Variant Group Pty Ltd v Tweed Shire Council [2026] NSWLEC 1186

Cases Cited: Kindimindi Investments v Land Cove Council & Anor (2006) 143 LGERA 277: [2006] NSWCA 23
Mullaley Gas and Pipeline Accord Inc v Santos NSW (Eastern) Pty Ltd [2021] NSWLEC 110
Parrott v Kiama [2004] NSWLEC 77
Planners North v Ballina Shire Council [2021] NSWLEC 120

Texts Cited: Tweed Shire Development Control Plan 2008
Tweed Shire Council, Development Design Specification D5 - Stormwater Drainage
Design

Category: Principal judgment

Parties: Variant Group Pty Ltd (Applicant)
Tweed Shire Council (Respondent)

Representation: Counsel:
T To SC (Applicant)
A Stafford (Respondent)
Solicitors:
Mills Oakley (Applicant)
Lindsay Taylor Lawyers (Respondent)

File Number(s): 2024/406644 (Class 1 appeal)
2025/230958 (Class 2 appeal)

Publication restriction: No

JUDGMENT

1. COMMISSIONER: These are two related appeals heard together. The Class 1 appeal (2024/406644) is made pursuant to the provisions of s 8.7(1) of the Environmental Planning and Assessment Act 1979 (NSW) (EPA Act) against the refusal of Development Application No. DA24/0388 for the subdivision of one Torrens title lot to create 18 residential lots ranging in size from 347m2 to 996m2, one communal lot containing internal roads, a system of retaining walls along the southern boundary and an area of remnant native vegetation (the proposal), at 4A Boyle Avenue, Banora Point (Lot 3 in DP 250581) (the site), by Tweed Shire Council (the Council).

2. The Class 1 appeal includes an application under s 138 the Roads Act 1993 (NSW) for some aspects of the connections and adjustments to the road that sit beyond the boundaries of the site within the Boyle Avenue and Fairway Drive road reserves (s 138 application). The Court has the power to determine this application under s 39(2) of the Land and Environment Court Act 1979 (NSW) (LEC Act).

3. The Class 2 appeal (2025/230958) is made pursuant to the provisions of s 176(1) of the Local Government Act 1993 (NSW) (LG Act) against the Council’s deemed refusal of an application under s 68 of the LG Act to carry out water supply and sewerage works servicing the site (s 68 application).

4. The appeals were subject to conciliation on 5 May 2025, in accordance with the provisions of s 34 of the LEC Act. As agreement was not reached, the conciliation conference was terminated, pursuant to s 34(4) of the LEC Act.

5. The Court, in the company of the representatives and the parties, viewed the site on Monday 20 October 2025. Prior to the site view, the parties agreed that the traffic, arboriculture, bushfire and landscaping experts were not required to attend the site view.

The applications are amended

6. The Applicant, by Notice of Motion heard on 21 October 2025, sought to amend the application (Class 1 appeal) to give effect to the various agreements and observations of the experts in the joint reports and described in detail in Ms Osborne’s affidavit attached to the Motion.

7. There are amendments to the s 68 application (Class 2 appeal). The Applicant noted that leave is not required because s 87 of the LG Act permits the Applicant to make amendments of a minor nature to the application.

8. The Respondent did not oppose the Motion, however submitted that there remain inconsistencies between plans and documents, and that some changes reflect the agreement of certain experts and not others, which would require (with the leave of the Court) the Respondent leading evidence during examination of those experts.

9. The Court made the following orders on 21 October 2025:

“(1) The Court grants leave for the Applicant, under s 64 of the Civil Procedures Act 2005 (NSW), to file and serve the further amended Class 1 application set out in tab 19 of Exhibit AO-1 to the Motion.

(2) The Court, under s 39(2) of the Land and Environment Court Act 1979 (NSW) exercising the functions of the consent authority under s 38(1) of the Environmental Planning and Assessment Regulation 2021 (NSW) agrees to the amendment of Development Application No. 24/0388 to rely on the plans and documents listed in Sch 1 of Exhibit AO-1.

(3) Pursuant to s 8.15(3) of the Environmental Planning and Assessment Act 1979 (NSW), the Applicant is to pay the Respondent’s costs thrown away as a result of the amendment of the application, as agreed or assessed.

(4) In relation to the Class 2 appeal for the application under s 68 of the Local Government Act 1993 (NSW), the Court notes that under s 87(1) of the Local Government Act 1993 (NSW), the Applicant has amended the documents accompany the application for an approval to include the documents listed in Sch 2 of Exhibit AO-1.”

10. Leave was sought, unopposed and granted on 23 October 2025, for the Applicant to amend the application to rely on amended Stormwater Plans prepared by OSKA Consulting Group (engineering plans DA 400 Issue 10 and DA 401 Issue 7, Stormwater Plan P004 Rev G) which incorporated changes contemplated by the stormwater experts but omitted from the previous iteration of plans for which leave was granted on 21 October 2025, such as concrete swales instead of grass swales within Lots 2, 11 and 12, and other changes made by Mr Purdon including adding a swale along the eastern boundary of Lot 8. The amended plans replaced those superceded plans in Exh C.

11. Leave was sought, unopposed and granted on 24 October 2025, for the Applicant to further amend the application to rely on an amended Subdivision Plan (Rev K, Annexure D [reproduced at Figure 2 below]) and a description of those amendments (which replaced the Subdivision Plan in Exh C), and an amended Community Management Plan (Exh G).

Issues

12. Following the amendment of the documents accompanying the s 68 application, the Council submitted that the issues raised in the Class 2 appeal are resolved.

13. The Council did not raise an issue regarding the s 138 application (Annexure C).

14. The Council submitted that the traffic and parking contentions (Exh 1, 1.3, 1.9, 3.1, 3.2, 3.4 3.7) are no longer pressed and noted that the proposed five visitor parking spaces within the proposal complies with the Tweed Development Control Plan (TDCP). The Council submitted that the contention requiring owner’s consent for the removal of a tree on the property to the north of the site (Exh 1, 1.11) is no longer pressed, nor are some of the contentions relating to stormwater infrastructure and impacts on the Endangered Ecological Community (EEC) (Exh 1, 1.6(f) and (h), 1.7(a), 1.8 and 3.5). None of the additional information contentions were pressed (Exh 1, contention 2) (Respondent’s written submissions at par 6 and Tcpt, 21 October 2025, p 15(14) – p 17(47)).

15. The Council submitted that the contention regarding limited opportunities for deep soil plantings between future dwellings is no longer pressed because the Council is content that the deep soil zones (and plantings) can be achieved consistent with the agreed bushfire management regime (Exh 1, 1.13(g), Tcpt, 24 October 2025, p 253(45)-(49)) and the Applicant’s written submissions at par 172).

16. Following the amendments made to the Class 1 application, the Council’s remaining issues can be summarised as (Respondent’s written submissions at par 4):

17. Land stability: The site is unstable and will be unstable after the works, the subject of the application, are completed. This cannot be resolved by a condition contemplating future applications because the Court cannot be satisfied that the works the subject of this application are appropriate, when the geotechnical experts are in agreement that the site will not be stable following the works proposed in this application.

18. Stormwater and flooding: The stormwater design is inappropriate and inadequate, including because there is no legal discharge point for stormwater leaving the site to the north. The proposal will put 22,000L per day onto the neighbouring property to the north, and a number of aspects of the stormwater management system have not been the subject of adequate design so that the operation of the stormwater management system can be properly modelled. Further design ought not be left to the construction certificate stage given the environmental and other constraints, and the controls requiring certain matters to be addressed before consent is granted.

19. Retaining wall design: The retaining wall design is inadequate and inappropriate, in that the designs proposed are not enough to stabilise the site as part of this proposal, given the evidence of the geotechnical engineering experts. The design involves large, tiered retaining walls located close to future dwellings, presenting greater consequences in case of failure, and making the walls challenging and expensive to maintain. Stormwater overtopping of the swales could jeopardise the structural integrity and longevity of the retaining walls, and there are challenges in constructing necessary walls as part of the dwellings if this is not done at the same time as the subdivision.

20. Access and maintenance: The access and maintenance of the retaining walls and swales is not resolved; the position of the civil engineering experts is at odds with the position of the Applicant’s town planner. While the Applicant appears to have embraced the position of the civil engineering experts moving the main retaining walls and swales, but not all the swales, within common property, the layout takes the common property only to the base of the retaining wall which does not provide for access by the community association to the base of the walls. The community management statement has not been updated to reflect the change in position, and this does not rectify concerns about appropriate funding arrangements or the risks identified.

21. Appropriate future dwellings: The concept designs for dwellings do not demonstrate that appropriate dwellings can be achieved within the lots.

