Versions of the Integrated Catchments (INCA) model have been developed for a range of water quality parameters, as well as for flow. Over the past twenty-five years, the models have been used to better understand and manage a range of water quality issues in Europe, Asia, Africa and the Americas.
All INCA water quality models simulate terrestrial (in the land) and instream processes. Processes include inputs, transformations, transport and losses. INCA models simulate pollutant inputs from, e.g., agricultural practices, wastewater discharge and atmospheric deposition. Transformations between, e.g., nitrate and ammonia or organic and inorganic forms of phosphorus are simulated. INCA models the transport of both dissolved and solid material. A number of loss processes including evasion to the atmosphere and burial in sediments can also be simulated.
INCA-N is the most widely used member of the family. It simulates the fate and transport of inorganic nitrogen (nitrate and ammonia).
INCA-P simulates the behavior of dissolved and particulate phosphorus (P). The latest version of the model also simulates in-stream ecology.
INCA-C simulates dissolved organic carbon (DOC). The model has been used to understand effects of forestry, recovery from acidification and climate change on catchment carbon balances.
As well as these members of the INCA family, a number of specialized versions of the model have been developed.
INCA-Sed is a physically based sediment production and transport model. The current version is incorporated in INCA-P.
INCA-Contaminants simulates the fate and transport of a broad range of anthropogenic micropollutants including legacy POPs, perfluorinated substances and microplastics.
INCA-Path simulates catchment dynamics of waterborne pathogens such as E. coli.
INCA-Metals was developed to model the riverine transport of a range of heavy metals.
INCA-Hg simulates catchment-scale behavior of methylmercury and total mercury.
The INCA family also includes a version focused exclusively on hydrology. PERSiST, the Precipitation, Evaporation and Runoff Simulator for Solute Transport is a flexible eco-hydrological rainfall runoff modelling toolkit that can support the INCA water quality models.