1. On the morning of 5 February 2011, the Applicant awoke to discover widespread flooding on his Land and neighbouring properties. Upon closer inspection, it became apparent that the culvert under the New Crossing was restricting the flow of water down Drain 5. According to the Applicant, the head of water upstream of the New Crossing was approximately 550 mm higher than the level of water downstream of the New Crossing.
2. Further, it is common ground that water from Drain 5 had overflowed at the intersection of Duncans Road and Hoppers Lane, being approximately 150 metres north of the New Crossing, causing significant flooding to a commercial property known as RP Motors, which is located at that intersection. Moreover, the increased level of water in Drain 5 upstream of the New Crossing also caused water to reverse or back-flow through the pipe connected to the Northern Box Culvert allowing water to enter the Vicroads Drain, which had, by that stage filled to capacity and was spilling over onto the Applicant's Land. According to the Applicant, the net effect of the back-flow through the Northern Box Culvert was that:
   • (a) water flowed from Drain 5 onto the Land; and
   • (b) water from the Central Drain was unable to discharge into Drain 5 via the Northern Box Culvert.
3. According to the Applicant, by about 11:30 am, there had been no significant change to head water levels on either side of New Crossing and to the upstream flooding of Drain 5, opposite RP Motors. Consequently, local residents decided to dig a trench around the New Crossing to enable water in Drain 5 to by-pass the New Crossing. Following the construction of that trench, floodwaters dissipated within six hours.
4. The loss suffered by the Applicant was substantial. Almost 60% of the Land had been under water for a period of time. Much of the crop affected by the flooding was mature and at a point ready to be harvested. A large component of this crop had been spoiled by the floodwaters and was unable to be sold. Consequently, it was ploughed back into the soil. In addition, the Applicant contends that the floodwaters emanating from the back-flow of Drain 5 carried spores of a fungal disease known as Club Root, which he claims infested parts of the Land and led to further losses. The total amount claimed by the Applicant is $118,300.[2] In addition, the Applicant seeks an order in the form of a mandatory injunction requiring SRW to enlarge the culvert under the New Crossing to a diameter not less than 1,200 mm or alternatively, construct a bridge crossing in lieu thereof.
5. The Applicant contends that the design of the culvert under the New Crossing is deficient, in that its diameter is too narrow. He claims that the flooding of his Land was caused by the throttling effect of the culvert, which caused water from Drain 5 to back-flow onto his Land, while at the same time prohibiting runoff from his Land being discharged into Drain 5. Consequently, the combined effect of these two factors led to the Applicant's Land being flooded or at the very least, flooded for a longer period of time than would otherwise have been the case, but for the effect of the culvert under the New Crossing.
6. The Applicant's claim is made under s 157 of the Water Act 1989 ('the Act'):
   1. Liability of Authorities arising out of flow of water

(a) as a result of intentional or negligent conduct on the part of an Authority in the exercise on a function under Part 8, Division 2, 3 or 5 of Part 10, or Part 11 or any corresponding previous enactment, a flow of water occurs from its works onto any land; and

(ii) damage to the property (whether real or personal) of any other person; or

the Authority is liable to pay damages to the other person in respect of the injury, damage or loss.

(2) If it is proved in a proceeding brought under sub-section (1) that water has flowed from the works of an Authority on to any land, it must be presumed that the flow occurred as a result of intentional or negligent conduct on the part of the Authority unless the Authority proves on the balance of probabilities that it did not so occur.

(3) For the purposes of a proceeding brought under sub-section (1) -

(a) a flow of water is to be taken to have occurred as a result of intentional conduct on the part of an Authority if the flow -

(ii) inevitably and without intervening cause resulted from the exercise of power by the Authority; and

1. The Applicant contends that SRW was negligent in authorising the construction of a 725 mm culvert under the New Crossing. This, he contends, is the single act which led to the flooding of his Land or at the very least, prolonged flooding for such a period such as to cause damage to his crop. The Applicant claims that SRW should never have authorised a 725 mm culvert under the New Crossing, especially in circumstances where the culvert upstream of the New Crossing was 1300 mm in diameter and the culvert downstream of the New Crossing was 850 mm. According to the Applicant, the appropriate design should have stipulated a much larger culvert diameter or an open bridge under the crossing.

1. SRW denies that it is responsible for the loss suffered by the Applicant. It defends the claim made against it on four principal grounds:
   • (a) The flow did not result from SRW's conduct. In that respect, SRW contend that the Land would have flooded even if the New Crossing had never been built.
   • (b) The authorisation of the culvert diameter under the New Crossing was not conduct on the part of SRW in the exercise of a function of any of the nominated statutory functions set out under s 157(1)(a) of the Act.
   • (c) The authorisation of the culvert diameter under the New Crossing was not negligent conduct, within the meaning of s 157 of the Act. In that respect, the authorisation which permitted the construction of the culvert was to a standard which provided a reasonable standard of capacity or efficiency. According to SRW, Drain 5 was designed to drain irrigation and rainwater run-off resulting from a 1 in 50 year ARI event.[3] It contends that the culvert would not have impeded flows from such an event. However, the storms which fell upon the Werribee South district on 4 and 5 February 2011 far exceeded a 1 in 50 year ARI event. SRW argue that the requirement to design Drain 5 to provide a reasonable standard capacity or efficiency did not require it to ensure that the drain would prevent any likelihood of flooding. Further it contends that the reasonable standard assumes water will remain on land for up to 24 hours.
   • (d) To the extent that any water back-flowed from Drain 5 onto the Land, that water was not material in the context of the extreme flood event, such that the inundation of the Land was not materially sourced from waters which flowed from Drain 5.
2. Dr Sadler, counsel for SRW, submitted that if the Tribunal found that the Land would have flooded even if the New Crossing had not been constructed, the Applicant's claim must fail and it unnecessary to consider the other defences raised by SRW. Substantial expert evidence was adduced by both parties going to this issue. In particular, the Applicant relied upon the opinion of Mr Bishop and Mr Wrigley, both consulting engineers with extensive experience in hydrological matters. SRW relied on the opinion of Mr Prout, consulting hydrologist and Mr Byrnes, Manager - Distribution Assets of SRW. Like Mr Prout, Mr Byrnes is a qualified engineer with experience in hydrological matters.
3. Dr Sadler pointed to the evidence of Mr Prout, whose hydraulic modelling indicated that the Land would have flooded to the same or a similar extent even if the New Crossing had not been built. In his report dated 20 December 2011, Mr Prout produced a number of flood maps covering various rainfall events. In particular, flood maps for both pre-works and current conditions were produced for rainfall events of a 10 year ARI, 50 year ARI, 100 year ARI and for the Storm conditions. In addition, flood maps only depicting the change in flood depth between pre and post construction of the New Crossing were produced for each of the above rainfall events. According to the Change in Flood Depth maps, there was no material difference between pre and post construction of the New Crossing for all but the 50 year ARI, which showed only marginal flooding predominantly in the adjoining property to the south of the Land. In essence, according to the Change in Flood Depth maps, there was no material change in flood levels on the Land as a result of the construction of the New Crossing, This was the case even though Mr Prout conceded that there was a back-flow of water from Drain 5 through the Northern Box Culvert, caused by an increase in the water level in Drain 5, upstream of the New Crossing.
4. Mr Prout opined that the Storm was an event well in excess of the 100 year ARI. He opined that the Storm exceeded a 100 year ARI event by 30 to 60%. He stated:

