Coundrelis v Roads and Traffic Authority of New South Wales

Coundrelis v Roads and Traffic Authority of New South Wales - [2008] NSWLEC 72 - NSWLEC 2008 case summary — Zoe

[24]

(a) before commencement of the road works, the retained land was not affected by flooding; or alternatively any flooding did not include overtopping of Windsor Road. After commencement of the road works, the retained land has been affected by flooding, or alternatively by an increase in flooding particularly via culvert MD2 under Nelson Road; (b) before commencement of the road works and at the acquisition date, the knowledge of the hypothetical prudent buyer and seller was that the retained land was flood free; or alternatively that any flood affection did not include flooding by overtopping of Windsor Road. After commencement of the road works, the knowledge of the hypothetical prudent buyer and seller was that the retained land was subject to flooding, or alternatively that it was subject to increased flooding particularly via MD2. 11 The RTA submitted that there has been no decrease in the value of the retained land by reason of the acquisition and carrying out of the road works under s 55(f) because: (a) the flood experts agree that as a result of the road works, the retained land is less affected by the average recurrence interval (ARI) 100 year flood event and that it is now cheaper to carry out works to permit future development; (b) the Court should accept the opinion of the RTA's flood expert that there is a net decrease in water flowing onto the site for all recurrence intervals after the road works; (c) the Court should not accept the applicants' claim that there has been a significant increase in nuisance flooding in minor rainfall events; (d) the Court should accept the evidence of the RTA's planning expert that acquisition and road works have not adversely affected the development potential of the retained land and has had no adverse effect on overall accessibility; (e) the retained land is in a improved position to be developed. 12 A major issue is whether (as the RTA contends and the applicants' dispute) prior to the road works a substantial volume of water would flow across Windsor Road onto the applicants' land in the 100 year ARI storm event, which has a 1 percent probability of being equalled or exceeded in a given year. It is common ground that after the road works any flooding from this source is eliminated. There is also a contest as to flooding before and after the road works from any other source, particularly via culvert MD2. Drainage Systems at Acquisition 13 When the applicants purchased their land in April 2004, and at the compulsory acquisition date, there were three drainage systems onto it:

[25]

(a) culvert MD2 under Nelson Road at its intersection with Windsor Road. It comprised two pipes with diameters of 375 mm and 525 mm. The discharge was directed into an open table drain between Windsor Road and the applicants' land from which flows were directed via an open table drain on the eastern side of Windsor Road through culvert MH9 to the Killarney Chain of Ponds Creek, slightly to the north of the applicants' land. If the capacity of the table drain were exceeded, water would flow onto the applicants' land. The RTA's flood expert, Mr Ian Rowbottom, thought MD2 catered for the 1:5 year ARI event. The applicants' flood expert, Mr Drew Bewsher, thought MD2 catered for between 1:5 and 1:20 year ARI; (b) culvert MB1 fed the applicants' dam in about the middle of their land by draining water under Nelson Road at a point about half way along the land's southern boundary; (c) two 450 mm diameter pipes about half way along the northern boundary (from Windsor Road) drained flows from the dam into the creek. It appears that it had potential to backflow in the event of flood in a fairly infrequent ARI event. The Road Works 14 The RTA road works, including associated drainage works, mostly commenced in 2006 and were largely completed by around December 2006. They included: (a) changing culvert MD2 under Nelson Road from two pipes to a bigger box culvert 1800 mm wide x 600 mm high. The new, prominent outlet directly faces the applicants' land and is 5 or 10 metres closer than the old pipes whose outlets were in the road reserve and not prominent; (b) replacement of the Windsor Road open table drain adjacent to the applicants' land with a 675 mm diameter low flow pipe from culvert MD2 to culvert MH9 (opening into the Killarney Chain of Ponds Creek), which has a surcharge pit adjacent to a gate on the retained land; (c) construction of culvert MD3 across Windsor Road roughly 500 metres south of the applicants' land. Its construction commenced in late 2005; (d) widening the eastern side of Windsor Road, raising the level of Windsor Road so as to act as a levy bank in all flood events up to and including the 500 year ARI flood event, and raising the level of Nelson Road.

