COMMISSIONERS: The applicant appeals Blacktown City Council's refusal of Development Application DA-13-1845 for Stage 1 bulk earthworks and associated activities on part of Lot 211, DP 830505, Riverstone (the site). The site is part of the Riverstone West Precinct, which in turn forms part of the NSW Government's North West Growth Centre.
The appeal is made under s 97(1)(b) of the Environmental Planning and Assessment Act 1979 (the Act).
[3]
The site and locality
The Riverstone West Precinct comprises Lot 211 and three other lots owned by utility providers. Adjoining the northern portion of Lot 211 are a Sydney Water sewerage treatment plant and a Transgrid electricity substation.
Lot 211 has an area of approximately 228 ha and is bounded by Bardon Road to the north, the Richmond railway line to the east, Eastern Creek to the west, and Garfield Road West to the south.
The site, the subject of this appeal, is limited to the northern half of Lot 211. The former Riverstone meat works is located towards the southern end of the site. Vineyard railway station is located near the north-eastern corner of the site. The township of Riverstone is to the east of the site on the eastern side of the railway line.
Lot 211 is primarily vacant and used for grazing.
The Riverstone West Precinct is surrounded by other identified precincts within the North West Growth Centre. Of relevance, in June 2014 the Minister released the precinct to the west, Marsden Park North, but it has not been rezoned for urban purposes. A parcel of land known as Lot 11 is located within this new precinct on the western side of Eastern Creek adjoining the Riverstone West Precinct.
A significant portion of the Precinct including the southern portion of the site is mapped as Flood Prone and Major Creeks Land in Sheet DVC_004, State Environmental Planning Policy (Sydney Regional Growth Centres) 2006. Relevantly, Eastern Creek forms the western boundary. The site is affected by flooding from Eastern Creek catchment flows as well as backwater inundation from the Hawkesbury-Nepean floodplain.
[4]
The proposal
The proposed development is described as Stage 1 and comprises:
Bulk earthworks and ground contouring;
Vegetation removal; and
Extended construction hours.
Essentially, the applicant is seeking approval for preparatory earthworks to facilitate the eventual development of the Precinct for industrial and commercial uses.
According to the Statement of Environmental Effects - Version 2 (SEE) (Exhibit A), the proposed earthworks are limited to an activity area of approximately 60 ha; generally in the northern section of the Precinct.
The SEE describes the proposal as the cutting, stockpiling and filling of part of the site to create a series of benches upon which future industrial development will occur. Approximately 1,400,000 m3 of on-site material is proposed to be cut from the higher northern portion of the site to be used to fill low lying areas in the southern and central portions. Another 125,000 m3 of excavated natural material (ENM) is to be sourced from projects such as the construction of the North West Rail Link.
The activity area will be retained by batters constructed to a maximum 1:4 gradient.
The height of the fill achieves a minimum level of RL 17.3.
The activity area provides for at least a 40 m buffer from Eastern Creek.
The proposed earthworks will remove all vegetation within the activity area. According to the SEE, this area is primarily comprised of land that has been 'biodiversity certified' under the Threatened Species Conservation Act 1995 (TSC Act). The effect of this certification is that the proposal is not considered to have a significant impact on listed species, populations or communities and the requirement for further ecological assessment is removed. The vegetation in the non-certified areas does not comprise any threatened ecological communities listed under the TSC Act.
The applicant seeks approval for extended construction hours in order to enable the development to be carried out more efficiently and in a reduced time frame. The extended hours of construction are proposed to be from 6 am until 10pm - Monday to Saturday. No works are proposed on Sundays or Public Holidays.
An acknowledged inconsistency in the proposal is the staging plan in Appendix E of the Worley Parsons Flood Management Strategy which shows stage 1 to be more limited than the 'Stage 1' proposed in the DA. The DA 'Stage 1' incorporates stages 1, 2 and 4 of the Worley Parsons FMS.
[5]
The Issues
At the time the Class 1 application was filed with the Court, the development was undetermined. Council subsequently determined and refused the DA on 3 December 2014.
The council contends that the proposed development should be refused for the following reasons:
Unsatisfactory impacts on the floodplain - contention 1;
Precedent and cumulative impact - impacts of filling of the floodplain - contention 2;
Traffic impacts on the Vineyard railway level crossing - contention 3;
Inadequacy of the applicant's Flood Emergency Response Plan (FERP) - contention 4; and
Inadequate identification of the source (and quality) of fill to be used - contention 5.
The council accepts that the traffic-related issues and the adequacy of the FERP can be addressed through the imposition of conditions of consent.
[6]
Planning controls
State Environmental Planning Policy (Sydney Regional Growth Centres) 2006 (SEPP - SRGC) applies. The SEPP was amended in 2009 by amending instrument State Environmental Planning Policy (Sydney Regional Growth Centres) Amendment (Riverstone West Precinct) 2009. The aims of the policy (in conjunction with amendments to the regulations under the Act relating to precinct planning) include:
(a) to co-ordinate the release of land for residential, employment and other urban development in the North West and South West growth centres of the Sydney Region;
(c) to provide for comprehensive planning for those growth centres,
Clause 20 SEPP - SRGC applies to 'Development on and near land at Riverstone West'. It states:
(1) This clause applies to the land 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 the 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.
