LASCAM (Large Scale Catchment Model)

LASCAM is a Rainfall runoff model plugin.

Adapted and re-written as a C# plugin for Source IMS framework by Joel Hall, Water Science Branch, Department of Water, Western Australia, 23/06/2011

Originally developed by Neil Viney and Murugesu Sivapalan, Centre for Water Research, University of Western Australia, 1996-2002

General Info

Plugin Description

LASCAM was developed with the aim of predicting the impact of land use and climatic changes on the daily trends of streamflow and water quality in large catchments ove long time periods. It was developed as a lumped, conceptual model, using sub-catchements as basic building blocks. Typical subcatchmetn sizes are 1 - 10 km2, although much larger subcatchments can be used.

LASCAM hydrology is built around three interconnected subsurface stores, the A store representing the near-stream aquifer system and riparian zone, the B store representing the permanent deeper groundwater system, and the F store representing an intermediate unsaturated infiltration store. These represent typical accumualations of soil water in duplex profiles where a shallow, gravelly or sandy and highly permeable A horizon overlies a clayey, less permeable B horizon.

For more information on how the fluxes and flows are explicitly modelled through these stores, refer to the literature presented below. It should be noted that many of the parameters in LASCAM were designed to only be estimated by calibration and then by comparison to observed streamflows.

The LASCAM hydrological routine is equivalent in LASCAM versions 2.0 - 2.6, and the Streamflow Quality Affecting Rivers and Estuaries (SQUARE), which is also used by the Department of Water in WA for nutrient modelling exercises.

AVAILABLE LITERATURE:

The following literature is available on the LASCAM rainfall runoff model:

- Sivapalan, M., Ruprecht, J.K., and Viney, N.R., 1996. Catchment-scale water balance modeling to predict the effects of land use changes in forested catchments. 1. Small catchment water balance model. Hydrological Processes, 10(3), 413-428 - Viney, N.R., Sivapalan, M., 1996. The hydrological response of catchments to simulated changes in climate. Ecological modeling, 86, 189-193- Viney, N.R., Sivapalan, M., 2000. Modelling catchment process in the Swan-Avon River Basin. Hydrolgoical Processes.
- Viney, N.R., Sivapalan, M., 2000. LASCAM: The large scale catchment model - user manual. Version 2. Research Report WP1392NV, Cenre for Water Research, Unviersity of Western Australia, Nedlands.

Plug-in alterations from original code:

Changes in the below code from the original code (in the attached literature) include:

- evaporation from throughflow (eg) is calculated
- total evaportranspiration (et) includes "eg" now (to satisfy mass balance)
- initial store parameters abar, bbar and fbar have been removed, and replaced by the half full stores (see the function initStoresFull())
- the default parameters are different to the literature, and are based a calibratoin from Nambeelup Brook, WA
- LAI and ep are entered as a time-series at the same time-step as the rainfall (the original code calcualted EP, and LAI was a monthly function of an annual value)
- no store disaggregation equation is used to initialise the stores
- no separate LAI for the riparian zone (as this can be done from within Source IMS framework if desired)

Using the plugin

See the User Guide on how to use Rainfall Runoff models.

Source Code

Source code available on Bitbucket here