Geotechnical evidence
113 The court has been assisted with geotechnical evidence prepared by Dr Fiona MacGregor, as a Parties' Single Expert (Exhibit R4). According to Dr MacGregor (p3/fol 97, pars 6.1-6.2) a prudent purchaser of the applicant's land "would engage a geotechnical consultant to provide an assessment of the possible geotechnical constraints to development of the site... The geotechnical assessment may include drilling of test bores or cone penetration tests, depending on the amount of money the purchaser is prepared to spend and whether permission to access the land can be obtained from the vendor."
114 A visual inspection of the site and the publicly available documents point to the following geotechnical features of the site (p5/fol 99, par 8.1):
· a flat low lying site with poor drainage and a high groundwater table;
· probably underlain by thick layers of soft compressible soils; and
· probably underlain by acid sulphate soils.
115 During her oral evidence Dr MacGregor, relying on the West Ballina Constraint Study, estimated that the depth of the compressible soils on the applicant's land to be approximately "8 metres on the western side increasing to greater than 10 metres, 15 metres to the east " (T21.11.08, p.47, LL39-46).
116 According to Dr MacGregor the main geotechnical constraints to development of the subject land, in both the "before and after" scenarios, are likely to be (p6/fol 100, par 8.2):
· long term settlement of compressible soils under loads of structures and/or filling;
· poor foundation conditions;
· potential for acid sulphate soils, if excavation of soils below 1 m is required;
· high groundwater table would also affect excavations below 1 m; and
· poor trafficability, particularly after wet weather.
117 Accordingly, the site is more constrained under certain uses than others. The following extract from Dr MacGregor's report sets out her views on the constraints on use (pp6-7/fol 100-1, par 8.5-8.12):
" 8.5 A) Rural residential / sugar cane farm . The site has previously operated as a sugar cane farm and a previous residence on the site has been removed. The only geotechnical constraint to operating a sugar cane farm on the site is that the presence of potential acid sulphate soils beneath the site means that excavation of new drainage trenches or deepening of existing drainage trenches may require treatment of the excavated soils to prevent acid drainage into nearby waterway. Trafficability across the site will continue to be difficult after periods of wet weather.
8.6 A rural residence may be constructed on the site, as previously, but it would be ideally be (sic) a flexible timber structure supported on pole foundations elevated above the ground surface to be higher than flood levels. A standard brick or concrete house constructed on a filled platform would have a number of issues as indicated below.
8.7 B) Residential dwelling house subdivision . Most current residential subdivisions are developed such that lot purchasers can build houses supported on concrete slabs-on-ground. In this area this type of subdivision would require a filled platform of 1-2 m to raise the ground level above the 1 in 100 year peak flood level. Assuming that there are deep compressible soils beneath the site then there is likely to be significant ongoing settlement due to the filling and the loads of the houses which could result in cracking of the new houses, roads and associated underground services. The settlement is likely to continue for decades and the damage to houses could be severe.
8.8 C) Caravan park / motel / hotel . All of these options are likely to require construction of fill platforms to raise the site above flood levels and the fill platforms will undergo significant ongoing settlement. The caravans in a caravan park can be moved and relevelled to allow for this settlement but associated structures such as amenities blocks, roads and underground services are likely to be damaged by the settlement.
8.9 Motel and hotel buildings tend to be more rigid structures and, unless they are fully articulated flexible structures, would have to be designed as suspended structures supported on deep pile foundations. Even if the structures are fully suspended, there are still likely to be interface problems between the piled building and the surrounding pavements and any underground services as the fill around the building continues to settle over time.
8.10 D) Service station / bulky goods retail / motor showroom . It is assumed that all of these options would again require a fill platform to be constructed to raise the site levels to above the 1 in 100 year flood level. All the structures would be affected by the ongoing settlement unless they are designed as fully suspended structures supported on piles. Even if the structures are fully suspended on piles then any surrounding pavements and connecting underground services will still be affected by the settlement.
8.11 The service station option has the added complication of requiring excavation for underground tanks into potential acid sulphate soils with a high groundwater table. Local temporary dewatering would be required during excavation, together with treatment of any acid sulphate soils. In addition the buoyancy of the underground tanks, particularly during flood events, would need to be considered.
8.12 E) Manufactured home residential development . Manufactured homes are better suited to development in this area because they can be moved and relevelled as the filling platform settles. The roads and any underground services, however, would still be affected by the ongoing settlement and there would be a need for flexible service connections to the homes and allowance for ongoing maintenance or replacement of services and roads."