22. Groundwater, surface water and impacts to the EEC and C****oastal W****etlands: The evidence is insufficient to form the necessary state of satisfaction under s 2.8(1) of State Environmental Planning Policy (Resilience and Hazards) 2021 (RH SEPP) that the proposal will not significantly impact on the quantity and quality of surface water flows to and from the coastal wetland to the north, or groundwater flows, and will not significantly impact the biophysical, hydrological or ecological integrity of the wetland. Dr Martens’ evidence as to the lack of clarity surrounding stormwater design and hydrological modelling should be accepted (his evidence is that the distribution of discharge of pollutants and flows to the Swam Sclerophyll Forest endangered ecological community (EEC) in the northwest corner of the site, and offsite in the adjacent wetland, remains unclear).

The site and its context

Figure 1: The site and its context, from Exh 1

17. The site is located within an established residential area of Banora Point, east of the Pacific Motorway, known locally as East Banora. The Tweed River is located approximately 105m to the east of the site.

18. The site is Lot 3 in DP 250581 and has an area of 1.916 hectares (ha) with a 29.33m frontage to Boyle Avenue. The topography of the site varies from steeply sloping on the southern portion to more gently sloping on the northern side. The site falls approximately 25m from south to north (Detailed Ecological Assessment, Exh A, tab 8).

19. The site is in a vacant unmaintained state and contains extensive overgrown elephant grass, and a stand of native and non-native trees within the north-western extent (Detailed Ecological Assessment, Exh A, tab 8). Stormwater from upstream catchments is diverted and directed onto the site in an uncontrolled manner, in the form of both broad surface flows as well as concentrated flows from a pipe that extends into the upper slopes of the site, observed on the site view (Applicant’s written submissions at par 19).

20. The property to the north of the site (the northern neighbour) is approximately 15 ha of low-lying land, a portion of which is cleared agricultural land presently used for grazing. The northern property includes a Coastal Wetland and is partly comprised of the EEC. The Coastal Wetland straddles a creek that is connected to the Tweed River.

Background and the proposal

21. The proposal is for the subdivision of one Torrens title lot to create 18 residential lots, one community lot containing internal roads and a system of retaining walls along the southern boundary. The proposal includes an area of over 3,000m2 including an onsite EEC known as the “Swamp Sclerophyll Forest”, to be restored and rehabilitated under the (amended) Habitat Restoration Plan by Abel Ecology dated 19 October 2025 (Exhibit C, tab 9).

22. Extensive civil engineering works are required to accommodate the proposal, including a/the cut in the upper slopes and fill in the lower portions, together with a series of retaining walls on the southern portion of the site (Exh C, tab 1, DA200-201).

23. The proposal includes capturing, diverting, treating and releasing stormwater, including stormwater from upstream catchments (Exh C, tab 2, P002 Post-Development Catchment Plan), at two areas of discharge that currently occur along the northern boundary of the site, one in the west through the onsite EEC, and a second broader section in the east. The external catchments represent 80% of the stormwater to be captured (Exh C, P001). A separate stormwater system will detail and treat the stormwater generated by the proposal, to be released at the eastern area of discharge. A forebay will direct treated stormwater in lower intensity storms in a westerly direction towards the onsite EEC, and in higher intensity storms allow a broad overflow to the adjacent land in a similar manner that presently occurs (Applicant’s written submissions at pars 23 and 24).

Figure 2: Proposed Subdivision Plan Rev K (Exh C, tab 5)

Planning framework

24. There is a coastal wetland to the north of the site, and part of the site is identified as a proximity area on the Coastal Wetland and Littoral Rainforests Area Map (Exh C, f 379). Section 2.8 of the RH SEPP is in the following terms:

2.8 Development on land in proximity to coastal wetlands or littoral rainforest

Note—

The Coastal Wetlands and Littoral Rainforests Area Map identifies certain land that is inside the coastal wetlands and littoral rainforests area as “proximity area for coastal wetlands” or “proximity area for littoral rainforest” or both.

(1) Development consent must not be granted to development on land identified as “proximity area for coastal wetlands” or “proximity area for littoral rainforest” on the Coastal Wetlands and Littoral Rainforests Area Map unless the consent authority is satisfied that the proposed development will not significantly impact on—

(a) the biophysical, hydrological or ecological integrity of the adjacent coastal wetland or littoral rainforest, or

(b) the quantity and quality of surface and ground water flows to and from the adjacent coastal wetland or littoral rainforest.

(2) This section does not apply to land that is identified as “coastal wetlands” or “littoral rainforest” on the Coastal Wetlands and Littoral Rainforests Area Map.

25. The site is within the coastal environment area. Sections 2.10(1) and (2) of RH SEPP is in the following terms:

2.10 Development on land within the coastal environment area

(1) Development consent must not be granted to development on land that is within the coastal environment area unless the consent authority has considered whether the proposed development is likely to cause an adverse impact on the following—

(a) the integrity and resilience of the biophysical, hydrological (surface and groundwater) and ecological environment,

(b) coastal environmental values and natural coastal processes,

(c) the water quality of the marine estate (within the meaning of the Marine Estate Management Act 2014), in particular, the cumulative impacts of the proposed development on any of the sensitive coastal lakes identified in Schedule 1,

(d) marine vegetation, native vegetation and fauna and their habitats, undeveloped headlands and rock platforms,

(e) existing public open space and safe access to and along the foreshore, beach, headland or rock platform for members of the public, including persons with a disability,

(f) Aboriginal cultural heritage, practices and places,

(g) the use of the surf zone.

(2) Development consent must not be granted to development on land to which this section applies unless the consent authority is satisfied that—

(a) the development is designed, sited and will be managed to avoid an adverse impact referred to in subsection (1), or

(b) if that impact cannot be reasonably avoided—the development is designed, sited and will be managed to minimise that impact, or

(c) if that impact cannot be minimised—the development will be managed to mitigate that impact.

26. The site is within the coastal use area. At s 2.11(2) of RH SEPP, development consent must not be granted to development on land to which this section applies unless the consent authority:

2.11 Development on land within the coastal use area

…

(a) has considered whether the proposed development is likely to cause an adverse impact on the following—

(i) existing, safe access to and along the foreshore, beach, headland or rock platform for members of the public, including persons with a disability,

(ii) overshadowing, wind funnelling and the loss of views from public places to foreshores,

(iii) the visual amenity and scenic qualities of the coast, including coastal headlands,

(iv) Aboriginal cultural heritage, practices and places,

(v) cultural and built environment heritage, and

(b) is satisfied that— (i) the development is designed, sited and will be managed to avoid an adverse impact referred to in paragraph (a), or

(ii) if that impact cannot be reasonably avoided—the development is designed, sited and will be managed to minimise that impact, or

(iii) if that impact cannot be minimised—the development will be managed to mitigate that impact, and

(c) has taken into account the surrounding coastal and built environment, and the bulk, scale and size of the proposed development.

27. The site is zoned R2 Low Density Residential pursuant to Tweed Local Environmental Plan 2014 (LEP 2014) and the proposal is permissible with consent. The objectives of the R2 zone, to which regard must be had, are:

Zone R2 Low Density Residential

1 Objectives of zone

• To provide for the housing needs of the community within a low density residential environment.

• To enable other land uses that provide facilities or services to meet the day to day needs of residents.

28. Clause 5.21 Flood planning of LEP 2014 applies to the proposal because the site is within a flood planning area. The provision is in the following terms:

5.21 Flood planning

(1) The objectives of this clause are as follows—

(a) to minimise the flood risk to life and property associated with the use of land,

(b) to allow development on land that is compatible with the flood function and behaviour on the land, taking into account projected changes as a result of climate change,

(c) to avoid adverse or cumulative impacts on flood behaviour and the environment,

(d) to enable the safe occupation and efficient evacuation of people in the event of a flood.

(2) Development consent must not be granted to development on land the consent authority considers to be within the flood planning area unless the consent authority is satisfied the development—

(a) is compatible with the flood function and behaviour on the land, and

(b) will not adversely affect flood behaviour in a way that results in detrimental increases in the potential flood affectation of other development or properties, and

(c) will not adversely affect the safe occupation and efficient evacuation of people or exceed the capacity of existing evacuation routes for the surrounding area in the event of a flood, and

(d) incorporates appropriate measures to manage risk to life in the event of a flood, and

(e) will not adversely affect the environment or cause avoidable erosion, siltation, destruction of riparian vegetation or a reduction in the stability of river banks or watercourses.

(3) In deciding whether to grant development consent on land to which this clause applies, the consent authority must consider the following matters—

(a) the impact of the development on projected changes to flood behaviour as a result of climate change,

(b) the intended design and scale of buildings resulting from the development,

(c) whether the development incorporates measures to minimise the risk to life and ensure the safe evacuation of people in the event of a flood,

(d) the potential to modify, relocate or remove buildings resulting from development if the surrounding area is impacted by flooding or coastal erosion.

