Enkelmann v Stewart[2025] QSC 77

SUPREME COURT OF QUEENSLAND

1. [1]
   The first plaintiff and the second plaintiff own a property, known as “Riverview” (Riverview)^[1], on which they undertake a farming business through the third plaintiff, a partnership with their son, Brett Enkelmann.
2. [2]
   The first defendant and the second defendant own the adjoining property, known as “Mikandra” (Mikandra)^[2], and undertake a farming business.
3. [3]
   The plaintiffs commenced proceedings against the defendants in 2016 which have gone through various iterations.  The defendants defended the plaintiffs’ claims and made a counterclaim.
4. [4]
   A trial was held over various dates in 2023 and 2024, with final submissions in September 2024. 
5. [5]
   At or about the time of the plaintiffs’ final written submissions, the plaintiffs:

   1. “abandoned” their claim in the Fourth Further Amended Statement of Claim (4FASOC) and, as the plaintiffs “[did] not press their claim against the defendants”, proposed that the claim be dismissed with costs; and
   2. maintained their opposition to the defendants’ counterclaim.
6. [6]
   Following this development, various issues arose as to the appropriate way for the plaintiffs’ claim to be dealt with, potential costs orders against non-parties,^[3] and the order in which these issues and the final submissions in respect of the counterclaim should be dealt with.
7. [7]
   Ultimately, it was agreed as follows:

   1. The Court would hear the oral submissions on the counterclaim and complete the trial.  This was done on 5 September 2024.
   2. The Court’s decision on the counterclaim would be reserved and reasons delivered in respect of the issues on the counterclaim.  These are those reasons.
   3. The Court will then hear further from the parties in respect of the appropriate final orders in relation to the plaintiffs’ claim and the defendants’ counterclaim.
   4. Once final orders are made, the Court will then proceed to deal with costs.
8. [8]
   At least one of the non-parties put on notice by the defendants’ retained lawyers sought to be heard if the Court was going to make adverse findings relevant to the issues impacting on potential costs orders against non-parties.  It was agreed that the defendants would not press for, and the Court would not make, findings of this nature in respect of the counterclaim.
9. [9]
   This line is practically difficult given the inter-relationship of the plaintiffs’ claim and the defendants’ counterclaim.  For the purpose of these reasons, I have adopted the approach that findings on legal issues and evidence (in particular admissibility of evidence) can and should be made relevant to the determination of the counterclaim.  Specifically, the issue of credibility of the plaintiffs’ expert, Mr Giles, will not be dealt with.  To the extent that the Court does need to address the evidence of Mr Giles, this can be done on other bases.
10. [10]
    In accordance with the agreed approach, below are the reasons in relation to the defendants’ counterclaim.

Counterclaim

11. [11]
    The parties agreed a list of issues in dispute prior to the trial commencing.  The issues in the Defence to the Fourth Further Amended Statement of Claim and Counterclaim (Amended Defence and Counterclaim) which remain relevant on the counterclaim are twofold:

    1. “The effect of the Temporary Levee on Riverview during flood events.”
    2. “Whether the [defendants] are entitled to an injunction that the Temporary Levee be removed.”
12. [12]
    These are the issues that remain to be considered and determined.  However, given the way that the proceedings ultimately progressed, and the closing submissions made, it is necessary to break these issues down further, including a consideration of what is described as the “Temporary Levee”.

Relevant pleading of the claim and counterclaim, including in respect of the Temporary Levee and the 2023 Works

13. [13]
    Whilst the plaintiffs have abandoned their claim and the “factual propositions underpinning it are no longer maintained”, it is necessary to consider aspects of the claim as it informs the counterclaim.
14. [14]
    The plaintiffs’ claim included:

    1. Damages for nuisance, claiming loss and damage including the costs to rectify damage, lost profits, and a diminution in the value of Riverview.
    2. Damages for negligence, claiming loss and damage including the costs of repairs and other losses (including in relation to the “Temporary Bank”).
    3. An injunction restraining the defendants from “diverting water onto Riverview” (practically, to remove certain alleged works on Mikandra that the plaintiffs asserted had this effect) or, alternatively, compensation for the diminution in value of Riverview (including the effect of the “Temporary Bank” on Riverview).
15. [15]
    Accordingly, the concept of the “Temporary Levee” in the counterclaim has its genesis in the “Temporary Bank” in the plaintiffs’ claim.
16. [16]
    Both Riverview and Mikandra are located on the Barambah Creek floodplain and over the years have been subject to flooding at various times.  The topography at a very general level is that Mikandra is uphill from Riverview, and water generally flows from Mikandra towards Riverview.  Water may also flow onto Riverview directly from Barambah Creek.
17. [17]
    The plaintiffs alleged that the defendants undertook certain works on Mikandra which altered the flow of water from Mikandra over Riverview, and also changed the effect of such water flow.  In particular, the plaintiffs alleged that the floods in February 1999, December 2010, January 2011, January 2013, February 2013, January 2022, and February 2022 were impacted to the detriment of the plaintiffs.
18. [18]
    As part of the losses pleaded and claimed in the 4FASOC, the plaintiffs claimed:

(a) [94(e)]:  “lost profits from a reduced cropping area resulting from the construction of a temporary levee bank (Temporary Bank) to provide potential protection to Riverview from the effects of floodwater following the New Course until injunctive relief can be obtained in the amount of $41,114;

Particulars

1. The bank was constructed in or about mid-2013 in accordance with:

1. The recommendation of FSA Consulting; and
2. The advice of Landform Survey and Design,
   2. The plaintiffs rely upon paragraphs 4.1.30 to 4.1.32 of the 2016 Vincents Report”.

(b) [94(g)]:  “the cost of building the Temporary Bank in the sum of $14,699”.^[4]

(c) [94(h)]:  “the costs of removing the Temporary Bank on injunctive relief being ordered in the sum of $18,000.00;

Particulars

The plaintiffs rely on the quote dated 12 October 2016 provided by M.J & N.T Armstrong.”

19. [19]
    Further, in the alternative to the injunction, the plaintiffs sought the diminution in value of Riverview as a result of “the likelihood of repeated flooding events in the amount of $1,420,000”.  The particulars of this claim included that inquiries from a potential purchaser would include an inspection which would show the “Temporary Bank” and the potential purchaser would “apprehend from that that the Temporary Bank was necessary to protect against floodwater flows from Mikandra”.^[5]
20. [20]
    The defendants denied the plaintiffs’ claim.  While some works had been done on Mikandra, the defendants submitted that the significant works alleged by the plaintiffs were not undertaken and did not have the effect as alleged by the plaintiffs.  Further, they submitted that the plaintiffs had done some works themselves which had altered the flow of water from Mikandra towards Riverview.
21. [21]
    In the Amended Defence and Counterclaim, the defendants plead in response to the plaintiffs’ claim:

    1. that from the 2022 flood event onwards, any adverse impacts on Riverview were due to the “Temporary Levee (Temporary Bank)”.^[6]
    2. that if Riverview did suffer loss and damage, that in all or in part was caused by alterations done by the plaintiffs, including the “Temporary Levee (Temporary Bank)”.^[7]
    3. a positive denial that the “Temporary Bank” was “a necessary or appropriate response to the flood events the subject of [the] proceeding” and a further denial that the “Temporary Bank” was justified by the Irrigation Infrastructure^[8] or any conduct by the defendants.^[9]
22. [22]
    A further issue arose between the first tranche of the trial in May 2023 and the resumption of the trial in March 2024 in respect of the Temporary Levee.  The defendants alleged that further works were done in or about July 2023 to alter the Temporary Levee and the Amended Defence and Counterclaim was further amended to include these allegations.^[10]
23. [23]
    The extent of these further works is controversial between the parties and was the subject of further evidence in the 2024 tranche of the trial.
24. [24]
    The counterclaim is set out at [101] to [116] of the Amended Defence and Counterclaim.  The relief claimed by the defendants is a mandatory injunction requiring the first plaintiff and the second plaintiff to remove the Temporary Levee (including the further works done in 2023) and to reinstate Riverview in the relevant area^[11] to the levels represented by the 2012 LiDAR referred to in the Fifth Markar Report, and costs.
25. [25]
    A summary of the material facts relied upon is as follows:

    1. Between 2013 and 2017, the Temporary Levee was constructed by the plaintiffs on Riverview, approximately along the southern boundary of Block 8.
    2. During “moderate flood events” the Temporary Levee causes water flowing in a northerly direction over Riverview to be blocked and to pool on Mikandra.
    3. As a consequence, silt and debris would be deposited on Mikandra, causing damage to crops in the areas of Block 1 and Block 2 where there would be pooling.
    4. This occurred in 2017, twice in 2021, three times in 2022, and is likely to occur again.
    5. In these circumstances, the Temporary Levee has the effect of “causing material damage to Mikandra”.
    6. The plaintiffs built the Temporary Levee “for the purpose of blocking overland water flow from Mikandra from entering Riverview along the southern boundary of Riverview Block 8”.
    7. It was “reasonably foreseeable (indeed inevitable) that the construction of the Temporary Levee would cause water flowing in a northerly direction over Riverview to be blocked and to pool on Mikandra, and consequently deposit silt and debris on Mikandra and cause damage to crops planted on Mikandra in the location of the pooling on Blocks 1 and 2 on Mikandra”.
    8. Consequently, the construction of the Temporary Levee was:
       1. unreasonable in all of the circumstances, including the effect it was likely to have on Mikandra;
       2. the cause of an unreasonable interference with the defendants’ use and occupation of Mikandra; and
       3. an actionable nuisance.
26. [26]
    The defendants further plead the specific additional works undertaken in 2023 (referred to as the 2023 Works) and the impact of those alleged changes to the Temporary Levee.  The effects of the 2023 Works are described as follows:

“The effects of the 2023 Works included that in the event of a major flood event, floodwaters would back up against the eastern part of the Temporary Levee and be diverted westwards, such that rather than flowing over Riverview in a north-westerly direction, water at increased velocity and depth would be diverted over the northern part of Mikandra Block 2 and over Riverview Block 9, causing:

1. erosion to the land (including both cultivated land and roadways) and damage to any crops planted in the affected part of Mikandra Block 2;
2. to the extent that the Temporary Levee (as varied by the 2023 Works) causes water to back up behind the Temporary Levee, any area so affected would likely:
   1. suffer siltation of any drains in the silt-affected area;
   2. as a result of being waterlogged be more difficult to traverse with machinery for an extended period of time, hampering cultivation and spraying and picking of cotton in the affected areas of cropping land”.

27. [27]
    The 2023 Works are alleged to have been done:

    1. Without advance notice to the defendants and without the defendants’ permission or consent.
    2. Without any modelling or investigation as to the effect or impact of the 2023 Works on the defendants.  It is alleged that in particular this is the case where:
       1. The Temporary Levee was built (and has continued) for “the purpose of protecting Riverview from surface water flowing and discharge from Mikandra”.
       2. The first plaintiff conceded that before the Temporary Levee was built and/or the 2023 Works, he knew the Temporary Levee would affect the flow of water across Mikandra, cause water to back-up on Mikandra, force water to the east and west of the Temporary Levee, cause silt to be dropped on Mikandra, and cause damage to Mikandra.
       3. The plaintiffs, and Brett Enkelmann, knew and understood that the defendants were alleging in the counterclaim that the effect of the Temporary Levee was that it caused damage to Mikandra, and that modelling was necessary to predict the likely flow of water in flood events over Riverview and Mikandra.
28. [28]
    The defendants also alleged that in undertaking the 2023 Works the plaintiffs knew certain matters, including the following:

    1. The Temporary Levee was intended by the plaintiffs to “have the effect of blocking overland water flow passing over Mikandra and onto Riverview in a significant flood event”.
    2. The Temporary Levee was likely to “block overland waterflow passing over Mikandra and onto Riverview in a significant flood event and cause water flow over Riverview Block 9 and Mikandra Block 2, thereby causing erosion to Mikandra Block 2 and damage crops in the area of that diverted water”.
29. [29]
    In respect of this knowledge, the defendants relied on a number of matters including the plaintiffs’ Amended Reply and Answer to the Defence and Counterclaim (Amended Reply and Answer).^[12]  This includes that the Temporary Levee was built “for the sole purpose of mitigating against the tortious conduct of the defendant[s]”, being the flow of floodwater from Mikandra onto Riverview.^[13]
30. [30]
    Further:

    1. The 2023 Works were built with the same substantive purpose as the Temporary Levee, including the purpose of “blocking overland water flow from Mikandra from entering Riverview along the southern boundary of Riverview Block 8”.
    2. It was reasonably foreseeable (and/or inevitable) that the construction of the 2023 Works would cause water flowing in a north-westerly direction over Riverview to be blocked and to be diverted westerly across the northern part of Mikandra Block 2, to cause erosion and deposit of silt and debris on Mikandra and cause damage to any crops in the area where water was diverted.
    3. Consequently, the construction of the 2023 Works was unreasonable, likely to cause unreasonable interference with the defendants’ use and occupation of Mikandra, and a likely cause of actionable nuisance to support an injunction to restore the area to the level existing prior to the construction of the Temporary Levee and the 2023 Works.
31. [31]
    The plaintiffs’ Amended Reply and Answer provides a traverse of the issues raised in the Amended Defence (now not pursued given the abandonment of the claim) and also a traverse of the issues raised on the counterclaim.  At the outset a difficulty arises as, in respect of the counterclaim, the plaintiffs plead:

“[71] The plaintiffs repeat and rely upon the matters pleaded at paragraphs 1 – 100 of the statement of claim.”

