Jo Thompson and Kate Harriden: Yarralumla Creek
Bottle number: 39
About the water
Collected at: Yarralumla Creek, Curtin, ACT
E: 688,825. N: 6,089,960.
Collected by: Jo Thompson and Kate Harriden, Waterwatch, Molonglo Catchment Group
Waterwatch since April 2008.
Water quality (as at 23 November 2009):
|Turbidity:||9 (means <10)|
|Salinity:||EC = 940µS|
|Phosphates:||0.03mg/L (= O-phos)|
|Dissolved oxygen:||4.8mg/L, 78%|
Water temperature: 19 degrees Celsius
Air temperature: 19 degrees Celsius
ACT Waterwatch says:
That's about the norm for Yarralumla Creek.
There are three factors at play here. Yarralumla Creek rises at the back of Isaacs, on the ridge that goes from Red Hill to Long Gully. It then flows through O'Malley, Garran, Phillip and Lyons and swings behind Curtin and into the horse paddocks above Yarralumla before meeting the Molonglo just below Scrivener Dam. For most of the way from Hindmarsh Drive to the Cotter Road (where the ladies took their sample) the creek is a wide, concrete lined gutter with storm-water drains all the way along. And it runs along the edge of the Hospital and Woden shopping precinct. So limestone catchment + storm-water feeds + two major car-parks and you have a wonderful mineral soup!
(Comment by Stephen Skinner, Molonglo Waterwatch Coordinator)
About the site:
The site is at the end of an urbanised catchment area. There is a gross pollutant trap about 300m upstream. Immediately upstream, one side of the creek has a cycle path beside a community sporting oval and the other side of the creek is rough open space. Downstream is an equestrian park. The site is at the boundary between a natural vegetated stream upstream and a concrete channel under the road. The creek upstream has vigorous reed regrowth.
Threats: increased residential density upstream.
What's going on:
Vigorous reed regrowth upstream. Invasive reed species evident. Bank undercutting at site. Heard Pobblebonk frog while testing. Moorhen on water at site. Galahs and magpies can be seen and heard.
Water quality testing monthly. Water bug survey (Nov 2009).