29. Clause 7.2 Earthworks of LEP 2014 applies to the proposal because development consent is required for earthworks at cl 7.2(2). Before granting development consent for earthworks, the consent authority must consider the matters under cl 7.2(3), as follows:

7.2 Earthworks

…

(a) the likely disruption of, or any detrimental effect on, drainage patterns and soil stability in the locality of the development,

(b) the effect of the development on the likely future use or redevelopment of the land,

(c) the quality of the fill or the soil to be excavated, or both,

(d) the effect of the development on the existing and likely amenity of adjoining properties,

(e) the source of any fill material and the destination of any excavated material,

(f) the likelihood of disturbing relics,

(g) the proximity to, and potential for adverse impacts on, any waterway, drinking water catchment or environmentally sensitive area,

(h) any appropriate measures proposed to avoid, minimise or mitigate the impacts of the development,

(i) the proximity to, and potential for adverse impacts on, any heritage item, archaeological site, or heritage conservation area.

30. Clause 7.6 Stormwater management of LEP 2014 applies to the proposal at cl 7.6(2). The objective of the clause is to minimise the impacts of urban stormwater on land to which this clause applies and on adjoining properties, native bushland and receiving waters. Before granting development consent to which the clause applies, the consent authority must be satisfied that the development, under cl 7.6(3):

7.6 Stormwater management

…

(a) is designed to maximise the use of water permeable surfaces on the land having regard to the soil characteristics affecting on-site infiltration of water, and

(b) includes, if practicable, on-site stormwater retention for use as an alternative supply to mains water, groundwater or river water, and

(c) avoids any significant adverse impacts of stormwater runoff on adjoining properties, native bushland and receiving waters, or if that impact cannot be reasonably avoided, minimises and mitigates the impact.

31. The Tweed Shire Development Control Plan 2008 (TDCP) applies to the proposal at section 1.2. The Subdivision Manual, at A5 of TDCP, applies to the proposal.

32. Section A5.4.6 Landforming has as the objective, the following:

“Natural topography is an important characteristic of an area. The extent of landform change to render a site suitable for subdivision should be kept to a minimum. Site regrading should be sensitive to existing landforms and topography (of both the subdivision site and neighbouring areas) so that the natural setting may be preserved to the greatest extent possible. The subdivision should be designed to fit the topography rather than altering the topography to fit the subdivision.”

33. The criteria for section A5.4.6 includes, “Proposals to alter natural landform must:… comply with the provisions of Development Design Specification D6 – Site Regrading, and the acceptance criteria in Table A5-3 below.” The civil engineering experts (Exh 13) identified the following criteria from Table A5-3 as being relevant:

“Batters and retaining walls are not permitted for the purpose of creating terraced lots.

…

A retaining wall or batter of maximum "combined height" (as defined in Section E) of 1.2m at or adjacent to inter lot boundaries may be permitted to ease lot gradients, where lot longitudinal or cross gradient would exceed 10% in the absence of such retaining wall or batter.”

34. Section A5.4.13 Infrastructure of TDCP includes the following criterion:

“A drainage system that provides Q100 immunity from local stormwater flooding and must have surface levels above the Q100 flood levels of regional river/creek flooding.”

35. Under Table A5-10 Subdivision Infrastructure Requirements, the standard of infrastructure refers to Development Design Specifications D5 and D7. The Council’s Development Design Specification D5 for Stormwater Drainage Design Version 1.4 includes, at D5-04(7), the following text (Exh 3, tab 8):

“For the design of major systems in Tweed Shire (overland flow paths, open channels, surcharge systems etc) a factor if safety of 1.2 shall be applied to design rainfall intensities, to properly account for blockages, obstructions to flow, deterioration of cross-sectional capacity over time, and the potential impacts of climate change.

Where major drainage systems are located adjacent to residential development have horizontal bends in excess of 45 degrees this factor of safety must be increased to 1.5.”

36. D5.12 Major System Criteria of Development Design Specification D5 includes the following regarding surcharging:

“1. Surcharging of drainage systems which would provide for water depth above the top of kerb will not be permitted except as defined below.

(a) Surcharging of drainage system for storm frequencies greater than the 20 year ARI storm event may be permitted across the road centreline where the road pavement is below the natural surface of the adjoining private property, and the road is not a high level access road for flood evacuation (refer DCP Section A3)…”

37. D5.12 Major System Criteria of Development Design Specification D5 includes the following regarding freeboard:

“3. Freeboard requirements for floor levels and levee bank levels from stormwater flood levels in open channels, roadways and stormwater surcharge paths are given in QUDM and shall not be less than the following:

…

(c) Cross sections of open channels and stormwater surcharge paths shall provide 0.5m freeboard above the Q100 design storm, before overtopping can occur.”

Public submissions

38. Five resident objectors gave evidence onsite. Their concerns can be summarised as:

39. The proposal does not address how the significant disruption to the natural landscape will be managed to protect the coastal wetlands.

40. The proposal does not consider recreational and community amenity for the future residents of the proposal.

41. The proposal underestimates the number of additional car trips per day. The proposal does not address traffic management in Boyle Avenue as the only entry/exit point to the site and the roads within the development are unsafe.

42. Clearing of land will reduce the protection for local flora and fauna species.

43. Excavation of the site is likely to disrupt the stability of the steep embankment making the land subject to erosion and potential slippage. Retaining wall details are not included in the application.

44. The stormwater proposal includes fill which introduces a risk of contamination for the wetland.

45. There is no acid sulphate soil management plan included in the application.

46. The proposal does not provide safe all-weather access for fire fighting vehicles; and there is only one point of entry/exit for the proposal in the event of fire.

47. The construction of the proposal, including the delivery of a significant volume of fill, will result in trucks and trades passing through the town.

Expert evidence

39. The Applicant relied on the expert evidence of Erin Holton (environmental engineering), Dr Neil Sutherland (groundwater), Nick Tong (ecology), Trent Purdon (stormwater and flooding, services, traffic and civil engineering), Glen Burkitt (geotechnical engineering), Lance Newley (town planning), Mark Mackinnon (bushfire) and Timothy Scott (arboriculture).

40. The Council relied on the expert evidence of Dr Daniel Martens (environmental engineering, geotechnical engineering, groundwater, stormwater and flooding), Terry Seymour (services), Michael [Mick] Denny (civil engineering), Judith Evans (town planning), Stuart McMonnies (bushfire) and Nathan Garvey (ecology and arboriculture).

41. The experts prepared joint reports, as follows:

42. Geotechnical engineering, Exhibit 8.

43. Stormwater and flooding, Exhibit 11.

44. Civil engineering, Exhibit 13.

45. Town planning, Exhibit 9.

46. Groundwater, Exhibit 12. A supplementary groundwater and geotechnical joint report, Exhibit 16, was admitted into evidence on the third day of the hearing.

47. Ecology, Exhibit 14.

48. Traffic, Exhibit 5.

49. Arboriculture, Exhibit 6.

50. Landscaping, Exhibit 7.

51. Services, Exhibit 10.

52. The following experts gave oral evidence concurrently during the hearing:

53. Geotechnical engineering experts; Mr Burkitt and Dr Martens.

54. Stormwater and flooding experts; Mr Purdon and Dr Martens.

55. Civil engineering experts; Mr Purdon and Mr Denny.

56. Town planning experts; Mr Newley and Ms Evans.

57. Groundwater and ecology experts; Ms Holton, Dr Sutherland, Mr Tong and Mr Garvey, Dr Martens.

Land stability

Expert evidence

43. Dr Martens confirmed that the further geotechnical testing contemplated by the agreement of the geotechnical engineering experts in their joint report (Exh 8 at [14]), for the purpose of providing a complete description of the site’s sub-surface environment, was carried out prior to the hearing. The experts, with the groundwater and civil engineering experts, completed a further supplementary groundwater/geotechnical/civil joint report filed in court on the third day of the hearing (Exh 16). An additional geotechnical report prepared by Mr Burkitt on 8 October (SSReport2) and an observation of that report prepared by Dr Martens (DM Report) are attached to Exh 16.

44. According to Dr Martens, the “factor of safety” ratio (FoS) is a measure of the stability of a structure; and seeks to quantify whether, in this case a ground slope, will or will not remain in place by measuring driving and resisting forces. Equilibrium is a FoS of 1 where the slope is stable and on the verge of instability. Above 1, the slope is stable. A factor of safety is added so that a stable slope is taken to be a FoS of at least 1.5. FoS assumes saturated conditions for a slope, which is standard practice according to Dr Martens, and not a conservative approach.