This event increased the flood level by 140 mm immediately upstream of the new drain crossing due to the recent works. Immediately downstream of the new drain crossing the flood level is 30 mm lower than prior to the recent works. There is no increase in flood level on the property leased by Mr Patsuris on the west side of Duncans Road. There is flow modelled across Duncans Road south of Hoppers Lane for the February 2011 event.[4]

1. Mr Prout's hydraulic modelling used a run-off routing software program developed at Monash University entitled RORB. He utilised RORB to calculate run-off hydrographs for input into his hydraulic modelling. All hydraulic modelling conducted by him used a TUFLOW method.[5]
2. Although this type of hydraulic modelling was accepted by all experts as being an appropriate method for modelling flood flows, both Mr Warwick and Mr Bishop criticised the flood modelling on the basis that the input data used by Mr Prout was questionable. In particular, Mr Miller of counsel, who appeared on behalf of the Applicant, submitted that the input data used by Mr Prout was erroneous and as a consequence, his flood maps did not accurately model flood patterns. The main areas of criticism raised by Mr Miller are:
   • (a) the use of unverified LIDAR data to establish surface topography (see below);
   • (b) the impact of the back-flow from Drain 5 onto the Land; and
   • (c) the magnitude of rainfall.
3. Consequently, despite neither Mr Bishop nor Mr Wrigley definitively stating that the presence of the New Crossing caused the flooding of the Land, they nevertheless opine that its presence compromised flow to and within Drain 5, and that water back-flowed through the Northern Box Culvert onto the Land. As I understand the Applicant's position, he therefore contends that it is reasonable to infer that the flooding of the Land was caused by the presence of the New Crossing. Consequently, the accuracy of Mr Prout's hydraulic modelling is critical in determining whether the presence of the New Crossing caused the Land to flood. Therefore, it is necessary to consider the Applicant's criticisms of Mr Prout's hydraulic modelling in more detail.

1. It is of critical importance that data concerning the topography of the land under consideration be reasonably accurate. Obviously, flow direction and depth of flooding are all dependent on the level and contours of the land in question. Mr Prout relied upon DSE LIDAR data (Light Detection and Ranging) concerning the topography of the catchment area under question. LIDAR data is obtained using aerial video mapping of land. The process measures distance by illuminating a target with a laser pulse and analysing the reflected light in order to produce a map of the topography of the land in question. This data is then obtained from DSE under licence.
2. Mr Miller submitted that although LIDAR is generally accepted as an appropriate means to measure the topography of land, it should be verified by the hydrologist before the data is used in flood modelling. In that respect, Mr Miller argued that seasonal changes to the topography of land are not unusual in the context of market gardens. Indeed, Mr Bishop stated in his report dated 4 June 2013 that:

Lidar - I believe that Lidar is an appropriate source of information to base this type of hydraulic modelling on. However when looking at detailed, localised areas that are highly sensitive, it is good practice to verify the data. I have done this for many investigations, often finding systematic errors of up to 300 mm. While it is fair to say that relative changes in topography are more important for this work than absolute levels, in this instance it would have been useful to undertake some checks on the Lidar given the critical nature of the results.[6]

1. Mr Miller raised questions as to the adequacy of the flood maps by pointing to video and photographic evidence of the flooding which he contended did not accurately match what was depicted in the flood maps prepared by Mr Prout. Mr Miller argued that these inconsistencies between what was observed and what was mapped demonstrate inaccuracies in the topographical data and the LIDAR levels.
2. By contrast, Dr Sadler contended that Mr Bishop's evidence, that he had previously found systematic errors of 300 mm, was irrelevant because it related to systemic errors. For example, where the whole surface plane had a common error relative to the correct survey datum. He argued, correctly in my view, that there was no evidence of any such systemic error in the present case. Indeed, Dr Sadler suggested that it was usual for there to be some minor discrepancies, given the impact of farm machinery regularly working the surface ground to prepare the paddocks for planting.
3. Ultimately, however, Mr Bishop conceded that LIDAR data was the best evidence available to identify the topography of the Land, even if there were minor topographical differences since the LIDAR was last flown (as a result of the Aplicant having worked his land which may have altered levels slightly). Accordingly, in the absence of any evidence demonstrating that there were significant systemic errors in such data, I accept that it was entirely appropriate to rely upon the LIDAR data for use in Mr Prout's hydraulic modelling.

1. As indicated above, it is common ground among the experts that the rising headwater in Drain 5 upstream of the New Crossing caused water to back-flow from Drain 5 out of the Northern Box Culvert into the Vicroads Drain. According to the Applicant, this flow of water significantly contributed to the flooding of the Land and was not properly considered in Mr Prout's modelling or reflected in his flood maps. According to Mr Bishop, the total volume of reverse flow water discharged was likely to be 4,300 m³ over a four hour period.[7]
2. By contrast, Mr Prout gave evidence that his modelling took into account reverse flow through the Northern Box Culvert while the water levels were very high in the D5 drain.[8] He states:

Mr Bishop estimates that the extra volume of flow onto the Patsuris property in February 2011 may have been approximately 4,300 m³, based on his total reverse flow estimate of 0.3 m³/s. By modelling the peak reverse flow in TUFLOW both with and without the Tsardakis culvert [the New Crossing] gives an increase in the maximum reverse flow of 0.10 m³/s. I would expect that the actual extra volume of reverse flow may therefore not be as large as the total volume of reverse flow of 4,300 m³ estimated by Mr Bishop, however I have not calculated the difference in volume, however expect that it could be in the range of 2,000 to 4,000 m³. To put the volume of extra reverse flow through culvert 1 [Northern Box Culvert] into perspective I have obtained the overall volume of run-off on 4/5 February from various sub-catchments from our RORB model as follows:

Catchment to culvert 1 [the Northern Box Culvert] 45,000 m³

Catchment to culvert 2 [the Southern Box Culvert] 38,000 m³

Catchment for D5 drain as shown on attached plan 231,000 m³

Therefore the extra reverse flow is less than 5-10% of the flow to culvert 1 and less than 1-2% of the total catchment flow.[9]

1. I accept Mr Prout's evidence that the back-flow through the Northern Box Culvert was factored into his modelling. I further accept his calculations, that the overall impact of the back-flow, in terms of its volume, was insignificant when measured against the total catchment flow. Indeed, there is no evidence to suggest that the volume of water that back-flowed through the Northern Box Culvert was hydraulically significant.[10]

