So v Blacktown City Council

The Site

1. The site is an irregular, triangular shape, surrounded by existing low density residential development.
2. The total area of the site is 1,512 m2.
3. The site fronts to Galbraith Street (western boundary) for a length of 49.5m and Quakers Road (eastern boundary) for 44.5m. The northern and southern boundaries of the site are 60m and 65.76m, respectively, and which adjoin residences and the disused portion of Voysey Close. Quakers Hill Parkway is located south of the site, adjacent to Voysey Close and vacant land. The remaining formed part of Voysey Close is a single lane access to Quakers Hill Parkway.
4. The site is currently vacant, covered with grass and mounds of excavated material, although has a pad mounted substation on its (mid) southern boundary.
5. A grassed drainage depression (for stormwater easement) runs along the northern boundary of the site, generally sloping/draining towards the west into a culvert in Galbraith Street, and is separated from the adjoining residences by an established fence.

Relevant Planning Controls

1. The requirements of the EPA Act are relevant for the Court's consideration to grant consent to the amended application under appeal, and specifically s 4.15(1) described below: 4.15 Evaluation (cf previous s 79C) (1) Matters for consideration - general In determining a development application, a consent authority is to take into consideration such of the following matters as are of relevance to the development the subject of the development application - (a) the provisions of - (i) any environmental planning instrument, and (ii) any proposed instrument that is or has been the subject of public consultation under this Act and that has been notified to the consent authority (unless the Planning Secretary has notified the consent authority that the making of the proposed instrument has been deferred indefinitely or has not been approved), and (iii) any development control plan, and (iiia) any planning agreement that has been entered into under section 7.4, or any draft planning agreement that a developer has offered to enter into under section 7.4, and (iv) the regulations (to the extent that they prescribe matters for the purposes of this paragraph), (v) (Repealed) that apply to the land to which the development application relates, (b) the likely impacts of that development, including environmental impacts on both the natural and built environments, and social and economic impacts in the locality, (c) the suitability of the site for the development, (d) any submissions made in accordance with this Act or the regulations, (e) the public interest.
2. Pursuant to s 4.47 of the EPA Act, I am satisfied that the relevant approval authorities have been given the opportunity to consider the amended application and that the GTA's provided are adopted in the draft conditions of consent.
3. Pursuant to cl 49 of the EPA Reg, the applicant has satisfied the Court with the provision of consent from the relevant landowners for works proposed by the amended application. This includes the proposed pedestrian path on Council's land along the site's southern boundary, part of former Voysey Close, and which Council agrees is appropriate to form part of the application.
4. The proposed centre-based childcare facility is subject to the requirements of the State Environmental Planning Policy (Educational Establishments and Child Care Facilities) 2017 (the SEPP Child Care). Clause 23 of the SEPP Child Care requires that the provisions of the Child Care Planning Guideline 2017 (hereafter the CCPG) be considered. It is noted that the relevant requirements for the design of a child-care centre are not in contention, and in its assessment of the amended application, the Court is satisfied that the relevant provisions of the SEPP Child Care and the CCPG are sufficiently addressed.
5. Pursuant to Chapter 4 of the SEPP Resilience, and specifically s 4.6 relevant to this amended application, the site must be deemed or capable to be made suitable for the proposed use with respect to contamination, prior to the grant of consent. Based on the supporting documents to the amended application, including the site validation report prepared by Geotechnical Consultants Australia, dated 30 September 2022 (Exhibit L), the Court is satisfied that the applicant has provided sufficient evidence, which together with the agreed draft conditions of consent and Council's assessment that the site has historically been used for residential purposes, address the relevant requirements of the SEPP Resilience.
6. On 2 December 2021, the State Environmental Planning Policy (Precincts - Central River City) 2021 (SEPP Precincts) commenced and replaced the State Environmental Planning Policy (Sydney Region Growth Centres) 2006 (SEPP Growth Centres), as at 18 November 2021. The provisions of the SEPP Growth Centres are directly transferred to the SEPP Precincts, as described in s 1.4 of the SEPP Precincts. The site is located within the North-West Growth Centre, Schofields Precinct, as described Appendix 7 of the SEPP Growth Centres.
7. The site is zoned R2 Low Density Residential, pursuant to Appendix 7 of the SEPP Growth Centres. The amended application also relies on the creation of a pathway on the adjoining Council land (former Voysey Close), which is zoned SP2 Infrastructure. The proposed development is permissible with consent in the relevant zone/s, and the Court is satisfied that the relevant objectives of the zones are sufficiently addressed.
8. Pursuant to consideration of the application under the SEPP Growth Centres, the Blacktown City Council Growth Centre Precincts Development Control Plan 2010 (DCP) is relevant for consideration, and the parties specifically reference sections 2.3.1 (flooding for subdivisions) and 4.4.2 (childcare centres), Appendix A (Glossary) and Schedule 5 Schofields Precinct, section 2.6 (drainage and flood evacuation).
9. The site is located within the Blacktown Local Government Area, however assessment of the amended application is not subject to the provisions of the Blacktown Local Environmental Plan 2015, pursuant to cl 1.4, or the Blacktown Development Control Plan 2015 (BDCP), as explained in Part A, clause 1.1, except with respect to the issue of the childcare centre being in a flood prone area in the Schofields Precinct, as described in clause 4.4.2.1 of the DCP.
10. With respect to the flooding related evidence, the experts refer to and rely on the following online tools and documents: 1. Blacktown City Council online (flood) planning maps (Exhibit F); 2. Chapter 15, Water Sensitive Urban Design Handbook for Blacktown City Council (hereafter WSUD); 3. Appendix D, Blacktown City Council Engineering Guide for Development, 2005; 4. NSW Flood Risk Management Manual: the management of flood liable land, pages 9-16; 5. Floodplain Development Manual 2005.