45. The experts agreed that the results of the slope stability modelling provided in the SSReport2 are similar to those presented in the joint report (Exh 8) and include assumptions for “intra-lot retaining walls required for future dwellings” (Exh 16 at par 33). The experts agreed that the pier foundations are shown in SSReport2 as deeper where rock was encountered, compared to previous assumptions, and Dr Martens observed that there are significant differences.

46. The experts agreed the revised modelling confirms that under adverse soil moisture conditions, the existing slopes and future slopes following completion of the subdivision, do not achieve a FoS against failure of 1.5, and that the retaining systems associated with future dwellings will be required to be constructed to achieve a FoS of 1.5 consistently on the land (Exh 16, pars 39-40 and pars 51-52).

47. Dr Martens agreed that the sections selected through the site, which were modified by him, are an appropriate way to assess conditions of the lots in the upper slopes (Tcpt, 22 October 2025, p 70(1)-(5)). The modelled circumstances were of both the subdivision engineering works (the retaining walls near the southern boundary) and the retaining walls for individual lots. The experts agreed that the engineering works for the subdivision should be carried out in conjunction with the retaining walls for individual lots.

Submissions

48. According to the Council, an application which includes the construction of the retaining works required for the individual dwellings, with the proposed construction of the works required for the subdivision, would permit the Council to get to a position where it would be comfortable that the geotechnical outcomes are appropriate (Tcpt, 21 October 2025, p 20(41)-(46)).

49. The Applicant offered conditions of consent, conditions 1A and 97A, to ensure that the agreement of the experts is given effect:

“1A

This development consent does not approve the construction of dwelling houses on proposed Lots 8-19, which is to be the subject of separate application(s) for development consent.

The applicant is to ensure that:

(a) the design of the retaining structures for the dwelling houses on proposed Lots 8-19 is prepared having regard to, and in co-ordination with, the detailed design for the civil and engineering works approved under this Consent to be submitted with the application(s) for any subdivision works certificate;

(b) the design of the retaining structures for the dwelling houses will not adversely impact on the approved civil and engineering works, and the stability of proposed Lots 8-19; and

(c) the works approved by a subdivision works certificate and the approved works for retaining structures for the dwelling houses on proposed Lots 8-19 will be carried out generally at the same time and in a co-ordinated manner.

A subdivision certificate cannot be issued unless development consent has been granted for the construction of a dwelling house on each of proposed Lots 8-19 and each of those dwelling houses is the subject of an occupation certificate under a development consent. In this condition 1A a ‘development consent’ does not include a complying development certificate.

…

97A

A subdivision certificate cannot be issued unless development consent has been granted for the construction of a dwelling house on each of proposed Lots 8-19 and each of those dwelling houses is the subject of an occupation certificate (as per condition 1A). In this condition a ‘development consent’ does not include a complying development certificate.”

50. The Applicant submitted that Condition 1A requires the co-ordinated carrying out of each of the subdivision and individual allotment retaining works and the legal effect of the condition is as follows:

(a) The subdivision application before the Court seeks consent only for the works sought and described (relevantly) in the engineering plans (Exh C, tab 1) and does not seek consent for retaining works within individual lots. (b) This choice reflects this intrinsic opportunity under the EPA Act for an Applicant to frame an application for development consent in chosen respects only. The Council agreed with this submission (Tcpt, 27 October 2025, p 312(14)). (c) If consent is granted to the subdivision application, the carrying out of the subdivision works, including engineering works, cannot take place until a subdivision works certificate (SWC) has been issued (s 6.13(1) of the EPA Act). (d) The application for the SWC will need to be accompanied by detailed engineering plans (s 30(2)(c) of the Environmental Planning and Assessment (Development Certification and Fire Safety) Regulation 2021). (e) These detailed plans that would, relevantly, including the retaining walls proposed in the subdivision application, details of the concrete swales, all roadworks, and the stormwater management system including the onsite detention tank (OSD) and the two-level spreading devices. (f) The effect of Condition 1A(a) is to require that the design of the retaining structures for the individual lots be carried out in conjunction with the detailed design required for the SWC. (g) The effect of Condition 1A(b) is to specify a clearly specified performance outcome for the individual lot designs (s 4.17(4) of the EPA Act). This ensures the design of one will not affect the other. (h) The effect of Condition 1A(c) is to require the works for each of the subdivision and individual lot retaining works to be carried out at the same time. In order to comply with this part of the condition, the Applicant will need to obtain both development consent and construction certificates for the dwellings on future individual residential allotments. This will authorise the carrying out of, inter alia, the individual lot retaining wall works. (i) As such, there is no situation in which individual lot owners are left to carry out retaining works on individual lots, this will be the obligation of the Applicant to obtain the necessary consents and construction certificates and to carry out the works, together with the subdivision works. This will take place before there are any individual lot owners. (j) Further, the fact that issue of the subdivision certificate cannot occur until occupation certificates for the individual dwellings have issued means that these dwellings will have been fully and acceptably constructed before each of proposed Lots 9-19 is created, or title transferred to any eventual purchaser.

51. The Applicant submitted that the fact that the retaining walls for certain individual dwelling houses must ultimately be carried out in conjunction with the proposed development does not make the development application deficient (Mullaley Gas and Pipeline Accord Inc v Santos NSW (Eastern) Pty Ltd [2021] NSWLEC 110 at [150]-[151]). The Court can be satisfied as to the impacts of the retaining walls for the individual dwellings.

Findings

52. I am satisfied that the geotechnical testing and stability modelling have been carried out and that the proposal is neither uncertain, nor a deferral. The detailed design of lot retaining structures is not necessary at this stage to understand individual allotment retaining walls will comprise individual piers at appropriately spaced centres, with retaining walls as assessed in the stability modelling.

53. I accept the Applicant’s submission that the stability of the land is agreed to be able to be achieved to a FoS of 1.5 or greater, provided the subdivision works are co-ordinated and constructed together with the retaining works for the lots including rear retaining walls and wall returns for driveways. This was done by Mr Burkitt preparing conceptual designs for retaining structures on Lots 14-19, being the lots on the upper slopes. The assessment has been carried out, notwithstanding that the retaining structures on Lots 14-19 are not part of this application, to understand the likely impacts of the development. Condition 1A requires the individual lot retaining works to be carried out at generally the same time and co-ordinated with the subdivision works, as agreed by the experts to achieve site stability, which is represented by an analysis of a factor of safety. It is of no matter that the works assessed on Lots 14-19 are not part of this application. The works that are proposed in this application will be informed by and developed in conjunction with the design of the retaining works for the individual lots.

54. The steps for obtaining a subdivision works certificate in the application will work in concert with the need to obtain construction certificates for individual dwelling lots. I accept the Applicant’s submission because the conditions give effect to the agreed position of the geotechnical engineering experts. I am satisfied that the imposition of these conditions will ensure that the slope will be stable to the satisfaction of the geotechnical engineering experts in the assumed condition of perpetually saturated soils.

55. The Council pressed for deferred commencement conditions that the Council then submitted, "do not fix the problem, because if approval is granted, we need something to try to do the best we can to fix those problems" (Tcpt, 27 October 2025, p 337(11)-(14)). The Applicant pressed for conditions 1A and 97A.

56. Conditions 1A and 97A are imposed in the conditions of consent at Annexure A. The Council’s deferred conditions of consent are deleted.

Stormwater and flooding

Submissions

57. The Council submitted, in summary, the following:

58. The Court cannot be satisfied on the matters under cl 7.6(3)(c) of LEP 2014 as the proposal results in an increase in stormwater discharged to the northern neighbour and that water is not discharged at an appropriate point.

59. The stormwater experts agreed that the modelling shows that the long-term average volumes of stormwater discharge to the northern neighbour increases from 64.2ML/year to 72.1ML/year, representing an average increase of around 22,000L/day discharged to the northern neighbour. According to Mr Purdon, this is not significant because increased water levels will occur on part of the site only in the 1-year annual recurrence interval (ARI) from his model. It is not credible that 22,000L/day more water being discharged onto the northern property does not involve a “significant adverse impact” under cl 7.6(3)(c) of LEP 2014, particularly in the context that the northern neighbour is zoned R1. It puts the burden of dealing with the additional water on the northern neighbour. Water quality discharged is also a relevant consideration for the purpose of "significant adverse impacts".

60. Dr Martens points out that the subdivision does not drain to a lawful point of discharge (such as a watercourse, existing public drain, drainage reserve or drainage easement) as required by section A5.4.7 of TDCP.

61. It is not the point that the current stormwater infrastructure on the site already discharges to the northern neighbour or that there may be some improvement in the water levels in other parts of the neighbouring site, particularly given the volume of the increase of stormwater discharge onto the northern neighbour.