118 Various mitigation strategies are available to address the geotechnical constraints on the applicant's land. The "preloading" or "surcharge" method is the subject of some discussion in the evidence (see Dr McGregor's report Exhibit R4 at p8/fol 102, and Mr Connelly 's report Exhibit B1, p29). When talking about the long term settlement of deep compressible soils, settlement can be divided into two components: primary settlement - the consolidation of the soils; and secondary settlement - "creep". Dr McGregor says (p7/fol 101, par 9.2):
"The magnitude and time required for primary settlement is usually considered to be a function of the properties of the clays, the applied load, the thickness of the clay layers and the possible drainage paths. Secondary creep is more unpredictable, continues for many years and is not necessarily related to the applied load."
119 The construction of a fill embankment to a level higher than the required soil level is proffered as the easiest treatment option (surcharging or preloading), but it may take 10-20 years for settlement to reach a level which would be suitable for development, especially if there are thick layers of soft clays. Constructing the fill embankment significantly higher than the proposed soil level ie "surcharging", should accelerate settlement, but more than 2-3 metres of fill embankment may cause shear/slip failures through weak soils. Surcharging may still mean many years of settlement before development is deemed possible. Installation of wick drains and construction of embankments supported on a grid of piles and a bridging layer of crushed rock (piled embankment), may reduce settlement time but is very expensive (see p8/fol 102, pars 9.3-9.6).
120 Absent a suitably engineered fill embankment, any structure will have to be constructed on supporting piles (made of either driven timber or precast concrete piles) drilled into a firm layer, estimated at 10-20m (p8/fol 102, par 9.7).
121 Excavation requires stockpiling of soil and treatment with lime to neutralise any acids within acid sulphate soils. "Excavation below the groundwater will require temporary dewatering which would involve installation of a number of spear points around the perimeter of the proposed excavation and possibly also construction of a low permeability barrier wall." (p8/fol 102, pars 9.8-9.9).
122 With regard to poor trafficability, Dr McGregor observes (p9/fol 103, par 9.10):
"[I]n dry weather it is likely that the surface soils will form a hard crust on which construction traffic can drive. During wet periods, however, this surface layer is likely to become saturated and a bridging layer comprise (sic) a layer of compacted crushed rock probably placed over a layer of geogrid will be required to allow vehicles to move across the site."
Hydrological evidence
123 The court has been assisted by hydrological evidence prepared by Dr Ian Joliffe, as a Parties' Single Expert (Exhibit R3). Dr Joliffe would advise a hypothetical purchaser (fol 14, par 8.2) to engage "a competent person to make the following enquiries:
· View the Council web site and obtain information that was publicly available from that source in respect to the site topography, existing zoning, potential changes to zoning, applicable policies applicable to the site, draft policies that were on exhibition or had recently been on exhibition and any other relevant information;
· Viewed the RTA website to examine any applicable documentation relevant to the site; and
· Possibly visit Council to make further enquiries of the planners, and/or possibly engineers after the above had been reviewed and considered.
Several of the available documents from readily available sources have identified the site as being flood prone for the 100 year ARI event. This is the event that is generally adopted when considering whether a property is flood affected. "
124 One of those publicly available documents is the "Ballina Floodplain Management Study" prepared by WBM Oceanics Australia, in October 1996 (Exhibit R2, tab 53), which aids in "[p]lanning for floodplain development and minimising flood related problems" (fol 689). Five anticipated development scenarios involving various filling of land and use of water canals or channels were modelled. One potential floodway (FW1) would encroach upon the applicant's land (DA3) along the western portion in a north-south direction (fol 776), and would be 40 metres wide (fol 777).
125 In order to construct new buildings on the land it "would be necessary to fill the site to the 100 year ARI flood level without impacting on adjoining properties" (Exhibit R3, fol 15). Regard would also be had to the 40 metre wide floodway (cf 60 metres in par [48]) envisaged in the floodplain management study.
F. Consideration
126 Mr Maston, for the respondent, relies on (1) the aftermath of the Council amalgamation in 1977, and (2) Council's support for Department of Agriculture desires for productive land to be retained for cane growing (see Exhibit R2, vol 2, tab 44), as evidence of Council's long-held planning preference for Ballina to expand to the north, rather than to the west (see T 9.12.08, p36), the prominent impact of the 1973 bypass route having become a/the dominant influence on planning in the town area.
127 He downplayed the significance of Mr Connelly's role in relevant events and decisions during his service with the local Council, and presented in his submissions comprehensive, but controversial, responses to Mr Connelly's evidence, which drew from Mr Webster allegations of misrepresentation (T 9.12.09, p51ff).
128 On the other hand, Mr Webster, for the applicant, is very critical of the evidence given by both the "parties' single experts", Drs Joliffe and McGregor, evidence which the respondent accepts, relies upon, and was prepared to defend, on the issues of development constraints.