32. [32]
    The effect of this pleading is that in the separate proceeding being the counterclaim, the plaintiffs incorporate their substantive claim.  However, that is the claim that has now been abandoned.  An issue arises as to how this pleading can now be understood.
33. [33]
    More specifically, the plaintiffs go on to plead:

    1. The Temporary Levee does not cause water flowing in a northerly direction over Riverview to be blocked and to pool on Mikandra and otherwise deny the allegations.
    2. A denial that the Temporary Levee has the effect contended for in the counterclaim.
    3. That the plaintiffs built the Temporary Levee for the “sole purpose of mitigating against the tortious conduct of the defendant[s] constituted by the Works”, and otherwise deny the allegations.
34. [34]
    In respect of the injunctive relief claimed, the plaintiffs pleaded the following matters as vitiating against the exercise of the discretion to grant injunctive relief:

    1. “[T]hat the building of the structure was in protection of the plaintiffs from the tortious conduct of the defendants;
    2. [T]he structure was constructed in accordance with expert advice obtained;
    3. [I]n the circumstances pleaded at sub-paragraph 75(a)^[14] ... the defendants do not have clean hands;
    4. [B]y refusing to remove the Works, the defendants have refused to do equity.”
35. [35]
    At the hearing of submissions, the plaintiffs conceded that (c) and (d) fell away given the abandonment of the claim. The plaintiffs acknowledged that (a) also fell away as the tortious act could not be made out, except to the extent of going to the plaintiffs’ purpose.^[15] Accordingly, (b) may fall to be considered in respect of the exercise of the discretion, if that point is reached.^[16]
36. [36]
    In respect of the 2023 Works, the plaintiffs dispute that the works alleged by the defendants were done, including the nature and scope of the works undertaken in 2023. While it is accepted that some works were done (defined as the Repair Works in the Amended Reply and Answer), the plaintiffs do not accept the 2023 Works as pleaded by the defendants were done. 
37. [37]
    The plaintiffs also plead that they relied on their own experience as farmers in carrying out the Repair Works and did not undertake any hydrological modelling or investigation prior to carrying out the Repair Works.  Further, the plaintiffs maintain that the Repair Works “do not infringe on the defendants’ rights or materially affect the proper functioning of Mikandra”.
38. [38]
    Consequently, witnesses were called and were cross-examined about various aspects of the Temporary Levee before and after the 2023 Works.
39. [39]
    As a consequence of the pleadings outlined above, consideration is to be given to the effect of the Temporary Levee as originally constructed and the effect of the current Temporary Levee with the 2023 Works.

Openings in respect of the counterclaim

40. [40]
    The defendants’ written opening relied on the opinion of Dr Markar to support the contention that the Temporary Levee causes water to back up onto Mikandra, damaging crops.^[17]  The defendants also contended that Mr Giles’ Third Report [PLF.149.001.0001] also has a similar effect, although based on different modelling: namely that, the Temporary Levee creates increases in the velocity of flowing water along the southern side of the Temporary Levee.
41. [41]
    Further, the defendants contended that the Temporary Levee impedes the flow of floodwater across Mikandra and has the effect of backing up water onto Mikandra based on the modelling of both experts and also logic.  The Temporary Levee operates as an embankment which “stands in the way of the natural flow of water from the local catchment and water from the larger Barambah Creek catchment as it exits the Channel”. 
42. [42]
    Further, the defendants contended that the Temporary Levee was designed to “protect” Riverview from a threat that did not exist (and which has now been abandoned): being the risk of increased flows over Riverview because of alleged works on Mikandra.
43. [43]
    In contrast, the plaintiffs’ opening in respect of the counterclaim relied on the report of Mr Giles to demonstrate “only minor effects on Mikandra”, including only a relatively small increased area on Mikandra where the water velocity exceeded the erosion threshold.
44. [44]
    Overall, the plaintiffs in the opening contended that nuisance was not established as the modelling did not support any significant increase in erosion on Mikandra.

Plaintiffs approach following the abandonment of the claim

45. [45]
    In the plaintiffs’ written submissions in reply dated 3 September 2024, the plaintiffs concede that the Temporary Levee^[18] “cannot be justified on the basis that it was a valid response to a nuisance on Mikandra”.  However, the plaintiffs’ position is:

“It does not follow that the [Temporary Levee] is an actionable nuisance.  It is still for the [defendants] to make out the elements of the tort.  Aside from the fact of the construction of the [Temporary Levee], none of the elements of the tort has ever been conceded.”

46. [46]
    Further, the plaintiffs contend that this is consistent with the position that has always been taken:  that is, the defendants would have to establish the elements of the tort.
47. [47]
    The plaintiffss position was further clarified at the submissions hearing on 5 September 2024 by Mr Ferrett KC as follows:

“… our case now … is really to say that the evidence on [the defendants’] case for the counter-claim, taken at its highest, doesn’t get them there.  It’s not part of our defence.  You don’t need to make any finding based on Mr Giles’ reports to find in [the plaintiffs’] favour”.^[19]

48. [48]
    Further:

    1. “[The plaintiffs do not] urge [the Court] to accept facts set out in – or opinions set out in the reports of Mr Giles… [the plaintiffs’] submissions … are based on the proposition that … the defendants, the counter-claimants, haven’t come up to proof”.^[20]
    2. “[The plaintiffs are] not going to urge [the Court] to accept anything in [Mr Giles’] reports”.^[21]
49. [49]
    From a practical perspective, the plaintiffs put the defendants to proof on the nuisance claim. 
50. [50]
    Further, the plaintiffs rely on the authorities of Gartner v Kidman^[22] and Gales Holdings Pty Ltd v Tweed Shire Council^[23] to support the proposition that the plaintiffs are entitled to erect a barrier to prevent water entering Riverview, even if it has the effect of concentrating water on Mikandra and causing loss to the defendants.
51. [51]
    The plaintiffs submit that this issue is raised on the pleadings and concede there is no deficiency in the pleadings by any party.^[24]

Issues to be determined on the counterclaim

52. [52]
    Given the matters identified above, the issues to be determined on the counterclaim require further specific focus rather than the more general issues identified at the commencement of the trial.
53. [53]
    Accordingly, the following issues will be considered in these reasons:

    1. Is the water which flows over Mikandra and onto Riverview at the location of the Temporary Levee a natural watercourse?
    2. Does the Gartner v Kidman “defence” apply in respect of the Temporary Levee?
    3. Have the defendants established nuisance?
    4. If so, should an injunction be granted requiring the plaintiffs to remove the Temporary Levee?
54. [54]
    Each of these issues incorporate a number of different sub-issues or components.  These will be dealt with under the main issue, together with any necessary findings of fact.

Is the water which flows over Mikandra and onto Riverview at the location of the Temporary Levee a natural watercourse?

55. [55]
    The defendants plead in the Amended Defence and Counterclaim as follows:

    1. “[T]he flow of water over Mikandra, Riverview and the Lagoon Land depended upon the location, timing, and volume of rainfall in the catchments which feed into those properties”.^[25]
    2. “[T]o the extent that water passes over Mikandra and enters Riverview during flooding events, the water does not enter Riverview at a single point or points”.^[26]
    3. “Riverview, Mikandra and the Lagoon Land are located in a floodplain”.^[27]
    4. “Riverview and Mikandra are affected in different ways by the flood events of different magnitudes”.^[28]
    5. “[I]n the event of significant flood events, Riverview is affected by overland flow which is not materially increased in terms of velocity, volume or duration by:
       1. the topography of Mikandra; or
       2. any improvements which [the defendants] have made to Mikandra, including but not limited to the Irrigation Infrastructure”.^[29]
    6. “[T]he relevant catchment which collects water which flows over Mikandra, Riverview and the Reserve in significant flood events is the Barambah Creek catchment which drains a catchment area of approximately 2,950km²”.^[30]
56. [56]
    In support of these contentions, the defendants led extensive persuasive and probative evidence as to the topography of Mikandra over the relevant period and also the water flows over Mikandra and Riverview, including in the identified flood events.
57. [57]
    I accept the evidence of the defendants and the lay and expert witnesses that gave evidence on behalf of the defendants.  I find the defendants, the defendants’ lay witnesses, and the defendants’ expert witnesses to be credible and reliable witnesses.
58. [58]
    The plaintiffs do not seek to rely on the evidence led at trial in respect of the now abandoned claim.  However, to the extent that the evidence touches on matters relevant to the counterclaim, it is necessary to deal with the evidence to that limited extent.
59. [59]
    As a consequence of the plaintiffs abandoning their claim and not relying on the evidence led at trial, the material facts in the 4FASOC and the Amended Reply and Answer have not been established.
60. [60]
    In any event, I do not accept the evidence of the first plaintiff and Brett Enkelmann unless it is contrary to the interests of the plaintiffs.  I find that their evidence was not reliable and was, in many respects, subject to later reconstruction.
61. [61]
    A further consequence is that any opinion evidence of experts called on behalf of the plaintiffs is not admissible as the underlying facts have not been proved and the assumptions the experts make are not established.^[31]
62. [62]
    The practical effect of the abandonment of the claim is that there is no evidence to contradict the evidence led by the defendants in respect of the facts and matters pleaded in the Amended Defence and Counterclaim.  It must operate effectively as a concession of the facts pleaded in the Amended Defence and Counterclaim, subject to the position taken on the counterclaim.  In any event, this outcome is supplemented by the acceptance of the evidence of the defendants and the defendants’ lay and expert witnesses outlined above.
63. [63]
    Accordingly, in respect of the topography of Mikandra and the water flow across Mikandra and onto Riverview, it is necessary to make some specific findings which in turn are relevant to the issue being considered on the counterclaim.
64. [64]
    In respect of the topography of Mikandra, I make the following findings:

    1. The topography of Mikandra includes the Irrigation Infrastructure admitted by the defendants at [6(a)] of the Amended Defence and Counterclaim.
    2. In respect of the “Works” defined in [6] of the 4FASOC:
       1. Levees 4, 5, 6 and 7 do not exist on Mikandra and have never existed; and
       2. Levees 1, 2 and 3 and the Ring Tank have no adverse effect on the flow of flood waters through Mikandra and onto Riverview.
    3. The topography of Mikandra is reflected in the modelling of Dr Markar.
    4. The topography of Mikandra is reflected in the drainage map [DEF.014.001.0027] prepared by Mr Byrom based on 2012 LIDAR data.
65. [65]
    Much of the trial focussed on the “pre-works” and “post-works” topography of Mikandra.  That is irrelevant.  What “is” the topography of Mikandra is that pleaded by the defendants and established on the evidence led by the defendants.
66. [66]
    In respect of the broader catchment and water flows surrounding Mikandra and Riverview, I make the following findings:

    1. I accept the evidence of Dr Markar:
       1. in the First Markar Report [DEF.012.001.1502];
       2. in the Second Markar Report [DEF.012.001.1503];
       3. in the Third Markar Report [DEF.014.001.0004];
       4. in the Fourth Markar Report [DEF.020.001.0022];
       5. in the Fifth Markar Report [DEF.998.001.0001]; and
       6. his evidence at trial.
    2. In particular:
       1. Riverview and Mikandra are located within the Barambah Creek catchment.
       2. There are “three significant local watercourses draining through Riverview and/or Mikandra:

• Hansens Gully, which is a tributary of Barambah Creek;
• A watercourse, which is a major tributary of Hansens Gully, labelled as ‘Fairdale-Leafdale Gully’ in the plaintiffs’ statement of claim …; and
• A watercourse labelled … as ‘Lagoon Gully’, which is tributary of Fairdale-Leafdale Gully.”^[32]
  3. Flooding of Riverview and Mikandra can occur from:
     1. Barambah Creek; and/or
     2. Hansens Gully and its tributaries: Fairdale-Leafdale Gully and Lagoon Gully.
  4. In respect of flooding from Barambah Creek, this can occur from overflow from the creek with or without local catchment flooding.
  5. Catchment flooding impacting Riverview would occur from the water flow entering Riverview predominantly from the Fairdale-Leafdale Gully and Lagoon Gully, and to a lesser extent Hansens Gully. There could also be direct rainfall and runoff on Riverview.  This local catchment flooding could occur with or without Barambah Creek flooding.
  6. Local catchment flooding of Riverview and Mikandra would occur due to intense short-duration rainfall bursts of less than approximately 6 hours duration, and this flooding would generally last only a few hours.
  7. Flooding of Riverview and Mikandra from Barambah Creek would occur due to prolonged rainfall events of approximately 12 to 72 hours duration, and this flooding would last a few days.
  8. Flooding of Riverview and Mikandra from Barambah Creek would be more significant than flooding from local catchments.