62. The fact that the subsisting circumstances may also be undesirable does not excuse the Court from considering “the likely impacts of [the] development, including environmental impacts on both the natural and built environments” under s 4.15(1)(b) of the EPA Act. That some level of mitigation has been achieved with the detention tank does not mean the impacts have been “minimised” when the failure to provide a design that avoids or further minimises the impact remains unexplained.

63. The Council relies on Dr Martens evidence regarding the deficiencies in the design of the stormwater system.

64. The Applicant submitted that when evaluating the likely impacts of the proposal, it should be kept in mind that the majority of stormwater, the subject of debate, is a consequence of that which has been imposed on the site by reason of Council’s historical decisions. Around 80% of the stormwater is not generated by the proposal but comes from catchments that are upstream of the site (P001, Attachment B to Exh 11 and agreed by the experts Exh 11 at [9]). Only 20% of the stormwater to be discharged to the northern neighbour is from the site following the development (Tcpt, 24 October 2025, p 213 (24)-(29)).

65. The Applicant submitted that three matters require specific resolution, and in each, the matter involves addressing imposed off-site stormwater:

(a) The capacity of swale 01 at a few locations, and overtopping in the 1% AEP and 1% AEP plus climate change events; (b) The capacity of a section of Road 01, and overtopping in the 1% AEP and 1% AEP plus climate change events; and (c) Whether the OSD tank appropriately addresses tailwater conditions such that flows from external catchment EXT 1 will not interfere with the stormwater generated by the proposal.

60. The Applicant relied on the expert evidence of Mr Purdon in determining these matters, and the proposed conditions of consent to achieve the performance outcome: conditions 22A, 22B and 22C. The Applicant relied on s 4.17(4) of the EPA Act to support the inclusion of performance conditions, where the intended result is sufficiently identified, but the means of achieving it are left to the proponent as there is an initial level of uncertainty and lack of finality (Kindimindi Investments v Land Cove Council & Anor (2006) 143 LGERA 277: [2006] NSWCA 23 at [56]).

61. The Applicant submitted that the issue of stormwater impacts involves two main matters:

(a) The extent of change of water conveyed to the northern property, including both lateral areas and depths, a largely factual identification; and (b) The determination of the impact of the change, an evaluative exercise that requires synthesis of the factual identification in the first matter above, with the information available about the context of the receiving environment, the northern property.

62. The Applicant submitted the following regarding stormwater impacts on the northern neighbour and the experts’ evidence:

63. The spatial extent of water is almost entirely unchanged, for both the northern neighbour and the Coastal Wetland.

64. The significance of any change in water depth must be understood in the context of prevailing conditions, that is, whether a particular part of the land is under water in the existing conditions scenario. Comparing Dr Martens’ Water Level and Water Depth existing and proposed plans for 12EY (90-minute storm) (FL02 and FL26, Attachment C to Exh 11), virtually all increases in depth are in areas that are under water in the existing situation. By repeating this exercise for each event and duration, in order to derive an understanding across the full range of storm events, it is evident that there are limited areas of increase in water depth; the occurrences of increased water depth are mostly in areas of the northern neighbour’s that are underwater in the existing scenarios; almost all the water depth increases greater than 2cm occur within the area of the onsite ECC (for all events less than the 1% AEP); and there are two distinct small areas of water depth increase outside the ECC adjacent to the northern boundary of the site (in the 1% AEP, 1% AEP plus climate change and the Probable Maximum Flood (PMF) storms).

65. The appreciation of impact should also account for the impact of riverine flooding, which is not mapped in Dr Martens’ series of plans (Attachment C to Exh 11), as his flood modelling eliminated the effect of riverine flooding in order to isolate and identify the flooding caused by stormwater (Tcpt, 23 October 2025, p 132(6)).

Expert evidence and findings

The stormwater management system has been adequately designed for the purpose of the application

63. Dr Martens agreed that a factor of safety has been applied to the design of the swales in accordance with the requirement under TDCP (quoted above at [35]) which accounts for, amongst other things, the potential impacts of climate change (Tcpt, 22 October 2025, p 77(5)-(7)).

64. Mr Purdon accepted that Dr Martens’ modelling showed overtopping at selected points of the swale in the 1% AEP and 1% AEP plus climate change events in the order of 100mm (Figures 5, 6 and 7 of Exh 11). The design specification for open channels and stormwater surcharge paths is the Q100 event plus a freeboard of 500mm (quoted above at [37] and confirmed by Dr Martens Tcpt, 22 October 2025, p 75(48)).

65. I accept Mr Purdon's evidence that the concrete swales (shown on DA401 Issue 7 of Exh C, tab 1) are engineered structures that are sufficiently certain for the purpose of the application; designed to accommodate the 1% AEP flow depth plus freeboard. According to Mr Purdon, the critical sections of overtopping are at the end of the channels where the swales connect into the stormwater drainage infrastructure as there is the most ponding in this location, and the swales can be deeper in these locations to achieve the 1% AEP flow depth plus freeboard (Tcpt, 23 October 2025, p 119(6)-(8)). I accept Mr Purdon’s evidence that there will not be any overtopping of the swales (Tcpt, 23 October 2025, p 120(14)) and the detailed design of the swales will be undertaken for the Subdivision Works Certificate stage. I accept the Applicant’s submission that this performance outcome is guaranteed by imposing condition 22A (Conditions of Consent at Annexure A).

66. I accept Mr Purdon’s evidence that the issue of the kerb capacity of Road 01 being exceeded in the relevant event as shown on Dr Martens’ Water Level and Water Depth proposed plan for 1% AEP (FL23, Attachment C to Exh 11) can be resolved by grading of the grassed land behind the kerb on the northern side of Road 01 to the south of Lots 2, 4, 5 and 6, and that the standard of Q100 event plus 100mm freeboard can be met. The preliminary earthworks over the site, which according to Mr Purdon is reasonably detailed for the application stage, would be further refined to nominate the precise levels to be achieved during construction (Tcpt, 23 October 2025, p 126(22)-(36)). The detailed design will be undertaken for the Subdivision Works Certificate stage. I accept the Applicant’s submission that the performance outcome is guaranteed by imposing condition 22B (Conditions of Consent at Annexure A).

67. I accept Mr Purdon's evidence that the concrete stormwater forebay and level spreader (shown on DA400 Issue 10 of Exh C, tab 1) are engineered structures sufficiently documented for the purpose of hydraulic modelling, although not for construction (Tcpt, 22 October 2025, p 110(1) – p 113(34), p 114(26)-(30) and Tcpt, 23 October 2025, p 126(42) – p 127(3)). The detailed design will be undertaken for the Subdivision Works Certificate stage.

68. Similarly, the stormwater detention tank is sufficiently documented for the purpose of hydraulic modelling, which demonstrates that the tank will detain flows to below peak levels in all events (Tcpt, 23 October 2025, p 117(29)-(40)). I accept Mr Purdon’s evidence that any tailwater issue can be addressed by a minor change to the internal weir height and the length (Tcpt, 23 October 2025, p 124(3)-(4)). The detailed design will be undertaken for the Subdivision Works Certificate stage. I accept the Applicant’s submission that the performance outcome is guaranteed by imposing condition 22C (Conditions of Consent at Annexure A).

Stormwater impact

69. Most of the stormwater to be discharged to the northern neighbour comes from catchments that are upstream of the site with no stormwater quality or detention controls (Exh 16, p 5), and this is imposed on the site by reason of Council’s historical decisions and the acquiescence of the previous owner of the site to accommodate the alignment of the existing pipe. It is appropriate to take into consideration the imposition of this large volume of uncontrolled off-site stormwater. I accept the Applicant’s submission that the Applicant should not be penalised for the diversion and concentration of upstream catchment stormwater on its land in the absence of formalised arrangements for the appropriate conveyance of stormwater.

70. The upstream stormwater has been considered in the assessment of impacts in the context of evaluation of stormwater, flooding, groundwater, ecology and the Coastal Wetland. The proposed stormwater system, including the swales, the level spreader to the onsite ECC and the concrete forebay, are largely required to deal with the imposed offsite stormwater.

71. Riverine flooding is not mapped in Dr Martens' series of plans (Attachment C to Exh 11), as his flood modelling eliminated the effect of riverine flooding in order to isolate and identify the overland flooding caused by stormwater. The experts agreed, as far as river flooding is concerned, in any of the larger events, 1% AEP, 1% AEP plus climate change and PMF, all the northern neighbour's land is underwater, probably by some meters. Even in the less extreme events, the northern neighbour’s land, or parts of it, will be underwater, although not necessarily to the same degree (Tcpt, 23 October 2025, p 131(50), p 132(6)).