129 The court had the benefit of hearing and observing the two single experts during Mr Webster's searching cross-examination, in the course of which the court was taken to some additional relevant expert evidence (the 1996 Carr report, in Exhibit R2 at tab 43, and the 1999 Coffey study, in Exhibit B6. See also Exhibit B7, Item 1). Mr Webster even put to the court that I should prefer Mr Connelly's evidence to Dr McGregor's on matters clearly within her area of specialty and beyond his. The court found Mr Connelly's factual (rather than expert) comments on her report (eg at p29 of Exhibit B1) useful, but he is not an expert in such matters.
130 In the end analysis I can find no reason not to accept the opinions Drs Joliffe and McGregor expressed on the present matter, so far as they go - the site conditions call for compression of soils, installation of, flexible water/sewerage services, and other special measures as part of any development. Requirements based on the relevant flood studies will also clearly need to be imposed and catered for. The discovery by a hypothetical purchaser of some of the material to which Mr Webster pointed Dr McGregor should not be readily assumed - Dr McGregor considered it would depend on how much such a purchaser might wish to spend on such investigations.
131 So far as the possible returns from establishment of a highway service centre are concerned, I am satisfied, on the agreed evidence of Messrs Coad and Paris, that, even if it were feasible to expect consent, such a venture is simply not viable.
132 While I make no criticism of the very professional approach taken by the various other experts engaged by the parties, I find myself, as the judicial valuer, ultimately preferring the town planning evidence of the applicant (Mr Connelly) and the valuation evidence of the respondent (Mr Hamilton).
133 Mr Connelly has the distinct advantage of past professional involvement with Council as it grappled over his time (1981-86) with the complex issues at the core of this case - (1) extreme and constant urban pressures on and close to the Ballina town centre, (2) the virtual sterilisation of a substantial area of otherwise suitable land over a long period of years (1973-1997) before the dramatic change in preferred route for the highway bypass, and (3) the natural development constraints on and near the applicant's land.
134 Although Smith No.1 and Smith No.2 concerned the bypassing of Alstonville, rather than of Ballina, the experience and observations of McClellan ChJ, and later Talbot J, are apposite to this present case. At [54]-[56] of his decision in Smith No.1, McClellan J, like me in this case, arrived at a preference for the witnesses who had relevant and close past associations with local Council decision-making. In this matter Mr Rowan's Council experience (Woollahra 1991-93), though relevant and more recent than Mr Connelly's, was in a vastly different development environment.
135 Mr Connelly's evidence regarding the Ballina Council's residential development strategy (1988) was particularly significant to my consideration of the case, whereas Mr Rowan considered that material of only peripheral relevance. Also, there is clear evidence to refute Mr Rowan's principal opinion that the western boundary of residential development was preferred by Council to be Fishery Creek.
136 I have concluded that the most comparable property studied in the evidence, and inspected on the view, is "Riverbend", rather than "River Oaks" (now Ferngrove Estate). While there are some unusual features about the "River Oaks" sale as such (see Talbot J in Smith No.2 at [19]), the evidence suggests that both land holdings may well suffer from the same geotechnical shortcomings or restrictions, perhaps to differing degrees (see Exhibit R13, p2 and Exhibit R14, but cf Mr Connelly's evidence T 24.11.08, pp44ff).
137 The fact is that a more conventional residential development was allowed on "River Oaks" than on "Riverbend", which is adjacent to the residue land. As Mr Connelly remarked, there was apparent movement over time in the Council's approach to risk, but I accept Mr Hamilton's evidence that the "River Oaks" site is superior to the applicant's land in several respects.
138 Accepting that the highest and best use of the residue land would be as a manufactured housing estate, along the lines of the adjacent similar development at "Riverbend", I have concluded that such use of the applicant's land will make it simpler and more likely that any remaining question of access will be able to be resolved via "Riverbend" (T 25.11.08, p55, LL 20-30), if not by the use of any of the three public roads there will be in the immediate vicinity after the motorway is built (T 9.12.08, p43, LL1-14).
139 So far as the "Riverbend" sale having occurred so long ago is concerned, I am satisfied that Mr Hamilton has made adequate allowance for the movement in the market between the date of the sale and the date of acquisition (four years at 15% - see T 25.11.08, p35, LL37-42, and par [94] above).
140 I do not accept Mr Wood's opinion that the bypass route will have a negative impact on residential development of the applicant's land. There is clear evidence to suggest it may indeed improve it, because of the effect of prevailing wind patterns on possible problems in the area with dust and noise.
G. Conclusion
141 The acquired land should be valued on the basis of Mr Connelly's Scenario 2 in the "before" situation, and the planners' joint Scenario 1 in the "after".
142 Accordingly, I have concluded that the value of the parent parcel before the subject acquisition was $3,700,000 (see par [90]), and the value of the residue parcel after acquisition is $3,275,000 (see par [99]).
143 I, therefore, determine compensation as follows: