Taronga Western Plains Zoo Wetland 20 yrs on
The intent of the wetland is to intercept runoff from the zoo – including animal wastes
Taronga Western Plains Zoo requested that Storm Consulting undertake an inspection and assessment of the treatment wetland.
Rod Wiese and Mal Brown of Storm were the Design Engineer and Project Manager of the wetland, respectively when they worked together for the NSW Government in the early-mid 1990s.
In the period 1994-96, the Western Plains Zoo treatment wetland was conceived, designed, constructed, commissioned, and launched.
The intent of the wetland is to intercept runoff from the zoo – including animal wastes – and to provide low energy, passive treatment in a purpose-built constructed wetland before the water flows into the nearby Macquarie River.
The wetland was configured to have a primary detention basin at the upstream end which allows sediment and organic debris to settle and be contained for periodic removal. Treatable flows pass from the detention basin through a pipe to the reedbed zone. The reedbed provides treatment of nutrients through various biotic processes. At the downstream end, an open water zone allows sunlight to kill off pathogens. An outlet structure allows low flows to exit the wetland, and also for the water level in the wetland to be adjusted. High flows would bypass the reedbed and the downstream embankment to protect the system from overloading and erosion.
The inspection undertaken by Mal Brown on 15th April showed that after almost 20 years of operation, the wetland is in very good condition and appears to be functioning effectively as intended. Water clarity at the downstream end is very high and the reedbeds are dense and healthy.
The only issues associated with the wetland are minor erosion and accumulation of sediment and organic debris in the primary detention basin.
Mal provided a schedule of works to address the minor works, and a water quality monitoring regime was suggested.