Golden Beach vegetated infiltration basin

The construction of a vegetated infiltration basin at Golden Beach was completed in September 2015. The basin was designed to reduce the stormwater impacts from the local Earnshaw Street catchment on Pumicestone Passage.

To provide feedback to the community, the stormwater industry and council on the function and performance of vegetated infiltration basins in a dunal environment, a community monitoring program was established. Members of the local Golden Beach community, representatives from the University of the Sunshine Coast and council officers have been involved in overseeing and delivering the monitoring program.

Project scope

The vegetated infiltration basin at Golden Beach was designed to treat diverted stormwater from the Earnshaw Street catchment before it discharges to Pumicestone Passage. The basin has been designed to capture the initial stormwater runoff from the local catchment. This allows the sediment in the runoff to settle onto the basin floor while the remaining water infiltrates through the soils below the basin. Nutrients in the stormwater runoff are absorbed by the vegetation both in and surrounding the basin. This helps the plants to grow, which then strengthens the dunes helping to protect them from tides and weather events. Figure 1 below illustrates the key elements of the Vegetated Infiltration Basin.

Project update

Since construction of the basin was completed in September 2015 routine maintenance of the basin is undertaken and any accumulated rubbish, such as litter and bottles, is removed. A new information sign was erected on site and the community monitoring program commenced.

Monitoring results are available for groundwater and sediment sampling.

Overview

The basin was designed to fit into the surrounding environment, park and adjacent coastal pathway. Low growing plant species have been carefully selected to ensure the basin blends into the surrounding landscape and views of Pumicestone Passage are not affected as the plants grow.

Pumicestone Passage is part of the Moreton Bay Ramsar site, listed under the convention on Wetlands of International Importance, and is a very significant location for migratory birds. In recent years, South East Queensland’s Healthy Waterways report card program has highlighted poor water quality in the northern Pumicestone Passage. Critical habitats and ecosystems within Pumicestone Passage are at risk from pollutants flowing off the greater catchment. The vegetated infiltration basin will contribute towards improving the water quality flowing off the local Earnshaw Street catchment into Pumicestone Passage. This particular site was chosen to locate a vegetated infiltration basin because it resulted in the least amount of lost grassed foreshore area possible. Alternate locations along Golden Beach were also considered but eliminated through the design process when factors such as existing pipe levels and tidal effects were taken into account.

The basin will remain dry most of the time and is not considered a health and safety risk for the community. Fencing has been installed on the western (road) side of the basin to prevent entry from the pathways and the basin is not expected to produce an odour. Experienced environmental engineers and landscape architects designed the basin and surrounding landscape to ensure it fits well into the environment, park and coastal pathway.

• Earnshaw Street Infiltration Basin, Golden Beach, Caloundra - Functional Design Report Part 1 (PDF, 5042KB)
• Earnshaw Street Infiltration Basin, Golden Beach, Caloundra - Functional Design Report Part 2 (PDF, 4644KB)
• Earnshaw Street Infiltration Basin, Golden Beach, Caloundra - Functional Design Report Part 3 (PDF, 4681KB).

Background

The Pumicestone Passage and Catchment Action Plan 2013-16 lists Golden Beach as a committed site for this important council project. The Pumicestone Passage waterway has high environmental values, with many plant and animal species and is listed under the convention on wetlands of International Importance as an important site for migratory birds and it also supports diverse wildlife including turtles, dugong in southern areas, fish, crabs, oysters and juvenile prawns.

• Causes of declining ecosystem health grades in the Pumicestone Passage (PDF, 2246KB)
• Community update - August 2015 (DOC, 1502KB).

Contacts

For more information, please contact council to speak with the flooding and stormwater team.