Expert evidence

1. The Court was provided with written evidence from the following experts: 1. Planning - Mr Jeffrey Mead and Ms Bertha Gunawan. 2. Flooding - Mr Billy Adzioski and Mr Laith Almoil. 3. Traffic - Mr Paul Corbert and Mr Nadeem Shaikh. 4. Civil Engineering - Mr Billy Adzioski and Mr David Yee.
2. Oral expert evidence was provided in the hearing by the flooding experts. By agreement of the parties and concurrence of the Court, the other listed experts were not called to give oral evidence because the contentions relevant to their expertise had been resolved to the satisfaction of the parties prior to and/or during the hearing, and the Court sought no further clarification in its assessment, based on their joint expert reports, supporting documents to the amended application and agreed draft conditions of consent.

Resident submissions

1. One objector made an oral submission to the Court at the start of the hearing, during the site view. The issues raised by the objector related primarily to the potential for excessive traffic along Galbraith Street and stormwater drainage impacts.
2. Further to the notification of the original application, the amended application was renotified by Council, with one submission in objection received.
3. The written submissions of all objectors during notifications are provided in Exhibit 1, and have been assessed by the Court in consideration of the amended application.

Is the proposed childcare centre as designed on the site, suitable and appropriate based on the potential for flooding impacts?

1. The primary contention of Council, as explained to the Court, is that there is a potential for adverse flood impact surrounding the site, there is an inappropriate mitigation design relying on an undercroft, and the site is unsuitable for a childcare centre.
2. It is the view of Council's expert that the flood assessment that supports the amended application identifies an unacceptable (post development) flood impact offsite, exceeding a 20mm (0.02 m) increase in water level, and that the proposed flood mitigation in the design of the building, relying on an 'undercroft', is not appropriate nor maintainable.
3. In assessment of the amended application, I first need to understand the actual flood conditions (pre-development), then assess whether the amended application will have any consequential impact post development, to determine the site suitability of this site for the proposed use.
4. It is noted that the issue of flooding was not articulated as a reason in the determination to refuse the application, however is described in Council's internal determination report (dated 28 July 2020), Exhibit 1, and the (amended) SoFC, which assess 'drainage engineering' as a key outstanding issue.

What is the flood affectation on the site, pre-development flood conditions, and relevant jurisdictional requirements to assess the application?

