Dataset Title: Hydrographic Catchments - Catchments

Custodian: Department of Environment

Abstract:
Catchment boundaries have been defined for more than 1800 key sites on streams throughout Western Australia.
The Subcatchments dataset contains polygons derived from all the defined boundaries. This catchments dataset
is derived from this on the basis of the catch_name field, determined by the scientific custodian.

Currency and Status:

Beginning Date- 01-01-1993
Ending Date- Ongoing
Metadata Date- 03-04-2003
Progress- Complete within current limitations on funding, further updates will be done as necessary.
Maintenance & Update Frequency- Ongoing, as required

Lineage:
1. The gauging station catchment boundaries (including Basin & Division boundaries) were drawn on hardcopy maps in 1994-95,
generally the best available scale topographic maps (1:25 000, 1:50 000, 1: 100 000 and 1:250 000), with reference to the elevation contours.
These maps were digitised and the information stored as a microstation design file. Calculated catchment areas only included sub-areas.

2. The microstation DGN files were converted to ArcView shapefiles and stored as a polygon SDE layer in 2000.
This layer remained unchanged until April 2003.

3. From 1997 to 2002, updates to original catchment microstation (line) file were undertaken off-line and not published.
These updates used the best available DOLA contours and in some cases LandMonitor contours and aerial photography, digital streamlines, and ground truthing.
Boundaries were extended to sites other than gauging stations. Where known, the accuracy is attributed to linework.

4. Updates were incorporated into a single dataset, attributed and published in April 2003 with linework and full catchment areas.

Positional Accuracy:
This is dependant on contour interval. Much linework in the Kimberley Region is poor, due to the lack of available contours.
Pilbara, Gascoyne and Murchison are fair, while the MidWest, SouthWest and South Coast are good.

Attribute Accuracy:
Variable. Area calculations are based on Albers Equal Area Projection for the whole state.

Logical Consistency:
Good.

Completeness:
As larger scale data become available, and demands dictate, these areas will be redigitised.

Access:
Standard WRC license agreement

Available Formats:
Any ESRI format.

Contact Persons

For external data provision:

Brett Harrison
GIS Data Administrator
Information Services
Business Development Division
9278 0719

For scientific/content queries:

Peter Muirden
Senior Engineer/Hydrologist (Surface Water)
Hydrology and Water Resources
Resource Science Division
9278 0456

For GIS technical queries:

Dan Sandison
Divisional GIS Coordinator
Regional Services
Regional Operations Division
9278 0554

------------------------------------------------------------------------
UPDATE
01.01.95
- Gauging station (open and closed) catchments defined on paper topography, and digitised in microstation format.

6.10.00
- Geometry regenerated from microstation (DGN) source and coastline replaced with 2000 SDE coastline.

03.04.03
- Comprehensive revision completed. Subcatchments linework has been extensively updated.
Coastline from South Australian border around to north of the mouth of the Gascoyne River updated with WRC (amended version of DOLA)
coastline from SDE, estuaries were closed and some redefined, sometimes with additions from the hydrography.
More detailed information about the source of each line is contained in the lines dataset which may be obtained by contacting the Technical custodian.
An attribute field combining 'basin_name' and 'catch_name' in the subcatchment polygon attributes was used as the dissolve field to create this dataset.

------------------------------------------------------------------------
DATA DICTIONARY

Catch_name - Catchment name, based on the name of the river emptying to the ocean, to which each catchment flows

Basin_name - Name of Hydrographic Basin in which catchment occurs

Basin_no - Number of Hydrographic Basin in which catchment occurs

Division - Name of Hydrographic Division in which catchment occurs

Area_km2 - Area in square kilometres

Perim_km - Perimeter in kilometres

UFI - Unique feature identifier