Lynne Turner - National Management Study Coordinator, Coastal CRC
Well good morning everyone and firstly before we get underway I'd really like to express my sincere gratitude to the Sutherland Shire Environment Centre and also to the Port Hacking Protection Society for their proactive stance in actually bringing this forum together. It's exactly this type of forum that we've been hoping communities all around Australia will use to actually help get estuaries on the agenda. Estuaries in Australia have very much been the 'middle child' of catchment and sea management. They live on the management and protection 'hand-me-downs' that catchments may offer them which may directly or indirectly - and quite often not - actually meet the specific needs of our estuaries. And similarly, estuaries also receive their share of bad press for creating problems for our seas.
Basically what I wanted to do was to leave you with two key thoughts. Firstly, that all Australian estuaries are unique systems; they are dynamic systems; they're constantly changing and that's part of what makes them special. But within that there are different types of estuaries and we can actually do some further characterisation of those into groups. The second point is that we know that some estuaries are suffering as a result of human activities and are not coping well with the increased pressures and stresses that our activities have placed upon their ecosystems.
If you could look at the map on the wall. Different coloured dots on that map show different types of estuaries. So you can see that North Queensland is predominantly blue on that map, and where we are here in NSW is predominantly yellow. If you contrast that then with the 'condition map' which tells us how healthy estuaries are, you can see here that where they're yellow over there, they're pretty much all red, because this is where all the people want to live and up here where you've got your blue class of estuaries, they're all in pretty good condition on this map. So that will all make sense to you a bit later on, but what I wanted to say at this point was that NSW is to be commended for its proactive stance in not writing-off our urban estuaries, in treating them as assets that are worthy of protection. Most of our wave-dominated estuaries occur in this section of coastline, and they're already experiencing a lot of stress. Our population in Australia will only continue to grow over the next 50 years unless we get serious about population capping and some of those other initiatives. And most people want to live where there isn't too much humidity, and where there aren't too many mosquitoes and I think that NSW and this section of coastline will probably be the section that faces a lot of that increased growth.
So the key issues, as I see them, from the work that I'm going to be presenting today as part of the National Land Water and Resources Audit, is that it's really difficult to asses the health of Australia's estuaries. You're comparing systems that are quite different from each other and very unique. And quite often we find it difficult to categorise "What is a healthy system for that particular system?" and we tend to look more at signs of 'unhealth'. So we can tell when a system is out-of-balance but it's often more difficult for us to tell when something's going great.
It's important to understand the different type of estuaries because some estuaries will trap sediments, whereas others will export sediments to the estuary's nearshore environment. I'm really pleased that I followed Gary and the Dharawal people presentation because the condition map only shows the legacy of the impact that we've managed to make as a society since 1770. So in that small amount of time, things have gone from green dots to a fair smattering of red dots. So I guess we've got a lot to learn from the indigenous culture in terms of our inability to read, understand and empathise with their landscape. And until we can actually harness that level of estuary literacy or just general landscape literacy among the general Australian population, we're going to have a lot of difficulty getting governments and decision makers to actually implement and act on policy that will help us bring about the things we believe are important. For instance, George highlighted some really topical local things where the local government has had some power to actually implement things but for various reasons, the political will hasn't always been there to bring about the change. So unless you can improve everybody's literacy and passion for estuaries, I think that it makes it very difficult for the decision makers to feel that they should be taking that stance.
And finally I just want to touch on some of the information products and knowledge that has come out of the National Land and Water Resources Audit. The information is available to all of you online via the Internet which can help you support your local decisions and also provide feedback. You are the ones who live, work, play in your estuary and know the system just as well, if not better, than most of the rest of us. Some people, indeed, have such a passion for a particular issue within an estuary that they spend their life doing scientific endeavour on it. However, they're a small exception. So I guess, what I'd also like to emphasise is that scientific knowledge isn't the only knowledge that's important in estuary knowledge. Local knowledge, indigenous knowledge and scientific knowledge all need to be integrated into a true partnership of knowledge-sharing before we can actually make a real differences for urban estuaries, particularly where there are so many stakeholder interests to be addressed.
The work that I'm presently here isn't my work exclusively. It's the work of a collection of many people from the University of Queensland, CSIRO Marine, Geoscience Australia, Coastal CRC and in NSW, the Department of Fisheries, DLWC and EPA.
We actually took a very broad definition of estuaries. What we wanted to do was not miss out some really key coastal waterways just because they aren't strictly from a geomorphological perspective true estuaries. I don't know why ports and shipping has jumped up over all these estuary values though I'm really glad that Dave Alden's coming next. But what I wanted to give you an impression of was that if you've got a system that's experiencing good ecological health, it can support a range of different beneficial uses. And the way that we actually see estuaries, in terms of our own value-system can actually bias assessments. But even the most staunch economic rationalist should be interested in the protection of these urban and other estuaries because wealth-creation is only part of our economic paradigm. It rests very squarely on capital protection of the assets that support such a range of values.