72. I accept Dr Sutherland’s evidence about the importance of a proper understanding of the landscape context (Exh 16 at par 28 and Tcpt, 24 October 2025, p 213(24)). The drains on the northern neighbour’s cleared land drains the cleared areas firstly towards the onsite EEC, and secondly from the onsite EEC towards the Coastal Wetland. The onsite EEC already receives the directed water from the cleared areas, as substantial parts of it are under water in even the frequent lesser storms (FL03, Attachment C to Exh 11). I accept the Applicant’s submission that the areas close to the onsite EEC are likely to be already wet in existing conditions. The impact of the increase in water depths from stormwater is minor in the context of the behaviour of water in the existing landscape. The Council’s submission regarding the daily average increase in water conveyed to the northern neighbour does not accurately characterise the behaviour of stormwater and storms; and is therefore not a meaningful description of impact. Furthermore, the increased water depth on the northern neighbour’s land attributed to the proposal is only a small portion of the overall increase. I am satisfied that the significant adverse impacts of stormwater runoff on adjoining land are avoided, or when not avoided, are managed and mitigated, pursuant to the cl 7.6(3)(c) of LEP 2014.

73. Based on the documentary evidence before me, I accept the Applicant’s submission regarding stormwater impacts on the northern neighbour and the experts’ evidence, quoted above at [71]. I am satisfied that there are limited areas of increased water depth on the northern neighbour’s land across the range of the storms and these areas are underwater in the existing conditions scenario. The discharge point for stormwater leaving the site to the northern neighbour is acceptable, taking into consideration all the circumstances of this matter.

74. I accept the Applicant’s submission that there is a public benefit in formalising the drainage of the upstream catchment stormwater, including the provision of formal easements, which weighs in favour of the application.

Retaining wall design

75. The civil engineering experts agreed that the proposal complies with the relevant requirement under Table A5-3 of TDCP. The experts agreed that the three-tiered retaining wall batters along the southern boundary of the proposal in the vicinity of Lots 14-19 exceed 1.2m, however, those retaining walls are located further than 5m from the site boundary. The two-tiered retaining walls along the southern boundary of Lot 12, which are within 5m of the site boundary, do not exceed 1.2m.

76. I accept the Applicant’s submission that the retaining wall in the vicinity of Road 02 is within a community lot, and not on an allotment boundary. This retaining wall is referred to in the civil engineering experts joint report (Exh 13 at par 35) as not complying with the maximum height of 2.4m. Table A5-3 Site Regarding Acceptance Criteria, under 2(a) states, “The combined height of retaining walls or cut/fill on an allotment boundary shall not exceed the following… residential, below street level 2.4m”. As the retaining wall is within a community lot, the control does not apply to that wall.

77. The Council submitted that the control’s intention is that the height of the retaining wall prescribed below road is to maintain the safety of the road and is intended to apply even though it is not at the lot boundary in the community title subdivision (Tcpt, 27 October 2025, p 333(12)-(22)). If the Council’s submission is correct, then I accept Mr Purdon’s evidence this wall is located within a community lot and sufficiently offset from the road to allow access from the driveway for machinery to reconstruct the wall should that ever be required (Exh 13 at par 37).

78. Mr Denny was concerned about the constructability and structural integrity of retaining walls if they were to be constructed after the subdivision works (see Exh 13 at pars 43, 46). The challenges in constructing retaining walls on the lots, if not done at the same time as the subdivision works, was raised in the contention. This concern has been addressed by the imposition of conditions on the consent requiring the co-ordinated carrying out of each of the subdivision and individual allotment retaining works.

79. According to Mr Purdon, there is not an issue in the unlikely event stormwater overtopping the swales about the southern retaining walls. The walls on the site, for example the walls in the northern portion of the site, will on occasion be exposed to inundation from the 100-year flood. Retaining walls are constantly exposed to weather and rain and are designed for fully saturated conditions (Tcpt, 24 October 2025, p 258(33)-(40)). According to Mr Purdon, if swales on top of retaining walls are full of water, the performance of the retaining wall will not be affected (Tcpt, 24 October 2025, p 259(18)). I accept Mr Purdon’s evidence, and I am satisfied that any overtopping of the swales on the walls will not introduce an additional risk.

80. According to Mr Denny, the extent of regrading required on the site to achieve an area on each lot suitable for a building footprint indicates that the site is not suitable for the proposal; including the extent to which the site needs to be regraded result in large, tiered retaining walls in close proximity to future dwellings and neighbouring boundaries, the resulting retaining structures will be extremely challenging and expensive to access for maintenance and repairs, and should there be a failure in any of the large retaining walls, it could result in significant damage to property or loss of life (Exh 13 at par 46).

81. The civil engineering experts agreed that a significant proportion of the retaining walls will be designed as Type C walls in accordance with Australian Standard (AS) 4678 Table 1.1 (Exh 13 at par 53 and Tcpt, 24 October 2025, p 257(22)). According to Mr Purdon, Type C retaining walls are the highest class of wall, designed “where failure would result in significant damage or risk to life” according AS 4678. He said the requirements under the AS are significant, including that the walls to be designed for a 60-year lifespan according to geotechnical and structural input, with significantly deep footings (Tcpt, 24 October 2025, p 257(22)-(29), p 260(9)-(10)). Mr Purdon agreed under cross-examination that such retaining walls are costly.

82. The civil engineering experts agreed on conditions to ensure that the potential risk of future failures of the retaining walls is appropriately minimised. Those agreed conditions (a) and (b) (Exh 13 at par 60) are imposed on the consent as Condition 28 Retaining Walls and Condition 108 Certification of Retaining Walls (conditions of consent at Annexure A). Their agreed condition (c) regarding the responsibilities of the future community association is beyond their purview.

83. The Council contended that issues of complexity and the additional cost for Type C retaining walls are indicators that the site is unsuitable for the proposal. I prefer and accept Mr Purdon’s opinion that the retaining walls should not alone be an indicator of the suitability of the site for a development. The sections through the site show indicative building envelopes that are responsive to the slope of the lots. I am satisfied that the evidence of the civil engineering experts is that the retaining walls can be sufficiently engineered to stabilise the site and that the risk of a catastrophic event is remote and not supported by the evidence. The cost of the proposal is a matter for the Applicant, not a reason to refuse an application.

Access and maintenance of the retaining walls

84. The civil engineering experts agreed that appropriate access is required to inspect the swales and retaining walls (Tcpt, 24 October 2025, p 266(8)-(10)). According to Mr Purdon, the required maintenance for the retaining walls is a periodic visual inspection (Tcpt, 24 October 2025, p 261(6)). The Applicant submitted that the swales are concrete, which will not require much maintenance other than an infrequent visual inspection.

85. The Council’s contention regarding this issue was drafted prior to the commencement of the hearing and included in the Respondent’s Opening Submissions, at pars 78-95. The various iterations of the Subdivision Plan relied upon during the hearing until the final Rev K plan resolved a number of aspects of the Council’s concerns regarding access and maintenance of the retaining walls, including locating the retaining walls within common property and the addition of various easements. The swales were changed from grass swales to concrete swales as part of the amendments made to the proposal (Exh C, tab 1, DA 400 Issue 10 and 401 Issue 7). Mr Stafford confirmed this in closing submissions, “the issues as discussed in the written submissions, that I handed up at the opening, have become less significant. Some have potentially become more significant…” (Tcpt, 27 October 2025, p 311(27)-(29)).

86. I accept the Applicant’s submissions that the arrangements for access and maintenance of the retaining walls and swales, including at the base of the walls, are provided for by the (amended) Subdivision Plan (Exh C, tab 5, Rev K, at Annexure D (see Figure 2)) and the Community Management Plan (Exh G), summarised as follows:

87. The main retaining walls (and swales) are within the community property, Lot 1. The Community Association is under an express statutory obligation to maintain these structures pursuant to s 109 “Duty of association to maintain and repair property” of the Community Land Management Act 2021 (NSW).

88. The Subdivision Plan identifies areas of lots are subject to a regime of easements, positive covenants and restrictions on use, including the concrete swales conveying minor stormwater flows through Lots 2, 8, 11 and 12.

89. The easements assure a right of access in favour of the Community Association, and the restrictions on use prevent lot owners from interfering with the facility or service, complemented by a positive covenant requiring ongoing maintenance by the Community Association.

90. A specific 3m easement is to be created for access to maintain the retaining wall, identified on the Subdivision Plan as E5. The Community Management Statement ensures a comprehensive right of access, inspection and maintenance over every lot where it concerns a matter the subject of an easement that benefits the Community Association.

91. I accept Mr Purdon’s evidence that the access proposed is proportionate to the design risk (Tcpt, 24 October 2025, p 268(29)) because there are easements provided around the walls to provide for the visual inspection of retaining walls and to ensure that structures do not encroach on the retaining walls (Condition 108 of the conditions of consent at Annexure A).