1. Mr Miller further criticises Mr Prout's modelling on the ground that he relied upon rainfall data from only one weather station, being the BOM[11] Werribee weather station. In his report, Mr Prout states:

Design rainfall data was obtained for Werribee for various ARI (Annual Recurrence Interval) storm events as well as recorded rainfall data for Werribee for February 2011 at 6 minute increments. From the rainfall data recorded on 4/5 February 2011 we note that the rainfall intensity significantly exceeded the 100 year ARI design rainfall intensity (by approximately 30 to 60% across the duration of the storm). Table 5-1 below gives context of the size of the February 4th rainfall event as compared to the 10 year, 50 year and 100 year events.[12]

1. Mr Miller referred to the evidence of Mr Wrigley who was critical of only using Werribee weather station as the source of rainfall data. He stated:

In my opinion the results presented can provide an indication only of hydrology and hydraulic conditions at Werribee South which impacted Mr Patsuris in February 2011. After 8 years of studying rainfall and hydrology at WTP [Western Treatment Plant Werribee] the variability of rainfall across the site is marked and annual differences from one site to another can be as much as 200 mm. Also rainfall events can impact one area and miss another due to the event based nature of coastal rainfalls. This experience results in difficulties in extrapolating data from the above-mentioned stations which are remote from sites under investigation. There are now a series of hydrological monitoring stations at WTP to try and secure better and more reliable event based data and the most eastern of these could provide hydrological data which better captures conditions experienced on the property of Mr Patsuris.[13]

1. In his report dated 14 March 2013, he states further:

The total rainfall for the storm(s) on February 3 and 5 as recorded at the BOM Werribee is 147 mm. During these events 106.8 mm was registered at Hoppers Crossing and 135.2 mm was recorded at Altona. Little River recorded much less. At the RAAF Base Laverton BOM Station the recorded rainfall was 117 mm. Based on local knowledge the Laverton data is likely to be more representative of the storm event that impacted Werribee South by comparison with the Werribee BOM Station data but it was not even considered. Of all five BOM stations in the district only at the BOM Werribee Station did the intensity of rainfall exceed 75 mm in 6 hours.[14]

1. Mr Miller referred to the judgment of Dixon J in Commissioner of Railways v Stewart,[15] where his Honour criticised the fact that records of previous rainfalls were confined to one place. His Honour observed that in judging such a matter a wide area should be considered and reasoning for analogy should play a part.[16]
2. In that respect, the rainfall recorded at the Hoppers Crossing weather station was 105 mm, compared with 147 mm recorded at the Werribee weather station. Mr Miller submitted that the use of rainfall data from the Werribee weather station assumed that the same intensity of rainfall fell throughout the 243 hectare catchment area. Mr Miller argued that that the Hoppers Crossing weather station was closer to the Land. Moreover, the evidence of Mr Patsuris and Mr Piovesan, the occupier of RP Motors, located opposite the Land, confirmed that the Storm passed over the Land at a time when the Hoppers Crossing weather station recorded its highest rainfall intensity. Accordingly, Mr Miller argued that the Hoppers Crossing weather station should have been considered as an appropriate source of input data, rather than relying solely on the rainfall recorded at the Werribee weather station.
3. This issue gained some prominence during the course of the hearing because only Werribee weather station recorded a rainfall intensity which exceeded a 1 in 50 ARI. The importance of this issue is that the culvert under the New Crossing has only been designed to cater for weather conditions up to a 1 in 50 ARI. Therefore, SRW argued that the intensity of rain exceeded the reasonable design parameters of Drain 5 and as such, any flooding did not result from inadequate design of the culvert under the New Crossing but rather, was an inevitable consequence of the severity of the Storm.
4. Consequently, SRW contends that its obligation, insofar as it may be liable for the design of the culvert under the New Crossing, is to ensure that the New Crossing did not compromise the ability of Drain 5 to drain irrigation and rainwater run-off resulting from rainfall intensity up to 1 in 50 ARI. Consequently, given that the recorded rainfall at Werribee weather station significantly exceeded a 1 in 50 ARI, SRW argued that it is not responsible for the consequences of that significant rainfall event. On the other hand, the Applicant argued, amongst other things, that the rainfall which inundated the catchment area did not exceed a 1 in 50 ARI and that the flooding which occurred resulted solely from the construction of the New Crossing.
5. Mr Byrnes gave evidence concerning the path of the storm. Rainfall radar images were produced showing the path of the storm and the indicative intensity at different intervals of time. Mr Byrnes opined that the radar images clearly showed that the most significant part of the storm passed directly over the Land and the relevant catchment area. He further produced data and flowcharts of the flow of water through Drain 5. He said that the peak flows experienced through Drain 5 were consistent with peak rainfall periods recorded at Werribee weather station, having regard to the time taken for run-off to reach the flow recording station in Drain 5. According to Mr Byrnes, the combination of these two factors supported his opinion that the rainfall measured at Werribee weather station was an accurate guide to the actual rainfall which fell on the Land and the surrounding catchment area.
6. I note in passing that Mr Miller submitted that the evidence given by Mr Prout and Mr Byrnes was that the Werribee rainfall station recorded its peak rainfall at the same time as the outfall of Drain 5 recorded its peak flow. Therefore, he contended that the peak rate of flow at the outfall of Drain 5 was not an accurate indicator of peak rainfall emanating from Werribee rainfall station because the two peaks could not physically occur simultaneously, given the time taken for upper catchment flows to reach the outfall of Drain 5. I do not find the evidence of Mr Prout and Mr Byrnes to be that the peak rainfall recorded at Werribee rainfall station coincided with the peak flow of Drain 5. My recollection of their evidence was that there was some time lag between the recording of peak rainfall and peak flow. Moreover, Mr Byrnes indicated that peak flows would be experienced at the outfall of Drain 5 within a short period after peak rainfall, given that Drain 5 was fed by a number of culverts downstream of the New Crossing, all of which would have contributed to its peak flow.
7. Mr Byrnes also compared flow rates down Drain 5 with other significant rainfall events, which occurred prior to the construction of the New Crossing. In particular, rainfall recorded at the Laverton weather station on 2-3 February 2005 was 125.4 mm, which exceeded the amount recorded at that weather station during the (2011) Storm. However, the flow rate in Drain 5 recorded during the 2005 storm was significantly less than the flow rate recorded during the (2011) Storm. According to Mr Byrnes, this supported his opinion that Werribee weather station was the most appropriate recording station to measure the rainfall.
8. In my view, it was appropriate for Mr Prout to utilise rainfall data from the Werribee weather station. In that respect, I accept the evidence of Mr Byrnes that the most severe path of the storm crossed over the catchment area surrounding the Land and feeding Drain 5. Moreover, the timing of the peak flows measured in Drain 5 seem to be consistent with it having carried run-off resulting from peak rainfall measured at Werribee weather station. The combination of these factors indicate to me that, on the balance of probabilities, Werribee weather station was the most representative weather station to measure rainfall over the relevant period.
9. In any event, the flood maps produced by Mr Prout also included predicted flooding for a 1 in 10 ARI, 1 in 50 ARI and 1 in 100 ARI rainfall events (for both pre-works and current conditions). In each case, there was little or no difference between the predicted flooding with or without the New Crossing. Therefore, even if it was incorrect to rely solely on the Werribee weather station, the pre-works and current conditions flood maps for various ARI rainfall events still indicate that the construction of the New Crossing made little or no difference to what was likely to occur on the Land based on those rainfall events.
10. Finally, I note that in Mr Bishop's supplementary report dated 4 June 2013, he conceded that Werribee weather station provided the closest representation to what was likely to have occurred in the area:

