Selected catchment boundaries and their SILO cell percentages for AWRA modelling for the Gloucester subregion

Abstract

The dataset was derived by the Bioregional Assessment Programme from multiple source datasets. The source datasets are identified in the Lineage field in this metadata statement. The processes undertaken to produce this derived dataset are described in the History field in this metadata statement.

This dataset includes files for catchment boundaries and SILO cell percentages.

The catchment boundaries were delineated using 1 sec Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM) dataset with gauge locations as pour points. Catchments were then intersected with SILO climate cells for use in gridded AWRA hydrological modelling. The new boundaries are better then those delineated using the Bureau of Meteorology's (BOM) Geofabric for all catchments, except for the catchment 209003 where a flaw in the SRTM derived flowpath excluded a valley when compared with the Geofabric. This catchment was manually edited to conform with the Geofabric representation of 209003.

The grid cell percentage was calculated for all 5km resolution SILO grid cells located within each catchment. The percentage information is used for gridded AWRA hydrological modelling and for weighting average for estimating streamflow aggregated at each gauge outlet.

Purpose

This dataset is intermediate, delineated using 1-sec SRTM DEM dataset, and is used for AWRA hydrological modelling.

Dataset History

A point feature dataset was created from the gauge location spreadsheet. This was compared with SRTM 1 sec derived flow accumulation and ArcMap Basemap imagery and point features manually snapped to the SRTM flowpaths reperesenting the river names in the gauge name.

Contributing catchment rasters were then generated using the ArcGIS 10.1 Spatial Analyst Tool "WATERSHED with snapped gauge location pour points and the SRTM derived flow direction grid as inputs.

Resultant catchment rasters were then exported as shapefiles and compared with the coarser Geofabric catchments. All but one catchment conformed in extent. SRTM derived catchment for gauge 209003 excluded a large flat valley (when compared to with the geogfabric due to a misdirected flowpath. This was manually corrected.

Catchment shapefiles were then intersected with BILO Climate model cells to obtain 1) percentage of cell in the catchment and 2) proportion of catchment made up by the cell. Both these determinations were based on intersected areas calculated on the Albers equal area projection.

These cell to catchments ratios were then exported to database file (dbf).

Dataset Citation

Bioregional Assessment Programme (2014) Selected catchment boundaries and their SILO cell percentages for AWRA modelling for the Gloucester subregion. Bioregional Assessment Derived Dataset. Viewed 18 July 2018, http://data.bioregionalassessments.gov.au/dataset/38f3a272-66cc-4fe2-bef9-ff4aedf6fc24.

Dataset Ancestors

• Derived From GLO SW Model Calibration Gauges v01

• Derived From Gloucester Surface Water Discharge & Quality extract v1 060314

• Derived From Geofabric Surface Catchments - V2.1

• Derived From BA SYD 1 sec SRTM (h) DEM and hydrological derivatives

• Derived From Mean Annual Climate Data of Australia 1981 to 2012

• Derived From Geoscience Australia, 1 second SRTM Digital Elevation Model (DEM)

• Derived From BILO Gridded Climate Data: Daily Climate Data for each year from 1900 to 2012

• Derived From Climate model 0.05x0.05 cells and cell centroids