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Standing Committee on Climate Change, Environment and the Arts
17/05/2012
Australia's biodiversity in a changing climate

PITMAN, Mr Colin, General Manager, City of Salisbury

Committee met at 09 :46

CHAIR ( Mr Zappia ): I declare open this public hearing of the House of Representatives Standing Committee on Climate Change, Environment and the Arts in Adelaide, as part of the committee's inquiry into Australia's biodiversity in a changing climate. The inquiry was referred to the committee on 2 June 2011. To date, we have received 80 submissions and the committee is in the process of visiting areas across Australia to gather evidence focusing on nationally important ecosystems. Yesterday the committee had the opportunity to visit the biodiverse wetlands of the Coorong, Lower Lakes and Murray Mouth region. The committee is grateful to officials from the South Australian Department of Environment and Natural Resources for facilitating yesterday's visits.

The committee is looking forward to hearing from the department and a range of other witnesses today. I welcome our first witness, Mr Colin Pitman, from the City of Salisbury. Although the committee does not require you to give evidence under oath, I should advise you that this hearing is a legal proceeding of the parliament and therefore has the same standing as proceedings of the House. Colin, we have not received a written submission to this inquiry from you, but in a moment we will ask you to make an opening statement. Before you do that, I want to thank you for your time, not only in being here today but for showing us through the Greenfields Wetlands here in the City of Salisbury and for giving us a rundown and understanding of the history of both the wetlands and Salisbury, how they operate and function and what their potential is. I will now hand over to you and you can give us an overview or briefing before we get into some formal questions.

Mr Pitman : First of all, Chair, I must acknowledge you as the previous mayor of the City of Salisbury and the work that you did in managing the issues I am about to talk about today from a political point of view. Much of what we are talking about today would not be possible without the efforts of Tony and his team whilst he was Mayor of the City of Salisbury and also as a councillor for many years. I am going to talk about two categories of work: firstly, the stormwater recycling project, which you have, in part, seen in the flesh; secondly, the grasslands project, which is actually a fairly significant initiative. It is the only initiative in this state at the moment which is designed to actually establish and re-establish grasslands in an urban area—it could also occur in rural areas—to offset the carbon footprint, in this case of the organisation for which I work.

In terms of carbon reporting, we have done a carbon assessment of the organisation and we are just on the boundary of having to move into reporting on carbon. We therefore have a challenge to keep our production of carbon down, in accordance with the new legislation, to a level which does not require reporting. That is coupled with many other initiatives that we have introduced which include energy management systems in all buildings and the stormwater recycling project, which is providing water to the city at a very low carbon footprint level. Copies of this presentation are available in the bags that you have so that you do not have to make any copies.

Aquifer storage recovery is about taking urban stormwater—that is, water that comes from industries and homes—cleaning that water, and pumping it into aquifers. We will talk about two cleaning techniques today. Aquifers are basically permeable beds of sedimentation, which are bounded above and below by clay layers. These are called the confining layers. In pumping the water in we can displace that water. The water displaces horizontally. In most places across the world the aquifers are connected to the sea. We store that water in a saline environment, generally. We do not tend to pump water into good, fresh aquifers, because those are the ones that people use and we do not want to be putting our water alongside somebody else's consumption. We pump that water out from the same bore.

I will just expand on the way in which we clean our water. We clean it in wetlands. The wetlands take out the heavy metals, which are taken out by the suspended solids—that is, the clay particles. The nutrient load is taken out by the macrophytes or the reeds, and the silts are deposited by sedimentation, fairly quickly. Within 24 hours we can get about 90 per cent of those taken out of the water column with the horizontal flow wetlands that you see here.