3. Mikandra and Riverview are located in the larger catchment that generally feeds downstream to the alluvial floodplain northwest of Murgon, which is variously described as the “Byee/Wheatlands floodplain”, the “Byee-Wheatlands-Mondure floodplain” or the “Byee floodplain” as shown in [DEF.001.001.0052], [DEF.004.001.0655_0008] and [DEF.004.002.0043_0006].
4. The topography of Barambah Creek and the surrounding area affects the “behaviour” of the floodplain.  See [DEF.004.002.0043_0006] and [DEF.001.001.0052_0007-0010].
5. Further, the floodplain drains generally north along both of the banks of Barambah Creek, through what are described as gullies and levee backswamps.  See [DEF.004.002.0043_0028].
6. The Lagoon referred to on the pleadings is a natural lagoon which is the confluence of two gullies, with local runoff and floodplain flows converging.  It is located on the west bank of Barambah Creek.
7. The Lagoon constricts the flow path, which concentrates and intensifies waterflows.  See [DEF.014.001.0005_0010, 0014, 0015, 0017, 0025, 0030, 0037]. This is also shown in the GHD Report at [DEF.004.001.0655_0057,0060, 0063].
8. I accept the evidence of Professor Bennett, in his report [DEF.014.001.0005] and his evidence at trial. In particular:
   1. The floodwater flows through the Lagoon, through Mikandra and into Riverview.
   2. The historical flow path is a corridor being an extension of Barambah Creek and its tributary gullies.  The tributaries feed into and form part of the creek.
   3. The analysis of the aerial photographs and Professor Bennett’s annotations of the aerial photographs in his oral evidence at trial in respect of the flow of water from the upstream reaches of Barambah Creek.
9. I accept the evidence of Mr Byrom, including the evidence contained in his report [DEF.012.001.1504] and his depiction of the gullies and stream network in the area of Mikandra and Riverview at [DEF.012.001.1504_0049] and the topography of Mikandra in [DEF.014.001.0027].

67. [67]
    This evidence is also largely consistent with:

    1. some earlier work by the Queensland Water Resources Commission in an “Agricultural Drainage Study” in October 1982 [DEF.001.001.0048]; and
    2. some later work that was done for a report prepared for the Burnett Mary Regional Group for Natural Resource Management Ltd in 2014 [DEF.004.002.0043]. 
68. [68]
    The plaintiffs contend that the relevant water flow is not a watercourse and rely on the reasoning of the High Court in Knezovic v Shire of Swan-Guildford^[33] in support of that conclusion.  In particular, the plaintiffs rely on the following statement of Barwick CJ as follows:

“It seems to me, on an examination of such authorities as exist and of the work of recognized writers on this subject, as well as the decision of the Court, that it is settled that a watercourse consists of a stream with a bed, with banks, and water.  That the flow of water in the stream is intermittent or seasonal will not prevent what would otherwise be a watercourse from being accounted such: but though it is quite true that a watercourse may exist though its bed be dry for some periods, the watercourse, in my opinion, must exhibit features of continuity, permanence and unity, best seen, of course, in the existence of a defined bed and banks with flowing water.  It must, in my opinion, essentially be a stream and be sharply distinguished from a mere drain, or a drainage depression in the contours of the land which serves to relieve upper land of excess water in time of major precipitation…”.^[34]

69. [69]
    The plaintiffs submit that here there is no defined bed and no defined banks through which the water flows.  Rather, it is a mere drain or drainage depression.
70. [70]
    In respect of this issue, the defendants submit that the evidence establishes that the water which flows through the Lagoon, Mikandra and onto Riverview, and is impacted by the Temporary Levee, is a watercourse.
71. [71]
    The defendants also rely on the following aspects of the authorities:

    1. In Gartner v Kidman Windeyer J relevantly stated:

“The propositions are general.  Their application in a particular case may be affected by circumstances.  They concern only surface waters, as distinct from the flow of natural watercourses to which riparian rights attach.  And, for this purpose, surface waters do not include the waters of a stream or river which when periodically swollen in time of flood flows in a wider channel than ordinarily, the super-abundant waters following the general course of the stream but flowing outside its ordinary bed.  Such “flood channels” are to be regarded as if they were part of the alveus of the stream.  The law of natural watercourses applies, not that of surface waters… On the other hand waters that are the occasional overflow of lakes or ponds, not being part of a stream, are surface waters.”^[35] (defendants’ emphasis)

2. In Menzies v Breadalbane, which was cited with approval in Gartner v Kidman, the Court considered the riparian rights attaching to natural watercourses at common law and stated as follows:

“… a superior heritor cannot divert any part of a stream to the prejudice of an inferior heritor.  It is also clear, that an inferior heritor cannot do that which shall cause the water to stagnate, to the prejudice of the superior; that is acknowledged to be clear law.  But it is said, that applies only to the alveus of the course.  But it does not appear to me, that there is any solid ground for the distinction.  The ordinary course of the river, is that which it takes at ordinary times; there is also a flood channel: I am not talking of that which it takes in extraordinary or accidental floods, but the ordinary course of the river in the different seasons of the year, must, I apprehend, be subject to the same principle”.^[36]

3. Further in Menzies v Breadalbane the Court concluded that:

“… the Respondent ought to be prohibited and interdicted from the further erection of any bulwark, or any other opus manufactum, upon the banks of the river Tay, which may have the effect of diverting the stream of the river in times of flood, from its accustomed course, and throwing the same upon the lands of the Appellant”.^[37]

4. In Gales Holdings Pty Ltd v Tweed Shire Council^[38] the Court affirmed Windeyer J in Gartner v Kidman and stated:

“[133] The flow of water can give rise to nuisance.  There is a difference between the flow of surface waters and the flow of natural watercourses.  Riparian rights attach to the flow of natural watercourses such as rivers or streams, but not to the flow of surface waters.  The word “riparian” derives from the Latin ripa for riverbank. A riparian owner, being the proprietor of the land on the banks of a natural stream of running water, is entitled to enjoy, and is obliged to accept, the flow of water past the land.  The law of natural watercourses, not surface waters, applies even to waters of a river flowing in a wider channel than usual, when the river is swollen in time of flood, even though they flow on land outside the riverbed while still following the river’s general course.  Such flood channels are treated as part of the alveus, or riverbed.

[134] A riparian owner can neither deprive those lower down the river of its flow, nor pen it back upon the lands of a neighbour higher up.  Riparian rights and obligations are proprietary, being natural incidents of the ownership or lawful possession of the land abutting on the stream or river.  They turn on who owns the riverbank, not the riverbed.”

72. [72]
    Further, the defendants submit that the evidence establishes that the relevant floodwaters are riparian flows, as Barambah Creek swells and moves in a wider and more direct channel than its ordinary, meandering bed.
73. [73]
    In oral submissions the defendants also sought to distinguish the authority of Knezovic v Shire of Swan-Guildford on the basis that the High Court had to consider whether or not one neighbour had a right of access to the other’s property under a statute which regulated watercourses.  Accordingly, it was not a case that considered the meaning of watercourses at common law and was not a nuisance case.
74. [74]
    Further:

    1. The case concerned a drainage depression that carried rainfall run-off that flowed only in the wet season.
    2. Barwick CJ considered and applied the relevant definition of a watercourse as contained in local government legislation.
    3. Barwick CJ went on, in obiter dicta, to consider wider matters that are reflected in the quote relied upon by the plaintiffs.
    4. McTiernan J agreed with Barwick CJ.  However, Kitto J expressly reserved his position about the distinction between a watercourse, creek, and river. Taylor and Owen JJ dissented.
75. [75]
    I accept the evidence of Dr Markar and Professor Bennett that the relevant water flow, being the water which flows over Mikandra and onto Riverview at the location of the Temporary Levee, is a natural watercourse which is part of the riparian flows through the various tributaries of Barambah Creek.  It is a natural watercourse, although it has been altered to some extent, and has been there historically as recorded in the reports of the experts who gave evidence on behalf of the defendants.  Accordingly, the relevant water flow for the counterclaim is a natural watercourse in the sense used in Gartner v Kidman.
76. [76]
    The factors of “continuity, permanence and unity” identified by Barwick CJ do exist to some extent.  The catchment maps include the water flow on the relevant flow path, and the water flow has been recorded consistently as is shown in the evidence included in the expert reports.  The topography shows a clear path which is evident on the aerial photographs over time.  While the water may not permanently flow, this case has always been about the water flowing on that flow path and whether it had been altered as the plaintiffs originally alleged.  All of this is consistent with the other evidence of it being a natural watercourse in the sense used in Gartner v Kidman.
77. [77]
    Accordingly, for the purposes of the counterclaim, I find that during rainfall events in which the Barambah Creek breaks its banks, water which flows over Mikandra and onto Riverview at the location of the Temporary Levee is a natural watercourse which flows with or without local runoff through Riverview.

Does the Gartner v Kidman “defence” apply in respect of the Temporary Levee?

78. [78]
    The plaintiffs contend that they are entitled to erect the Temporary Levee to prevent water from entering Riverview on the basis identified in Gartner v Kidman, in that the Temporary Levee turns away the natural flow of surface water from Riverview. 
79. [79]
    The defendants’ submissions describe this as the “Turn Back Defence”, and it is convenient to adopt that shorthand description.
80. [80]
    The plaintiffs seek to rely on the Turn Back Defence as stated by Windeyer J in Gartner v Kidman as follows:

“Although [the lower proprietor] has no action against the higher proprietor because of the natural unconcentrated flow of water from his land, he is not bound to receive it.  He may put up barriers and pen it back, notwithstanding that doing so damages the upper proprietor’s land, at all events if he uses reasonable care and skill and does no more than is reasonably necessary to protect his enjoyment of his own land.  But he must not act for the purpose of injuring his neighbour.  It is not possible to define what is reasonable or unreasonable in the abstract.  Each case depends upon its own circumstances. 

It may be added that the proprietor’s right to defend his land against water coming upon it by erecting barriers, is generally speaking restricted to penning it back on to the higher land whence it would otherwise have naturally come.  It does not entitle him to divert it on to the land of a third proprietor to which it would not have natural gone to the damage of that proprietor.”^[39] (plaintiffs’ emphasis)

81. [81]
    This principle has been accepted and applied, including as follows:

    1. By Muir J in Warne v Nolan [2001] QSC 53 at [84] and on appeal in Nolan v Warne [2001] QCA 537 at [13] (McPherson JA, Mackenzie and Mullins JJ agreeing).
    2. In Gales Holdings Pty Ltd v Tweed Shire Council (2013) 85 NSWLR 514 at [138] (Emmett JA, Leeming JA and Sackville AJA agreeing).
82. [82]
    However, as identified in the statement of Windeyer J set out at [71(a)] above, the Turn Back Defence does not apply to riparian flows.  This position was also accepted in Gales Holdings Pty Ltd v Tweed Shire Council in the extract set out at [71(d)] above.
83. [83]
    Having found that the water which flows over Mikandra and onto Riverview at the location of the Temporary Levee is a natural watercourse, I find that the Turn Back Defence is not available. 
84. [84]
    However, given the nature and history of this matter I consider it appropriate to go on to consider the other elements of the Turn Back Defence. If:

    1. contrary to the above finding, the water which flows over Mikandra and onto Riverview at the location of the Temporary Levee is surface water, whether natural or altered; or
    2. the Turn Back Defence applies in respect of a natural watercourse;

and the Turn Back Defence is available, then the following considerations arise.

85. [85]
    The other elements of the Turn Back Defence are:

    1. whether the plaintiffs had a purpose of “injuring [their] neighbour” or a malicious purpose for constructing the Temporary Levee;
    2. whether the plaintiffs used reasonable care and skill in constructing the Temporary Levee; and
    3. whether the plaintiffs did, and continue to do, no more than is reasonably necessary to protect their use and enjoyment of Riverview.

Whether the purpose was to injure their neighbour or a malicious purpose?

86. [86]
    The plaintiffs contend that there is no evidence of any purpose to injure the defendants, the Temporary Levee was built on advice, and it was not more than reasonably necessary to protect Riverview.  Accordingly, the Turn Back Defence would apply. 
87. [87]
    The defendants contend to the contrary.  That is, the plaintiffs had an ulterior purpose in erecting the Temporary Levee, it was built without reasonable care and skill, and its construction was more than what was reasonably required to protect Riverview. Central to the defendants’ contention is the position taken by the plaintiffs in the claim, which has now been abandoned.
88. [88]
    The plaintiffs contend that they did not have an “ulterior purpose” within the principle discussed by Windeyer J in Gartner v Kidman in constructing the Temporary Levee, namely:

“But he must not act for the purpose of injuring his neighbour…”.^[40]

89. [89]
    The plaintiffs describe the relevant purpose as being “the purpose of interfering in the [defendants’] use and enjoyment of Mikandra”.  The plaintiffs ultimately submit that such a purpose cannot be inferred from the evidence which is relied upon by the defendants.
90. [90]
    Further, the plaintiffs rely on the evidence of the first plaintiff, Brett Enkelmann, and Steven Hanlon that the Temporary Levee was built to protect Riverview.  It is submitted that the evidence of the first plaintiff and Brett Enkelmann in this regard was candid and should be accepted.
91. [91]
    In submissions the plaintiffs do accept that it is true that:

    1. the plaintiffs constructed the Temporary Levee in circumstances where they considered that works on Mikandra were adversely affecting flooding on Riverview; and
    2. the plaintiffs said that they were happy for the Temporary Levee to be removed once the works on Mikandra were removed.^[41]
92. [92]
    However, it is then submitted that “[n]one of that is to the point”.  It is argued that the purpose of the Temporary Levee was to protect Riverview from flood waters emanating from Mikandra and it does not matter whether those flood waters were natural or artificial.  In this regard reliance is placed on the comments of Emmett JA in Gales Holdings Pty Ltd v Tweed Shire Council:

“… the lower proprietor is entitled a degree of defensive self-help.  It can put up barriers and pen back even the natural, unconcentrated flow of water, as well as the altered flow.  It can do so even if doing so damages the higher proprietor’s land, so long as it uses reasonable care and skill and does no more than is reasonably necessary to protect the enjoyment of its lower land…”.^[42] (plaintiffs’ emphasis)

93. [93]
    Accordingly, the plaintiffs’ position is that they were entitled to defend Riverview against the flow of water, regardless of whether this water flow was from natural flows or flows affected by works on Mikandra.
94. [94]
    In contrast, the defendants say that an essential part of the plaintiffs’ case has always been that the Temporary Levee did not in fact “block” or “pen back” the water flowing from Mikandra on to Riverview, nor “pen back” the water on Mikandra.  In respect of the counterclaim, at [73(a)] of the Amended Reply and Answer, the plaintiffs expressly state:

“… the Temporary Levee does not cause water flowing in a northerly direction over Riverview to be blocked and to pool on Mikandra”.