There has been some conjecture about the amount of rain that fell on the catchment in February 2011. Unfortunately there is no definitive answer to this question as rainfall is highly variable, in both space and time. Inevitably in practice we use the best available information and hence derive a best estimate of rainfall from an event. Along with other factors, this is one of the reasons that, even with a dense rain gauge network in many catchments, accurate flood forecasting can be extremely difficult.

The best available information on rainfall depths is gained from pluviographs and rain gauges. Spatial distribution is generally best described by rainfall radar information. Figures 3 to 6 show information on temporal and spatial variability of rainfall in the vicinity in February 2011. These highlight the changes that occur over a small distance. I believe based on this data that the Werribee Station provides the closest representation to what is likely to have occurred at the subject site's catchment, however this is not to say that the Werribee station represents exactly what occurred on the catchment. It appears from the radar images that the centre of the storm effectively passed through Werribee and that there could have been a reducing gradient of rainfall to the south towards the study site.[17]

1. Although Mr Bishop raises the possibility of there being less rainfall over the subject site, I understand his evidence to be that the Werribee weather station was still the most representative weather station. That view is consistent with the opinion of Mr Prout and Mr Byrnes. Therefore, I find that the data from the BOM Werribee weather station was the most representative gauge of rainfall intensity affecting the catchment area surrounding the Land and flows in Drain 5.

1. Having regard to my findings above, I am of the opinion that the flood maps produced by Mr Prout represent the best evidence as to the impact of the New Crossing. In that regard, I accept Mr Prout's opinion that the construction of the New Crossing had little or no impact on the flooding which occurred over the Land as a result of the Storm. I have formed this view notwithstanding the evidence given by Robert Piovesan, the operator of RP Motors, that his premises had never previously been flooded in its 42 year history. This is despite the fact that BOM data was produced by Mr Miller indicating significant rainfall events being recorded at Laverton and Little River weather stations during the 70s and 80s. Indeed, the Applicant gave evidence that:
   1. The rainfall records for Laverton RAAF indicate that there have been comparable and bigger rain storms in the area prior to the February 2011 rain event. In February 2005 Laverton RAAF had 25.6 mm of rain on 2 February 2005 and 99.8 mm on the 3 February 2005 giving a total of 125.4 mm for the two days. In 2005 there was only some flooding in the burrows of paddock 1 due to the heavy rain and on the 2 and 3 February 2005, this water came from the Duncans Road table drain, there were no crop losses as the water level was low and it remained for only a short time. The highest recorded daily rainfall at Laverton RAAF was 188 mm on 8 April 1977. In 1977 the Claimant's land was farmed under flood irrigation and consequently had numerous banks and channels that were necessary to deliver the irrigation water to the crops. It is my recollection that at the time of the very heavy rain in April 1977 there were some flooding in paddocks 1 and 2 only, which caused minimal losses, but none in paddocks 6, 7, 15, 4, 5.
2. However, there is no evidence to indicate how significant rainfall measured at those two weather stations would impact on the load carried by Drain 5 or waters draining through the Centre Drain and Southern Drain of the Land. Accordingly, it is unclear to me how relevant those rainfall events are to any potential flooding either on the Land or affecting RP Motors. This is further highlighted by the evidence of Mr Byrne, who prepared a graph showing recorded flows at the Drain 5 monitoring site for the (2011) Storm, 4-5 February 2005 storm and 26-25 May 2012 storm. The graph illustrates that the Storm resulted in significantly higher flow rates in Drain 5, peaking at approximately 330 ML/day, compared with a peak of approximately 225 ML/day for the 2-3 February 2005 storm event. Mr Byrne states further:
   1. In May 2012, the area which is the subject of the proceeding experienced a rain event of approximately 1 in 2 to 1 in 5 ARI. On this occasion, the culvert which is the subject of the proceeding functioned effectively. As a result of the storm event, and despite the culvert drain operating effectively, part of the Applicant's land was inundated. I attach photographs of the inundation and Drain 5 and the culvert ...[18]
3. The photographs referred to in Mr Byrnes' witness statement depict some minor flooding alongside the Central Drain at its eastern end. However, it appears from the photographs that water from the Vicroads Drain is still draining into the Northern Box Culvert, consistent with Mr Byrnes' evidence that Drain 5 was still functioning adequately at the time.
4. Moreover, Mr Prout gave further evidence that:

The 2005 storm was mentioned in the Further Supplementary Witness Statement of Paul Byrnes of SRW. I haven't obtained any data for the 2005 event, other that in Mr Byrne's statement. I am not in a position to offer a definitive opinion about this event, other than my recollections that it was wide spread storm with a longer duration and lower rainfall intensity than the February 2011 storm ...[19]

1. I have also taken into account Mr Miller's submission that some of the flooding depicted on the various flood maps prepared by Mr Prout does not accurately reflect the images seen on a video and photographs taken by the Applicant on 5 February 2011. In particular, the flood maps show flooding in Paddocks 12 and 13 but those paddocks were not observed to have significant flooding on 5 February 2011. Moreover, the flood maps did not indicate that Paddocks 6 and 7, which are in the lowest part of the Land, would experience significant flooding. However, the video taken by the Applicant on 5 February 2011 showed significant flooding of those paddocks.
2. I accept that there are discrepancies between what is observed on the video and photographs taken by the Applicant and what is depicted on the flood maps. However, Mr Prout opined that the differences were not of any great significance and were explicable. In particular, he suggested that the time when the Applicant took the video and photographs was not during the peak period of flooding. Therefore, Paddocks 12 and 13, which are at the western end of the Land and which drain either south or east, would have had an opportunity to drain. Similarly, Paddocks 1 and 6, which are located at the eastern end of the Land, would have accumulated water draining from the west, exacerbating the impact of flooding. This explanation seems to be accepted by Mr Bishop in his report dated 26 May 2013, wherein he comments about the difference in peak level across the New Crossing as observed on 3 February 2011, compared with what is depicted in the flood maps. He states:

I believe Mr Prout's explanation of the difference between the peak level difference across the crossing (that may have occued [sic] during the evening) and the difference the next morning is plausible. It should also be noted he would 'expect that the flood level downstream of the new crossing would drop more quickly than the flood level upstream". This confirms that the duration of flooding experienced upstream of the crossing and potentially impacting the subject site (through backwater) would also be extended.[20]

1. Moreover, minor differences in surface level caused by groundwork could also have impacted on the amount of flooding experienced. In my view, the explanations proffered by Mr Prout are feasible and more than likely explain minor discrepancies between what was observed on 5 February 2011 to what is depicted in the flood maps. Therefore, I do not accept that those discrepancies undermine the accuracy of the flood maps prepared by Mr Prout.
2. In my view, the most likely scenario is that flood waters emanating from properties to the west of the Land, together with run-off from the Land, inundated the Land because that water was unable to discharge into Drain 5 through the Northern Box Culvert or Southern Box Culvert quickly enough to prevent flooding of the Land. No doubt, the back-flow from the Northern Box Culvert and its inability to drain flood water, may have exacerbated the problem. Importantly, however, there is no evidence that these two factors actually caused the flooding of the Land.
3. A similar result arose in State Rivers and Water Supply Commission v Crea and Anor.[21] In Crea, the relevant water authority had approved a drainage scheme for a dairy farm property. The owners of the dairy farm alleged that during 1967 to 1972, their property had been flooded repeatedly after severe rain as a result of the overflow of water from the drain and the discharge of water from the irrigation channels. They attributed the flooding to the design of the drain and its structures, and the inadequate maintenance of the drain. Ultimately, the Full Court held that there was inefficient evidence to conclude that the design of the drain caused the flooding:

The drain was constructed to remove a limited quantity of water from the sub-catchment. It followed, and it was recognised in the planning of the drain, that when water was accumulating in any part of the sub-catchment faster than the drain was capable of removing it, there would be ponding or flooding. It did not follow that the ponding or flooding resulted from the construction of the drain.

On the evidence in this case, it is not possible to hold that the construction of the drain, by accelerating and concentrating flow caused more extensive or more prolonged flooding on lot 27 than would have occurred otherwise.[22]

1. Therefore, I accept Dr Sadler's submission that there is insufficient evidence to find that the flooding was caused by water entering the Land through the Northern Box Culvert or water being unable to drain from the Land through the Northern Box Culvert. In essence, the only evidence supporting that conclusion are the anecdotal observations of Mr Patsuris and Mr Piosevan that flooding of the same magnitude has never occurred in the previous 40 years prior to the construction of the New Crossing. However, there is no evidence of the same rainfall being recorded at the Werribee weather station over that period of time. Therefore, it is impossible to make direct comparisons with the Storm event. Moreover, against that evidence is the expert evidence of Mr Prout and the flood modelling he has undertaken.
2. Therefore, I find, on the balance of probabilities, that the likely cause of the flooding to the Applicant's Land is the flow of water emanating from the west and north, and not as a result of the New Crossing throttling the flow of water flowing down Drain 5. As indicated above, the amount of back-flow from the Northern Box Culvert was insignificant when compared with the amount of the water moving over the Land towards and into the Vicroads Drain. The fact the Northern Box Culvert was rendered inoperative, when the head waters upstream of the New Crossing rose above the invert of the pipe feeding into Drain 5 does not, in my view, establish that the probabilities are that this caused flooding on the Land. As I have already indicated, the modelling conducted by Mr Prout indicates to the contrary. Therefore, I find that, in all probability, the flooding of the Land would have occurred even if the New Crossing had not been built.
3. As indicated above, Dr Sadler submitted that a finding that the flooding would have occurred in the absence of the New Crossing disposes of the Applicant's claim. I do not accept that submission. In particular, the Applicant also claims damages associated with contamination of his crop due to the infestation of Club Root. He contends that this disease was introduced onto the Land through water that originated from Drain 5. In that respect, it is common ground that some water from Drain 5 back-flowed through the Northern Box Culvert. In my view, this aspect of the Applicant's claim is distinct from his claim relating to damage caused by flood water. In particular, this aspect of the Applicant's claim does not focus on damage caused by the flooding of the Land but rather, whether the culvert under the New Crossing:
   • (a) caused water contaminated with Club Roots spores to flow out of Drain 5 and onto the Land; and if so
   • (b) whether that flow arose as a result of intentional or negligent conduct on the part of SRW (in the exercise of a function under the relevant parts of the Act).
4. In my opinion, this aspect of the Applicant's claim requires further consideration.

Did Club Root spores flow onto the Land from Drain 5?

1. It is common ground that the Applicant's crops were affected by Club Root disease during the flooding of the Land. In particular, the Applicant gave evidence that:
   1. I understand that the Club Root disease can be carried in spores within water and believe that this came from the muddy water that flooded out from Drain 5. Club Root has never been an issue on the Claimants land but I saw significant evidence of it within two weeks of the flood and only in the area that had been flooded. On the 31 March 2011 I arranged for five plants to be submitted testing by Crop Health Services. Its report dated 6 April 2011 stated that Club Root was detected as determined by visual examination of the symptoms and microscopic identification of the fungus inside the swollen root cells. I have since been treating the affected areas of the land to protect future crops. The affected areas are Paddocks 1, 4, 6, 7 and part of 15.[23]
2. The extract of the Applicant's evidence is supported by the evidence of Armando Perri, a market gardener who crops a 27 acre property to the north east of the Land and which drains into Drain 5. In his witness statement, Mr Perri states:
   1. When I took over the lease of this 10 acre property, I first fumigated it with metam sodium. I then planted 5 acres with artichokes, which are not susceptible to club root and the remaining 5 acres with broccoli. This first planting of broccoli had significant infestation of club root. Consequently I lost money on this planting. I then again fumigated with metam sodium and planted another crop of broccoli. This second crop of broccoli was also affected by club root but not as badly, I broke even on this planting. I then fumigated a third time with metam sodium and planted broccoli again. The plants in this crop are still quite small, thus as yet I have been unable to assess whether or not they will be affected by club root. My neighbour to the west of this Hoppers Lane property also has a bad problem with club root.[24]
3. The Crop Health Services report referred to in the Applicant's evidence was produced during the course of the hearing. Although SRW denies that the source of Club Root infestation manifests from Drain 5, it conceded that parts of the Land were infested with the disease.
4. There are difficulties in establishing the precise source of the Club Root infestation, especially in circumstances where the Land was inundated with water draining from other market gardens to the west. However, the Applicant's evidence that the Land had not previously suffered from Club Root infestation (even though properties to the west drained through the Central Drain) coupled with the fact that the Land had not previously received water from Drain 5, leads me to conclude that the source of the Club Root infestation may have originated from Drain 5. This conclusion is consistent with the evidence given by Mr Perri that the property which he cropped had a history of Club Root infestation. That property drained into Drain 5 upstream of the Northern Box Culvert. Therefore, it is possible that the likely source of Club Root infestation was water emanating from Drain 5, which back-flowed through the Northern Box Culvert and eventually onto the Land.
5. However, a finding that contaminated water flowing onto the Land from Drain 5 does not, in itself, establish liability. As highlighted in Crea:

