By way of background, the evidence established that for many decades, prior to 1995, Shell Australia Limited (Shell) leased from the Yass Shire Council land adjacent to the old Hume Highway at Yass and erected thereon a service station which, prior to the new expressway by-passing Yass township, was apparently, one of the busiest service stations in Australia.
5 As a result of the by-pass Shell closed the service station and pursuant to its responsibilities under the lease, it was required to decommission the site which was thereafter to be used by the Council as a depot.
6 Shell commissioned OTEK Australia Pty Limited to prepare an environmental site assessment and, in particular, to ascertain the existence of any hydrocarbon contamination in the sub-surface soil at the site. Tests conducted by OTEK showed concentrations of hydrocarbons in the sub-surface soil in excess of EPA criteria at the site of old underground storage tanks. This was obviously as a consequence of leakage, over the years, from the tanks and consequential contamination of the sub-soil surrounding the tanks.
7 The appellant is experienced in the decommissioning and remediation of old service station sites and was retained by Shell to decommission the subject site. Work commenced under the contract on 28 June 1995. The appellant engaged Keough's Plumbing Service (Keoughs) as sub-contractors to carry out specific tasks, including the removal and disposal of two 110,000 litre tanks, two 55,000 litre tanks and two 26,000 litre tanks, the removal and treatment of contaminated soil as well as the reinstatement of the holes with clean fill and compaction to 98% dry density. The contaminated soil was removed to an open area of land owned by Yass Shire Council adjacent to the northern boundary of the service station site. The appellant's site supervisor was Mr Mark Stuckey, who was responsible for supervising the manner and method of disposal of the contaminated soil. Keoughs carried out that work under his instructions. Mr Stuckey supervised on-site excavations, on-site placement of soil and on-site validation. After the soil was moved to the remediation area, a process of bio-remediation was adopted to allow the removal of contamination of the soil by hydrocarbons.
8 It is convenient now to describe the characteristics of the site and, in particular, its drainage characteristics prior to certain excavation works being carried out by the appellant, to which reference will be made shortly. For the sake of convenience, a sketch plan of the site (which was in evidence at the trial) is appended to this judgment.
9 The service station site is on the northern side of the old Hume Highway which runs generally, in this location, in an east-west direction. The remediation soil area (the remediation pad) is directly to the north of the service station site. The land, comprising the service station site and remediation pad, slopes downhill in a westerly direction towards Bango Creek which flows into the Yass River. As far as drainage is concerned, there is a Stormwater channel which runs downhill from the service station site in a westerly direction. Roughly parallel to, and immediately to the north of that channel there is a drainage channel (the Shell channel) which carries water downhill from a drainage point on the service station concrete apron. These two channels merge into a main channel (the Main Channel) which flows into Bango Creek. Prior to the excavation work, to which we shall refer, there was what has been described as "a grassy swale", created by an old track, which swale ran downhill, alongside the track, from the south-western corner of the remediation pad roughly parallel to and to the north of the Main Channel. This swale formed the southern boundary of a paddock which had formerly been a keyline irrigation area. The swale proceeded down the western boundary of that paddock and reached a culvert in the old track consisting of a 300mm diameter pipe of 3 metres in length (the culvert). This culvert allowed water traversing the grassy swale to pass underneath the old track. The grassy swale then continued downhill until it merged with the Main channel. Thereafter, the Main channel reached a confluence (the confluence) with a large Sewerage Treatment Plant channel (the Large STP Channel) which entered from the north. From this confluence the Main channel proceeded, as a single channel, to Bango Creek. (The Small STP channel shown on the plan to the east of the Large STP channel may effectively be ignored for the purposes of these proceedings.)
10 Thus, in summary, the service station site was drained by the Stormwater channel and the Shell channel which both merged into the Main channel which was joined downstream by the grassy swale which drained the area of the remediation pad and the former keyline irrigation paddock. Finally, the Large STP channel merged with the Main channel at the confluence. It was no part of the prosecution case that the appellant polluted waters within the Main channel prior to it being joined by the grassy swale.
11 We turn now to the sequence of events leading to the alleged offence.
12 By 25 August 1995 all the tanks had been pumped out and the surrounding contaminated soil transferred to the remediation pad.
13 On 25 August 1995 Mr Stuckey observed damage below (i.e. immediately to the west) of the remediation pad in that the grass in the first three lines in the adjacent former keyline irrigation area was yellow. Investigation revealed other areas of dead vegetation leading downstream as far as Bango Creek.
