GWH upgrade 2009

As part of its redevelopment of the Great Western Highway at Lawson, the then RTA (RMS) had to manage the stormwater flows of the new four lane road, and proposed the construction of a large stormwater detention basin south of the GWH, near the end of Ferris Lane and adjacent to Lawson Creek and swamp. From the outset of this project the bushcare group was registered as a stakeholder and was extensively involved in negotiations with the RTA Lawson project management team in order to mitigate the potential adverse environmental effects of this stormwater work.

Detention basin construction west of Lawson creek/swamp July 2009

Detention basin construction by RTA July 2009

Detention basin construction by RTA July 2009

Detention basin construction by RTA July 2009

Major issues were the route of the pipeline from the GWH (minimising bushland impacts), the size of the detention basin (not too small), the rate of discharge flow from the detention basin into Lawson Creek (not too fast), the route of the channel into Lawson Creek (avoiding the swamp) and the possibility of building holding ponds as part of the stormwater dispersal system, as an alternative to a channel through the swamp.

 

Detention basin channel cut through swamp to Lawson creek Nov 2009

Detention basin channel cut through swamp to Lawson Creek Nov 2009

The detention basin channel area has, to a certain extent, regenerated well, and this is largely due to the planting of Tea-tree (Leptospermum polygalifolium) by the bushcare group in 2011 and ongoing weeding. However, it is infested with Juncus microcephalus, and in the future the seed from this weed will continue to flow into Lawson Creek.

Detention basin channel, Jan 2017

Same detention basin channel area, now well vegetated, Jan 2017

 

————————————————–