Gungahlin Pollution Control Ponds

• Location
• Description of Facilities
• Lake uses and values
• Potential Hazards associated with the facility
  

Location

The Gungahlin Pollution Control Ponds, comprising Gungahlin Pond and Yerrabi Pond, are located upstream of Lake Ginninderra within Gungahlin. They can be found on our Gungahlin map. Further ponds/wetlands are to be constructed, including Moncrief Pond on the western (upper) arm of Ginninderra Ck upstream of Gungahlin Pond, and the Gungahlin wetlands on Gungaderra Ck (tributary of Ginninderra Ck). The pond waters are comprised of stormwater discharge from urban and rural areas. Another pond (Gold Creek Pond) has been privately constructed and is integrated into the Gold Creek Golf Course.

Description of Facilities

Gungahlin Pond was constructed in 1989, as part of the early Gungahlin town development. Yerrabi Pond was constructed in 1994 as part of the ongoing Gungahlin development. Gungahlin Pond is formed by an embankment across Ginninderra Ck opposite Nudurr Dr. The primary spillway comprises a drop structure and culvert through the embankment. The secondary spillway, an earth and vegetated channel, is constructed on the eastern abutment of the embankment.

Yerrabi Pond is formed by the Mirrabei Drive embankment across East Ginninderra Ck. The primary spillway comprises a drop structure and culvert through the embankment. The secondary spillway comprises a concrete weir and chute on the western abutment of the embankment.

Both Gungahlin Pond and Yerrabi Pond have extensive open water areas, with limited macrophyte zones around their margins. Both Ponds have Zone 1 type areas at their upstream reaches, and Zone 2 areas covering their middle to lower reaches.

Both ponds have gross pollutant traps installed on their inlets, to limit trash discharge.

Lake uses and values

Both ponds were constructed as part of the Gungahlin Stormwater Pollution Control and Belconnen Flood Protection (flow detention) Strategy (refer to Gungahlin Environmental Impact Statement 1988).

The ponds and other land development controls have been designed to limit pollutant loading on Lake Ginninderra to levels consistent with water pollution control, aesthetic and recreational use objectives. In addition, both ponds include provision for substantial temporary stormwater storage during periods of high rainfall, to limit peak flows within downstream stormwater drains to levels within the stormwater drain capacity.

The ponds were also designed as landscape and passive recreation facilities, with particular attention to the shape and vegetation of shorelines, and to maintaining acceptable in-pond water quality.

Potential Hazards associated with the facility

Elevated water flow velocities in the vicinity of the spillway at times of heavy rainfall represents a potential safety hazard.

Lake edges have been gently graded along the areas of deep water to avoid sudden drops which might create difficulties for small children, should they enter the water.

This section was written by ACT Government in collaboration with Ian Lawrence of the Cooperative Research Centre for Freshwater Ecology.