92. I accept the Applicant’s submission that funding for maintenance of the retaining walls is assured. Beyond the basic statutory obligation to levy for maintenance and repair of the community association property, the same requirements are extended under the Community Management Statement to those facilities and services within individual lots that benefits the Community Association (Tcpt, 27 October 2025, p 343(35)-(37)).

93. I am satisfied by the evidence before me that an appropriate regime will be in place for the inspection and maintenance of the retaining walls.

Appropriate future dwellings

90. The Council submitted that if all other site constraints can be fixed, then other than Lot 11, an appropriate dwelling footprint can be accommodated on each lot (Tcpt, 27 October 2025, p 325(1)-(4)).

91. The Council submitted that no legal issue is raised regarding whether appropriate dwellings can be achieved on the future allotments, however, the Court’s planning principle in Parrott v Kiama [2004] NSWLEC 77 (Parrott v Kiama planning principle) is relevant because it is not unreasonable to expect that constraints should be put on future buildings where allotments are smaller than usual or environmentally sensitive, or where significant impacts on neighbours are likely. The Parrot v Kiama planning principle is in the following terms, at [17]:

“When should a subdivision application include information on the buildings to be built on the resulting allotment(s)? It is normal practice in Australia to subdivide land without constraints on the buildings that can later be built. While this practice is appropriate in most cases, it is not always so. I have adopted the planning principle that a subdivision application should provide constraints on future buildings when the proposed allotments are smaller than usual, or environmentally sensitive or where significant impacts on neighbours is likely and needs careful design to minimise them.”

92. According to Ms Evans, the site area and building platform (the future building footprint) for Lot 11, which has an area of 347m2 and a building platform of 139m2, is less than the performance criteria under the TDCP section A5.4.12 for lot layouts in the R2 zone which are a minimum area of 450m2 containing a building platform with minimum dimensions of 10m x 15m. Furthermore, it is constrained by an easement (Tcpt, 24 October 2025, p 270(24)-(25)).

93. The building platform of Lot 11 is 10.355m x 12.73m according to Mr Newley, which is sufficient in his view.

94. The town planning experts disagree on whether Lot 11 is consistent with the residential lot size and diversity performance criteria, including:

“Smaller lots and lots capable of supporting higher density are to be located close to town and neighbourhood centres, public transport and adjacent to high amenity areas such as parks.”

95. According to Mr Newley, Lot 11 is consistent with this criterion because the resident can drive to the Tweed town centre. According to Ms Evans, this provision is aimed at higher density residential lots close to transport and local centres, such as the R3 Medium Density Residential zoned areas. I accept and prefer Ms Evans’ interpretation of the criterion. Mr Newley’s interpretation would include all suburban properties from which the resident can drive to a neighbourhood centre. The purpose of the criterion is to identify lots with high urban amenity from which services can be easily accessed.

96. I agree with Ms Evans’ evidence that the building platform of Lot 11 is considerably constrained and that the location of the site is not consistent with the residential lot size and diversity performance criterion quoted above. I do not, however, consider that this issue is of such significance to be determinative of the appeal. I am satisfied that a smaller dwelling can be successfully accommodated on the future Lot 11.

97. I am satisfied appropriate dwellings can be accommodated on the remaining proposed lots because they comply with the numerical controls under section A5.4.12 of the TDCP for lot layouts in the R2 zone. I accept that the future dwellings will need to be skilfully designed due to the considerable constraints of the site.

98. Mr Newley noted that any rear fencing required by the future owners of Lots 8 to 19 will have to be located within their lot, following the amendments made to the subdivision plan by the Applicant to include the retaining walls as part of common property.

Groundwater, surface water and impacts to the EEC and coastal wetlands

Submissions

99. The Council submitted that the evidence before the Court in respect of the impact of the proposal on the Coastal Wetland is insufficient to allow the Court to form the necessary states of satisfaction required under the RH SEPP (Planners North v Ballina Shire Council [2021] NSWLEC 120 at [51]). Mr Garvey’s expert evidence is that the impacts of the proposal of the Coastal Wetland are not fully understood and so a definitive conclusion on whether the proposal will have a significant impact on the biophysical or ecological integrity of the wetland is challenging. This is enough of the Court to consider that it does not have evidence that would support positive satisfaction of the requirements under s 2.8(1) of the RH SEPP.

Expert evidence and findings

Groundwater

100. The experts agreed that based on the groundwater monitoring and modelling, the earthworks and retaining structures associated with the subdivision and future dwellings are not likely to intersect the permanent groundwater table (Exh 12 at par 9). The groundwater conditions were sufficiently understood, and the Applicant’s groundwater model was appropriately calibrated so it could be used to assess any potential impacts, and there were no impacts.

101. Following the experts’ agreement in their joint report (Exh 12), further geotechnical investigation was undertaken (SSReport2, Appendix 1 to Exh 16), which included additional boreholes. This additional information caused Dr Martens to question the accuracy of the groundwater model (DMReport Appendix 2 to Exh 16 at pars 9(b), 12(a) and 17(a)). Based on a comparison of a water level observed in Borehole 11 (BH11), which was around 1.5m higher than the highest modelled water table under wet conditions near proposed Lot 18 (Exh 16 at par 45), Dr Martens concluded that the ground water level was higher than previously predicted because the observed water strike occurred above the modelled groundwater levels. Dr Martens further extrapolated likely higher groundwater from two other matters: the variability of groundwater heights in a nearby borehole BH04, and observations of water in previously dug test pits. The experts prepared a supplementary joint report (Exh 16).

102. The experts disagreed about whether observed water level represented groundwater, according to Dr Martens and Mr Denny, groundwater levels are typically higher than the water strike levels, and according to the Applicant’s experts, localised water strikes are often above the established water table, particularly in unconfined conditions such as on the site (Exh 16 at pars 6 and 13). According to Ms Holton, the modelling is based on average groundwater levels which cannot be calculated or estimated from a single reading in time. You need multiple readings at the same location in order to inform model calibration (Tcpt, 23 October 2025, p 158(34)-(35)). It is her evidence that water strikes are not an indication of the groundwater table. A groundwater model is modelling the saturated zone, the groundwater table, and a water strike is not an indication of that (Tcpt, 23 October 2025, p 148(32)-(34)). According to Ms Holton, the calibration of the model provided a close match to the measure groundwater levels at the site (Exh 16 at par 15). Furthermore, the observations in previously dug test pits were part of the dataset on which the experts had reached agreement in Exh 12 at par 9.

103. I am not persuaded that the water strike in BH11 conclusively indicates a higher groundwater table than modelled. I accept Mr Burkitt’s evidence that a water strike or seepage is not necessarily the same as a groundwater table, and that the intersection of water strike was identified through the observation of moisture in drill cuttings from the boreholes, not standing water (Exh 16 at par 9). I accept and prefer Ms Holton’s evidence that the modelling is based on average groundwater levels which cannot be calculated or estimated from a single reading in time (Tcpt, 23 October 2025, p 149(7)-(8)) and the calibration of the model provided a close match to the measure groundwater levels at the site (Exh 16 at par 15). It is appropriate, having regard to all the evidence before me, to rely on the agreed evidence regarding groundwater (Exh 12 at par 9), because the additional geotechnical information does not alter the agreement earlier reached about groundwater and its effects.

104. According to Dr Martens, and based on the new groundwater information, excavation or retaining structures associated with the proposed subdivision works or anticipated to occur for future dwellings, will likely intersect with the groundwater table (Exh 16 at par 7). According to Dr Sutherland, all structures will be drained and discharged to the stormwater system, irrespective of the potential intersection of the groundwater (Exh 16 at par 12). In Mr Burkitt’s opinion, the foundation piers could intercept the groundwater levels but will not interfere with its flow as they are discontinuous and will allow ready groundwater flow (Exh 16 at par 30).

105. I am satisfied that the groundwater table is unlikely to be intercepted by retaining structures, as agreed by the experts (Exh 12 at par 9). I note the Applicant’s experts’ evidence that if the groundwater is in fact at a higher level within the mid to upper slopes of the land than previously reported, then it will be appropriately drained by the proposed retaining system minimising any risks to the structures or the receiving environment [Exh 16 at par 44). The groundwater removed uphill will be reintroduced through the level spreader above the onsite EEC. In this way, I accept that there will be no change following the proposal in groundwater for the onsite EEC (Tcpt, 23 October 2025, p 172(29)-(34)).