When a claimant has established the flooding which caused him damage resulted from the works of an Authority (which he will do by proving, in the words of a phrase used by Dixon J in the Commissioner of Railways (WA) v Sewart [1936] HCA 51; (1936), 56 CLR 520 at p.536 that the flooding "as a matter of physical causation appears to be connected with the existence of its works") s.274(2) places on the Authority the burden of proving that the damage was not caused by intentional flooding or by negligence as those terms are defined in s.274(3).[25]

1. Therefore, a number of factors need to be considered before liability on the part of SRW is established:
   • (a) Has the Applicant proved that there was a flow of (contaminated) water onto the Land from the SRW's works? As indicated above, that scenario is a possibility.
   • (b) Has the Applicant proved that the flow of water causing damage to the Land resulted from SRW works? SRW raise two grounds in its defence. First, s 157(1) states that the conduct on the part of an Authority is conduct in the exercise of a function under Part 8, Part 9, Division 2, 3 or 5 of Part 10, or Part 11 of the Act. SRW contend that the water constituting the offending flow was not as a result of the exercise by SRW of a specific nominated statutory function and therefore did not result from SRW works. Second, SRW contend that even if it was exercising a function under the Act, the culvert under the New Crossing did not cause the reverse flow. SRW contend that the reverse flow occurred as a result of the extreme weather event and would have occurred even if the New Crossing had not been built.
   • (c) Has SRW proved that the flooding was neither intentional nor negligent? This is also in contention. In particular, SRW argue that the New Crossing was only ever designed to cater for a 1 in 50 ARI rainfall event, which it says is reasonable, having regard to the matters set out in s 157(3)(b) of the Act. However, the Storm exceeded that intensity.
   • (d) Has the Applicant proved that he suffered loss and damage as a result of the infestation of Club Root disease? SRW says that the loss of profit claim arising out of damage caused by the infestation of Club Root disease is too remote and not recoverable under s 157(4)(c) of the Act.

1. Dr Sadler submitted that SRW is an irrigation authority exercising functions under Part 11 of the Act. He argued it has no other relevant statutory powers. It does not have floodplain management functions, as set out under Division 4 of Part 10 or waterway management functions. He submitted that under s 157 of the Act, in order to establish liability, the Applicant must demonstrate that the flow resulted from conduct by SRW in the exercise of its irrigation function. That irrigation function is set out in s 221(a) as follows:

221 Functions of Authorities and under this Part

An Authority has the following functions in relation to the irrigation district of the Authority -

(a) to provide, manage and operate systems for the delivery of water to lands and appropriate drainage and protection of those lands;

(b) to identify community needs relating to irrigation, drainage and salinity mitigation, and plan for the future needs of the community relating to irrigation, drainage and salinity mitigation;

(c) to develop and implement programmes for improved regulation practices, improved drainage practices and improved salinity mitigation practices;

(d) to investigate any matter related to its functions, powers and duties in relation to irrigation, drainage and salinity mitigation.

1. Section 222(1)(a) states further that in performing that function, SRW:

... must provide the service of delivering water to the owner or occupier (where the occupier is not the owner) of each service property in its irrigation district -

1. Dr Sadler submitted that the drainage function referred to in s 221 is limited to providing drainage to manage irrigation run-off, as opposed to stormwater drainage. He argued that SRW has no statutory function to manage drainage to accommodate stormwater. Therefore, he argued that the authorisation of the culvert under the New Crossing was not conduct on the part of SRW in the exercise of a function under Part 11 of the Act. Alternatively, even if the authorisation of the culvert was the exercise of a function under the Act, that function was limited to managing irrigation run-off and not stormwater drainage.
2. Dr Sadler referred me to the decision of Emerton J in D'Agostino v Goulburn Murray Rural Water Corporation.[26] That case concerned the obligation of an irrigation Authority to provide drainage to irrigated land under the Act. In D'Agostino, the plaintiffs owned land within the Shepparton Irrigation Area. Accordingly, the Authority was required to carry out its functions under the Act to provide irrigation and drainage for that land. The Authority, through a transfer agreement, sought to assign responsibility to the municipal council to provide drainage. This was done as part of a project to decommission the rural drainage network in the area to allow for the future implementation of an urban drainage scheme.
3. Although not dealing directly with the same issue as is presently before me, Emerton J stated:
   1. The provision, management and operation of systems for appropriate drainage is linked in to s 221(a) to the provision, management and operation of systems for the delivery of water to lands under Part 11 of the Act. 'Appropriate drainage' is therefore referable to the delivery of water for irrigation and is most likely limited to the management of irrigation run-off. Sections 221 (b) - (d) also confer functions on an Authority in relation to drainage, again in the context of irrigation.
   2. In my view, the central obligation of an irrigation Authority is the provision of the service of delivering water. Its drainage function is subsidiary and incidental to that obligation.
   3. There are sign-posts in other parts of the Act and elsewhere that support the conclusion that the provision of drainage by an irrigation Authority is subsidiary to the service of water delivery and is not something that an irrigation authority is bound to provide through its own efforts.
4. In my view, the decision in D'Agostino does not answer the question whether the authorisation of the culvert under the New Crossing constituted an exercise by SRW of a function under Part 11 of the Act. D'Agostino was concerned with whether there was an obligation to provide drainage unrelated to the delivery of irrigation water. However, in the present case, drainage ancillary to the provision of irrigation water was provided through Drain 5.
5. Mr Miller correctly pointed out that Drain 5 is managed and operated by SRW in the exercise of a function under Part 11 of the Act. In my view, authorising the size of the culvert under the New Crossing is part of the management and operation of Drain 5. As Mr Miller correctly submitted, irrigation authorities have to design irrigation channels and drains so that they do not direct floodwaters to locations where they otherwise would not have flowed. This function has nothing to do with stormwater or flood plain management. It is concerned with the drainage and protection of irrigated land.
6. The central issue, insofar as the Club Root claim is concerned, is whether in exercising its function to provide that drainage, it caused, either intentionally or negligently, the flow of water from its works to flow onto the Land. In that regard, I do not consider that SRW is able to disassociate the authority it gave to construct the culvert under the New Crossing from the functions set out under s 221(a) of the Act.
7. The fact that the provision and maintenance of drainage is ancillary to its irrigation functions is beside the point. If, by the construction, design or approval of works concerning the provision, management or operation of irrigation water and ancillary drainage, there is a flow of water from such works (including ancillary drains), that conduct is the exercise of a function under Part 11. SRW gave specific direction and authorisation, pursuant to a licence, to construct the New Crossing over its asset. It specified the diameter of the culvert that was to be installed in Drain 5.
8. In my view, work (including the authorisation of work) to Drain 5, being an asset owned and managed by SRW, is conduct in the exercise of its functions under Part 11 because it is conduct which concerns the management and operation of appropriate drainage associated with the delivery of irrigation water. If, by reason of that conduct, a flow of water occurs from Drain 5 causing damage to land, it is liable to pay damages in respect of that damage, where it is determined that the conduct was either intentional or negligent.
9. The matters raised by Dr Sadler also touch on the question whether the conduct was intentional or negligent. In particular, as I understand the argument advanced by Dr Sadler, it is not a function of SRW to construct a drain which would prevent flooding of the Land. Although that may be correct, the question is not directly relevant to the issues concerning the Club Root claim. Consideration of the Club Root claim requires an examination of whether the authorisation of the culvert under the New Crossing was appropriate, having regard to the matters set out in s 157(3)(b) of the Act and whether the reverse flow was caused by that authorisation.

