Monitoring in the Darwin Harbour Catchment

Most of the streams in the Darwin Harbour catchment are seasonal. Therefore sampling is carried out once in the early dry season, between April and June.

Peel Creek in the wet season	Peel Creek in the dry season

The ‘edge habitat’ is sampled using a rake to disturb the habitat and a net to catch the water bugs and plant material that is raked loose. This procedure needs two people working together (see photo).

Sampling of the edge using a rake and net.	The edge habitat which is mainly composed of large and fine roots and soil.

The Darwin Harbour catchment is the focus of urban and industrial activity and development in the Northern Territory. The health of the streams in the catchment is important. Regular monitoring commenced in 2001 with 12 sites. This was increased to 18 sites over the following years (see map below)

Map: Overview of AUSRIVAS monitoring sites in the Darwin Harbour catchment.

Moving the mouse over a site brings up the name of the stream. Clicking on a site opens a page with details on the site.

An overview of the aquatic health expressed in AUSRIVAS bands for all of the locations is given in Table1. The OE50 scores obtained are available for each stream by clicking on the location on the map.

The site location numbers are allocated in collaboration of NRETA’s Water Resources hydrological database.

Location	Stream	01	02	03	04	05	06	07
G8150102	Bees Creek	A	B	A	B	A	B	coming
G8155511	Bennett Ck			A	A	C	A
G8155088	Berry Creek	X	X	X	A	B	A	coming
G8155469	Blackmore River	A	A	B		A	B
G8155474	Brookings Creek Site 1	A	B	B		B	C
G8155471/new	Brookings Creek Site 2	A	B				C
G8155479	Darwin River		A	A		B	A	coming
G8155476	Elizabeth River Site 1		A	X		B	B
G8155472	Elizabeth River Site 2	A	A	A		B	o.m.
G8155473	Elizabeth River Site 3	A	B	X	B	B	B	coming
G8155478	Fly Creek		A	A		A	A
G8155475	Howard River Site 1	A	A	A			A
G8155477	Howard River Site 2	A	A	X	A		B
G8150179	Howard River Site 3	B	B	B	B	C	B
G8155468	Mitchell Creek Site 1	A	A	B	A	D	B	coming
G8155607	Mitchell Creek Site 2					B	A
G8155470	Peel Creek	A	A	A	A	B	C	coming
G8150127	Rapid Creek Site 1	C	C	B	B	C	B	coming
G8155182	Rapid Creek Site 2					B	B
G8155142	Rapid Creek Site 3					C	B
G8155510	Wells Creek			B	A	A	B

o.m. = outside model: The inputs to the model were outside of the model’s experience which precluded the model’s use.

• Definition of the bands used in table 1 (above) and their interpretations according to the AUSRIVAS user manual.

Overall the stream health of the Darwin Harbour catchment is very good with most of the streams revealing a condition comparable to undisturbed reference steams. Rapid Creek is of poorer health being the only stream with a large proportion of the catchment urbanised, though OE50 scores have increased recently. Mitchell Creek seems to show a decrease in water quality over the years, which is likely to be related to the pressure of urban development in the catchment.

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