysis. From these models, a catchment management decision support tool was designed for application by catchment managers to support decision-making of land-use and expected water quality related to water resources for drinking water supply.