1. The experts confirm that the site is not identified on the Development Control Map, sheet DVC 006 of the SEPP Growth Centres, as either flood prone or major creeks land. However, the flooding experts agree that the site is affected by flooding due to overland flow, resulting from stormwater accumulated in Quakers Road (east of the site). Stormwater is directed through the easement along the northern boundary of the site, towards and into the stormwater infrastructure in Galbraith Street.
2. Although the site is not mapped as flood prone on either Council's online mapping or in the SEPP Growth Centres, the site was identified as being 'within a local flooding area' in a letter from the Council to the applicant, dated 23 October 2020, titled 'Additional Information Response'.
3. The experts agree that the site is: mapped and affected by flooding in a Probable Maximum Flood (PMF); located in a 'low risk flood' precinct; and is affected by localised, short duration overland flooding.
4. Relevant to assessing the flooding contention and related jurisdictional requirements, cll 19 and 20 of the SEPP Growth Centres, are a consideration: 19 Development on flood prone and major creeks land - additional heads of consideration (1) This clause applies to development requiring consent that is carried out on flood prone and major creeks land (other than any such land to which clause 20 applies). (2) Consent is not to be granted to the carrying out of development to which this clause applies unless the consent authority has taken the following into consideration - (a) whether or not the development will adversely affect flood behaviour resulting in detrimental increases in the potential flood affectation of other development or properties, (b) whether or not the development will alter flow distributions and velocities to the detriment of other properties or the environment of the floodplain, (c) whether the development will enable safe occupation of the flood prone and major creeks land, (d) whether or not the development will detrimentally affect the floodplain environment or cause avoidable erosion, siltation, salinity, destruction of riparian vegetation or a reduction in the stability of the riverbank/watercourse, (e) whether or not the development will be likely to result in unsustainable social and economic costs to the flood affected community or general community, as a consequence of flooding, (f) whether or not the development is compatible with the flow conveyance function of the floodway, (g) whether or not the development is compatible with the flood hazard, (h) in the case of development consisting of the excavation or filling of land, whether or not the development - (i) will detrimentally affect the existing drainage patterns and soil stability in the locality, and (ii) will significantly impact on the likely future use or redevelopment of the land, and (iii) will adversely impact on the existing and likely amenity of adjoining properties, and (iv) will minimise the disturbance of relics, and (v) will adversely impact on any watercourse, drinking water catchment or environmentally sensitive area. 20 Development on and near certain land at Riverstone West (1) This clause applies to the land shown outlined in red on the North West Growth Centre Development Control Map. (2) Despite any other provision of this Policy (including any Precinct Plan), the consent authority must not grant consent for development on land to which this clause applies unless it is satisfied that the proposed development - (a) will be undertaken in a manner that is consistent with the Floodplain Management Strategy (being part of the Riverstone West Precinct Development Control Plan), and (b) does not increase flood levels on adjoining properties in events up to the design 100 year recurrence flood, and (c) limits any increases in flood velocities on adjoining properties in events up to the design 100 year recurrence flood to minor increases only, and (d) is not likely to result in adverse flood impacts on adjoining properties (including during any construction stage of the proposed development). (3) This clause does not apply to development that the consent authority is satisfied is minor and will not result in unacceptable adverse flood impacts on adjoining properties.
5. The site is burdened by a (3m wide) grassed drainage easement which runs along the northern boundary of the site, graded 1.6% towards Galbraith Street, which conveys overland (stormwater) flow and also contains stormwater infrastructure (pipes and pits).
6. The flooding currently experienced on the site relates to the capacity of the site and associated stormwater system, including in surrounding streets, to capture and sufficiently direct stormwater as overland flows in major rain events. There is a sag point and insufficient infrastructure capacity in Galbraith Street, which results in overland flooding during large rainfall events. Quakers Road also is affected by an accumulation of stormwater during large rain events, that causes localised flooding to properties east of the site (as noted by the resident objector in his oral submission). Flooding on and around the site is understood to be from short duration events, that rapidly enters and exits (drains from) the site.
7. It is recognised that flooding from overland flow differs from mainstream/floodway flooding, as typically shown in flood mapping. The key difference between these types of flood events is that (mainstream, floodplain and floodway) flooding results from water that rises up from a water source such as a river or creek, whereas overland flow flooding results from ponding of typically stormwater, typically due to inadequate infrastructure to convey the flow. Overland flooding is generally localised, short duration, whereas mainstream type flooding is often more extensive in area and longer duration.