14 It was thought by representatives of the respondent that this damage was likely to have been caused by hydrocarbons being washed off the remediation pad during heavy rain. Indeed, the appellant was charged with (deemed) pollution of waters consistently with this belief. That charge was dismissed by Talbot J on 21 November 1997, such charge having been dealt with concurrently with the subject matter. His Honour held that the real prospect of any hydrocarbon contamination from the remediation pad reaching Bango Creek had not been established by the evidence and therefore could not be regarded as " likely " within the meaning of subs. 16(2)(a)(ii) of the Act.
15 His Honour formed the view that some person or persons unknown (for whom the appellant was not responsible) had pumped product containing hydrocarbon directly onto the area immediately to the west of the remediation pad thus causing the damage observed to the vegetation in that area and downhill of the area.
16 The immediate events leading to the circumstances which gave rise to the subject charge are that there was a site meeting between representatives of the EPA, Yass Shire Council, Shell, and the appellant on 15 September 1995 when Mr Nigel Sargent, an environment protection officer with the EPA in Queanbeyan presented a plan (Exhibit G) in the form of a schematic diagram to clean-up the site as a result of the hydrocarbon contamination of the vegetation to which we have referred. Part of the plan was to remove dead or dying grass from areas affected by the hydrocarbon contamination, which areas included those above and below the culvert. Earth bunds were to be placed in strategic positions and hay bales were to be staked at intervals. Also silt fences were to be erected lower down the land. The EPA officers insisted that the work was to be done so that no erosion or sediment left the site.
17 Between 15 September 1995 and 3 October 1995 the appellant, using heavy machinery, excavated contaminated soil and vegetation both above and below the culvert in the vicinity of the grassy swale to which reference has been made. Specifically, the swale between the culvert and the junction with the Main channel was excavated to a depth of between .5 to 1 metre. This excavation was such that it created a permanent or semi-permanent body of water in which aquatic vegetation had become established by the time it was inspected by experts in 1997, in the course of preparing reports for these proceedings.
18 Certain bunds were erected by the appellant and hay bales were put in place and silt fences were erected for which shade cloth was used as silt cloth was not available locally. However, when an EPA officer returned to the site late in September 1995 he formed the view that what had been done was insufficient to prevent significant damage occurring in the event of further rain. And indeed, it rained heavily on 3 October 1995 - the day of the alleged offence.
19 The prosecution case before Talbot J (as explained by his Honour) was that the appellant, by removing the contaminated soil and vegetation above and below the culvert and in its omissions in implementing adequate works to control the flow of sediment and to stop erosion, caused pollution in that " dirty water " was flowing downhill from the excavated area above the culvert, through the culvert all the way down towards Bango Creek. The water was said to be made " dirty " by virtue of the erosion where the soil had been disturbed.
20 His Honour specifically referred to the fact that Mr Sargent (an EPA officer) gave evidence that in his opinion, the area below the culvert from where dead grass had been removed was " a channel " on the basis that it had been excised with banks.
21 It is convenient now to note relevant sections of the Act. Subs (1) and (2) of s 16 are in the following terms:
" Prohibition of pollution of waters
(1) A person shall not pollute any waters.
(2) Without limiting the generality of subsection (1), a person shall be deemed to pollute waters if:
(a) the person places any matter (whether solid, liquid or gaseous) in a position where:
(i) it falls, descends, is washed, is blown or percolates, or
(ii) it is likely to fall, descend, be washed, be blown or percolate,
into any waters, on to the dry bed of any waters, or into any drain, channel or gutter used or designed to receive or pass rainwater, floodwater or any water that is not polluted, or causes or permits any such matter to be placed in such a position, or
(b) the person places any such matter on the dry bed of any waters, or in any drain, channel or gutter used or designed to receive or pass rainwater, floodwater of any water that is not polluted, or causes or permits any such matter to be placed on such a dry bed or in such a drain, channel or gutter,
and the matter would, had it been placed in any waters have polluted or have been likely to pollute those waters."
22 Section 5 (Definitions) defines " pollute ", in relation to any waters, to mean:
"(a) to place in or on, or otherwise introduce into or on to, the waters (whether through an act or omission) any matter, whether solid, liquid or gaseous, so that the physical, chemical or biological condition of the waters is changed, or
(b) to place in or on, or otherwise introduce into or on to, the waters (whether through an act or omission) any refuse, litter, debris or other matter, whether solid or liquid or gaseous, so that the change in the condition of the waters or the refuse, litter, debris or other matter, either alone or together with any other refuse, litter, debris or matter present in the waters makes, or is likely to make, the waters unclean, noxious, poisonous or impure, detrimental to the health, safety, welfare or property of persons, undrinkable for farm animals, poisonous or harmful to aquatic life, animals, birds or fish in or around the waters or unsuitable for use in irrigation, or obstructs or interferes with, or is likely to obstruct or interfere with persons in the exercise or enjoyment of any right in relation to the waters, or
(c) to place in or on, or otherwise introduce into or on to, the waters (whether through an act or omission) any matter , whether solid, liquid or gaseous, that is of a prescribed nature, description or class or that does not comply with any standard prescribed in respect of that matter, and pollutant and pollution have corresponding interpretations." (Our emphasis).