[28]

17 During the period from 2004 to September 2006 prior to completion of the road works, Mr Coundrelis observed that neither the applicants' land nor the adjoining Lot 112 flooded. He observed that only a small quantity of water reached Nelson Road from the south into culvert MD2. This, to his observation, was due to the following: (a) over a distance of some 500 metres between Nelson Road and culvert MD3 to the south, the vast majority of runoff flowed across Windsor Road from east to west; (b) between culvert MD3 and Nelson Road, a table drain on the eastern side of Windsor Road was virtually non-existent and had no practical capacity, and there were driveway crossings with small pipes which acted to direct runoff across Windsor Road; (b) the small quantity of runoff that did reach Nelson Road at MD2 travelled along the Nelson Road table drain towards culvert MB1 or drained through culvert MD2 and along the Windsor Road table drain to the creek. He never observed water flow from the latter table drain, or the creek, entering the applicants' land. There was an intense one hour storm on 27 February 2006 prior to the road works but the applicants' land did not flood. Observations of Flooding after Road Works 18 On five occasions after commencement of the road works, Mr Coundrelis witnessed the retained land being flooded extensively: on 7 September 2006, 12 February 2007, 9 June 2007, 16 June 2007 and 20 August 2007. Photographs he took of the flooding on 9 June 2007 and 20 August 2007 are in evidence. The flooding on 20 August 2007 was of similar magnitude to the flood on 7 September 2006. On 20 August 2007 the majority of the water discharged from the surcharge pit located adjacent to culvert MH9 and in front of the gate on the north-western corner of the applicants' land. The magnitude of the five rainfall events were of a very minor nature. Storm events of an equal or greater magnitude that he witnessed prior to commencement of the road works did not cause flooding. Rain falling during these five flood events was similar to the rain that fell on 27 February 2006 when there was no flooding. Water broke the banks of the creek during these five flood events but did not do so on 27 February 2006. The flooding was of a transient nature.

[42]

(a) overtopping of Windsor Road with flood flows travelling in a north-easterly direction; (b) overtopping of Nelson Road at Culvert MD2; (c) spilling of flows from the Killarney Chain of Ponds Creek downstream of Culvert MH9 into the subject property in a generally easterly direction. There may also be potential for flood flows to surcharge Culvert MB1 and flow into the subject site in a generally north westerly direction. 26 Mr Bewsher did not carry out detailed modelling but reviewed Mr Rowbottom's modelling. In his initial report, he agreed with Mr Rowbottom's modelling in relation to the 100 year ARI flood but disagreed in relation to minor flood events, as follows: 17. Subject to the qualifications presented in Paragraphs 18-20 below, I believe the RTA's modelling provides a reasonable approximation of flow behaviour over the site during major events such as the 100 year flood. Given the complex behaviour and the models used, I would anticipate that the flow predictions made by the RTA's consultants were accurate to + 30% and the flood level predictions are within + 0.3 to + 0.5m. Subject to these inaccuracies, the model would still provide, in my opinion, a reasonable basis from which to assess development potential. 18. In smaller events (say those less than a 20 year flood, say the 1 year, 2 year and 5 year ARI events) overtopping of Windsor Road would not occur and the RTAs modelling indicates that the flows coming into the southern part of the site would occur from three sources under "pre" and "post" works scenarios: (a) from culvert MD2; (b) from the Windsor Road table drain adjacent to the site (or the 675mm diameter pipe which is proposed as a replacement for the table drain); (c) overtopping of the fill in Lot 112. 19. In my opinion, it is unlikely that the RTA's modelling correctly predicts the flooding mechanisms (a) or (b) referred to in paragraph 18 above, for the "pre" works scenario. I say this because the old MD2 culvert delivered flows to the Windsor Road table drain and thence to the Creek, and had not been observed to overtop onto the property. 27 Mr Bewsher in this report assessed the capacity of the Windsor Road table drain approaching culvert MD2 as follows: 20. I have also carried out a preliminary hydraulic assessment of the hydraulic capacity of the Windsor Road table drain upstream of culvert MD2 which suggests that " pre" works, a maximum of only about 1m3/sec would reach the upstream side of culvert MD2. Flows in excess of this amount would cross Windsor Road in a westerly direction. In addition, flows arriving at the entrance to MD2 could also flow towards MB1. 21. In Figure 1, I have summarised my assessment of the changes inflows which will occur on the site as a result of the RTA's works. As shown on the figure: (a) flows from MD2 would be increased in minor and major floods. (I use the term "major flood" to indicate floods generally in excess of about a 20 year flood when significant overtopping of Windsor Road occurs); (b) flows overtopping Windsor Road in major floods would be eliminated; and (c) flows from Lot 112 would be increased in major floods and there would be little change in minor floods, or possibly a small increase. 22. In my opinion, in major floods the net flow coming on to the site from all sources will decrease, but will be increased in minor floods. 28 Mr Bewsher's conclusions included the following: 39. In minor floods (such as the 5 year event) when waters would not have overtopped Windsor Road in the "before" situation, the RTA's works will divert more water onto the subject site. In major floods (such as the 100 year event) when significant flows would have been overtopping Windsor Road in the "before" situation, the RTA's works will eliminate such overtopping. Whilst in this situation some additional flows will still be coming onto the subject site from culvert MD2, the net effect of all flow changes will be a reduction in total flows coming onto the site. 40. As the flood behaviour which occurs in the 100 year event is usually one of the primary considerations for the Council when assessing development options on a site, the net reduction in flows coming onto the subject site in this event will likely lead to some reduction in the cost of developing the site to overcome its flood problems (assuming the full extent of the flood problem was known to the Council and the developer). 41. In summary, having regard only to flooding issues, there appears to be a net detriment to the site in minor floods and a net benefit to the site in major floods. 29 In a joint report, the flood experts agreed the accuracy of Mr Rowbottom's models as follows: Accuracy of RTA's Hydrologic Model 24. The experts agree that the hydrological model is likely to be accurate to within + 30%. The experts also agree that the order of accuracy is consistent with best practice.