8. The traditional approach to assessing mainstream flooding is by defining a Flood Planning Area (FPA) and adopting Flood Planning Level's (FPL). This approach has limitations in assessing overland flow flooding, because the definition of the FPA is not as straight forward. The definition of a FPA in an urban environment is also made difficult by the complex interaction between multiple flow paths and the filtering of flood/land surfaces. The site itself does not have a defined FPL as described in the SEPP Growth Centres, although is affected by a PMF events.
9. The application relies on a flood study (Exhibit B), dated 11 March 2020, which was amended (Exhibit J), to assess the local overland flooding, pre and post development, originating from Quakers Road. The flood report goes on to consider a 100-year annual recurrence interval (ARI), equivalent to the 1% Annual Exceedance Probability (AEP), which is a statistical 1-in-100 event. The results of the modelling assist in assigning a theoretical FPL for the site, based on a 1% AEP, and which is adopted to design floor levels of the proposed childcare centre.
10. To identify the relevant assessment requirements for the amended application, the flood experts provided a joint expert report, tendered as Exhibit 9. This assessment helpfully informs the Court.
11. The results of the amended flooding modelling (Exhibit J) in a 1% AEP event, describe a 15-minute peak flow and indicate the following pre-development overland flood conditions: 1. Water depths (D) and velocities (V) along Quakers Road, Galbraith Road and within the site reach up to 0.7 m and 2.2 m/s. 2. Floodwaters generally pond within Quakers Road and Galbraith Street, and are directed across the site in a westerly direction, breaching the existing easement channel. 3. The assessed hazard (V*D) and hazard category is generally less than 0.3, except for minor breaches at the head of the easement onto the site and at the intersection of Voysey Close and Galbraith Street.
12. Clause 4.4.2.4 (site selection and location) of the DCP, states that "Child care centres are not appropriate on the following land: … flood liable land or land affected by local overland flooding (refer to clause 2.3.1)…". The experts agree the site is affected by local overland flooding and therefore this clause is relevant for consideration of the amended application.
13. The experts also agree that clause 2.3.1 of the DCP is relevant for consideration as outlined below (although it is recognised this clause references subdivision): "2.3.1 Flooding and water cycle management 2.3.1.1 Objectives a. to manage the flow of stormwater from urban parts of the Precinct to replicate, as closely as possible, pre-development flows; b. to define the flood constraints and standards applicable to urban development in the Precinct; c. to minimise the potential of flooding impacts on development. 2.3.1.2 Controls - General 1. No residential allotments are to be located at a level lower than the 1% Annual Exceedance Probability (AEP) flood level plus a freeboard of 500 mm (i.e. within the 'flood planning area'). 2. Pedestrian and cycle pathways and open space may extend within the 1% AEP flood level, provided the safe access criteria contained in the NSW Floodplain Manual are met. The Flood Prone Land figure in the relevant Precinct's Schedule shows indicatively the extent of the 1% AEP flood level. Note: Where development is proposed within or adjacent to land that is shown on the Flood Prone Land figure, in the relevant Precinct's Schedule, as being affected by the 1% AEP level, council may require a more detailed flood study to be undertaken by the applicant to confirm the extent of the flood affectation on the subject land. 3. Stormwater is to be managed primarily through the street network in accordance with council's Water Sensitive Urban Design Development Control Plan. 4. Roads on primary drainage lines shown on the Key elements of the water cycle management and ecology strategy figure, in the relevant Precinct Schedule, are to be constructed in the locations shown, and are to be designed in accordance with specifications of council in relation to management of stormwater flows and quality. 5. Roads are generally to be located above the 1% AEP level. 6. Management of 'minor' flows using piped systems for the 20% AEP (residential land use) and 10% AEP (commercial land use) shall be in accordance with Blacktown Council's Engineering Guidelines for Subdivision and Development. Management measures shall be designed to: • prevent damage by stormwater to the built and natural environment, • reduce nuisance flows to a level which is acceptable to the community, • provide a stormwater system which can be economically maintained and which uses open space in a compatible manner, • control flooding, • minimise urban water run-off pollutants to watercourses, and • meet the standards for a 20% AEP flood level. 7. Management of 'major' flows using dedicated overland flow paths such as open space areas, roads and riparian corridors for all flows in excess of the pipe drainage system capacity and above the 20% AEP shall be in accordance with Blacktown Council's Engineering Guidelines for Subdivision and Development. Management measures shall be designed to: • prevent both short-term and long-term inundation of habitable dwellings, • manage flooding to create lots above the designated flood level with flood free access to a public road located above the 1% AEP flood level, • control flooding and enable access to lots, stabilise the land form and control erosion, • provide for the orderly and safe evacuation of people away from rising floodwaters, • stabilise the land form and control erosion, and • meet the standards for a 1% AEP flood level. 