Did the New Crossing cause the reverse flow and if so, did that occur because the culvert was negligently designed?

1. Section 157(3)(b) of the Act states:

(b) ... in determining whether or not a flow of water occurred as a result of negligent conduct on the part of an Authority, account must be taken of all the circumstances including any permission or failure, in the planning, design, construction, maintenance or operation of the works, to provide reasonable standards of capacity or efficiency or exercise reasonable care or skill having regard to the following matters -

(i) the state of scientific knowledge and knowledge of local conditions at any relevant time;

(B) the maintenance and operation of the works; and

(C) works which it would have been necessary to construct to avoid the occurrence of any relevant injury, damage or loss.

1. As has been made clear by Cavanough J in South East Water Ltd v Transpacific Cleanaway Pty Ltd, there is no need to establish a common law duty of care when considering whether an Authority has acted negligently:
   1. In my view, the references to negligent conduct in s74 of the WIA do not require that an independent duty of care be identified in accordance with the common law principles that govern the tort of negligence.
   2. In any event, s 74(1) itself contains provisions that substantially occupy the ground they would be occupied by duty of care principles in a common law negligence claim, leaving little or no room for those principles to operate. It sets up a relationship, broadly corresponding to an Atkinian "neighbour" relationship, between a licensee exercising a function under its licence and any other person who might suffer personal injury, property damage or economic loss if a flow of water were to occur from the licensee's works (as defined) onto any land. Subject to questions of causation and remoteness, the relationship will give rise to liability where the flow of water occurs as a result of intentional or negligent conduct on the part of the licensee and the watercourses personal injury, property damage or economic loss to any person.[27]
2. Section 74 (1) of the Water Industry Act 1994 has been repealed. However, that provision is largely duplicated in s 157(3) of the Act.
3. The Applicant contends that SRW acted negligently by specifying a culvert of inadequate diameter, which ultimately caused a reverse flow through the Northern Box Culvert onto the Land. Although SRW has the burden of proving that its conduct was not negligent, it is difficult to isolate this line of enquiry from the question of causation. For example, it is unlikely that SRW would be found negligent if it is accepted that it was reasonable to design the culvert under the New Crossing to cater for a 50 year ARI storm, and it is proved that no reverse flow would occur in weather conditions up to that severity. Therefore, a finding of negligence is premised on a finding that the reverse flow would have also occurred during a 50 year ARI storm event.
4. It is common ground between the experts that a nominal 50 year ARI design standard was reasonable for the Werribee South district.[28] According to the experts, this meant that the drain was designed to remove, within a 24 hour period, irrigation and stormwater from 75 mm of rainfall falling over a six hour period.
5. According to Mr Bishop, the culvert under the New Crossing compromised that design standard. He opined that:

Based on the hydrologic and hydraulic analysis performed I believe the 750 mm culvert in the new drain crossing is not adequate to cater for the nominated design standard (75 mm, 6 hour storm).

1. Mr Prout disagreed. As discussed above, his flood modelling demonstrated that the Land would have flooded, irrespective of the presence of the culvert under the New Crossing. However, that does not answer the critical question whether, in a 50 year ARI storm, the culvert under the New Crossing would cause a reverse flow through the Northern Box Culvert, causing water to flow onto the Land. The flood maps produced in Mr Prout's report dated 20 December 2011 do not specifically answer that question.
2. Mr Bishop gave evidence that:

I believe it is questionable whether the existing system is able to cope this [sic] the nominated design standard for the system. Whilst the drainage infrastructure may be able to perform the stated aim of draining water off farmland in 24 hours, I believe there are concerns with respect to the peak flood impact on surrounding infrastructure, in particular the road reserve and dwelling access. Due to the close proximity of the new crossing to the previous one, I believe a 900 mm culvert would be inadequate for this location and a 1200 mm culvert would provide an acceptable level of hydraulic performance. This has been simulated and is shown as a longitudinal section in Figure 7-1 below. This larger culvert size would reduce the head-loss to a more reasonable level of around 100 mm.[29]

1. As highlighted by Mr Bishop, there is an inconsistency in having a smaller diameter culvert under the New Crossing compared with the size of the culverts that exist both upstream and downstream:

It is an unusual practice that a particular culvert on a drain would be sized smaller than the immediate upstream culvert (unless there is some other hydraulic feature to justify this such as a diversion or flow, which in this case there is not). In addition to reduced flow capacity, the smaller culvert size has an increased risk of blockage, although this could be considered a marginal change, it is also unusual.[30]

Changed Patterns of Flow - The reversal of flow from the 525 mm culvert [Northern Box Culvert] can be considered to be an impact on flow distribution as the Crossing has induced a flow that was not experienced previously. In addition, the modelling suggests that there is a new flow path over Duncans Road near (just to the south) of the residence on the subject site. These two changes in flow pattern are shown on Figure 2.

The significance of the changed flow patterns is that they could lead to changes in flow duration and potentially settlement/water quality issues as water from areas further away from the site is able to flow into the site.

Change in Flood Duration - Irrespective of the extent to which peak flood levels at the subject site may have changed, it is important to consider if the new crossing is likely to have had an impact on flood duration. Due to the backup of water in Drain 5 upstream of the crossing, there was an observed and modelled reversal of flow into the subject land (rather than draining away from the subject land). I believe it is likely that this would have caused there to be an extended period of inundation at the subject site as water would have taken longer to drain away due to the elevated level in Drain 5 and the backwater impact.[31]

1. In response to that report, Mr Prout prepared a supplementary report, in which he states:

In relation to the extra reverse flow in culvert 1 [the Northern Box Culvert] and the overall change in flow patterns and flood levels I have extracted the following more detailed information from the TUFLOW models for the February 2011 flood event ...