Ecology

106. According to the Applicant's groundwater experts, the drainage will be delivered to the onsite EEC in a similar manner to the pre-developed case (Exh 16 at [18]). According to Dr Sutherland, the recent history of the onsite EEC and the Coastal Wetland is one of little apparent change under a wide range of rainfall conditions. According to Ms Holton, no groundwater change is anticipated across the majority of the onsite EEC, however, there is a predicted increase in groundwater levels in the isolated hillslope occurrences of the onsite EEC (Exh 14 at par 42).

107. Mr Garvey resiled from his earlier expressed views in the joint report (Exh 14) about groundwater and its effects of the onsite EEC in light of the information provided as part of the additional geotechnical report (SSReport2, Appendix 1 of Exh 16) and the subsequent joint expert report (Exh 16) (Tcpt, 23 October 2025, p 144(39)-(45)). He said:

“…in light of the information provided as part of the geotechnical report… the conclusions that are drawn in the joint expert report may no longer stand, and that additional information groundwater and surface water modelling may be required to understand the impacts to the coastal wetlands and the… EEC.”

108. Given my finding at [103] above, the additional information does not alter the agreement earlier reached in Exh 14 by the experts about groundwater and its effects.

109. Ms Holton and Mr Tong, and Dr Martens and Mr Garvey, agreed that in relation to the onsite EEC and the Coastal Wetland, the proposal will result in the Coastal Wetland having fewer dry periods and there will be short term reductions in stormwater during stochastic events (Exh 14 at par 35) and the proposal will result in a minor increase in groundwater levels in the onsite EEC and changes in water levels and flow during more frequent rainfall events (Exh 14 at par 38).

110. The ecological experts agreed that the extent of the EEC is unlikely to decline or become extinct following the development (Exh 14 at pars 40 and 50). The experts agreed that the proposal will result in an average annual increase in freshwater discharge to the EEC and a change in water levels during more frequent rainfall events (Exh 14 at par 37(b)) as a result of surface water changes, which will change the EEC such that water-preferring species will tend to flourish, while less tolerant species will not.

111. The onsite EEC and Coastal Wetland already experience, and are adapted to, a very broad range of drying and wetting. The proposal, whilst adding additional water, does not alter that regime in any significant respect. Ms Holton and Dr Sutherland analysed a 51-year record of daily rainfall (Appendix 2 to Exh 12). The range and magnitude of flows received at the onsite EEC are recorded in Table 1 (Exh 12, f 36) and at the Coastal Wetland in Table 2 (Exh 12, f 38). The range is large in each case, as both the onsite EEC and the Coastal Wetland experience years which are very dry and years which are very wet. The range and magnitude of flows received at both locations has no significant impact on the EEC or the Coastal Wetland. I accept the Applicant’s submission that all increases in surface water will fall within the range of flows already experienced, except for the maximum year. I accept that a change that is already within the range of change is not significant, and the range and likelihood of wetting and drying is not materially altered. This can be appreciated by the close correspondence between the pre-development and post-development flow volume comparisons for the onsite EEC and the Coastal Wetlands shown in Figures 1 and 2 (Exh 16, ff 38 and 40).

112. According to Mr Tong, any changes in composition is likely to be within the natural range of composition for the onsite EEC (Exh 14 at par 48). He noted that the (amended) Habitat Restoration Plan (Appendix 5 to Exh 14) includes planning/revegetation of the onsite EEC and surrounding area which will help to maintain and improve the integrity and resilience of the onsite EEC, as well as increasing its extent, mitigating the potential impacts from the changes in hydrology (Exh 14 at par 51). The ecology experts agreed that the Habitat Restoration Plan’s holistic approach to managing of the site, such as including a weed management plan for the roads and residential lots, is a sensible approach (Exh 14 at par 167).

113. The ecology experts agreed that the modelling shows the proposal results in no change in groundwater levels in the Coastal Wetland and that changes in freshwater flow rates and levels within the mangroves will be minor and short term in nature. Given the tidal influences in this area, this is unlikely to result in impacts to mangrove vegetation (Exh 14 at pars 79-80).

114. The ecology experts agreed that measures are included in the proposal to minimise and mitigate impacts on environmentally sensitive areas including the onsite EEC and Coastal Wetland (Exh 14 at par 114). I accept Ms Holton and Dr Sutherland's evidence that no drawdown is predicted for the average, dry and wet climate scenarios for the onsite EEC and that the proposal will not significantly impact upon the biophysical, hydrological or ecological integrity of the adjacent Coastal Wetland, or the quantity and quality of surface and groundwater flows to and from the Coastal Wetland (Appendix 2 to Exh 12 p 62).

115. I am satisfied that the proposal does not result in a significant impact on the integrity of the onsite EEC or on the Coastal Wetland on the northern neighbour’s land, or the quantity or quality of surface and ground water flows, in terms of the matters to be considered under Ch 2 of the RH SEPP. I accept that the matters for consideration under cl 7.2(3) of LEP 2014 are addressed by the reports listed in the table at Appendix 5 of Exh 12, prepared by Ms Holton and Dr Sutherland. I accept the conclusions included in the table. I am satisfied that the impacts of the proposal on the onsite EEC and the Coastal Wetland are not such as to justify refusal of the application.

Disputed conditions of consent

116. Condition 20 is agreed (Exh 19) and is imposed.

117. Condition 53 is agreed (Tcpt, 27 October 2025, p 339(21)-(22)) and Council’s version is imposed.

118. I accept the Applicant’s objection to Condition 112(c) requiring a positive covenant that all future dwellings comply with the deep soil zone requirements of the TDCP (Tcpt, 27 October 2025, p 325(41) – p 326(47)). The lots, other than Lot 11, meet the performance criteria under the TDCP section A5.4.12 for lot layouts in the R2 zone. The assessment of future applications for dwellings on the lots will be a matter for the consent authority at that time, under the applicable planning regime. Condition 112(c) is deleted.

119. I accept the Applicant’s submission that the responsibility for maintaining structures is legally imposed on the Community Association, as well as under the Community Management Statement (Exh G), and that the Subdivision Plan Rev K (Exh C, tab 5) records the positive covenants that bind the Community Association to maintenance.

Bushfire protection

120. The Council’s contention regarding bushfire risk assessment was not pressed in the Amended Statement of Facts and Contentions (Exh 1).

121. The Rural Fire Service (RFS) replied to the Council’s request for general terms of approval for the proposal made pursuant to s 100B of the Rural Fires Act 1997 (NSW). The reply dated Wednesday 15 October 2025 (Exh 4, tab 7 ff 385-388), incorrectly stated that the development is Integrated Development (under Div 4.8 of the EPA Act), and provided General Terms of Approval including conditions. The conditions include a requirement for the creation of easements to restrict the user of certain lots from constructing a Class 1, 2 or 3 building within 6m of another Class 1, 2 or 3 building, referencing the Bushfire Assessment Report provided in the application (Exh C, tab 12). The Council submitted that only the conditions proposed by Mr McMonnies should be imposed on the consent because the requirement for easements in the RFS letter is unworkable.

122. The Applicant did not oppose these conditions (other than condition 112(c) which does not concern bushfire protection). These agreed conditions are imposed in the conditions of consent at Annexure A.

Conclusion

123. Although this is a challenging site, having regard to the principal contested issues, I am satisfied that it is appropriate to grant consent to the proposal, because there are no unacceptable environmental impacts in terms of the issues raised.

124. I accept the Applicant’s submission that a significant public benefit arises from the application, as the proposal is to comprehensively address the poor environmental state of the site and improve its ecological values; by clearing the site of weeds, restoring the EEC to a fully functional habitat, and capturing, diverting, treating and releasing the stormwater, a significant proportion of which comes from upstream catchments, in a controlled manner.

Orders

125. The orders of the Court are:

126. Pursuant to s 8.15(3) of the Environmental Planning and Assessment Act 1979 (NSW), the Applicant is to pay the Respondent’s costs thrown away as a result of the amendment of Development Application No. 24/0388 on 21 October 2025, as agreed or assessed.

127. The Class 2 appeal is upheld.

128. The application to carry out water supply and sewerage works servicing 4A Boyle Avenue, Banora Point (Lot 3 DP 250581) is determined by the grant of approval, subject to the conditions of approval at Annexure B.

129. The Class 1 appeal is upheld.

130. Development Application No. 24/0388 for the subdivision of one Torrens title lot to create 18 residential lots, one community lot containing internal roads, a system of retaining walls along the southern boundary and an area of remnant native vegetation, at 4A Boyle Avenue, Banora Point (Lot 3 DP 250581), is determined by the grant of consent, subject to the conditions of consent at Annexure A.

131. The exhibits, other than Exhibits 1, 2, 17, 18, A, B, D, E, F, H and J, are returned.

Susan O’Neill

Commissioner of the Court

Annexure A (473 KB, pdf)

Annexure B (191 KB, pdf)

Annexure C (149 KB, pdf)

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