8. Where practical, development shall attenuate up to the 50% AEP peak flow for discharges into the local tributaries, particularly Category 1 and 2 creeks. This will be achieved using detention storage within water quality features and detention basins. 9. The developed 1% AEP peak flow is to be reduced to pre-development flows through the incorporation of stormwater detention and management devices. 10. In general, council will not support development, including the filling of land, within the floodway due to its function as the main flow path for flood waters once the main channel has overflowed and the possibility of a significant threat to life and property in a major flood. 11. The trunk stormwater system is to be constructed and maintained by council in accordance with the Riparian and Water Cycle Management Strategy at Appendix B, and to achieve water quality targets set by the Department of Environment, Climate Change and Water in Table 2-1." [Emphasis added] Also apply Part A, Section 9 of DCP where there is inconsistency.
14. The experts disagree whether the clauses of the BDCP are relevant in consideration of the amended application, specifically objectives and controls in Chapter 10 that relate to overland flooding, below: "10.4 Control of development on land subject to local overland flooding 10.4.1 Heads of consideration In determining any application for development on land designated as affected by local overland flooding Council will take into consideration those matters listed under Section 79C of the Environmental Planning and Assessment Act 1979. Council will also take into consideration the following: (a) Whether the proposed building footing design and/or materials are suitable. The severity of local overland flooding may warrant the preparation of a special structural design / report by a suitably qualified and experienced Structural Engineer recognised by the Institution of Engineers Australia under the National Professional Engineers Register (NPER-3) in this field. This report would demonstrate how the structure has been designed to withstand all flood loads, including impact loads due to flotsam carried by the floodwaters. (b) Whether the building extent and/or location is such that it will minimise the flood risk to the property and surrounding properties. (c) Whether proposed structures or any filling of land are likely to affect flood depths and velocities and hence flood risk. (d) Whether the type and location of boundary and other fencing may hinder the movement of local runoff. (e) Whether any filling and/or regrading of the site is appropriate given local overland flooding constraints. (f) Whether the scale of the development and/or the severity of the local overland flooding regime warrants the preparation of a hydraulic investigation/report by a suitably qualified and experienced Civil Engineer recognised by Engineers Australia under the National Professional Engineers Register (NPER-3) in this field. (g) The proposed use of the building, e.g. some uses like child care centres, hazardous goods storage centres etc may be considered inappropriate in these areas. Whilst assessing any Development Application, Council can only take into account information that is known to Council at the time of determining the application. 10.4.2 Planning and design criteria The development controls contained in this section apply to all land shown affected by local overland flooding - major drainage and local runoff under Council's DCP. These controls may be used for other areas that are subsequently identified as subject to local overland flooding which has not yet been investigated and/or listed at that time. Development Applications for building development on affected land must be accompanied by an Australian Height Datum (AHD) survey, prepared by or under the direction of a Registered Surveyor, over the whole of the property as well as areas outside the site boundaries in the general direction (either upstream and/or downstream as required) of the overland flows. The survey must define existing buildings / structures and/or proposed buildings / extensions (including fences), with existing and proposed floor levels indicated. The survey must be sufficiently detailed to define the overland flowpath with contour intervals for sites with an average grade of <1% of 100mm, 200mm intervals if average grades are <5% and 500mm for 5% or steeper. Each proposed development would have site-specific development constraints and each Development Application will be treated on its individual merits. However, typical development controls may include, but are not limited to, consideration of any or all of the following: (a) Minimum finished habitable floor levels based on specific site conditions and flood risk (b) Restricting cut or fill and limiting concrete 'slab on ground' floors (c) Flood compatible building footing design and/or materials (d) Extent and/or location of the building footprint to ensure adequate provision for movement of overland flow and site drainage (e) Limiting the type and location of fencing to ensure unobstructed overland flows (f) Restricting filling / regrading within the defined overland flowpath (g) Restricting future landscaping in medium density and non-residential developments which might raise flood levels and/or adversely redirect overland flows (h) Restrictions as to user and/or positive covenants on the property title under Section 88B of the Conveyancing Act 1919. Although each proposal is assessed on its merits, certain building methods or development options are inappropriate in an overland flowpath locality. Common contemporary building designs / practices may exacerbate the flooding situation if not carefully controlled."