Overall the flood levels in the table above and flows in culverts 1 [the Northern Box Culvert] and 2 [the Southern box Culvert] showed changes in the flow patterns due to the Tsardakis crossing [the New Crossing] as being:

• An increase in flood levels in the during peak rainfall periods in the D5 drain upstream of the Tsardakis crossing.
• A decrease in flood level on both sides of Duncans Road downstream of the Tsardakis crossing.
• An increase in reverse flow in culvert 1.
• An increase in flow in a southerly direction along the west side of Duncans Road [the Vic Roads Drain]. This is due to an increase in the hydraulic grade on the west side of Duncans Road [the Vic Roads Drain] between culvert 1 and culvert 2 x 11 mm (2 mm decrease at culvert 1 and 13 mm decrease at culvert 2) allowing more overland flow to flow down the west side of Duncans Road. While this is a small change in hydraulic grade the flow width is sufficient to pass the extra flow from the reverse flow from culvert 1 down the west side of Duncans Road without increasing flood levels on the Patsuris property.
• A very small increase in the peak flow through culvert 2.[32]

1. There are two aspects to Mr Prout's supplementary report of significant relevance. First, he opines that the presence of the culvert under the New Crossing has 'increased' the reverse flow through the Northern Box Culvert. I understand this to mean that under the same weather conditions as experienced in the present case, water would have back-flowed through the Northern Box Culvert even if the New Crossing was not there. Second, the water which back-flowed through the Northern Box Culvert was able to flow down the Vicroads Drain without increasing flood levels on the Land.[33]
2. I note that in his report dated 26 May 2013, Mr Bishop suggests that the original modelling undertaken by Mr Prout, showed a positive head difference over each side of the New Crossing, which would:

... induce a "reverse" flow in the culvert upstream of the new crossing that is consistent with the observations of Mr Paturis in February 2011.[34]

1. It is not clear from Mr Bishop's statement whether he holds the opinion that the reverse flow only occurred as a result of the presence of the New Crossing, as his comments were focused on responding to other matters raised by Mr Prout in his report dated 13 May 2013. Moreover, Mr Bishop offers no opinion as to whether the reverse flow would occur during a 50 year ARI storm event.
2. Other the other hand, Mr Prout opines that the reverse flow of water would have occurred irrespective of the presence of the New Crossing, given the severity of the Storm. In particular, his supplementary analysis of the Storm for both pre and post construction of the New Crossing states that there was an increase in reverse flow in the Northern Box Culvert.[35]
3. That being the case, I find that the reverse flow was an incident of nature that could not reasonably have been prevented by SRW, having regard to the accepted design limitations of Drain 5. In particular, I accept the uncontested expert opinion that it was reasonable to design Drain 5, including the culvert under the New Crossing, to cater for a 1 in 50 ARI event. What occurred in February 2011 was an extreme weather event, which concentrated on a relatively small catchment area. I accept that the severity of the Storm far exceeded a 1 in 100 ARI storm event and that it was not reasonable for SRW to have designed systems for the delivery of irrigation water and appropriate drainage to cater for such an event. Given that there is no evidence suggesting that the back-flow would occur in a 1 in 50 ARI storm event, it cannot be said that the reverse flow water occurred as a result of negligent or intention conduct of the part of SRW. Therefore, I find that the reverse flow cannot be attributed to any negligence or intentional conduct on the part of SRW, in so far as those terms are to be considered under the Act.
4. Moreover, when the issue is further considered in terms of causation, there simply is no evidence that the reverse flow would have occurred in a 1 in 50 ARI storm. At best, Mr Bishop's evidence only establishes that a reverse flow occurred. However, he does not, in my view, say that the reverse flow occurred but for the presence of the New Crossing or that it would also occur during a 1 in 50 ARI storm or less.
5. Therefore, despite the fact that water back flowed from Drain 5 out of the Northern Box Culvert, I find that it was:
   • (a) not caused by the presence of the New Crossing; and importantly
   • (b) did not result from negligent or intentional conduct on the part of SRW.
6. One may speculate that there may have been simple mechanical devices installed in the Northern Box Culvert or the pipework that flows from it to prevent back flow. However, that is not relevant to the question of whether SRW was negligent, given that the Northern Box Culvert and the pipework connected to it are not assets owned or maintained by SRW.[36]
7. Having regard to my findings, I am left with no option but to dismiss the Applicant's claim. No doubt my finding will make his loss harder to bear. However, I am guided by the expert evidence which I consider weighs against a finding in favour of the Applicant.

[1] Data derived from the Western Irrigation Futures Atlas (January 2009) at page 10.

[2] Applicant's Further Amended Points of Claim dated 30 January 2013.

[3] The Average Recurrence Interval (ARI) is a measure of the rarity of a rainfall event. It is the average, or expected, value of the periods between exceedances of a given rainfall total accumulated over a given duration.

[4] Expert report of Andrew Prout (Engeny) dated 20 December 2011 at page 7-8.

[5] TUFLOW stands for Two-Dimension Unsteady Flow. It is a two dimensional flood modelling software program that simulates the movement of water and depicts predicted flooding through flood maps.

[6] Report of Warwick Bishop dated 4 June 2013 at page 1.

[7] Water Technology report dated 4 June at page 2.

[8] Report of Andrew Prout (Engeny) dated 14 June at page 3.

[12] Engeny report dated 20 December 2011 at page 5.

[13] Roger Wrigley report dated July 2012 at paragraph 7.0.

[14] Roger Wrigley report dated 14 March 2013 at page 5.

[15] [1936] HCA 51; (1936) 56 CLR 520.

[17] Expert report of Warwick Bishop dated 4 June 2013 at page 4.

[18] Further supplementary witness statement of Paul Byrnes at page 4.

[19] Expert report of Andrew Prout (Engeny) dated 13 May 2013 at paragraph 10.

[20] Expert report of Warwick Bishop dated 26 May at page 2.

[21] [1980] VicRp 50; [1980] VR 513.

[23] Witness statement of Tom Patsuris dated 20 March 2013.

[24] Witness statement of Armando Perri dated 27 May 2013.

[25] State Rivers and Water Supply Commission v Crea and Anor [1980] VicRp 50; [1980] VR 513 at page 521.

[26] [2011] VSC 668.

[27] (2010) 27 VR 387 at page 408.

[28] expert report of Warwick Bishop dated October 2011 at page 13.

[29] Expert report of Warwick Bishop dated October 2011 at page 13.

[31] Expert report of Warwick Bishop dated 4 June 2013 at page 3.

[32] Expert report of Andrew Prout (Engeny) dated 14 June 2013.

[33] This is consistent with oral evidence given by Andrew Prout on 28 May 2013.

[34] Expert report of Mr Bishop dated 26 May 2013 at age 2, prepared in response to Mr Prout's report dated 13 May 2013.

[35] Expert report of Andrew Prout (Engeny) dated 14 June 2013.

[36] Oral evidence of Paul Byrnes given on 5 June 2013.