Model (UKCEH) INCA-P (Integrated Catchments Model - Phosphorus dynamics)
INCA-P operates at a daily time step, tracking the stores and fluxes of water, sediment, dissolved and particulate P in both the land and in-stream phases of a river catchment. The model is spatially ‘semi-distributed’: the water course is split into reaches with associated sub-catchments. Two spatial set-ups are possible – the traditional set-up, in which there is a single main stem, or a ‘branched’ set-up. The latter allows in-stream processes, effluent inputs and residence times in tributaries to be simulated, and can be particularly useful in larger catchments or complex river networks. Each sub-catchment is split into landscape classes – there can be as many of these as desired or warranted by the data resolution or needs of the study. Landscape classes are “functional units” and within each unit P inputs, plant P uptake, soils and flow pathways should be similar, though for convenience classes are often based on land use and/or soil type. All land-based processes are calculated for a generic 1 km2 cell for each landscape class within each sub-catchment. Water, sediment, total dissolved P (TDP) and particulate P (PP) outputs from the 1 km2 cell for each land class are multiplied by the land class area, and summed to provide total inputs from the sub-catchment to the reach. These inputs are assumed to enter the stream reach directly, rather than being routed spatially from one land class to another. Reach inputs are therefore from the land phase and from any upstream reaches.
INCA-P is freely available for non-commercial use and can be obtained under license for commercial applications. The executable can be requested from the Norwegian Institute for Water Research (NIVA) at www.niva.no/inca/inca-phosphorus
INCA-P is a 32-bit Microsoft Windows application written in C++. It is available as a command-line version (1.27 MB) or with a graphical user interface (3.75 MB), and will run on Windows XP onwards. The RAM required during simulation depends on the application set-up (number of reaches and landscape units) and application period (number of time steps). A simple one year, single reach set-up requires 6.6 MB of RAM.
Microsoft Windows, Graphical User Interface, control files
Limited support from model developers
River reach and sub-catchment with structure designed by user
Estimate phosphorus loss at different timescales in response to environmental change and catchment management
Key Output Variables
Stream flow, sediment and phosphorus concentrations and loads, phosphorus process loads, soil, soil water and groundwater P concentrations
Jackson-Blake LA et al. 2016. The Integrated Catchment model of phosphorus dynamics (INCA-P): Description and demonstration of new model structure and equations. Env. Modelling and Software 83: 356-386. http://www.sciencedirect.com/science/article/pii/S136481521630158X
INCA-P model description and example application http://www.sciencedirect.com/science/article/pii/S136481521630158X
Observed river flows and stream water phosphorus concentrations
Daily time series of Flow, Stream water suspended sediment concentration, Stream water total phosphorus concentration, Stream water total dissolved phosphorus concentration, Stream water particulate phosphorus concentration