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Varsity Lakes Wetlands & Enivornmental Park
As man made wetlands, the area is a tremendous demonstration of what can be achieved through environmental design excellence.
Any community which benefits from the wetlands, must ensure that it is continually maintained as a significant environmental and recreational resource.
The Varsity Lakes Conservation Park is part of the Delfin Lend Lease Varsity Lakes development, a residential and commercial development of 343 hectares. On completion, expected to be sometime in 2010, the development will house approximately 7,800 people and have a town centre (named Varsity Central) of 40 hectares. Varsity Central is expected to employ over 5,000 people.
Housed within the area is Varsity College which is spread over two campuses – on the southern side is the Junior Campus and on the northern side, separated by Lake Orr, are the Middle and Senior Campuses. In 2008 the total number of students reached 2,700 making it one of the largest Government schools in Queensland.
Within Delfin’s development area at Varsity Lakes are 56 hectares of open space including parks and wetlands. Lake Orr adds a further 76 hectares.
The Varsity Lakes Conservation Park and environmental area covers 22.44 hectares with approximately 3.4 hectares being wetlands and the remainder being covered by remnant forests and open grasslands.
The Park consists of 6 individual wetlands varying in size from 1,500m2 to 13,000m2 and will contain 34,000m3 of water.
The Park also contains a number of remnant forests which vary from Open Dry Sclerophyll Forests (containing trees such as blackbutt and bloodwoods) to Swamp Forests (containing paperbarks and sheoaks).
Open Dry Sclerophyll Forest
There are 3 main sections of open woodland within the Park:
Area 1: Is identified as a high priority conservation area and in fairly good condition, particularly in the mid and upper levels. The lower story is a little stressed most likely due to frequent firing. This area also includes the Pink Bloodwood Eucalyptus siderophloia which is regarded as an endangered species. It also contains Acacia fimbriata which attracts the black cockatoo.
Area 2: This area is nominated as a conservation area and it is largely young regrowth with some under story weeds
Area 3: Thick under story of weeds infest this area and will require an intensive maintenance regime.
Swamp Forest / Tall Open Swamp Sclerophyll Forest
These forests are low lying areas that are quite often filled with water. The type of plants that live in these forests have the capacity to live in waterlogged soils. Some examples are the broad leaf Paperbark Melaleuca quinquenervia and River Sheoak Casuarina cunninghamiana.
Two main areas exist:
Area 1: Due to the canopy cover there is a low diversity of sedges (a type of wetland reed), with exotic grass dominating the under story where it abuts broad clear areas. The mid and upper stories are in a reasonable condition.
Area 2: About 60 years ago Reedy Creek was redirected along this line and the swamp forest has evolved. The area immediately surrounding the creek is in excellent condition with the under story full of grass, reeds and shrubs such as Lomandra hystrix. The area outside this has a number of weeds both in the lower and mid stories.
What wetlands do . . .
The Varsity Lakes Conservation Park is used to treat stormwater, which is any water that runs off lawns, roads, roofs and other surfaces.
Stormwater can be a major problem in urban areas where there are so many sealed surfaces such as roadways and roofs.
Here stormwater runs off quickly, rather than soaking into the ground. It picks up sediment, dog poo, oil and all kinds of rubbish as it rushes along the street and into stormwater drains. Stormwater flows untreated into our creeks and rivers, and finally into the Broadwater and the Pacific Ocean.
Some of the problems that stormwater creates are:
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Nutrients from grass clippings, fertilisers, detergents, and dog poo encourage algal growth. Algae uses up the oxygen in streams, which can lead to fish kills.
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Sediment cuts down on the light penetrating the water. In Moreton Bay it smothers seagrass and kills other important food sources for fish, dugong and turtles.
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Weed sprays and other chemicals can kill our wildlife.
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Plastic bags, cigarette butts and other rubbish clogs up our waterways and can kill wildlife when they become entangled in the rubbish or mistake it for food.
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Hydrocarbons (from leaked fuel, greases, oils, tyre wear) and heavy metals (copper, lead, zinc and iron) poison our waterways and kill wildlife.
This is where the wetlands play a vital role, through shape, change of water depth and selective plantings wetlands will help achieve:
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Removal of excess nitrogen and phosphorus.
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The settling out of sediments.
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Assists in the removal of heavy metals and other chemicals.
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Helps oxygenate the water.
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Reduces smells.
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Helps reduce mosquitoes.
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Provides food and shelter for fauna.
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Important breeding ground for fish and other aquatic life.
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Removal faecal coliform.
How do wetlands work . . .
Wetlands keep our waterways healthy because they act as natural filters.
The movement of water is slowed down and this allows heavy particles like sand and soil to fall to the bottom of the wetland. These sediments often have chemicals and nutrients attached to them.
By capturing sediments in stormwater, wetlands help to keep downstream waterways clean.
The water is slowed down by the use of:
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Level changes, which also allows a variety of plants to be used, which absorb different chemicals and nutrients.
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The plants themselves.
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Shaping the wetlands to a series of bends to allow the water to meander its way through, thereby allowing the filtering process to take place.
In urban areas, stormwater can contain high levels of nutrients such as phosphorous and nitrogen that can pollute our waterways and be carried down to the sea. Wetlands help to filter out nutrients, and they are taken up and used by water plants.
Harmful bacteria can also get into stormwater from animal poo or sewage. Many of these bacteria will die when exposed to sunlight. The shallow waters found in wetlands provide perfect conditions for this natural sterilization process to take place.
Fauna in the Park
There is quite a diverse range of fauna, however no rare and endangered species have been found.
There has been a number of initiatives to help the fauna have been tried, some of which are:
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120 hollow logs have been distributed throughout the area.
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80 nesting boxes have been installed in trees, these are not only for birds but also for mammals such as squirrel gliders and bats.
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Removal of the fence into the adjoining property to allow the wallabies access to 2.5 hectares of grass. This is due to the drought and also while creating the wetlands 60,000m3 of soil was removed resulting in damage to grass lands which have now started to regenerate.
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Before any clearing is done anywhere on the project an animal spotter is employed to relocate any wildlife to the Reedy Creek area. The animal spotter remains on site the whole time any clearing is done to relocate anything he may have missed.
Park maintenance
Wetland Maintenance
Once established, the wetlands are pretty much self maintaining, all that is required is to excavate the sediment ponds once every five years or so if required. For this purpose access points have been provided to all wetland sediment ponds.
Dry Sclerophyll Forest Maintenance
After the initial removal of weeds and planting of replacement stock, an ongoing maintenance program needs to be set up. As the council is very unlikely to have the resources or finances to maintain at the area to sustainable environmental levels required we are in the presently looking at getting the community involved.
There are a number of areas that the community can be involved:
Swamp Sclerophyll Forest Maintenance
This is similar to dry forests however once the canopy has been established and weeds removed there will be less and less maintenance to be done except for around the edges. To help in this area a 3 metre buffer zone will be planted that inhibits wind born seeds. This also allows birds and animals to rest in this area and leave behind their droppings and therefore the seeds of weeds that they have consumed.
Conclusion
The creation of these wetlands is a great step in the treatment of stormwater we as developers, society and individuals can and should do a lot more for the environment in general.
At this point in time Delfin Lend Lease is presently doing a complete review of its sustainable developments looking at such things as rain water tanks, solar hot water and use of grey water just to name a few.
This is where all of us should be asking ourselves:
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