Blacktown Creek, near Tucks Rd, Toongabbie

· UBD Map 189 Q3

· Natural regeneration of wetland plants following blockage of low flow drain Þ succession of wetland species

· Industrial area, oil contamination of Tucks Rd drain and significant chemical spills

· Flood containment in sporting fields

Site Information

McCoy Park Basin was completed in 1984. It is the second largest flood-retarding basin in the catchment. The basin temporarily stores water during major storms and then releases the water at a slower rate, thus mitigating downstream flooding. A wetland has started to naturally regenerate upstream of the low flow drain, because the outflow from this drain does not work. This wetland now helps to improve water quality by absorbing nutrients and retaining sediments on site. A natural succession of plants has established itself from the colonising willows and Commelina. Native wetland species such as Persicaria, Phragmites and Juncus are colonising the wetland.

Future activities may include the formalising of this accidental wetland to further improve its performance. However the Trust is concerned about potential toxic sediments in the wetland area. The McCoy Park Basin will be overtopped in a 100-year flood event, and requires significant works by Parramatta Council to improve its safety in major floods.

Upstream of the McCoy Park Wetlands is the Seven Hills industrial estate, which is the largest industrial area in the catchment. A large number of chemical spills, both accidental and deliberate have occurred in this area and flowed into the wetlands. Where the Tucks Rd stormwater drain flows into Toongabbie Creek there is clear evidence of significant industrial pollution. Soil samples taken from the banks indicate a 25% oil content. There is a large industrial area upstream from the drain.

1. Enter park at end of Tucks Road beyond Anvil Road. Observe drain on left. What signs of pollution from stormwater coming from industrial estate can you see?

Look upstream and note the flood-retarding basin. Describe how this system is designed to reduce flooding.

Note Greystanes creek and how it is channellised upstream. Why was this creek channellised?

3. Follow informal path down to the level of the wetland and follow it back downstream across the cement to where the water drains from beneath the wetland. Water testing can be easily performed here. (Teacher note: This will need to be checked carefully if there has been recent rain).

4. After water testing cross to the other side of the wetland and follow path to the top of the retaining basin walls. Continue along wall noting the extent of the flood-retaining basin. What is the approximate depth of the flood basin?

By continuing up Greystanes creek this site can be combined with site 5 at the Toongabbie Bowling Club. After dropping students at Tunks Road the bus can make its way to the Toongabbie Bowling Club in Station Road. Take care crossing Station Road. There is a traffic island near Greystanes Creek.

Field Trip 4 - McCoy Park Wetlands