BC2C

Software

Support

Contact

Phone: 1300 5 WATER (1300 5 92837)
Email: support@ewater.org.au

eWater
Innovation Centre
University of Canberra
ACT 2601
www.ewater.org.au

Features and Limitations

Input Data

All input data sets for BC2C must be projected and have their projection properly defined.

BC2C requires the following input data:

1) A raster representing a Digital Elevation Model (DEM). The DEM will be used to disaggregate the catchment into Groundwater Response Units (GRUs) and calculate for each GRU a working height, length and area.

2) A Groundwater Flow Systems (GFS) coverage. The GFS should be a polygon shape-file with the following fields:

Aquifer thickness, d (m)

Vadose zone thickness, d? (m)

Specific yield, S, of aquifer as a fraction of 1 (values from 0 to 1)

Hydraulic conductivity, K, of aquifer in metres per year (m/yr)

Recharge, R, as a fraction of 1. The 'recharge fraction' is the fraction of excess rainfall after ET is removed that becomes recharge rather than runoff.

Groundwater salinity in mg/l or microS/cm.

Recharge Success as a fraction of 1 (values from 0 to 1). For most cases this will be set at 1 (all recharge is modelled). However there may be special cases where not all recharge discharges through the immediate catchment (e.g. Great Artesian Basin intake beds), where values of less than 1 may be used.

GFS Type is a field which identifies each GFS type (e.g. Local systems in fractured basalt). It can be any text string.

3) A raster or rasters representing different vegetation scenarios. The Vegetation Module will allow you to import as many rasters as you wish and add them to your GRU coverage for processing. Trees are given a value of 1, such that each vegetation raster has these values:

A value of 1 = 100% trees, 0% grass for that cell

A value of 0 = 0% trees, 100% grass for that cell

A value of 0.5 = 50% trees 50% grass for that cell

4) A raster representing average annual rainfall in mm/yr

Optional Input Data:

5) Rainfall salinity (mg/L or microS/cm). Either as a single catchment-wide value, or as a raster.

6) Latitude correction grid. A correction which modifies the water balance terms in the Zhang curves. May be useful when modelling very large areas such as the Murray-Darling Basin

Output Data

The main outputs from BC2C are catchment scale water and salt export quantities following a change in landuse.

Outputs are presented as annual timeseries for each Groundwater Response Unit (GRU) of salt in tonnes and discharge in ML.

Caution Notes For User

General

BC2C is a simple prioritisation model which does not predict daily/monthly/annual changes in water and salt balance ? it uses long-term average values.

BC2C is intended for local-upland catchments ? areas where groundwater flow lengths are typically less than 10 km.

BC2C uses simple and representative groundwater properties, and while it operates at a single GFS (Ground Flow Systems) scale, its results should be aggregated to a whole-of-catchment level.

Software testing

Model algorithms: The results have been compared against those of the original ArcInfo implementation of BC2C. Small differences can exist between Toolkit and ArcInfo results due to generalisation or transfer of data from raster to vector based models. These do not appear to affect the utility of the results for the purposes listed in the User Guide.

Software use: The software has been run using datasets from several catchments.