95. [95]
    This pleading is, at least to some extent, inconsistent with the position now taken by the plaintiffs.  Blocking the flow of water to Riverview has to be the effect of the Temporary Levee if the purpose was to in fact protect Riverview.
96. [96]
    Further, at [75(a)] of the Amended Reply and Answer, the plaintiffs also expressly state:

“… the plaintiffs built the Temporary Levee for the sole purpose of mitigating against the tortious conduct of the defendant[s] constituted by the Works”.

97. [97]
    With the abandonment of the claim, and in light of the findings I have previously made, those alleged “Works” were never done by the defendants on Mikandra.  Therefore, the plaintiffs pleaded sole purpose has no foundation, and never did.
98. [98]
    The defendants point to there being no evidence of a purpose of “penning back” surface water on Mikandra,^[43] and submit that in all of the circumstances an “ulterior purpose” can be inferred for seeking to maintain the Temporary Levee.
99. [99]
    On the authorities, the Turn Back Defence is not available if there is a purpose to injure the neighbour or a malicious purpose.  Here, if the evidence of the plaintiffs is accepted, the purpose of constructing the Temporary Levee was a purpose of at least “redirecting” water flowing from Mikandra to Riverview in times of flood.  If the evidence is not accepted, there is either no evidence of their purpose, or a possible inference that the purpose was flood mitigation generally. An inference of an intent to injure the defendants is not readily drawn from the admissible evidence. 
100. [100]
     Questions may be asked about the logic and reasonableness of the purpose in all of the circumstances (which is discussed further below).  However, even with the late abandonment of the plaintiffs’ claim, without something more there is not a sufficient basis to find a purpose to injure the defendants or a malicious purpose in constructing the Temporary Levee.
101. [101]
     It is less clear if it is relevant to consider the maintenance of the Temporary Levee on an ongoing basis, where it must now be considered in light of the evidence of damage and detriment to the use and enjoyment of Riverview itself.  There may be a point in time when the continuation of a position becomes malicious.^[44]  However, given the consideration of the second and third elements below, I do not consider it necessary to conclusively determine whether that point has been reached in this case.

Whether reasonable care and skill was used in constructing the Temporary Levee?

102. [102]
     The construction of the Temporary Levee was the subject of evidence at the trial.  At that time it was relevant to both the plaintiffs’ claim and the defendants’ counterclaim.
103. [103]
     The plaintiffs rely on the evidence which includes:

     1. The affidavit of the first plaintiff sworn 7 February 2023 [PLF.139.001.0005]:
        1. Construction commenced in about June 2013 and took about 6 months.
        2. The design and construction of the Temporary Levee was based on expert advice from Mr Steven Hanlon.
        3. Riverview suffered damage in the January and February 2013 flood events, including erosion, siltation and deposition of debris.
        4. Mr Hanlon was an agricultural engineer with expertise in irrigation design and he provided advice to the plaintiffs.
        5. Mr Hanlon suggested the plaintiffs contact Mr Peter Watts of FSA Consulting Engineers to obtain advice “in relation to what measures [the plaintiffs] should put in place to limit future damage and what avenues of redress may be available to [the plaintiffs] to address the past flood events”.
        6. Mr Watts told the plaintiffs (as stated in the first defendant’s affidavit and the exhibited email) that “certain approvals may have been required from Local Government”.^[45]
        7. Mr Watts attended Riverview on 25 May 2013 and suggested that the plaintiffs should “construct an over-topping protection bank near the southern boundary of Riverview to try to slow and spread the flood water on the southern boundary of Riverview to mitigate against any future damage from flood events”.
        8. Mr Halon was then asked by the plaintiffs to design a protection bank on Block 9.
        9. Mr Hanlon provided “verbal advice” to construct a levee of 600 mm in height with a minimum batter slope of 10:1.
        10. The plaintiffs followed the advice of Mr Hanlon and Mr Watts and constructed the Temporary Levee, resulting in the loss of about 3.7 hectares of irrigated land.
        11. The construction of the Temporary Levee involved creating a drain near the Riverview boundary and using that dirt as the base of the Temporary Levee as well as dirt from other areas.
        12. Mr Hanlon later surveyed the area of the Temporary Levee.
     2. The first affidavit of Brett Enkelmann sworn 7 February 2023 [PLF.139.001.0001], including:
        1. The Temporary Levee was a “flood mitigation measure”.
        2. At the same time as building the Temporary Levee, a drain was built as part of the mitigation.  The drain was built to “help draw the water down the below Ground Waterway on the southern side” of the Temporary Levee.
        3. The Temporary Levee was designed “to allow water to feed around behind it and then to overtop the [Temporary Levee] in larger flows of floodwater, with the effect of spreading and slowing the water flow”.
     3. The affidavit of Steven Hanlon [PLF.139.001.0008]:
        1. Mr Hanlon suggested that the plaintiffs build “a temporary protection bank” to try to “prevent the worst of the effects of future floods”.
        2. He suggested that it be built in the same location as “the old, raised strip … about one metre above the natural surface with an extended base and a flatter batter at the northern side”.
        3. The Temporary Levee was “not designed to be a permanent fix to stop all future damage likely to result from the flood waters coming from Mikandra … it was designed by [him] to head off the worst of the effects of future flood waters until such time as a better and more permanent solution could be reached about controlling flood waters in the area”.
        4. Mr Hanlon was not well at the time and recommended that the plaintiffs approach Peter Watts at FSA Consulting Engineers to assist them “further with any farm design work”.
        5. Mr Hanlon visited “in the years since 2013” and saw the Temporary Levee had been built but he was “not involved in its construction”.
104. [104]
     The plaintiffs submit that the evidence of the first plaintiff and Brett Enkelmann should be accepted as it was not disturbed in cross-examination and was, in part, supported by the evidence of Mr Hanlon to the extent of his involvement.  Further, there was no cross-examination of Mr Hanlon in respect of the Temporary Levee.
105. [105]
     Ultimately, the plaintiffs contend that the Temporary Levee was “a rational and moderate response to the flooding on Riverview” and “did not go beyond what was reasonably necessary to protect Riverview”.
106. [106]
     The defendants contend for the contrary conclusion.  The defendants submit that the proposition that the Temporary Levee “was ‘designed’ in any relevant sense is fanciful”.  This is in the circumstances where no design was ever produced, and the Court would need to accept the evidence of the first plaintiff, Brett Enkelmann and Mr Hanlon.
107. [107]
     As to the credibility and reliability of the first plaintiff, Brett Enkelmann and Mr Hanlon as witnesses, the defendants submit that the Court should not accept their evidence.  In part this is also due to the late abandonment of the plaintiffs’ claim where the same witnesses were integral to the advancement of a case which is now conceded to be hopeless.
108. [108]
     The requirement of reasonable care and skill would apply to the building of the Temporary Levee and also in considering the impact on neighbours.  The case of Furness v Clarke^[46] is relied on for the proposition that a relevant consideration is foreseeable damage to neighbouring property.
109. [109]
     This proposition is also consistent with the comments of Windeyer J in Gartner v Kidman as follows:

“…in doing so he must not act recklessly of his neighbour so as to cause wanton damage to him”.^[47]

110. [110]
     The defendants submit that the plaintiffs had no regard to the interests of the defendants at all and further that the “advice” from Mr Hanlon and Mr Watts of FSA was very limited.
111. [111]
     The “advice” that was given, even if the evidence is accepted, is limited in its scope and nature and does not look at any hydrology issues, including modelling and any adverse impacts on both Mikandra and Riverview.
112. [112]
     To the extent that Mr Hanlon provided expert advice, if his evidence is accepted, it was limited generally and also by his area of expertise.  He is not a hydrologist.  Nor was Mr Watts.  From the evidence that there is, the consideration seems to be limited to the size and formation of the Temporary Levee to provide some, accepted as imperfect, protection of Riverview.
113. [113]
     In cross-examination, Mr Hanlon gave evidence that he had kept a note of what he saw on Mikandra and he no longer had it as he “accidentally burnt the … wrong set of files”.^[48]  This evidence goes to the credit of Mr Hanlon.  This evidence is implausible, and I generally do not accept the evidence of Mr Hanlon.
114. [114]
     Mr Watts was not called to give evidence by the plaintiffs, and the defendants submit that a Jones v Dunkel inference should be drawn.
115. [115]
     Further, there is evidence that the plaintiffs were told by Mr Watts that Local Government approval may be required.^[49]  The plaintiffs were thereby on notice that approval may be required.  The defendants submit this in turn informs whether the plaintiffs had a genuine and legitimate purpose for building the Temporary Levee, whether it was constructed with “reasonable care and skill”, and also whether it was no more than reasonably necessary to protect their use and enjoyment of Riverview.
116. [116]
     Ultimately, the defendants submit that the Court cannot be satisfied on the balance of probabilities that the Temporary Levee was constructed with reasonable care and skill, particularly where:

     1. The plaintiffs were concerned solely with their own position.
     2. No consideration was given to the impacts on Mikandra, or even the wider impacts on the use and enjoyment of Riverview (for example, the diminution in value).
     3. There was no detailed advice or design, including considerations of hydrology issues and impacts. 
     4. Reasonable care and skill go beyond merely the earthworks to build a wall.  It includes considerations of dimensions, structure and positioning so as not to cause “wanton” damage to neighbours and can only be to the extent reasonably necessary.^[50]
117. [117]
     The plaintiffs were conscious of the impact of structures on water flows which was the very complaint that they said they had about the alleged works on Mikandra. In circumstances where the plaintiffs were aware of the impact of structures on the floodplain, and in particular in the flow path, acting reasonably and with due care for their own interests and the interests of the defendants as their neighbours, a detailed design focused on hydrology issues would have been required prior to the construction of the Temporary Levee. At best, even if the evidence is accepted, the approach that was undertaken in the design and construction of the Temporary Levee was “rough and ready” and was not sufficient to meet the requirement of reasonable care and skill in the particular circumstances.
118. [118]
     On the plaintiff’s evidence, the steps taken in respect of the construction of the Temporary Levy follow alleged conversations in 2011 and 2013 between the first plaintiff, Brett Enkelmann, and the first defendant complaining about the alleged, but non-existent, work on Mikandra.  The affidavits of first plaintiff and Brett Enkelmann are consistent with the plaintiffs’ claim which has been conceded and found to be unproven.  In these circumstances, and given my earlier findings in respect of not accepting the evidence of the first plaintiff and Brett Enkelmann unless it is contrary to their interests, this element is not established on the balance of probabilities.
119. [119]
     Even if the evidence specifically in respect of the construction of the Temporary Levee was accepted and lesser weight given to it because of the concerns about reliability and recreation of evidence, the evidence is not sufficient to satisfy this element on the balance of probabilities.

Did the plaintiffs do no more than was reasonably necessary to protect their use and enjoyment of Riverview?

