How healthy is our water?
Ongoing urban development, climate change and a lack of awareness about the activities that affect water quality are putting the health of our waterways at risk.
The ACT region has old soils, high in iron and clay content, leading to naturally turbid waters. The 1999-2010 drought severely affected the groundwater system supporting the creeks, ponds and wetlands and, in 2003, the worst bushfire in 100 years led to large amounts of sediment being washed into the waterways.
Canberra’s beautiful deciduous trees produce lots of leaves which, over autumn and winter, are blown and washed into the stormwater system and end up in our waterways. This large organic load is very high in nutrients and, along with other gardening activities, has the most obvious impact on water quality.
A large network of concrete drainage channels prevent water from soaking naturally into the ground. They also produce high velocity run-off during rain events which causes damaging erosion as it discharges into natural streams.
All this means that our water isn’t as clean as it could be and it’s susceptible to rapid and dramatic changes, particularly after big rain events that wash large amounts of nutrients, pollutants and sediment into our lakes, often resulting in closures. According to the ACT Water Report, Lake Tuggeranong was closed for 42 consecutive days during the 2014-2015 summer.
The most recent Catchment Health Indicator Program report ranked 37 of the 56 monitored waterways in the ACT as either ‘fair’ or ‘poor’. Eighteen earned a ‘good’ ranking and just one was ‘excellent’.
Tellingly, most of the 19 healthy waterways are located in nature reserves high up in the catchment or well away from the suburbs, while the rest are mostly found in highly urbanised areas.
These results are alarming and prove that urbanisation has a huge negative effect on water quality. With the population in the ACT projected to grow 25% by 2033 (according to ACT Treasury projections), we need to act now to improve water quality and protect our waterways.