Is the site and surrounding area adversely flood impacted due to the proposed development? Is the proposed childcare centre suitable on the site?

1. The fact that the site is not actually mapped as being flood prone in a 1% AEP, proved a significant issue between the experts in assessment of application.
2. Whilst the jurisdictional requirements to assess flooding impact acceptability on the site is focused on cll 19 and 20 of the SEPP Growth Centres, and the DCP, the experts also draw on relevant guidelines and objectives/controls to undertake their merit assessment, as does the Court.
3. I accept that the site is not mapped, either in the SEPP Growth Centres or in Council's online mapping as being flood prone, subject to 1% AEP flood events or local overland flooding. However, I also accept the evidence of the experts that the site is in reality affected by short duration flooding resulting from overland flow, due to inadequacies of the stormwater infrastructure system in both Galbraith Street and Quakers Road, to distribute and direct stormwater, particularly in events exceeding the 1% AEP. I understand the site is mapped as being affected by flooding in a PMF event, identifying it as 'low flood risk' in Council's online assessment tool (Exhibit F).
4. Council's delegated report (after internal determination of the original application), dated 28 July 2020, explained that there is a requirement for a flood and hydrology model to ensure a maximum isolated rise in flood level of less than 0.02 m in the 1% AEP event as a result of any development on the site. It is noted that this requirement does not derive from either the DCP or the BDCP. Mr Almoil considers however that this criterion of an 'acceptable impact' has consistently been adopted by Council as described in the WSUD at section 15, as well as the Court in Rothshire Pty Ltd v Blacktown City Council [2022] NSWLEC 1125 at [37-38].
5. The experts agree that any designed (flood) mitigation relied on in the amended application should focus on addressing the 1% AEP event. To this effect, the amended application relies on a ground floor level designed above the calculated FPL, and an undercroft (elevated ground floor level) to allow floodwaters to flow beneath the building. The undercroft, as designed, is elevated up to 0.7 m above a concreted ground surface with a 1% gradient (slope) across the site. Adjustable louvers are to be fixed to the outside edge of the undercroft to allow unimpeded floodwater flow through the site, with gates to allow maintenance access.
6. The amended application is supported by a Flood Risk Management Plan, dated 9 May 2022. The designed floor levels are agreed as being above the calculated FPL, and the proposed evacuation plan (Exhibit B) is accepted by the experts as being sufficient. The Court agrees with this assessment of the experts as being appropriate.
7. An added complexity to the Court's assessment is a recognition by the experts that the amended flood model (Exhibit H) before the Court inaccurately assesses a blockage from a stairwell to (flood)water flow onto the site. The applicant has however not sought a further amendment of the flood model to address this issue. The applicant's expert, Mr Adzioski, is confident that the model results currently before the Court depict a worst-case scenario and are sufficiently accurate for the Court's assessment purposes. It is noted that the Court has already allowed an adjournment, and that the applicant had utilised this time to amend the flood model, which Mr Almoil, as Council's expert has assessed in the supplementary expert report (Exhibit 10).
8. The results of the amended floodi modelling (Exhibit J) in a 1% AEP event, describe a 15-minute peak flow and suggest the following overland flood conditions resulti from the proposed development (post development): 1. No blockage - 1. Overland flow depths (D) and velocities (V) within the site increase by up to 0.11 m and 0.5 m/s, respectively, and along Quakers Road and Galbraith Road reduce by up to -0.05 m and increase up to 0.5 m/s, respectively. 2. The entry point of the drainage easement on the site observes an increase in water level of up to 0.06 m, which affects an adjoining property. 3. Floodwater's increasingly pond on the site, although are less along Quakers Road and Galbraith Street. Floodwater is directed across the site in a westerly direction and are more contained within the (deepened) easement channel, although still breach the channel across the south of the site. 4. The hazard (VD) and hazard category remain unchanged on the site, generally less than 0.3, except for a minor increase at the head of the easement onto the site. There is an observed general reduction offsite. 1. Full/100% undercroft blockage - 1. Overland flow depths (D) and velocities (V) within the site increase by up to 0.11 m and 0.5 m/s, respectively, and along Quakers Road and Galbraith Road increase by up to 0.11 m (eastern edge of undercroft) and 0.5 m/s. 2. The entry and discharge points of the drainage easement on the site observe an increase in flood level of up to 0.11 m, which affects adjoining properties. 3. Floodwater's increasingly pond along Quakers Road, Quakers Hill Parkway and Pacific Road, being directed around the site in a south-westerly direction, although waters, although are more contained in the (deepened) easement channel on the site. 4. The hazard (VD) and hazard category generally do not increase across the site, being generally less than 0.3, except within the (deepened) channel. There is an observed reduction offsite along Galbraith Street.
9. Based on my consideration of the amended model results, I find that there is likely an unacceptable impact to adjoining properties and surrounding area (streets) resulting from the proposed development, as designed. The modelling suggests that when the undercroft is (partially/fully) blocked, there are increases in flood (water) levels in areas beyond the site, impacting adjacent properties and surrounding streets. The modelled flood levels show an increase by up to 0.11 m at locations beyond the site, particularly if the undercroft becomes fully blocked. I accept that the model scenario before the Court presents a worst-case situation due to the stairwell blockage being included in the model design, however this is the evidence before the Court in consideration of the amended application. I have no certainty that remodelling to remove the stairwell causing a blockage would result in a sufficient improvement to post development flood conditions off the site. It is apparent that blockage of the undercroft causes the most significant impact, and I am not satisfied that the proposed maintenance is adequate to be relied on to prevent this occurrence.