So in the assessment, we talked a little bit about the importance of understanding the type of estuary, and understanding the estuary condition. Firstly, the type. When we come to NSW, the type we're predominantly looking at are the wave dominated estuaries. The reason why type is so important is because type governs how the estuary will actually function. So for instance, around tropical North Queensland and up in the Territory and Gulf, the estuaries tend to be net exporters of sediment. So anything that comes down through the catchments actually enters the nearshore environments via the estuary. The estuary just 'handballs' it straight on. What tends to happen in your NSW estuaries - your wave dominated estuaries - is that you've got a naturally high sediment-trapping efficiency. So a lot of the material that actually enters the estuaries from the catchment and from adjacent landuse will stay within that estuary. And that is a significant issue when you've got things like septic systems, and nutrient inputs. So it's important to note that there are different estuary types and that different estuary types have different susceptibilities to different triggers such as sediments, turbidity, circulation and nutrification. We've tended, in the past in Australia, to adopt a northern hemisphere approach to estuary management which hasn't always taken into consideration the diversity of Australian estuaries which is not surprising given that we tend to take awhile to appreciate the diversity of our own landscape.
The process-based classification is done by balancing or calculating the relative importance of wave, river and tidal energy in governing how a particular system works. But basically the take-home message is to look at this section of the NSW coastline and contrast it with the northern section which is where the predominance of 'near pristine' estuaries are. I'd really like to reinforce Ron West's point about the need for a comprehensive and representative system of estuaries and even just habitat types within particular estuaries. The situation we have is that people have wanted to live in the same types of estuaries because they have the same types of characteristics, They offer us good places to live so what happens is that we destroy what we've come to enjoy. So even though when you look at the statistics for Australian estuary condition, you see that half of them are in really good condition, they're not where the people are, and they're a different type of estuary.
This is just an example of some of the habitat types that you can find in different types of estuaries. We actually got Geosciences Australia to confirm that triangular plot on this map (slide) by doing some mapping of the geomorphologies because some of the different sedimentary environments that you find are diagnostic of different estuary types.
The condition assessment. Its really hard to work out what's considered healthy. So what we basically did was an assessment of the extent or the characteristic of the different flora and fauna types that Ron West pointed out to us as well as an assessment of the pressures they face, e.g. is there a port there, is there a city there, how is that estuary being used? So underneath the State score: if an estuary was experiencing serious caulerpa outbreaks, or serious events of inexhearin hypoxia, it could not be classified as a 'near pristine' estuary so you therefore put that particular estuary straight into one of the 'modified' categories. We used the term 'near pristine' as an acknowledgement that no system has been unimpacted by man in some way. So to have the concept of a 'pristine' estuary in a modern context is not usually acceptable.
We also then focussed on water quality and sediment quality together, then habitat condition, and fish condition. The fish condition one was really tricky and I'm sure Rob Williams will make great inroads on that one for us. With the 'pressure score', we wanted to take into account both the natural susceptibility of a system in terms of its flow and flushing differences, (for instance, wave dominated estuaries, as we've seen, trap more material within them so they are naturally more susceptible), and also the extent to which we've changed the natural flow and flushing regime. So, for instance, if you've put an impoundment or a dam upstream and the freshwater flows are no longer reaching the estuary, then that's the type of thing that was included there. We also had a look at the utilisation index which measures how the estuary is used and how it's managed for multiple use if that's appropriate. We had a look at 'responses', but we didn't score 'responses', we just made a note of those to assist anyone who's interested in adaptive management.
A lot of the NSW urban estuaries fall in to the 'severely or extensively modified category experiencing high pressure' category. So what we'd ultimately like to do is to protect some of the systems within those estuaries where possible because if they're still intact now, then they're worth protecting because they really are at risk. And we'd like to prevent any further decline for a lot of those systems. But obviously the type of 'response' that you'd actually take is one that is up for community discussion and debate and depends on community priorities. But if you're talking about maintaining the ecological health of estuaries it does give you an indication of some of the appropriateness of certain management responses.
I just wanted to mention that we do regard community information as being worthy of inclusion in assessments such as this and so we developed a range of data-confidence tags so that we could incorporate both anecdotal information and community information collected through programs like Waterwatch. This represent valuable sources of information and are really worthwhile. We could not have actually done as many of the estuary assessments as we did without those community groups and their generousity in providing data because the scientific community has only really studied about 50 of Australia's 1000 estuaries in any detail.
NSW, with South Australia has one of the highest percentages of 'extensively modified' estuaries and the smallest percentage of 'near pristine' estuaries. You can see there's very few green dots in NSW and those that do occur are within the national park systems, so they're already protected systems. A lot of those wave-dominated systems are in the 'extensively modified' category. So of the 92 'extensively modified' systems, roughly a quarter of them are wave-dominated estuaries. Tidal flats and creeks are the most predominant type of estuary that we looked at. These wave dominated estuaries only really make up 16% of the total types of estuaries that we looked at.
In terms of the focus, I think we need to move away from estuary management in terms of managing the estuary better. Rather, it's people that we need to manage and I think George's presentation bears that out. I think the heartening thing is that we can do things better. People know what many of the solutions are now, and if we can improve general community literacy about what is acceptable and what isn't acceptable in terms of maintaining healthy estuaries, then I think we'll go a long way to actually getting the political will to actually achieve what can be achieved.
The important thing is that estuaries are valued by Australians, and that, even though we've treated them so dreadfully, they're pretty much the reason why we live and play where we do.
I'd just like to let you know that NSW being proactive will hopefully help the rest of us in addressing a lot of the issues. You have been leaders in terms of estuary management on a national scene and I don't think that Bruce would mind me saying so, but a lot of the work that has been initiated in NSW has been picked up at a national level and we'll certainly continue to do so through the driving of the National Coastal Policy. |