120. [120]
     The plaintiffs submit that “reasonably necessary” is to be understood in the context of nuisance where the interference is both substantial and unreasonable.  Further, the context is also the balancing of the competing rights of neighbouring landowners.
121. [121]
     This balancing exercise is reflected in the comments of McMurdo JA in State of Queensland v Michael Vincent Baker Superannuation Fund Pty Ltd as follows:

“In Hargrave v Goldman, Windeyer J said that, in essence, a nuisance could be defined as an “unlawful interference with a person’s use or enjoyment of land, or of some right over, or in connexon with it”.  Not every use of a person’s property which interferes with the use or enjoyment of other land is an unlawful interference.  In general, an unlawful interference is an unreasonable interference with the use or enjoyment of other land.  That criterion of reasonableness has been difficult to apply in some cases, but it is a necessary constraint on the operation of the tort which has been consistently recognised.”^[51]

122. [122]
     Further, McMurdo JA also referred to the statement of Windeyer J in Gartner v Kidman that:

“[t]he idea of reasonableness, that is basic to so much of the common law, is firmly embedded in the law of nuisance to-day.  Pronouncements concerning the scope of nuisance as a tort avoid stating rights and duties as absolute.  In respect of both what a man may do and what his neighbour must put up with, its criteria are related to the reasonable use of lands in question.  In some recent cases there is perhaps a more explicit recognition than there was in some earlier cases that a landowner’s duty to his neighbour qualifies his right to do what he likes with his own land and on his own land.”^[52] (emphasis added)

123. [123]
     There is an issue as to whether the plaintiffs were required to plead “reasonableness”.  While the Amended Defence and Counterclaim pleaded unreasonableness in respect of the counterclaim, the plaintiffs did not positively plead that the construction of the Temporary Levee was reasonable.  The plaintiffs contend it was open on the pleadings, and that evidence was lead and witnesses were cross-examined on it.
124. [124]
     In all of the circumstances of this case, I do not consider it necessary to determine whether “reasonableness” was required to have been specifically pleaded.  The purpose of the construction of the Temporary Levee was plainly in issue and was explored at trial, even if some of the focus was on unreasonableness for the purposes of the nuisance claim.
125. [125]
     The defendants contend that what is reasonable or unreasonable depends on the particular circumstances, consistent with the statement in Gartner v Kidman. 
126. [126]
     Here, the Temporary Levee harms both Riverview and Mikandra.^[53]  The plaintiffs’ pleaded claim specifically identified the harm to Riverview of the reduction in cropping area.  There was a claim for loss of profits as well as the costs of building and removing the Temporary Levee.  There is also evidence of physical damage to Riverview as a result of the impact of the Temporary Levee on water flow: for example around the ends of the Temporary Levee as described in Dr Markar’s reports and observations by the first defendant.^[54]
127. [127]
     The defendants submit that there is no evidence that the Temporary Levee’s height, length, and position is no more than reasonably necessary to protect Riverview.  No alternatives were modelled.  The only modelling that was done was the impact of the Temporary Levee.
128. [128]
     The construction of the Temporary Levee was in response to a perceived risk of floodwaters with increased velocities from Mikandra as a result of works that were never done.  The scale of the alleged works  on Mikandra was such that it is difficult to see how a reasonable person would think they had been done, when that was not reflected in what was actually occurring on the ground on Mikandra.
129. [129]
     Further, it is difficult to see how construction of the Temporary Levee could be no more than reasonably necessary when it is founded on an unreasonable belief or perception of what needed to be addressed or protected against.  What is reasonably necessary must be related to the reasonableness of what gives rise to the necessity itself. 
130. [130]
     Here, the plaintiffs in effect took action to construct the Temporary Levee causing their own farming business harm, and also physical harm to their own property, to deal with a perceived threat of increased water velocities caused by works claimed to have been done on Mikandra.  That is not rational given the water flow from Mikandra to Riverview had historically occurred and was not changed between flood events, other than each flood being unique.
131. [131]
     Further, the plaintiffs’ claim also included a claim for substantial diminution in value of Riverview as a result of the Temporary Levee.  At the time it was constructed, it is difficult to see how it was reasonable to protect the use and enjoyment of Riverview given this impact on the value of Riverview and the farming business.  If it was to protect Riverview, in particular the use and enjoyment of Riverview, by its very existence it did the opposite.
132. [132]
     Even if it was reasonable when first constructed, the continued maintenance of the Temporary Levee does not make logical or commercial sense. This is particularly so where it now has to be acknowledged that there was no threat or risk of floodwaters with increased velocities due to works on Mikandra.   There just remains the risk of flood events as there always has been in respect of properties on the floodplain.
133. [133]
     The defendants also point to the evidence of Brett Enkelmann in cross-examination in respect of the Temporary Levee that:

“... we want to pull it down as soon as we get some of those nuisance levees in Mikandra down.  It’s the whole reason we put it up.”^[55]

134. [134]
     While it was consistent with the plaintiffs’ claim which ran at trial, now it is in effect a statement against interest, and I accept this evidence of Brett Enkelmann to this extent.
135. [135]
     With the abandonment of the plaintiffs’ claim and the necessary acceptance that there were no “nuisance levees” on Mikandra, the rationale for the Temporary Levee since it was constructed in 2013 has no logical and reasoned basis.  The continuation of the Temporary Levee suffers a similar fate.
136. [136]
     There is no evidence for the Court to be satisfied on the balance of probabilities that the Temporary Levee was no more than was reasonably necessary to protect the plaintiffs’ use and enjoyment of Riverview. Accordingly, this element is not established.

Turn Back Defence

137. [137]
     If:

     1. contrary to the above finding, the water which flows over Mikandra and onto Riverview at the location of the Temporary Levee is surface water, whether natural or altered; or
     2. the Turn Back Defence applies in respect of a natural watercourse,

and the Turn Back Defence is available, I am not satisfied that the Turn Back Defence is established as the requisite elements discussed above have not be satisfied. 

138. [138]
     In particular, even if the plaintiffs did not have a purpose to injure the defendant or a malicious purpose, I am not satisfied on the balance of probabilities that the Temporary Levee was constructed with the necessary reasonable care and skill.  Nor am I satisfied on the balance of probabilities that the Temporary Levee was no more than was reasonably necessary to protect the plaintiffs’ reasonable use and enjoyment of Riverview.
139. [139]
     Accordingly, I find that even if the Turn Back Defence is available, on the evidence the plaintiffs have not established the defence.
140. [140]
     It is necessary to proceed to consider the claim by the defendants for nuisance.

Have the defendants established nuisance?

141. [141]
     In considering whether the defendants have established their claim in nuisance, it is necessary to consider several issues, namely:

     1. What are the elements necessary to establish nuisance?
     2. Have the defendants established that the Temporary Levee caused a substantial and unreasonable interference with the defendants’ use and enjoyment of Mikandra?
     3. Have the defendants established that the current Temporary Levee as modified by the 2023 Works caused a substantial and unreasonable interference with the defendants’ use and enjoyment of Mikandra?
142. [142]
     I will deal with each of these considerations in turn.

What are the elements necessary to establish nuisance?

143. [143]
     Nuisance is a liability in tort which may arise in respect of a wrongful interference with another person’s use and enjoyment of land.  A person’s use and enjoyment of land may extend to use for purposes such as agriculture or commerce, and also the pleasure and enjoyment derived from occupancy of the land.
144. [144]
     Interference includes a variety of possible things.  For example, interference may be physical damage to land and buildings, the disturbance of the comfort, health or convenience of the occupant of land, or even an “affront” to reasonable neighbours as the result of a use in a certain area.  However, not every interference gives rise to an action in nuisance.
145. [145]
     To establish nuisance, the interference must be:

     1. substantial; and
     2. unreasonable.
146. [146]
     Nuisance actions often arise between owners of neighbouring land and it is recognised that:

“[t]he paramount problem in the law of nuisance is therefore to strike a tolerable balance between conflicting claims of neighbours, each involving the privilege to exploit the resources and enjoy the amenities of his property without undue subordination to the reciprocal interest of the other.”^[56]

147. [147]
     This is exactly the scenario that arises in the current case.
148. [148]
     Whether there is substantial interference requires consideration of the gravity of the harm, which in turn requires consideration of issues such as the character and duration of the harm. The type or kind of injury gives rise to considerations of whether there is actual damage to property or other discomfort or inconvenience. Consideration of duration is also relevant, including whether temporary or occasional, and whether recurring or continuing. 
149. [149]
     Where there is physical damage to property, it is logically easier to show a substantial interference.  However, that does not mean that physical damage is always required.
150. [150]
     Whether there is a substantial interference is decided on an objective basis, viewed by the “normal person” in the particular location.^[57]
151. [151]
     The plaintiffs in their submissions refer to a number of cases considering what is required to constitute substantial interference.  The authorities use terms such as “real”, “material” and “significant”.  In Fearn v Board of Trustees of the Tate Gallery Lord Leggatt recognised that these terms indicate that:

“… the interference with the use of the claimant’s land must exceed a minimum level of seriousness to justify the law’s intervention”.^[58]

152. [152]
     The authorities of Warne v Nolan and Gales Holdings Pty Ltd v Tweed Shire Council previously considered in these reasons also provide some assistance on this issue.
153. [153]
     Muir J in Warne v Nolan observed that the issue of whether there is substantial or material interference is to be determined “… according to what are reasonable standards for the enjoyment of the premises concerned”.^[59]
154. [154]
     Similarly in Gales Holdings Pty Ltd v Tweed Shire Council, Emmett JA stated:

“Regard must be had to the character of the locality in which the inconvenience is created and the standard of comfort that those in the locality may reasonably expect. The reasonable use of land may occasionally cause annoyance about which neighbours cannot reasonably complain … In considering whether an inconvenience is unreasonable, allowance must be made for reasonable give and take…”.^[60]

155. [155]
     Relevantly, it is also recognised that in the context of nuisance:

“‘Reasonableness’ .. is a two-sided affair.  It is viewed not only from the standpoint of the defendant’s convenience, but must also take into account the interest of the surrounding occupiers.  It is not enough to ask: is the defendant using his property in what would be a reasonable manner if he had no neighbour? The question is, is he using it reasonably, having regard to the fact that he has a neighbour?”^[61]

156. [156]
     The balancing exercise was described in Southern Properties (WA) Pty Ltd v Executive Director, Department of Conservation and Land Management by McLure P as follows:

“… To constitute a nuisance, the interference must be unreasonable.  In making that judgment, regard is had to a variety of factors, including: the nature and extent of the harm or interference; the social or public interest value in the defendant’s activity; the hypersensitivity (if any) of the user or use of the claimant’s land; the nature of established uses in the locality (eg residential, industrial, rural); whether all reasonable precautions were taken to minimise any interference; and the type of damage suffered.

This exercise involves weighing the respective rights of the parties in the use of their land to make a value judgment as to whether the interference is unreasonable.  Although the “fault” of the defendant may be a relevant consideration in an assessment of whether the interference with the claimant’s enjoyment of land is unreasonable, the duty not to expose one’s neighbour to nuisance is not necessarily discharged by the exercise of reasonable care.  Liability in nuisance is strict.  Once a prima facie case has been established, it is for the defendant to prove its defence”.^[62]

157. [157]
     Actual physical damage is not required in all cases.  Recently, in Jalla v Shell International Co Ltd, Lord Burrows concluded that:

“[t]his requirement is satisfied for private nuisance by establishing the undue interference with the use and enjoyment of the land.  That includes physical damage to the land itself and damage to buildings or vegetation growing on the land.  But commonly there will be an undue interference with the use and enjoyment of land – as by impact of noise or smell or smoke or vibrations or, as in Fearn, being overlooked – even though there is no physical damage to the land or buildings or vegetation”.^[63]

158. [158]
     As is evident from the authorities considered previously in these reasons, there have been numerous cases dealing with claims in nuisance based on the discharge of water from one property to another.  These are particularly relevant to the considerations in the current case.
159. [159]
     In Gartner v Kidman, Windeyer J, before finding that the “defence” applied in the particular circumstances, stated the general principle as follows:

“The lower proprietor: he may recover damages from, or in appropriate cases obtain an injunction against, the proprietor of the higher land who is, for any of the reasons given above, liable to an action because he has concentrated or altered the natural flow”.^[64]

160. [160]
     Relevantly, Windeyer J states earlier that:

“[The higher proprietor] is not liable merely because surface water flows naturally from his land on to the lower land.

He may be liable if such water is caused to flow in a more concentrated form than it naturally would.

It flows in a more concentrated form than it naturally would if, by the discernible work of man, the levels or conformations of land have been altered, and as a result the flow of surface water is increased at any particular point”.^[65]

161. [161]
     In the current case, the plaintiffs are in the position of the “proprietor of the higher land” (as a result of the construction of and nature of the Temporary Levee) and the defendants are in the position of the “lower proprietor”.
162. [162]
     The facts in Warne v Nolan^[66] are similar to the current case in that the Court had to consider a claim in nuisance in respect of a levee bank on one property that allegedly resulted in water flowing and causing damage on a neighbouring property.  Similar to here, many of the claims were abandoned during the trial, with only a claim for injunctive relief in relation to the levee bank to be determined.  The levee bank had been altered at various times since construction and was located on a floodplain.  The evidence at trial included expert evidence on hydrology issues, including the impact on water flows.
163. [163]
     Muir J made findings in respect of the expert evidence, including accepting the view of one expert that the impact of the relevant property caused by the levee bank’s “interaction with flood waters [was] limited in nature”.^[67]
164. [164]
     Muir J noted:

“Liability may arise out of the continuation or adoption of a nuisance where a person fails to remedy the nuisance without undue delay after having become aware of it.^[68] Liability is not limited to the mere creation of a nuisance and extends to leaving a nuisance on the land.^[69]”^[70]

165. [165]
     Ultimately, it was found that even though the levee bank was not a nuisance when constructed, that did not prevent it from becoming one as a result of other causes and changes in conditions.^[71] That case, unlike here, also raised consideration of the defences of consent and assumption of risk. 
166. [166]
     In the factual circumstances of that case, Muir J stated:

“In a rural community, particularly on a flood plain, the normal operation and management of a farm has the potential to adversely affect a neighbour’s enjoyment of his or her property. In accordance with the principles of law discussed earlier, the fact that something on or done on one property has an effect on an adjoining property does not necessarily give rise to a cause of action.

Putting it broadly, any interference with the Nolans’ enjoyment of Corella resulting from the levee bank in its degraded state is within the range of those matters which in a rural community one neighbour ought be expected to tolerate from another. I am, of course, referring to the impact of the degraded levee bank at times after the Nolans gave notice that its presence was unacceptable to them and after Mrs Warne had had a reasonable time within which to consider the complaint and take action if necessary”.^[72]

167. [167]
     Ultimately Muir J found that the evidence did not establish any “adverse affectation or the likelihood of future adverse affectation”.^[73]
168. [168]
     Whilst it is relevant to consider that both Mikandra and Riverview are farming properties located on a floodplain, it is necessary to consider the relevant admissible evidence and to undertake the exercise required in respect of the elements of nuisance.