10. The proposed enhancement (deepening) of the drainage channel and improved stormwater infrastructure in the easement is recognised as a positive outcome to the stormwater and flood management in the local area.
11. However, I assess that the proposed development does not ensure the free flow of floodwaters across the site, sufficient to mimic existing (pre-development) conditions, and thereby increases the likely flood impact to adjoining properties and streets.
12. I am not satisfied that the proposed design is appropriate in the context of the flood constraint on the site. Whilst I am not opposed to the concept of an undercroft, it is my opinion that the undercroft as designed is not sufficiently elevated to mitigate blockages which impede floodwaters.
13. I accept the criteria adopted by Mr Almoil that limits flood (water) levels at adjoining properties to an increase by no more than 20 mm (0.02 m) post development, as described at section 15.1 of the WSUD. It is noted that this section relates to overland flooding, as experienced on the site, and is therefore a relevant criterion to assess flood impact. The amended application does not satisfy the designated impact criteria in the WSUD because (modelled) flood levels post development are unacceptable, predicted to increase by up to 0.11 m (110 mm) on adjoining properties and in streets surrounding the site.
14. Therefore, in consideration of the evidence, I assess that the amended application does not satisfy the flooding requirements of the DCP, particularly clause 2.3.1. Whilst I note that clause 2.3.1 specifically references 'subdivision', I am guided to consider these criteria, pursuant to clause 4.4.2.4 of the DCP. I find that the proposed development does not satisfy the objectives in cl 2.3.1.1, "(a) to manage the flow of stormwater from urban parts of the Precinct to replicate, as closely as possible, pre-development flows," or "(c) to minimise the potential of flooding impacts on development".
15. With respect to the controls described in clause 2.3.1.2 of the DCP, the amended application has not demonstrated that the proposed development prevents short-term inundation of habitable dwellings on adjoining properties or ensures that the developed 1% AEP peak flow approximates pre-development flows through good architectural design and the incorporation of appropriate stormwater detention and management devices. During the 1% AEP peak (overland) flow, the modelled floodwaters, post development, suggest an impact to adjoining properties and surrounding streets with an increase of flood levels up to 0.11 m, particularly if the undercroft (or easement) is blocked. It is not reasonable to assume, as Mr Adzioski suggests, that a partially/fully blocked situation would never occur. Therefore, the impact to flood levels offsite is not demonstrated to my satisfaction as being sufficiently mitigated.
16. With respect to consideration of clause 4.4.2.4 (site selection and location) of the DCP, childcare centres are generally not acceptable on flood liable land. The relevant controls to assess childcare centres (on flood liable land or affected by overland flooding) refer to clause 2.3.1 of the DCP and Part A, Chapters 9 and 10 of the BDCP, pursuant to clause 4.4.2.1 of the DCP.
17. I have assessed that the objectives and controls of clause 2.3.1 of the DCP are not satisfied, therefore clause 4.4.2.4 of the DCP is not satisfied for the proposed childcare centre on the site.
18. There is a dispute between the flooding experts as to whether the site is affected by major or minor drainage, as described in Chapter 10 of the BDCP. The site is a sloping area where overland flows develop along alternative paths once the (stormwater) system capacity has been exceeded, including the drainage easement directed through the site.
19. I prefer Mr Almoil's assessment that the site is affected by major drainage-overland flooding. I recognise that this criterion is not mapped on Council's online mapping, which I consider is not reliable, because it does not represent the actual flood conditions experienced on the site, as agreed by the experts. It is recognised that flood conditions change over time due to development in the surrounding area and climate change impacts, and also that the flood prone area mapping generally focuses on mainstream flooding. Therefore, I rely on the evidence of the experts on the actual flood conditions on the site, rather than the mapping in the SEPP Growth Centres and Council online tool in this instance.
20. I am satisfied that the requirements described in Chapter 10 of the BDCP are addressed by the amended application, because the designed floor levels are above the FPL, there is no increase in flood risk (as flood hazard remains unchanged and probability of occurrence is not affected), the grade of the site is suitable (at 1%) to support free flow and evacuation procedures are sufficient.
21. I accept that the amended application relies on an evacuation plan that sufficiently mitigates the risk to those accessing the childcare centre on the site. I am satisfied that Schedule 5 Schofields Precinct, clause 2.6 (drainage and flood evacuation) of the DCP is addressed.
22. However, based on my assessment of the evidence and as described above, I find that the amended application does not satisfy cll 19 and 20 of the SEPP Growth Centres because the proposed development will likely increase flood levels on adjoining properties in events at or above the 1% AEP event, and the proposed development will alter the flow and distribution of floodwaters to the detriment of other properties and surrounding streets. I am not satisfied that the proposed development sufficiently addresses the requirements of the SEPP Growth Centres, pursuant to s 4.15(1)(a)(i) of the EPA Act.
23. In consideration of the amended application, I am also not satisfied that the proposed development sufficiently addresses the requirements of the relevant development control plan, specifically the DCP, pursuant to s 4.15(1)(a)(iii) of the EPA Act.
24. I find that the proposed childcare centre, as described in the amended application, is not suitable for the site because it potentially results in unacceptable impacts to adjoining properties and in the surrounding area, pursuant to s 4.15(1)(c) of the EPA Act.

