DEEP CREEK

The Hon. SANDRA KANCK (14:35): I seek leave to make a brief explanation before asking the Minister for Environment and Conservation questions regarding advice from departmental officers about the drying of Deep Creek.

Leave granted.

The Hon. SANDRA KANCK: When departmental officers appeared before the Natural Resources Committee's Deep Creek inquiry, conflicting and unhelpful answers were given. Dr Deering at one point stated that he could not pre-empt the outcome of the water allocation process that was under way but that forestry 'may well be treated as a water-affecting activity', but then he said, 'the allocation of volumes of water for use for different activities is very clearly a water allocation planning process.'

Mr Harvey told the committee that the department does not know how many dams were in the area in the past, whilst Dr Deering told us that they have 'quite extensive aerial photos and surveys of a whole range of dams,' which was then tempered by Mr Harvey's statement that, 'Our interpretation was based on two sets of aerial photographs. This is the best information we have.'

The minister's response to the committee states, 'Government considers the impact of rainfall, dams and any further development of forestry are a more significant issue than the removal of plantation area.' Yet Mr Harvey told the committee that 'interpretation of those dam findings is speculative, and those aggregate volumes could vary by plus or minus 50 per cent.'

Asked about providing the committee with up-to-date research, Mr Harvey said, 'I do not think we can provide you with anything that will be particularly helpful in this discussion at this time.' When pressured, he referred to what he described as a 'technical report' that was 'considered not necessarily appropriate'.

That so-called technical report is most likely a 30-page CSIRO report by Casanova and Zhang entitled (and listen to the title) 'Fleurieu Peninsula Swamp Ecology, Swamp Hydrology and Hydrological Buffers'. The information about the existence of this report was not volunteered to the committee and only came about through private citizens making us aware of it.

Mr Harvey told the committee that people within the department had dismissed it because they preferred something called a 'water balance' theory and 'they did not feel it was useful in our environment in South Australia'.

This report, although rejected by the bureaucrats, disproves the minister's statement that there is no scientific evidence that the Upper Deep Creek catchment was a perennial stream. Asked whether it was the case that all the bureaucrats could offer us was 'an educated guess' as to what is going on down there, Mr Harvey simply replied, yes. Dr Deering described the departmental view as 'informed speculation'. My questions are:

1. What is the minister's explanation for the conflicting points of view of the departmental advisers?

2. Why did the departmental officers not volunteer information to the committee of the existence of the Casanova and Zhang report? Were the authors of that CSIRO report placed under any pressure by bureaucrats to alter that report?

3. Given that the minister claims that there is no scientific evidence that the Upper Deep Creek catchment was a perennial stream, how does she account for the existence of the Foggy Farm swamp? Is she aware of any scientific evidence, anywhere in the world, of swamps forming and existing without an all-year round supply of water? Will the minister advise the parliament how many years it takes for a swamp to become a climax ecosystem?

4. On the basis of conflicting statements and a knowledge base described as or admitted to by the bureaucrats as being either an 'educated guess' or 'informed speculation', what is the scientific basis of the minister's conclusion that dams are more the cause of the creek drying than forest plantations? Is her view also based on informed speculation?

5. Did any of the departmental officers mislead the committee, and has the minister herself been misled by them?

The Hon. G.E. GAGO (Minister for Environment and Conservation, Minister for Mental Health and Substance Abuse, Minister Assisting the Minister for Health) (14:40): I thank the honourable member for her questions. The land use in that area has changed considerably over the years and so, too, the land use has impacted on the watercourse and on the water catchment area. That has changed over the years from native vegetation to being cleared for farm use—which a lot of that area still is–and some of it is now used for forestry. The land use has changed and, as the land use has changed, so, too, has the impact on the watercourse.

The bottom line is (and I have talked about it in this place before) that the government does not agree with all of the outcomes of the parliamentary committee's report. We have, in fact, supported eight out of 10 of the recommendations made by the Natural Resources Committee; so eight out of 10 we have agreed with or support, and there are two we do not. One is outside our jurisdiction and the other one relates to the buffer zones, which is clearly the issue that the Hon. Sandra Kanck is concerned about.