[44]

30 Importantly, in the same joint report the flood experts agreed that it would now be cheaper to develop the retained land because the road works have reduced the 100 year ARI flow coming onto it: 26. The experts agree that the cost of works necessary to allow development of the Subject Property would be reduced in the "after" scenario compared to the "before" as the total 100 year ARI flow coming onto the Subject Property would be reduced. 27. The experts disagree on the magnitude of flows at culvert MD2 in both the "before" and "after" scenarios. However, they agree that the differences do not change the agreement expressed in Paragraph 26. 28. Further the experts agree that, from a flooding perspective, the development potential of the Subject Property is largely governed by the flood constraints imposed by the 100 year ARI event. 31 The applicants conceded that this evidence, if accepted, does considerable damage to their case. 32 However, they submitted that I should not accept it because it assumed, rather than established, overtopping of Windsor Road pre-road works in the 100 year ARI event and that I should not be satisfied on the evidence that was so. I do not accept the submission. The experts were not merely expressing an assumption. They were expressing their opinions or conclusions. Indeed, earlier Mr Bewsher in his initial report said that flood waters would overtop Windsor Road onto the applicants' land in major flood events, which he defined as being in excess of about a 20 year ARI flood: see [25] and [27] above. In cross-examination he said that the most likely situation was that in a 100 year ARI flood, water would have overtopped Windsor Road before the road works and he agreed with Mr Rowbottom's estimate that the magnitude of such water would have been between 300 and 500 millimetres crossing the whole of the Windsor Road frontage. Moreover, Mr Bewsher in his initial report also said that the net effect after the road works will be a reduction in total flows coming onto the site: see [28] above. There was no contrary evidence called by the applicants (which may have required leave of the Court given that the experts had reached agreement in a joint report).

[51]

39 In my opinion, there has been an increase in nuisance flooding by reason of the road works. I agree with Mr Bewsher for the reasons that he gave. The observations of Mr Coundrelis that there has been such an increase are telling. It is unnecessary to go further but I note that anecdotal evidence he obtained from neighbours of absence of flooding before the road works provides further support even after making due allowance (as submitted by the RTA) that they may not always have been present during storms or may not have had particular reason to recall flooding. 40 Mr Bewsher, like Mr Coundrelis, said and I accept, that in more frequent, less serious rainfall events there is, post road works, increased ponding on the retained land. Mr Bewsher attributed this to the road works. Mr Rowbottom expressed the opinion that the likely cause was not the road works but a development that took place on the other side of Nelson Road, on Lot 30, involving a large impervious asphalted area and a large shed. He considered that water from Lot 30 previously would have been largely dissipated but now largely goes towards culvert MB1 which drains to the dam. Although the flood experts agreed that the development of Lot 30 has resulted in increased runoff to the retained land to culvert MB1, I do not accept Mr Rowbottom's opinion. The development on the other side of Nelson Road was carried out in 2003. It does not explain Mr Coundrelis' observations, which I accept, that nuisance flooding increased after the road works and that in the period 2004 to 2006, prior to the road works, there was no flooding from culvert MB1. Mr Rowbottom considered that photographs taken by Mr Coundrelis on 20 August 2007 show water backing up from the dam onto the low lying portion of the retained land. Mr Bewsher disagreed and considered that it came from the MH9 surcharge pit. I believe Mr Coundrelis who testified that, to his observation, it came from the surcharge pit. 41 Since August 2007 extensive work had been undertaken in the vicinity of culvert MH9 and as a result it is less likely to surcharge. That was the evidence of Mr Warwick Jones, the leader of the team of engineers responsible on behalf of the RTA for the Windsor Road upgrade, which I accept. Therefore, to the extent surcharging from MH9 may be the source of flooding of the applicants' land post road works, that affection should be less, but to what extent is unclear.