Conclusion

1. The amended application has been considered, based on the evidence before the Court, including all (amended) supporting plans, documents, agreed draft conditions of consent, and expert reports and oral submissions. The amended application has been assessed against the relevant jurisdictional requirements and with a merit consideration.
2. In consideration of the amended application under appeal, I am not satisfied that application sufficiently addresses the relevant jurisdictional requirements, established in s 4.15(1) of the EPA Act. Pursuant to my consideration of s 4.15(1) of the EPA Act, I am not sufficiently satisfied that the amended application has demonstrated the site is suitable for the intended use as a childcare centre, due to an unacceptable flood impact to adjoining properties.
3. I therefore refuse consent of Development Application DA-20-01096, pursuant to s 4.16(1)(b) of the EPA Act.

Orders

1. The Court notes that: 1. The Blacktown City Council, as the relevant consent authority has agreed, under cl 55 of the Environmental Planning and Assessment Regulation 2000, to amending the application for development consent (DA-20-01096).
2. The Court orders: 1. Leave is granted to the Applicant to rely upon the amended plans and documents filed in the appeal. 2. The appeal is dismissed. 3. Development Application DA-20-01096, as amended seeks approval to construct a two-storey childcare centre for 76 children, with (27 car space) parking and associated earth/civil works on Lot 1 in DP 1221556, also known as 2 Galbraith Street, Nirimbia Fields, is refused. 4. All exhibits are retained.

DISCLAIMER - Every effort has been made to comply with suppression orders or statutory provisions prohibiting publication that may apply to this judgment or decision. The onus remains on any person using material in the judgment or decision to ensure that the intended use of that material does not breach any such order or provision. Further enquiries may be directed to the Registry of the Court or Tribunal in which it was generated. Decision last updated: 17 January 2023