Have the defendants established that the Temporary Levee caused a substantial and unreasonable interference with the defendants’ use and enjoyment of Mikandra?

169. [169]
     The plaintiffs contend that the defendants fail to establish unreasonableness and substantial interference.
170. [170]
     In respect of unreasonableness, the plaintiffs rely on the evidence of the first plaintiff, Brett Enkelmann, and Mr Hanlon in respect of the construction of the Temporary Levee and its purpose. This has been considered at [103] and following above.
171. [171]
     In respect of the argument that substantial interference with the use and enjoyment of Mikandra is not established, the plaintiffs contend that it is not enough that the Temporary Levee has caused and will cause water to be blocked and pool on Mikandra, depositing silt and debris and causing damage to the crops in parts of Blocks 1 and 2 on Mikandra.  The plaintiffs submit that as Mikandra is a commercial farm, it would need to be shown that the Temporary Levee substantially interferes with the defendants’ capacity to use the land in that way.
172. [172]
     In respect of the defendants’ evidence, the plaintiffs’ position is that:

     1. The evidence of the first defendant does not establish a substantial interference with Mikandra.
     2. The evidence of Dr Markar:
        1. taken at its highest, does no more than establish that the Temporary Levee caused increases in both velocities and peak flood levels; and
        2. is subject to question in respect of its precision on those issues.
173. [173]
     The defendants submit that the evidence establishes a substantial interference with the defendants’ use and enjoyment of Mikandra.  In general terms:

     1. The Temporary Levee does block waterflow.
     2. There is no purpose for the Temporary Levee to be there other than to block water, particularly where the arable land on Riverview is reduced as a result of the Temporary Levee.
     3. The expert evidence in the Third Markar Report [DEF.014.001.0004] shows that the Temporary Levee causes water to back up onto Mikandra and damage crops.^[74]
     4. The Temporary Levee creates increases in velocity along the southern side of the Temporary Levee.
     5. The Temporary Levee is perpendicular to and directly in the path of Barambah Creek water flows which pass through the Lagoon and gully onto Riverview.
     6. The Temporary Levee has the effect of blocking water unless and until it is overtopped.
174. [174]
     It is necessary to consider the evidence relied upon by the defendants in respect of these contentions.
175. [175]
     As discussed earlier in these reasons, the plaintiffs do not rely on the evidence led in respect of the claim.  Nor do they submit for the evidence of Mr Giles to be accepted on the counterclaim.  Rather, the plaintiffs put the defendants to proof of the nuisance claim.
176. [176]
     Consistent with the findings earlier in these reasons, I accept the evidence of:

     1. Dr Markar.  He was an objective, careful and considered expert who gave his opinions in a measured and persuasive manner.  He was able to explain his methodology and approach.  The fact that there were various iterations and refinements of his modelling is not something that impacts on his credibility.  If anything, this strengthens his credibility as he was open to making adjustments as the issues unfolded and developed, but also was able to provide an explanation for doing so.
     2. Professor Bennett. 
177. [177]
     I also accept the evidence of the defendants in respect of the impact of the Temporary Levee, and in particular the first defendant as to his observations of the impact of the Temporary Levee at the times of the relevant flood events.
178. [178]
     While I have found that the expert reports of Mr Giles are not admissible as the underlying facts have not been established, I do note that there is some corroboration of Dr Markar’s opinion in Mr Giles’ Third Report [PLF.149.001.0001] where Mr Giles reports that the Temporary Levee creates increased velocity along the southern side of the Temporary Levee.  While this is not evidence, it does suggest that even on the plaintiffs’ own case prior to the abandonment there was some support for the defendants’ position.
179. [179]
     The evidence in respect of the counterclaim in effect builds on the evidence that was led in respect of the plaintiffs’ claim.  That is the reason why it adopts the earlier modelling approaches and is also addressed in later reports of Dr Markar.  While the plaintiffs have abandoned their case, it remains necessary to consider how the evidence evolved over time as that has an effect on the way that some of the evidence was ultimately presented on this issue.
180. [180]
     Further, the expert evidence in respect of the counterclaim does to some extent build on the analysis that was done in response to the allegations in the claim.  An example of this is the analysis of water velocities and the effect on erosion.  Initially this was undertaken in respect of the claim, and then later in respect of the counterclaim.  To some extent the analysis in respect of the counterclaim needs to be considered in the context of the earlier analysis.  This is the unfortunate result of the way that the case was run, and also the late abandonment of the plaintiffs’ claim after many weeks of trial and when only a small amount of evidence on the counterclaim was outstanding.
181. [181]
     The defendants also submit that the plaintiffs are now in effect making submissions to the opposite effect of the case that was maintained for years.  Now the plaintiffs are submitting that the modelling does not establish a substantial interference as a result of the extent of changes in waterflow and that there is a lack of certainty about the erosion velocity threshold.  This is despite the plaintiffs for years maintaining a case relying on much lesser changes in waterflow to support their claim.
182. [182]
     The defendants are critical of the submissions of the plaintiffs in this regard, particularly that:

“[79] It is incredible for the [plaintiffs] to submit,^[75] as they do, that the changes which Dr Markar models in his Third Report [DEF.014.001.0004]^[76] over a broad area which includes farmed land do not constitute a nuisance when the [plaintiffs] maintained until the very last moment that an increase in water flows at RP1 (and only that point of non-farmed land on the border of Riverview) of very small amounts, and on parts of Riverview as low as 0.05m/s,^[77] constituted a nuisance which entitled them to injunctive relief and damages.

[80] Equally, it is rich for the [plaintiffs] to submit, as they do … that the erosion threshold velocity could fall within a broad range, such that it can be of no assistance to the [defendants] in their Counterclaim.  That is the precise opposite of the case which the [plaintiffs] propounded for several years, which relied entirely on a specific erosion threshold velocity being accepted at all locations and in all food events over 23 years”.^[78]

183. [183]
     Further, to the extent that the plaintiffs now submit that the Temporary Levee did not cause substantial interference to the use and enjoyment of Mikandra because it would have flooded and suffered significant damage in any event, the defendants contend that this is completely at odds with the way that the claim and counterclaim have been framed for years.  Both the claim and counterclaim proceeded on the proposition that there was an increase in the damage over and above what would have been caused by the natural operation of the floodplain.
184. [184]
     If the counterclaim had just been litigated on its own, then some of the evidence on this point may have been addressed differently.  However, as the counterclaim was effectively deployed defensively to the plaintiffs’ claim, which included a claim in respect of the Temporary Levee, the consequence is that some of these issues may not have been “unpacked” to deal with the counterclaim alone.
185. [185]
     Equally, that does not mean that the plaintiffs’ assertions in this regard are reflective of the evidence that is available in respect of this issue.
186. [186]
     Turning to look at the evidence in respect of the effect of the Temporary Levee on Mikandra.  At the outset, it is necessary to note that the plaintiffs’ written submissions in reply dated 3 September 2024 [PLF.009.003.0024] do not reflect all of the evidence relied upon by the defendants.
187. [187]
     The defendants submit that the evidence establishes that the effect of the Temporary Levee is to redirect water across Mikandra and “pen up” the water in Mikandra which is likely to cause substantial harm to a sufficient extent to found a claim in nuisance.
188. [188]
     In respect of the evidence of the first defendant:

     1. The First Affidavit of the first defendant [DEF.014.001.0013] deals with the March 2017 rain event (which is relevantly after the construction of the Temporary Levee) at [402] to [404].  In summary, this evidence establishes that the water was banking up from the Temporary Levee onto Mikandra and there was damage to Blocks 1 and 2 on Mikandra in the nature of siltation on cotton and siltation in drains.
     2. The First Affidavit of the first defendant [DEF.014.001.0013] deals with the First and Second November 2021 flood events at [408] to [409].  In summary, this evidence establishes that the water was banking up from the Temporary Levee onto Mikandra during those flood events.  The first defendant’s evidence at [408(c)] relevantly is that:

“… once the water passed through the Lagoon it met with the Temporary Levee on Riverview.  The Temporary Levee prevented the water from travelling in the normal flow path and instead water began back filling and pooling on Block 1 and Block 2 on Mikandra”.

3. The series of photographs exhibited to the First Affidavit show the progression of the flood events.  These include:
   1. Still photographs showing water backed up into the cotton cropping rows on Mikandra, with the Temporary Levee located between Mikandra and Riverview: [DEF.010.001.1198], [DEF.010.001.1202] and [DEF.010.001.1219].
   2. Drone photographs taken later on the same day showing water backed up on Mikandra: [DEF.010.001.1244] and [DEF.010.001.1246].  The defendants submit that these photographs also show that the water level in the Below Ground Waterway is at the same level as the water level on Mikandra.  It is submitted that this is understandable as the Temporary Levee constrains the Below Ground Waterway.
   3. Images from the opposing angle showing the same effect: [DEF.010.001.1215] and [DEF.010.001.1253].
   4. Further images from an angle more directly above the backed up water on Mikandra: [DEF.010.001.1282] and [DEF.010.001.1134].
4. The photographs are consistent with the evidence of the first defendant.
5. The First Affidavit of the first defendant [DEF.014.001.0013] deals with the January 2022 flood event at [410] to [418].  The first defendant’s evidence [412(c)] relevantly is that:

“… once the water passed through the Lagoon it met with the Temporary Levee on Riverview. The Temporary Levee initially prevented the water from travelling in the normal flow path and instead the water began back filling and pooling on Block 1 and Block 2 on Mikandra; however, the Temporary Levee then failed and overtopped”.

6. The series of photographs exhibited to the First Affidavit show the progression of the flood event.  These include:
   1. A photograph from a drone which shows a significant volume of water present at or around the time that the Temporary Levee was overtopped: [DEF.010.001.0672].  The first defendant’s evidence is that the water shown in this photograph backed up behind the Temporary Levee about 250 metres into Block 2 and 200 metres into Block 1 on Mikandra.  The first defendant estimated the distances based on him stepping out the distances after the water had receded. 
   2. The defendants submit that this photograph also shows the direction of the flow – in effect in a straight line – from Barambah Creek, through the Lagoon, over Riverview and beyond.  That is, once the water level had reached the top of the Temporary Levee and overflowed the Temporary Levee, the water returned to the natural flow path.  Up until that point, the water had been redirected back onto and pooled on Mikandra.
   3. Photographs taken on 9 January 2022 showing the water overtopping the Temporary Levee and the water flows during the progression of the flood event:  [DEF.006.001.0165], [DEF.006.001.0167], [DEF.006.001.0165], [DEF.010.001.0064], [DEF.010.001.0646], [DEF.010.001.0649], [DEF.010.001.0650], [DEF.010.001.0652], [DEF.010.001.0654], [DEF.010.001.0662], [DEF.010.001.0677], [DEF.010.001.0680], [DEF.010.001.0683], [DEF.010.001.0786], [DEF.010.001.0692], [[DEF.010.001.0693], [DEF.010.001.0700], [DEF.010.001.0725], [DEF.010.001.0731], [DEF.010.001.0777] and [DEF.010.001.0753]. 
   4. Photographs taken on 14 January 2022, which show the damage on Mikandra, including the absence of foliage on crops on Mikandra which were destroyed by water backed up onto Mikandra: [DEF.010.001.0515], [DEF.010.001.0518] and [DEF.010.001.0521] by way of example. 
7. The photographs are consistent with the evidence of the first defendant, including the further evidence by the first defendant as to what can be seen in the photographs.
8. In cross-examination in respect of the photograph taken on 14 January 2022 [DEF.010.001.0555], the first defendant explained that in the photographs the backed-up water was not visible at all points under the crop and he gave evidence of the area where the silt was dropped.  Further in re-examination, the first defendant explained how he estimated the extent of the backing up of the water by walking the affected area.^[79]
9. Paragraph [413] of the First Affidavit of the first defendant [DEF.014.001.0013] identifies the damage suffered in the January 2022 flood event including: 
   1. loss of topsoil;
   2. erosion on the eastern boundary of Block 1 and the western boundary of Block 2;
   3. “the tail drains on Block 1 and Block 2 were eroded and silted up”;
   4. “the water backed up into the cotton and we lost 24 hectares of cotton on Block 2 and 10 hectares of cotton on Block 1 which went under water”;
   5. “the remaining cotton was silted up to approximately ¾ of the way up the plant the ground (sic) which caused siltation of the cotton and the bolls to be unpickable”;
   6. some reduction in the quality of the cotton; and
   7. deposits of rubbish in Block 2 which flattened the cotton in that area.
10. The First Affidavit of the first defendant [DEF.014.001.0013] deals with the February 2022 flood event at [421].  The evidence of the first defendant is that Mikandra suffered damage due to the February 2022 flood event, including:
    1. loss of topsoil;
    2. erosion on the eastern boundary of Block 1 and the western boundary of Block 2;
    3. “the tail drains on Block 1 and Block 2 were eroded and silted up”;
    4. “the water backed up into the cotton and we lost 24 hectares of cotton on Block 2 and 10 hectares of cotton on Block 1 which went under water”; and
    5. “the remaining cotton was silted up to …approximately 15 nodes from the ground in Block 2 and up to approximately 12 nodes from the ground which caused us to lose those cotton bulbs due to boll rot”.
11. The damage suffered in the February 2022 flood event was similar to the damage suffered in the January 2022 flood event.

