Water filtration and storage using geology. First Creek Wetland is a constructed wetland ecosystem, and an integral part of a stormwater recycling scheme that will eventually supply all of the Botanic garden’s irrigation needs. Prior to the creation of the wetland, First Creek overtopped its banks in this part of the garden about three or four times per year. Sediment and rubbish accumulated in the creek, which was unsightly and contributed to poor water quality.
At the listed coordinates you are standing on an important part of the wetland system. These boulders act a giant filter to slow down the velocity of the water flow so that it does not damage the fragile ecosytem of the filter pond. In this pond larger aquatic native plants and microscopic microbiological life remove pollutants, viruses and bacteria from the water.
The boulders are hard resistant quartize quarried from the foot hills of Mt Lofty. Examine the boulders and answer the following tasks. Send your answers to the cache owner by message or email.
- What is the typical size of the boulders? Why are they this size?
- What is the typical gap between the boulders? Why is the gaps this size?