The water that is pumped into the aquifer and taken out is distributed in Salisbury through 121 kilometres of pipeline. The Commonwealth government assisted us in rolling this program out. The pipeline layout you see on the plan distributes water to key water-consuming customers. As I indicated, this business that we have created, which is an internal business with an external board, is designed to make a profit. All costs attributable to the production of that water are costed to the production of that water—that is, energy costs, depreciation costs, debt-servicing costs, operating costs, pump costs and replacement costs of equipment. In that layout we have 13 production sites, all receiving water from a combination of wetlands. I will show you a plan shortly of how those wetlands can combine. There can be several wetlands on the one stream and they can combine to produce a series of production sites along that stream.

You will notice that we have the sea on the left-hand side of the screen. The sea is the Barker Inlet. It is very similar to many other inlets around Australia. We have a target of making sure that all stormwater that enters the sea is cleaned through wetlands before it enters the sea to ensure that the ecology of the sea is also maintained.

At the moment we have 24 bores into the tertiary 2 aquifer, which is 190 metres deep, and 37 into the tertiary 1 aquifer, which is 100 metres deep. There are two aquifers there. Generally the deeper one is the one we are focusing on. It is the one we have the least number of extraction bores from that other people are using. We have to be careful we do not over-pressurise the aquifer and cause artesian effects on other bores. So we are focusing on the tertiary 2 aquifer. In Perth, Sydney, the Gold Coast and recently in the Grampians we have been focusing on the tertiary 2 aquifers. The age of those aquifers is what gives them their designation.

We have 71 wetlands, of which 29 have ASR bores. Many of them have flood control dams leading to them. These flood control dams enable us to hold water back and batch process that water into the wetlands downstream at the pace the wetlands can clean it. There is 121 kilometres of pipe. We have 31 schools connected and 41 businesses. That has increased recently because we have been able to secure a major chicken processor, who is taking our water because it is cheaper. They are cleaning it to drinking water quality on-site and using it in the chicken processing. Interestingly, they now fillet their chickens with a very high pressure jet of water. I was shocked the other day to see them cutting little heart shapes out of the side of a chicken using computer controlled techniques to supply a product to the market which is associated with American customs.

As I said, there are 41 businesses. There are also a large number of council reserves. We sell to the council itself; we do not give the water to the council. So the business sells the water to the council at the same price it sells to the private sector. We have 2,700 homes now connected and we supply about 2½ thousand homes outside the city, at a subdivision called Lightsview in Northfield. So we do not just supply within the city; we have customers outside the city. There are 4,300 at Mawson Lakes, which is a subdivision to our east, and a large number of other customers.

We have the capacity to supply about 12 gigalitres to the market and we hope to eventually get to about 25 gigalitres. Twenty-five gigalitres in dollar terms is about $80 million worth of water and, in Adelaide terms, about one-quarter of Adelaide's consumption from the River Murray. So we are not a small player in the market. This little old council actually has the capacity to produce enough water to supply a quarter of the consumption of Adelaide from the River Murray.

Ms MARINO: What is the price per gigalitre?

Mr Pitman : Approximately 75 per cent of drinking water prices in Adelaide.

This is one of our projects, on Parafield Airport. The airport is in the middle there, around the blue things. Those blue lines are drains. We take water from those drains, clean it in wetlands and supply it to customers. That particular project is netted. It is next to the runway at Parafield Airport, just north of here. You will see there are three white areas there. One is the receiving basin, another is a storage basin and the other is the wetlands. It is all under a net because we are not allowed to increase birdlife on the airport, and it is not on our land. You do not have to put these wetlands on your own land; you can put them on somebody else's. We lease that land for 99 years, and that is a sublease from the Commonwealth. So we have a degree of permanency at that airport.

These are the wetland plants underneath the white netting to restrict bird activity at that site. These are the recharge bores on the site. We have nine recharge bores at that site. It is a very good site. We have two very good sites in Salisbury where we inject a lot of water. We supply water to people like wool processors. Michell Wool, which currently employs about 250 people, were going to pull out of Adelaide and go to China. They partly have but they have been able to retain their business here because our water prices are low and salinity is low. They are able to use that water three or four times. So we have kept that business here and they have not offloaded to China. While the exchange rate has been high, they have been sending wool over there; they have still kept this business going. If the exchange rate drops, they will be cleaning wool here and sending it to China rather than the other way round where they send slightly dirty wool to China and we, of course, buy it back in garments.