189. [189]
     In respect of the expert evidence:

     1. Dr Markar’s opinion is that the modelling shows that the effect of the Temporary Levee on Mikandra is significant.
     2. I accept the evidence of Dr Markar in each of the First Markar Report [DEF.012.001.1502], the Second Markar Report [DEF.012.001.1503], the Third Markar Report [DEF.014.001.0004], the Fourth Markar Report [DEF.020.001.0022] and the Fifth Markar Report [DEF.998.001.0001].  As explained above, it is necessary to have regard to all of the reports to understand the development of the modelling and also the evolution of the issues being addressed.  In respect of the various reports and modelling, the “post-works” conditions reflect the “on the ground” actual conditions of Mikandra.^[80]
     3. In respect of the Third Markar Report:
        1. At [215], Dr Markar expresses his opinion that:

“The Riverview flood mitigation embankment has significantly altered predicted peak water levels and velocities on both Mikandra and Riverview and has caused significant adverse flood impacts on Mikandra:

• The predicted peak velocities on Mikandra Block 2 are increased where flows are concentrated and diverted to the northwest corner of the block by the embankment;
• The predicted peak flood levels on Mikandra Blocks 1 and 2 are increased by up to 0.3 m due to the Riverview flood mitigation embankment (See Appendix B, Figure B-69).”
  2. At [215], Dr Markar states his further opinion in respect of the February 2022 flood event that:

“… the predicted adverse impacts on Riverview at its southwest corner … are in fact due to the Riverview flood mitigation embankment”.^[81]

This shows that the Temporary Levee has an adverse impact on Riverview as well as Mikandra.

3. Dr Markar calculated the “change in peak velocities” on Mikandra to analyse the effect of the Temporary Levee.  This analysis is shown in several Figures in the Third Markar Report, including:
   1. Figure 6-3: Predicted change in peak velocities and flood levels under post-works conditions, with and without the Riverview flood mitigation embankment, December 2010 flood event.
   2. Figure 6-6: Predicted change in peak velocities and flood levels under post-works conditions, with and without the Riverview flood mitigation embankment, January 2011 flood event.
   3. Figure 6-9: Predicted change in peak velocities and flood levels under post-works conditions, with and without the Riverview flood mitigation embankment, January 2013 flood event.
   4. Figure 6-12: Predicted change in peak velocities and flood levels under post-works conditions, with and without the Riverview flood mitigation embankment, February 2013 flood event.
   5. Figure 6-15: Predicted change in peak velocities under post-works conditions, with and without the Riverview flood mitigation embankment, January 2022 flood event.
   6. Figure 6-19: Predicted change in peak velocities under post-works conditions, with and without the Riverview flood mitigation embankment, February 2022 flood event.
4. In respect of the impacts of the Temporary Levee, Dr Markar states:

“[223] For the six historical flood events investigated in this report, Mikandra Works had no material adverse flood velocity, discharge or level impacts on Riverview in the absence of the Riverview flood mitigation embankment.  However, unlike the Mikandra works, the Riverview flood mitigation embankment has an adverse impact on predicted flood levels and velocities on Mikandra.

[224] The 2022a LiDAR data shows that since the February 2022 event, the Riverview flood mitigation embankment has been further raised, by up to about 1 meter in places.  In my opinion, these additional works will result in further adverse flood impacts on Mikandra beyond what are shown in the updated Markar modelling results.”

5. Further:

“[300] The previous Markar Reports found that for the above four historical flood events, Mikandra Works would have no adverse flood discharge or level impacts on Riverview in the absence of the Riverview flood mitigation embankment.  However, the flood mitigation embankment on Riverview would have a material impact on peak flood levels in the northern portion of Mikandra due to the flow obstruction caused by the Riverview flood mitigation embankment for moderate flood events similar to December 2010 and February 2013.  This impact would diminish for large flood events similar to the January 2011 and January 2013 events when the Riverview flood mitigation embankment is overtopped.

[301] The previous Markar Reports also found that the flood mitigation levee constructed in Riverview would cause adverse flooding impacts on Mikandra during future moderate flood events similar to the December 2010 and February 2013 events.  During future large flood events similar to the January 2011 and January 2013 events, these adverse impacts would diminish with increasing flood discharges when the Riverview flood mitigation levee is overtopped.”

6. In addition, Dr Markar updated the hydraulic modelling taking into account additional information and concluded to a similar effect as outlined above:

“[310] The updated Markar model shows that, for the six historical flood events investigated in this report, Mikandra Works had no material impacts on flood velocity, discharge or level on Riverview in the absence of the Riverview flood mitigation embankment.  However, unlike the Mikandra works, the Riverview flood mitigation embankment has an adverse impact on predicted flood levels and velocities in Mikandra.

[311] The 2022a LiDAR data shows that since the February 2022 event, the Riverview flood mitigation embankment has been further raised, by up to about 1 meter in places.  In my opinion, these additional works will result in further adverse flood impacts on Mikandra beyond what are shown in the updated Markar modelling results.”

7. Dr Markar also expressly models the change in peak velocity caused by the Temporary Levee, the result of which can be seen in the Figures in the Third Report, including:
   1. Figure B-36: Predicted change in peak velocities and flood levels under post-works conditions, with and without Riverview flood mitigation embankment, December 2010 event.
   2. Figure B-43: Predicted change in peak velocities and flood levels, post-works conditions, with and without Riverview flood mitigation embankment, January 2011 event.
   3. Figure B-50: Predicted change in peak velocities and flood levels, post-works conditions, with and without Riverview flood mitigation embankment, January 2013 event.
   4. Figure B-57: Predicted change in peak velocities and flood levels, post-works conditions, with and without Riverview flood mitigation embankment, February 2013 event.
   5. Figure B-63: Predicted change in peak velocities, post-works conditions, with and without Riverview flood mitigation embankment, January 2022 event.
   6. Figure B-64: Predicted change in peak flood levels, post-works conditions, with and without Riverview flood mitigation embankment, January 2022 event.
   7. Figure B-70: Predicted change in peak velocities, post-works conditions, with and without Riverview flood mitigation embankment, February 2022 event.
   8. Figure B-71: Predicted change in peak flood levels, post-works conditions, with and without Riverview flood mitigation embankment, February 2022 event.
8. In respect of the impacts of the Temporary Levee, Dr Markar concludes:

“[596] The model results show that, unlike the Mikandra Works, the Riverview flood mitigation embankment has a significant impact on predicted flood levels and velocities on both Mikandra and Riverview.

[597] Consistent with the findings of the original Markar modelling, model results show that the Riverview flood mitigation embankment has significant adverse impacts on flooding at Mikandra Blocks.

[598] The 2022a LiDAR data shows that since the February 2022 event, the Riverview flood mitigation embankment has been further raised, by up to about 1 meter in places.  In my opinion, these additional works will result in further adverse impacts to flooding on Mikandra beyond what the updated Markar modelling results show.”

4. Dr Markar also gave oral evidence consistent with the opinions expressed in his reports, including in cross-examination as follows:
   1. “ … is it correct to say that you can think of the levee having an effect in terms of backing up water whist the water level remains below the top surface of the levee, but once the water gets above the top surface of the levee, you will have the same amount of water backing up into Mikandra whether or not the levee is there? Correct. Yes.

Is that correct?  Yeah.  It’s not only the backing up of water.  It is also the redistribution, re – redirecting of water away from the western part of - sorry, eastern part of Riverview and into the western part of Riverview through where the gully is.  So there are two impacts:  one is the levee would back up and slow down and redirect water the other way, and … once it’s overwhelmed, that impact dissipates.”^[82]

2. As to the effect of blocking and redirecting water:

“So that’s heading west over into – … towards the western boundary of Riverview; is that right? ‑‑Yeah. ….

And – all right. I understand that?-‑‑So you’re basically blocking it here and forcing it to go – – – All right. But if you were to continue that path, am I correct to say that it will continue over towards the west into that next property above the other part of Mikandra; is that right? …As I understand it – correct me if I’m wrong – you’re saying that apart from the effect that the temporary bank has in pushing the water back, it also has an effect in redirecting the water; correct?‑‑‑Yeah. …  And you’re representing, with the yellow line, where the water is  redirected –Yep. – – – by the temporary bank; correct?‑‑‑That – that is, very roughly. After that, once it gets here, it will find its own way depending on the lay of the land.

All right?‑‑‑So … some of it will go that way, that way, sort of. And once it’s – comes here, they will also join and go in the same – same direction, so north-west, one body of water. Understood.

HER HONOUR: So can I ask you: so the yellow line, you’re saying it pushes it to the west?‑‑‑Yeah. But once it overtops the levee it might go towards that more central line that you’ve got on the – it will go … wherever depending … on the lay of the land. Yeah.”^[83]

3. As to the adverse impacts on Mikandra:

“Now, sir, it’s correct to say, then, that on this modelling, you also showed that the Riverview levee would not cause a significant adverse impact on Mikandra during a large future flood event, similar to the January 2013 event. Can I ask you this, when you talk about impacts, what do you mean?‑‑‑I have spoken about the imp – in here, the impact on peak water level – peak flood level. And then also the peak velocities. …

Now, you say they are based on the hydraulic model results for the February 2013 flood event, …. The adverse impacts that you identify there are, first of all, peak flood levels and extents; correct?‑‑‑Correct.

And by extent, you mean the area under flood water; is that right?‑‑‑No. The extent – I mean there is the area where it’s been im – extent of the area impacted. In other words, if the flood level was at X, it’s gone to Y. It’s a difference between with and without the mitigation – – –

Yeah? … So you’re saying that’s a larger area which has been impacted. Where – the area which has a higher flood level – higher peak flood level due to the mitigation levee.

Let me just see if I can understand that. Is it correct to say that when you talk about the peak increasing, the extent also increases because as the water level rises, it extends – the water covers a greater area in the field; is that – – –?‑‑‑Correct.”^[84]

190. [190]
     The evidence of Professor Bennett is also relevant and I accept the evidence of Professor Bennett in his report and also his oral evidence. Relevantly:

     1. Professor Bennett in cross-examination gave evidence that in his opinion the Temporary Levee altered the flow of water and blocked the natural water course:

“And your view, as I understand it, in your report, is that you can’t find any structures on Mikandra or Riverview that really alter the flow of water very much at all; correct?‑‑‑There’s structures on Riverview that certainly alter the flow of water.

By that, you mean the protection bank? …

By that – I should be more careful. We use a lot of different labels for the same thing in this case. ... Just looking at that map, you’re referring to – you can see the southwest corner of the red property, block 9? You see that?‑‑‑Yes.

And is that the locality where you’re talking about a structure on Riverview?‑‑‑Insofar as a structure, I mean that’s one of the structures that  unsuccessfully attempts to – – – All right?‑‑‑ – – – you now, move – protect the land from water. But, no. I’m more specifically referring to the diversion of the channel around 1993.

…. And you said a moment ago that there aren’t any structures on Riverview that alter the water course at all. Is that your opinion? Sorry, in Mikandra, I mean?‑‑‑My opinion is that the flow-line through which the water moves is natural. That’s my opinion.”^[85]

2. Further, Professor Bennett gave evidence in respect of the potential for erosion given the nature of the soils and that they may “detach” at low velocities.^[86]

3. Professor Bennett annotated a map showing the watercourse in the February 2022 flood event which shows the Temporary Levee in the flow path of the water [EXH.002.001.0001].