[58]

(i) Lot 15 was zoned Rural 1(a) under Baulkham Hills Local Environmental Plan 2005 with recognition that the land had future urban potential; (ii) Lot 15 was within the Box Hill Industrial Precinct in the NW Growth Centre first announced in December 2004 and exhibited in June 2005, however, it was not within a Precinct identified for immediate release; (iii) Lot 15 was designated for industrial purposes in the Draft Structure Plan exhibited in June 2005 for the NW Growth Centre; (iv) according to the June 2005 exhibition material, the next Precincts for release were expected to be identified in 2007/08. Those areas could be ready for development in 2009/10 (following precinct planning). These timeframes could be extended by up to 1-2 years; in Mr McKenzie's view if development pressure emerged the process could be expedited; (v) on this basis, if the Box Hill Industrial Precinct were to be identified for release in the next round, it could be released in 2008/09 and it could be ready for development in 2010/11. Otherwise its release may be timed to meet the supply of industrial land for employment purposes commensurate with the release of land for residential development and be subject to the availability of services; in Mr Sanders' view in such circumstances it would be uncertain when the land would be released over the overall timeframe of the program. (vi) in accordance with the June 2005 exhibition, once land is released a precinct plan is required to be prepared before development can occur. (vii) No development contribution charges were provided for development of industrial land. (viii) Lot 15 was not affected by the Landscape and Rural Lifestyle Zone proposed as part of the draft Structure Plans for the NW (and SW) Growth Centre in the June 2005 Exhibition which was abandoned in November 2005 following an announcement by the Minister for Planning. (ix) new land release constraint maps released in November 2005 indicated that Lot 15 was unaffected by constraints. Part of Lot 5 (the residual lot) was identified as being subject to flooding. Mr McKenzie has sought further information on this matter as it may not impact on development potential as is inferred. In Mr Sanders' view, the acquisition of Lot 15 would not change the extent to which the residue land was affected by such a constraint. (x) the release of detailed maps referred to in the November 2005 announcement had not occurred by the date of acquisition of Lot 15 on 9 December 2005. 47 The planners also said in this joint report that had a hypothetical prudent purchaser made enquiries of them to identify the development potential of the acquired land as at the acquisition date, they would have advised that part of the retained land was identified as being subject to flooding.

[65]

54 The relevant date, however, is the date of compulsory acquisition in December 2005 and prior to the road works. By then the following flood information was available to the prudent buyer and seller: (a) a draft Department of Planning map, entitled " Draft Sydney Region Growth Centres Development Control Map - North West Growth Centre " which showed the applicants' retained land to be partially nominated as " Flood prone and major creeks land " from the direction of Lot 112 and the creek. A note on the map indicated that it was based on information provided by local councils and State authorities and was an estimate. A copy of this map was obtained by Mr Coundrelis in October 2005. This map was on public exhibition after the acquisition date, from January to March 2006; (b) from 3 November 2005 a second version of that map was available on the Department of Planning's website which nominated part of the applicants' retained land as " Preserve flood prone land and important creeks ". 55 The planning experts stated in a joint report, and I accept, that they would have advised a hypothetical prudent purchaser who inquired of them to identify the development potential of the land, that new land release constraint maps released in November 2005 indicated that part of the retained land was subject to flooding. 56 The flood experts agreed that advice to a prospective purchaser at the acquisition date might be given in stages, with each consecutive stage providing more detailed advice if the circumstances required it: (a) Stage A advice comprised initial advice without a site visit or calculations. No specific advice would have been given as to whether the land was flood prone or not. Rather, the purchaser would have been advised to refer to information that might have been available from the council or other authorities. The flood experts disagreed as to what would have happened after Stage A. Mr Bewsher considered no further advice would have been sought from a flood expert, and said that was his experience. Mr Rowbottom believed further advice would have been sought. (b) Stage B advice extended to a site visit and, possibly, preliminary calculations. Both experts agreed that if advice proceeded to Stage B, following site inspection, the prospective purchaser would have been advised that the site may have been flood prone. Mr Rowbottom believed prospective purchasers would have requested additional information as to the likely severity of flooding. Therefore, in addition to the Stage B site visit, Mr Rowbottom would have advised, based on preliminary hydrologic and hydraulic calculations (i.e. the probabilistic rational method outlined in the publication " Australian Rainfall and Runoff" ) that this section of Windsor Road was likely to overtop during events greater than the 20 year ARI flood. That information could be provided at a reasonable cost without the need for detailed survey or computer modelling. (c) Stage C advice required computer modelling. Mr Bewsher considered that a prospective purchaser would only be seeking advice after Stage B if the property market and the local council were aware of the flood prone nature of the site and the difficulties that might be faced in developing it. Mr Rowbottom considered that given the low lying nature of the property and its location downstream from a sag point in Windsor Road, preliminary calculations would have been required at the date of acquisition and these would have been sufficient to advise a prospective purchaser as to likely flood affection. Following acquisition, a computer model would be required to more accurately define flood behaviour to support any future development application. However, neither flood expert suggested that a buyer would go to the expensive stage C advice before buying the property.

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