This slide is of another wetlands type that we have got out here—horizontal flow. It is another large wetland, which is a high-producing wetland. It is there for flood purposes. It is about two kilometres by one kilometre. It is the type of thing that we have been doing. This is what it looks like at ground level. This is one of the batch processing dams where we capture water in creeks. We hold it and batch process it downstream so that we can increase the production from a stream and treat the water at the right rate before we put it into the aquifer. We must meet EPA targets before we put that water into the aquifer.

This slide shows another variety of wetlands—and we are not far from the end of this particular section—where we have put in sand filter beds. The water flows vertically in through the sand—about a metre and a half. One of those cells performs the same thing as this whole site here and at a much faster pace. That is the technology of the future. We have got 21 of those installed now. They are not large. You can put them on an urban block and clean the water for a subdivision of about 500 homes. That is the type of thing for the future.

Dr WASHER: Sorry to interrupt, Colin. Just to clarify: it is only 1½ metres of sand that you are running the water through.

Mr Pitman : It is 1½ metres of sand. It is gap graded sand but it has what we call a nanotechnology coating on it, which is a single cell thickness of material which we invented here at Flinders University that covers it, and the cleaning rate is very, very rapid.

Dr WASHER: 1½ metres; that is incredible.

Mr Pitman : It is not a lot. If it does not clean properly in one, you tip it into the next one. Once it is at the right quality, it goes straight into the aquifer. The energy consumed in transferring that water is very low because it is a transfer pump rather than a lift pump.

In the geographical context, Salisbury has a lot of rivers running through its city and that enabled us to look at those sites for carbon offsets. You will see on this slide a tree line running through the city. That is the Little Para and this is one of the sites where we have just planted 10 hectares of grassland. Grassland in the form of wallaby grass and spear grass is actually green in summer and brown in winter. So it is not a fire hazard in summer; it will not burn. In fact, spear grass—as some of you from the northern part of our country would know—is very difficult to burn in the wet season; it just will not burn. That is the type of thing we are propagating.

Mr KELVIN THOMSON: Are you saying the same thing about wallaby grass? It does not burn?

Mr Pitman : Yes. That is the same river. It has been highlighted. We can actually plant that whole river line-up with this type of grass. Here is another series of sites which are embedded in our community. These sites are also used for wetland plantings but also in those wetlands we were able to plant these carbon offset plantings. We are currently the leading council in Australia propagating this type of plant. It has not been done anywhere else in Australia to the level that we are doing it here. This slide shows one of the wetlands where we are going to plant the spear grass and wallaby grass.

This is the last slide. Just to indicate what the system can achieve, we have here the spear grass and wallaby grass. It is carbon credit versus agents of the plant. It grows fairly quickly, in a few months, to the right offset point. Within 10 years we are actually getting a return of $20,000 per annum on 10 hectares. This is not taking into account the fact that we do not have to cut this grass. That is $20,000, for 10 hectares, of savings in carbon credit. That is the direction we are heading to offset our carbon.

A lot of science has gone into this already, unlike with woodland. You will know from people that present to you that the science attached to the carbon offsets associated with woodland is not thorough. In relation to grassland, there has been some very good work done. We continue to innovate in this area and we get a lot of press inquiries, and that is one of them.

CHAIR: Thank you very much for the presentation. Even though I am familiar with the work that the city has been doing for years, I think the work now with your grasslands is equally exciting, given that not only is it good for the environment and for biodiversity generally; it also fits in very well with trying to capture carbon and reduce our carbon emissions across the country. I might hand over to my colleagues, given that I probably know much of the answers to the questions that I might have asked. But, in terms of the grasslands, how far are you down the track with that work and how long do you think it will be before the city is in a position to claim the credits from the work you are doing?

Mr Pitman : The initial work over the first three years was to get these grassland seed banks established. Nobody has reaped this type of plant in a broadacre sense previously. We have been developing a technique whereby we can actually reap the seed and collect it. Just to give you an example: the way in which we collect the seed for wallaby grass is that we have developed lawnmowers which are mounted on high wheels, and we cut the top off and the seed just drops on the ground, and then we run over it with a sucker and suck it into something like a street sweeper on the front of a truck and suck that seed into a bin and then bag it up. Getting to that point, to know how we could do that, was last year's exercise. This year's exercise is to plant 10 hectares. Next year's exercise is to plant another 30 hectares and market the seed. We have just had a grasslands conference here in Adelaide, put on by the Salisbury council here at Mawson Lakes and attended by 150 people—very good attendance. There has been a lot of interest and already we have got orders leading out many years for our seed bank.

Coming back to answer your question: my guess is that immediately we plant we are going to get some increase in carbon offset, and that will tie in with our reporting requirements, which start in June of this year. We have got around 400 hectares to plant, so you can see a lot of benefit will be created. We will be able to trade those credits into the market, because we will be producing more than we need. That is our intent anyway—to trade credits and also to trade the seed bank into the market.

Ms HALL: Are there any negatives associated with introducing the wallaby grass to this area?

Mr Pitman : We do not know of any. Wallaby grass grew here originally. It was a native—a particular variety of wallaby grass.

Ms HALL: And that is the variety that you are using?

Mr Pitman : They are the ones we have planted. We have actually reaped native Indigenous plants from around the area on roadsides where it has not been decimated by farming, and that is the seed stock we are using.

Ms HALL: I thought you were introducing it from another area.

Mr Pitman : No. This debate about where you are able to take your grasses from is quite strong in that industry. I had not realised it until I went to this conference and saw people debating the genetic variability of plants on the Eyre Peninsula, exactly the same plant as they are in Adelaide but they are genetically quite different. We have said that if you buy our plants we are not going to sell to the eastern states, we are going to sell them here where we know they have been originally. That might be shooting ourselves in the foot but it says, 'We will show you how to do your planting and how you reap it,' because that is the technique. You have got to lay plastic down, cut holes and plant there so that when you reap the seed it falls on the plastic and you do not lose it and get it mixed up with other plants. There is a technique there. We are going to operate a consultative service to assist people in understanding how they do this piece of work, but we are not intending to market our product into areas where it has not been previously grown.

Dr WASHER: Coming back to the salt, I am fascinated because WA is the king for salt; we have plenty of salt. When you said you got a high-salt soil and you grew grasses and you got shrubbery there that takes up the salt, my assumption is that these plants take up salt and they can excrete some salt back out but at the end of the day if you going to get rid of it you have got to feed it to something or cut them and take them away. You said with the heavy metals it is not necessary. You manage to retain the salt for some considerable time, but surely at the end of the day you must have to cut those plants or take them way because there would be a limit to the storage of salt before you supersaturate them.

Mr Pitman : There are two components to the plantings. The terrestrial plantings are on the land. They do not take up any salt at all, they survive on the boundaries because of the freshwater interface. The salt that is in the soil is held very tightly in clay, what they call micro clay. There is some in Perth but not a lot of it. Most of your land is sandy. That salty water is held in those mounds which we have created. This is a flat area and these mounds have been created artificially. We have taken soil and put it up in the mound. The water has stayed in the mound, a bit like the water mounds in Perth where the water gets drawn up. The salt water has actually stayed there.

Dr WASHER: Stops leaching.