191. [191]
     Ms Perrett also prepared an expert report on soil erosion [DEF.014.001.0002].  This report is relevant as it identifies the range of erosion threshold velocities applicable to the soils in the area.  I accept the evidence of Ms Perrett.
192. [192]
     The water velocities modelled by Dr Markar in relation to the effect of the Temporary Levee on Mikandra are within the range of velocities identified by Ms Perrett. Considered together, the expert evidence of Dr Markar and Ms Perrett is consistent.
193. [193]
     A review of all of this evidence also leads to the conclusion that the evidence of the first defendant and Dr Markar is largely consistent.  That is, the observations of the first defendant of the effect of the Temporary Levee and the photographs in evidence are consistent with Dr Markar’s modelling and opinion as to the effect of the Temporary Levee on Mikandra.
194. [194]
     This consistency of evidence heightens the level of satisfaction that is reached in respect of whether it is more probable than not that there is a substantial interference with the use and enjoyment of Mikandra.
195. [195]
     The plaintiffs make a number of criticisms of the evidence relied upon by the defendants.  However, the majority of those criticisms do not withstand my acceptance of that evidence and also a proper consideration of that evidence.
196. [196]
     The plaintiffs do suggest that all floods are different and that there is a prospect that Mikandra may suffer similar damage even without the Temporary Levee.  That submission misses the point that, on the evidence, the ongoing existence of the Temporary Levee presents an ongoing, real future risk to the use and enjoyment of Mikandra.  The observations and modelling support the conclusion that the Temporary Levee has had a substantial impact in a number of different flood events in the past.  This risk of an expanded and increased impact remains as a future risk to Mikandra across a range of potential flood scenarios.
197. [197]
     Further, the plaintiffs’ submissions accept that the hydrologists^[87] agree that the Temporary Levee has altered the flood behaviour and that it has had an adverse impact on the flood levels and velocities through part of Mikandra.^[88]  From this it appears that the main issue for the plaintiffs is whether the interference is substantial.
198. [198]
     It is not an answer to look at the percentage of Mikandra affected, nor to look at the dollar value impact on the overall farming business operated on Mikandra.  As is evident from past flood events, the interference is real, identifiable and repeated.  It is not negligible.  It impacts the use of Mikandra more than mere inconvenience.
199. [199]
     The Temporary Levee is perpendicular to the floodplain and, on the evidence, operates to impact the speed and direction of water flowing from Mikandra to Riverview, which results in adverse impacts to Mikandra (and Riverview).  On the evidence, the Temporary Levee results in a real future risk to the use and enjoyment of Mikandra.
200. [200]
     Considering the evidence of the lay and expert witnesses who gave evidence for the defendants, and in particular the evidence identified above, I am satisfied on the balance of probabilities that the Temporary Levee causes substantial interference with the use and enjoyment of Mikandra.
201. [201]
     It is also necessary to consider whether the interference is unreasonable.  Many of the factors considered in respect of “reasonableness” in respect of the Turn Back Defence considered above are equally relevant to the consideration of whether the interference is unreasonable.
202. [202]
     The Temporary Levee was built before the proceedings were commenced.  However, it is clear from the evidence of the first plaintiff and Brett Enkelmann that the concerns reflected in the claim commenced in 2016 existed, at least to some extent, in 2013 when the Temporary Levee was first constructed.
203. [203]
     Again, the plaintiffs’ case for years was that the Temporary Levee was only necessary because of the alleged works on Mikandra, and it caused loss and damage to the plaintiffs as reflected in the claims for the costs of building and removing the Temporary Levee and the diminution in value of Riverview.
204. [204]
     On the plaintiffs’ own evidence, some impacts on Mikandra from the Temporary Levee were known and the Temporary Levee was only to remain until the alleged levees on Mikandra were removed.^[89] 
205. [205]
     The claim in respect of those alleged levees has been wholly abandoned and there is no credible evidence that those levees ever existed.  At best, the plaintiffs had a belief or perception that Mikandra was causing a problem on Riverview which resulted in the Temporary Levee being built.  But no reasonable basis for the plaintiffs’ view is established.
206. [206]
     Even if the initial construction of the Temporary Levee could be found to be reasonable, the continued maintenance of the Temporary Levee after the abandonment of the plaintiffs’ case cannot be justified on any rational basis.
207. [207]
     The design of the Temporary Levee was quite rudimentary and did not consider the hydrological impacts on Mikandra or Riverview.  The expert evidence shows that the Temporary Levee has an adverse impact on Riverview itself, in addition to the matters the plaintiffs originally pleaded.
208. [208]
     More broadly, the plaintiffs knew that structures on the floodplain could have a detrimental impact on properties.  The plaintiffs were actively involved in wider community considerations of the impacts of flooding on the floodplain.
209. [209]
     In all of the circumstances, on the balance of probabilities I find that the interference with the use and enjoyment of Mikandra by the Temporary Levee was unreasonable.
210. [210]
     Accordingly, the defendants’ claim in nuisance is established.
211. [211]
     It remains necessary to consider the Temporary Levee as modified by the 2023 Works.

Have the defendants established that the Temporary Levee as modified by the 2023 Works caused a substantial and unreasonable interference with the defendants use and enjoyment of Mikandra?

212. [212]
     Between the 2023 hearing and the 2024 hearing of the trial, further works were undertaken by the plaintiffs in respect of the Temporary Levee.
213. [213]
     A volume of additional evidence was led in relation to the nature and extent of the works undertaken in 2023, and also to the impact of those changes on the modelling.  The survey evidence was analysed in minute detail at the final hearing in an attempt to identify with precision the changes to the Temporary Levee.
214. [214]
     Ultimately, it may not be necessary to make definitive findings in some respects having already found that the Temporary Levee prior to the 2023 Works was a substantial interference with the use and enjoyment of Mikandra.  At best, the works undertaken in 2023 do not significantly alter the Temporary Levee so the impact remains as found above.  At worst, the changes exacerbates the impact.
215. [215]
     The defendants contend that it is necessary to consider the circumstances in which the further works in 2023 were done by the plaintiffs. 
216. [216]
     The first part of the trial in May 2023 was completed and the plaintiffs had “all but” completed their evidence (despite taking up the entire time allocated to complete the trial). By that stage there had been considerable engagement with the modelling undertaken by Mr Giles and it was clear that it was controversial between the parties as to the impact of the Temporary Levee.  It was clearly in issue on the claim and also the counterclaim.
217. [217]
     In or about July 2023, the plaintiffs undertook further work on the Temporary Levee.  The defendants say this was done without notice to them.  The plaintiffs say the work done was consistent with the evidence of Brett Enkelmann prior to the allegation of the 2023 Works arising. That is, the purpose of the 2023 Works was to repair flood damage and not to increase the height.
218. [218]
     This further work gave rise to pleading amendments as reflected in the Amended Defence and Counterclaim and the Amended Reply and Answer, further lay and expert evidence, and lengthened the trial even further.  The subsequent abandonment of the plaintiffs’ claim left some of this further evidence to be dealt with just prior to the final submissions.
219. [219]
     In respect of the evidence of the first plaintiff and Brett Enkelmann, consistent with my earlier findings I do not accept their evidence in respect of the scope and nature of the works undertaken in 2023.
220. [220]
     I accept the evidence of the defendants in respect of this issue including:

     1. The evidence of Dr Markar in the Fifth Markar Report [DEF.998.001.0001] in respect of the changes to the Temporary Levee, including relevantly:
        1. Between 2022 and 2024 as illustrated in Figure 3-6: Difference grid, 2024 LiDAR – 2022a Lidar.
        2. Between 2012 and 2024 survey data as illustrated in Figure 3-4: Difference grid, 2024 LiDAR – 2012 Survey.
        3. Figure 3-7: Cross-section at A0, which graphs the changes at this point over the various datasets.
        4. Figure 3-12: Cross-section E1, which also graphs this point over time over the various datasets.  I note that this point corresponds with “RP1” which was the subject of considerable analysis in respect of the plaintiffs’ original claim.^[90]
        5. His opinion in respect of the potential impacts of the current Temporary Levee on Mikandra:

“[25] Due to time constraints, I have not undertaken any new hydraulic modelling to assess the potential impact of the current configuration of the Riverview Flood Mitigation Embankment on flooding at Mikandra. Therefore, the opinions expressed below are based on results and findings from the modelling undertaken and presented in the Third Markar Report (Markar, 2023).

[26] Markar (2023) modelling showed that the 2020 configuration of the Riverview Flood Mitigation Embankment had an adverse impact on flood levels and velocities on Mikandra, mainly in Block 1 and Block 2, and that these impacts are greater for more regular and smaller flood events.

[27] The comparison of the current (2024) topographic configuration of the Riverview Flood Mitigation Embankment and the surrounding area with the 2020 configuration shows that the eastern end of the 2024 embankment is slightly (up to 0.2 m) higher than the 2020 embankment assessed in Markar (2023).

[28] Based on the previous modelling results, I believe the small increase in the embankment height in 2024 when compared to 2020 is likely to slightly increase the adverse impact on flood levels and velocities on Mikandra predicted in Markar (2023). It is not possible to estimate the magnitude of this incremental impact without undertaking hydraulic modelling for the current embankment configuration.”

2. The evidence of Dr Markar in cross-examination was that the further work done in 2023 did not in any appreciable way change the impact of the Temporary Levee:

“Do you remain of the opinion today, with the structure of a mitigation bank as it is today, of the opinion that that will be the general direction in which water is redirected from it?‑‑‑Based on the latest survey data I received a few weeks ago – that’s the  – that data shows that the mitigation [levee] has been raised compared to 2020. So, therefore, the impact for the smaller floods that doesn’t over top is prob – it – impact will be there for a bigger flood than what was there before.

All right. Just pausing there, the question I asked you was about redirection of the water?‑‑‑Yeah. It’s the same principle.

Yes. So, really, what you’re saying is that redirection is likely to be a factor in those circumstances for a much larger flood peak than before; is that right?‑‑‑Correct.

But we’re not talking about the direction being changed in any appreciable way because of the modifications to the temporary bank, or the mitigation bank?‑‑‑No.”^[91]

3. The evidence of Alistair Byrom, in particular the Fourth Byrom Report [DEF.998.001.0073] dated 25 March 2024 which considered the works undertaken in 2023 in respect of the Temporary Levee and analysed the available survey data.

221. [221]
     The defendants submit this evidence shows:

     1. That soil had been placed behind (to the north of) the eastern part of the Temporary Levee.  However, the areas in front of and behind the western part of the Temporary Levee had been lowered.
     2. The main body of the Temporary Levee seemed to have retained the same height, but the bank had been built up and strengthened (at approximately the point previously identified as RP1).
     3. The area around RP1 appeared to be higher and further to the north.
222. [222]
     The defendants contend that the final joint report of the surveyors [DEF.997.001.0001] identifies that there are no points of difference between the surveyors (Mr Byrom and Mr Gavin Mackenzie) who agree that the Temporary Levee was altered between 2022 and 2024, but not in a “radical way”.
223. [223]
     Ultimately, the defendants submit that the work undertaken in 2023 on the Temporary Levee does not change the appropriateness or necessity for the Temporary Levee to be removed.  The impacts that result from it being an elevated structure in the flow path of the break out water from Barambah Creek remain.
224. [224]
     The plaintiffs note that the defendants only seek a finding that the further works done in 2023 did not remove the nuisance.  The plaintiffs do not assert that the further works done in 2023 had any ameliorative effect.  Nor do the plaintiffs contend that the further works in 2023 lessened any impacts on Mikandra.
225. [225]
     Ultimately, the plaintiffs submit that the issues in respect of the further works done in 2023 are “unimportant”, and that this position is reflected in the analysis of the surveyors.
226. [226]
     However, the plaintiffs do submit that the evidence does not prove that the height of the Temporary Levee was increased by 0.2 m at the eastern end.  In this regard some criticism is raised in respect of Dr Markar’s analysis.
227. [227]
     The survey data is subject to the limitations identified in the survey reports, including the identified error margins. Dr Markar in the Fifth Markar Report used the raw numbers from the data in his analysis. The limit of accuracy of +/- 0.15m may impact some aspects of the analysis, together with consideration of the combined accuracy as addressed by the surveyors.
228. [228]
     The margins of error in respect of the use of the survey data has always been an issue in the analysis done in these proceedings.  It became more contentious in respect of the work done in 2023 on the Temporary Levee as a result of the circumstances in which the work was done and the evidence put before the Court.  I do not consider that this impacts on the credibility of Dr Markar.  Dr Markar acted independently and sought to assist the Court with an evolving set of circumstances.  His methodology and approach is not impugned in any way as a result.
229. [229]
     It is clear from the evidence that the impact of the Temporary Levee remained after the further work was done in 2023 and may have increased but not to a significant extent.
230. [230]
     Given the accuracy of the survey data is +/- 0.15m, it is impossible to make a precise finding as to the actual changes made, particularly as to any increase in height at the eastern end of the Temporary Levee.
231. [231]
     However, on the evidence, I find as follows:

     1. In 2023 the plaintiffs undertook further works that altered to some extent the Temporary Levee, including raising, lowering, and broadening the structure in different areas.
     2. The changes made in 2023 did not “dramatically” change the Temporary Levee.
     3. The impacts on Mikandra that result from the Temporary Levee being an elevated structure in the flow path of the break out water from Barambah Creek are not diminished or lessened as a result of the works done by the plaintiffs in 2023.
232. [232]
     Accordingly, on the balance of probabilities the evidence supports a finding of a substantial interference in respect of the current Temporary Levee (which includes the works done in 2023).
233. [233]
     In respect of whether the substantial interference is unreasonable, that finding is also made in respect of the current Temporary Levee.  To the extent that the 2023 Works have increased the risk of future impacts on Mikandra, any additional interference with the use and enjoyment of Mikandra would be unreasonable in the circumstances, particularly where the work was done in the course of a trial where the impact of the Temporary Levee was a central issue and contentious between the parties.
234. [234]
     In all of the circumstances, I find that the interference with the use and enjoyment of Mikandra by the current Temporary Levee, as modified by the works in 2023, is substantial and unreasonable.
235. [235]
     Accordingly, the defendants’ claim in nuisance is established.

If so, should an injunction be granted requiring the plaintiffs to remove the Temporary Levee?

236. [236]
     The defendants submit that if nuisance is established, there is no basis for the Court not to grant an injunction requiring the removal of the Temporary Levee.
237. [237]
     In all of the circumstances:

     1. There is no farming or irrigation reason for the plaintiffs to retain the Temporary Levee.
     2. There is evidence that the Temporary Levee is detrimental to Riverview.
     3. No rational reason for the maintenance of the Temporary Levee has been identified.
238. [238]
     Having found that the Temporary Levee as constructed and in its current form is a substantial and unreasonable interference with the use and enjoyment of Mikandra, and there being no persuasive factors against the Court exercising the discretion to grant an injunction, it is appropriate to order an injunction requiring the removal of the Temporary Levee.
239. [239]
     I will hear further from the parties as to how the injunction should be framed, including any necessary reference to the 2012 LiDAR.

Other orders

240. [240]
     Consistent with the agreed approach, I will also hear further from the parties as to any other appropriate orders in light of these reasons.