23 It will be noted that in paragraph (c) there is reference to "any matter, …that is of a prescribed nature, description or class". Regulation (2)(b)(iii) of the Clean Waters Regulations 1972 prescribes the following as " matter" for the purposes of paragraph (c) of the definition of " pollute" in s 5 of the Act:
(iii) "inorganic matter of any description including ashes, ballast, soil, earth, mud, stones, sand, clay residue or washings from any mineral processing or extractive operation or soil, spoil or washings from any dredging operation,"
24 It should be noted, that the prosecutor particularised the charge as one of actual pollution of waters in breach of s 16(1) of the Act by removing the contaminated soil and vegetation above and below the culvert and omitting to implement adequate erosion and sediment controls as required by the EPA, thereby introducing into waters solid matter being sediment or non-filterable residues so as to change the physical condition of the waters or to make the waters unclean. The prosecution relied on all three alternatives in the definition of "pollute" and upon Regulation (2)(b)(iii) for identification of the prescribed matter for the purposes of paragraph (c) of the definition.
25 In respect of each alternative, it was necessary for the prosecution to establish that the appellant had placed in or on or otherwise introduced in to or on to the waters the relevant matter. However, in relation to paragraph (c) it was not necessary for the prosecution to prove that the condition of the waters was thereby changed.
26 Section 5 defines " waters" to mean:
"any river, stream, lake, lagoon, swamp, wetlands, unconfined surface water, natural or artificial watercourse, dam or tidal waters (including the sea), or part thereof, and includes water stored in artificial works, water in water mains, water pipes and water channels, and any underground or artesian water, or any part thereof."
27 In this regard, his Honour noted that the prosecution relied (inter alia) upon the words " natural or artificial watercourse " including " water in water pipes and water channels " in the above definition.
28 The prosecution submitted that the relevant "waters", as defined , commenced, at least, at the eastern end of the culvert. It was submitted that the culvert was a combination of a natural or artificial watercourse and water channel. Thereafter the " waters " continued all the way down to Bango Creek.
29 The appellant submitted, however, that one did not reach "waters" , as defined, until the confluence of the Main channel and the Large STP channel and that by the time the sediment reached the confluence, the matter was already in the " waters ". Thus there was no physical placing of matter by the appellant in the " waters " at that point. The relevant act of placing was the exposure of the soil at the point where the removal of vegetation occurred. However, that was further upstream than the confluence. It was submitted that, at best, the area upstream of the confluence was a depression enlarged by the action of the appellant solely for the purpose of removing the dead grass.
30 In his judgment, Talbot J referred to the definition of "watercourse" by Barwick CJ in Knezovic v Shire of Swan - Guildford (1967) 118 CLR 468 and 475, where the Chief Justice expressed the view that at common law a " watercourse "
"must exhibit features of continuity, permanence and unity, best seen, of course, in the existence of a defined bed and banks, with flowing water. It must, in my opinion, essentially be a stream and be sharply distinguished from a mere drain, or a drainage depression in the contours of the land which serves to relieve other land of excess water in times of major precipitation."
31 Talbot J accepted that, prior to the excavation, there was no defined bed or banks to raise the depression (which we have called the grassy swale) between the culvert and the confluence to the status of a "watercourse". His Honour went on to say:
"Although Mr Lloyd [who appeared for the prosecution] is correct when he says that waters as defined include waters in artificial or man made channels, the Court does not accept his further assertion that if anyone had any doubt whether the depression was a channel before it was cleared out, it clearly became a channel after it was cleared out.
The purpose of removing the vegetation was to reclaim the area polluted by hydrocarbon fluids. The installation of silt filtration devices such as hay bales and fences was to prevent the exposed soil being washed downhill and into the watercourse below. By omitting to carry out these works effectively the defendant allowed the loose soil to fall, descend, be washed, or percolate into the waters below. These waters comprised a watercourse with banks leading from the confluence with the water channels down stream including the channel leading directly from the old service station site and the separate channel running from the sewerage treatment works."