Mr Pitman : It does not penetrate the wetlands alongside. You would think the rainfall would push it outside. We have not observed that, so that has been a plus. Coming back to the nutrients that are in the plant, the metamorphosis of the plant nutrients, the nitrates and phosphates in the plant, it is a bit like the plant you have in your garden where you put phosphates and nitrates on your garden. The nitrates are absorbed by the plants and are extruded to the atmosphere as nitrogen. The phosphates and other components are taken up by the soil in stable forms, not forms that will leach back into the system. That has been our finding. We did not think it was going to occur originally but that has been our finding. We have had botanists and biologists poring over these sites trying to understand what was going on. We intuitively did these things not knowing what the science would find, but the science has now confirmed it, so we are okay. Papers have been written on this, and they are available for people to read on our website. They are the papers we know about; a lot of papers have been written about the wetlands that we do not know about. They are available for a given community to observe. Clearly in some parts of Australia and overseas the geology is not the same and therefore you have different situations. We are working with a Berlin university with trials in Spain, one in Calabria, one in Slovenia and one in Syria. It is the same sort of system but different soils and slightly different aquifers. Many of the learnings we have had here are able to be reciprocated there, but there are obviously some local conditions which do not necessarily pattern themselves on the same sort of thing we are doing here.

Ms MARINO: Thanks, Colin. There are just a couple of things. You have wetlands coexisting in the community. In the initial stages, was there resistance from the community to that type of work?

Mr Pitman : Good question. Tony Zappia would recall that we had quite a degree of negativity in the press about the building of the wetlands: 'Why are you building these duck ponds? Why are you spending ratepayers' dollars on building duck ponds?' It took a lot of communication with the community to lift the level of the community's understanding. Tony would know. He, I and people before him were in the press a lot. It lifted people's understanding and their education in relation to what we were doing. It would have taken five or six years to get that plateauing out of people's understanding generally. There were still doubters in the community, but our argument was that in places like this it is not there just for water recycling; it is there for cleaning water before it goes to sea and it is there to ensure that these areas do not flood. They are fairly sound arguments. We pounded the airwaves with that philosophy, and it actually caught on. That is why other councils are doing it now.

Ms MARINO: You know some of the issues in Western Australia. Has there been any issue with increase in mosquitoes and concern about the likes of Ross River virus and other problems associated with wetlands in such close proximity?

Mr Pitman : Good question. By the way, there is a wetland conference next month in Perth which I am presenting to, so there will be an elevation of this issue in the Western Australian environment. There has been this incessant concern about mosquitoes. We sample water in backwaters in our wetlands to see if we can pick up evidence of mosquito larvae, and we just cannot find them. That is because our wetlands are infested with mosquitofish, and the larvae are their only diet. If you walk over to the edge of that water there, you will see masses of little fish about that long. They have a mouthpiece which sucks. All they eat is the larvae of mosquitoes, which hang off the meniscus of the water, and we just cannot detect the larvae. We have also had a university study done here where they have captured mosquitoes in this area, and 99.9 per cent of mosquitoes are saltwater mosquitoes; they breed in the mangroves. They are not freshwater mosquitoes, so that doubles the evidence that we are not increasing the mosquitoes in the community. We have not had that virus in our community here in any strong way. We have had an increase in Ross River virus; I think it was about two years ago. It was not related to this; it was related to the fairly heavy rainfall event after the long drought. There was a jump in reports of Ross River virus at the time.

Ms MARINO: Thank you for that, Colin. Given the location and the pressures and challenges facing councils for land use planning, and given that you have quite an extensive wetland area, in the agreement between council and others in relation to planning, how extensive has been the pressure from outside to use that land for alternative purposes given its location and its value?

Mr Pitman : That is again a very good question. We in Salisbury, by the nature of our development, had to create wetlands because we did not have large drainage infrastructure across our city. It has a very flat floodplain and it is not easy to get water to the sea. That means they are really locked into the urban form because of the need to retain them for the purpose of managing floodwaters off residential areas. Along has come the concept of water-sensitive urban design, whatever that may be—I am sure this committee has heard about it incessantly across the nation—but wetlands complement that. In other words, they take the water from the residential or the urban form, clean it and deposit it. So it has become an essential part of the city. Having said that, there are other parts of our urban form—reserves and the like—where we have over-taken from the developer.