We do not support the recommendation to create buffers by removing portions of existing plantation forestry in the Foggy Farm area. We have indicated that, in terms of the NRM water allocation planning process, we believe that, as our science has improved and been fed into our planning processes, the water allocation planning process will pick up a lot of the new science, and the rules about buffer zones and suchlike will change. That is a good thing. Nevertheless, we are talking about a forest that was legally planted at a time when the particular science we have now was not available.

Forestry occupies only six per cent of the total Deep Creek catchment area, and it is not considered that forestry has been the principal reason for stream flow decline, as reported by the committee. On this matter, the technical conclusions that I had been advised of within the report appear not to have taken into account all the available technical information. That is the best technical advice that I have received from my people. The Natural Resources Committee appears to have based its observations—this is the information I have been given—in respect of the Deep Creek inquiry particularly on the Foggy Farm area in the upper Deep Creek catchment.

Foggy Farm is located on a very small tributary at the lower end of the upper catchment area. Unlike some of the suggestions in the report and some of the comments made by other members, Foggy Farm is at the lower end of the upper catchment and not the upper end of the lower catchment. Everything that occurs goes from east to west and north to south, so everything that occurs at the top of the catchment area occurs at the lower end of that upper catchment area.

This particular area does not necessarily typify the broader Deep Creek catchment, nor the overall risks for that particular catchment area. I have been advised that Foggy Farm is about 200 hectares and is less than five per cent of the total Deep Creek catchment of 4,128 hectares. The committee reported that there were no dams in the upper Deep Creek catchment and ignored the impact of dams on flows in the total Deep Creek catchment.

An honourable member interjecting:

The Hon. G.E. GAGO: I have been there and have seen the dams: there are 37 of them. I have driven around there and seen those dams in the upper end of the catchment area that feeds into the Foggy Farm area. To suggest that there are no dams there, members need to get out of their seats and go and have a really good look around—not a biased and skewed look around: they should open their eyes and look at all the facts and not at just their own personal biases. Based on aerial imagery from 2001, there are 37 dams located in the upper Deep Creek catchment, with an estimated capacity of 50 megalitres, according to the advice I have been given. We can give or take a megalitre here or there, but nevertheless there are dams there of a significant number and of significant volume.

The total Deep Creek catchment dam number has nearly doubled and the dam volumes have increased four-fold, according to my advice, since 1972. That advice also indicates that in 1972 there were only approximately 106 dams, with an estimated capacity of 185 megalitres; in 1989 this had increased to 126 dams, with an estimated capacity of 333 megalitres, which increased further in 2001 to 157 dams, with an estimated capacity of 744 megalitres. So we can see that the volumes estimated for these dams have significantly increased over time.

I am advised that the current modelling by CSIRO indicates that a relatively small reduction of 15 per cent in rainfall, an estimation, can reduce catchment water yield by 30 per cent. Obviously the current drought is most likely to have a significant impact on this catchment area as well. I am further advised that the committee failed to adequately consider the technical advice from the agencies, and the official rainfall record at the nearest official recording station indicates a significant trend of reducing rainfall since 1991. These things must be monitored over periods of time, and it is important that single yearly calculations are not considered in isolation but are trended over periods of time.

Over the past 10 years there has been significantly below average rainfall for that area, according to my advice. This has been accompanied by an increase in the diversions to dams since 1980. It is important to stress that since 1980 only in seven years has rainfall reached or exceeded the long-term mean. We can therefore see the significant impact of climate and rainfall patterns in this area. This is in contrast to the decade of the 1970s, when seven of the 10 years had rainfall in excess of the long-term mean. So we can see that there have been significant patterns of change in rainfall.

Moreover, I am advised that potentially removing up to 126 hectares of plantation forestry along the Foggy Farm tributary, as recommended by the committee, is unlikely to ensure perennial stream flows in the Upper Deep Creek or Deep Creek catchments. That is the advice I have received with the best science available to me. I am further advised that the removal of plantation forestry from less than 3 per cent of the Deep Creek catchment area alone is unlikely to have a significant impact on run-off in that catchment area.

In summary, whilst the government acknowledges that forestry has impacted on flow regimes it also recognises that other important factors—including rainfall decline and, in particular, the reduction in summer rainfall and the amount of water captured by dams—have also had a significant impact in further reducing flow duration.