In South Australia, 12½ per cent of each residential development should be allocated open space. It is different in every other state; let me tell you, I hear about it every time I move from one state to the other. Some states have more than that; some states have none. Because we did not know what the future would hold, we have pocket reserves across our city. There are about 400 of them, allotment size. They are of no use to the community for recreation unless they have some facilities on them—a playground or the like. We are going through a process of selling those off. That money is going back in to offset debt. At this stage, it does not go into operating costs or budgets at all. It all goes into offsetting debt. A council like ours, because of high growth, still holds debt—not significant debt, but now that growth has stopped we cannot afford to continue with that level of debt and we have to offset some of it. So that is what we are doing.

We have a large program of urban renewal. We have one project in the town centre of Salisbury at the moment, trying to attract residential development. We have urban renewal occurring because we have intervened, along with the state housing authority, and there have been a lot of knockdowns and rebuilds. In those cases, we have actually consolidated reserves to make them effective and functional within the urban form and we have taken out a lot of those pocket reserves where we have identified them as not being useful. A lot of consultation has gone on; very heavy consultation has taken place. A typical example, which Tony would be aware of, is Salisbury North, where we consulted incessantly to make sure the community were across what we were doing. That has been an outstanding success at one level. It is up for a Planning Institute of Australia award next month. That is the type of accolade we are getting.

Ms MARINO: Concerning the monitoring of the aquifers themselves, you mentioned they are all connected to the sea and that, as you pump in, it forces water out. So, as you extract, the pressures would bring seawater in. With regard to the ongoing monitoring of the aquifers, how is that managed and who is responsible?

Mr Pitman : The responsibility fundamentally rests with the Department for Water in Adelaide, which has been set up to handle Murray River issues as well as all other water issues. It used to be part of the department of environment but, because water now has a bigger focus, South Australia—like every other state—created their own department of water, and that is where the responsibility rests. They have a statutory responsibility to monitor the water levels in the aquifer. They also have an obligation to license extraction from the aquifer. In our case, they offer us a licence on extraction on the basis of our injection volume: we are not allowed to extract any more than we inject. We must be in balance. At the moment, we are in credit; we have about 12 gigalitres in the aquifer in reserve in the event we have a drought. So we own that water, effectively, by licence.

Ms MARINO: For how long?

Mr Pitman : For 10 years. If we put water in 10 years ago and we do not consume it, we would then lose it. We also, rightly or wrongly, have to leave 20 per cent of what we inject in the aquifer. We are only allowed to extract 80 per cent of what we inject.

Mr KELVIN THOMSON: My questions have been answered in the course of the inspection and the presentation and in the written materials you have provided, but I want to make the observation that I think this is a really exciting piece of work. My own council, the City of Moreland, together with the local water authorities, Melbourne Water and Yarra Valley Water, has been doing work on a substantial stormwater harvesting and recycling project. I shall certainly be taking this material back to them to find out how aware they are of the City of Salisbury's work. It seems to me that the experience you have built up in terms of the business model and the environmental model is terrific and worth spreading as far and wide as we can.

Mr Pitman : That is an important point: getting the message out. I get dragged all over the country to tell people about it and to talk to councils.

Ms HALL: I am talking to my council and Hunter Water about your project and I will be handing the material I have received today to them. It is very impressive.

CHAIR: Thank you for your time and for the insight you have been able to provide to committee members with respect to the work occurring here in the City of Salisbury and around it. I am a little disappointed we did not have more time to talk about some of the other biodiversity projects I am aware the city is involved in, because they also relate very much to the terms of reference of this committee. You have presented the committee with some information and I ask a member of the committee to move that the document entitled 'Australia's biodiversity in a changing climate', presented by the City of Salisbury, be accepted as evidence and included in the committee's records.

Mr KELVIN THOMSON: So moved.

CHAIR: Thank you for your evidence.