The land to which clause 20 applies is shown on sheet DVC_004 and includes the Riverstone West Precinct and Lot 11 in the recently released yet to be rezoned Marsden Park North Precinct. North West Growth Centre Land Zoning Map - Sheet LZN_004, SEPP-SRGC shows the zoning of the portion of the Riverstone West Precinct relevant to the proposed development; notably, Lot 11 is land not zoned for the purpose of the North West Growth Centre and is shown beyond the North West Growth Centre Precinct Boundary.
Appendix 3 of the SEPP provides the land use and other planning controls resulting from precinct planning for the Riverstone West Precinct of the North West Growth Centre. The development site is variously zoned IN1 - General Industrial, IN2 - Light Industrial and RE2 - Private Recreation. Earthworks are permitted with consent. Blacktown City Council is the consent authority for development within the Precinct.
Of relevance is Riverstone West Development Control Plan 2009 (RWDCP) prepared by the Department of Planning in 2009. It is assumed that this DCP applies as it is called up in cl. 20(2)(a) SEPP-SRGC, however the second paragraph in clause 1.1 Name of this Plan states:
This DCP was adopted by the Director General (or delegate) of the Department of Planning on (date to be inserted) and came into force on (date to be inserted).
Amongst other things, the purpose of RWDCP is to "consolidate and simplify the planning controls to ensure the orderly, efficient and environmentally sensitive development of the Riverstone West Precinct as envisaged by the North West Growth Centre Structure Plan, State Environmental Planning Policy (Sydney Regional Growth Centres) 2006…and as refined by the Riverstone West Indicative Layout Plan" (s 1.2.2).
Section 1.7.1 RWDCP sets out the development assessment process. Step 2 requires an applicant to prepare relevant Precinct-wide plans/ strategies identified in the table in s 1.7.3. Section 1.7.2 allows variations to development controls providing the applicant can demonstrate that the proposed development is consistent with the vision and development objectives for the precinct as well as the relevant objectives and controls in SEPP-SRGC.
Unusually, the table in s 1.7.3 does not indicate a requirement for a precinct-wide Cut and Fill Plan for earthworks development applications.
Section 1.7.3 goes on to provide the specific requirements for all precinct wide plans and strategies that must be submitted with a DA. Relevantly, and amongst others, a Floodplain Management Strategy (FMS) and an Integrated Water Management Strategy are required.
In regards to the FMS, the DCP states:
The Floodplain Management Strategy (FMS) must comply with the requirements of Appendix C in this DCP.
The purpose of the FMS is to:
∙ Define existing flooding at the site and in the vicinity of the site in accordance with the NSW Floodplain Development Manual, 2005 procedures:
∙ Determine the flood impacts on account of the proposed development, and investigate mitigation options which will input to the FMS;
∙ Develop a strategy that demonstrates flood impacts at the site and adjoining the site are managed in accordance with the requirements of the Growth Centres SEPP Amendment (Riverstone West Precinct) 2009 and the development controls in Section 4.3 of this DCP; and
∙ Develop a Flood Emergency Response Plan (FERP) in consultation with the State Emergency Services (SES).
Section 2.2 Development Objectives, relevantly states:
The development objectives of Riverstone West are to [amongst other things]:
1) Maximise employment opportunities within Riverstone West for the local and regional communities
2) Ensure development does not cause any offsite flood impacts that are unacceptable to Council.
Section 4.3.2 considers Flood Management within the overall context of s 4.3 - Integrated Water Cycle Management. Of relevance are the following subclauses.
1) The management of floods must comply with Growth Centres SEPP Amendment (Riverstone West Precinct) 2009 and demonstrate compliance with the requirements in Appendix C of this DCP.
2) The minimum fill level must be above the existing climate flood level (100 year Annual Recurrence Interval (ARI)) ….. for commercial and industrial development. The future climate flood planning level will be determined through the Floodplain Management Strategy as described in Appendix C of this DCP. All buildings are to be constructed with a minimum floor level of 17.9 metres AHD.
RWDCP Appendix C - Floodplain Management Strategy is therefore relevant. This appendix outlines the specific requirements for the preparation of an FMS. The appendix states:
The land to which this strategy applies (the Subject Land) is Lot 211 DP 8300505 (located within the Riverstone West Precinct) and [emphasis added] Lot 11 DP 816720 Riverstone Parade, Riverstone located immediately to the west of the Precinct (refer Figure C).
The objectives of Appendix C are to:
1) Define exiting flooding at the site and in the vicinity of the site in accordance with the NSW Floodplain Development Manual, 2005, the Growth Centres Development Code and Council procedures
2) Determine the flood impacts on account of the proposed development, and investigate mitigation options which will input into the Floodplain Management Strategy
3) Develop a strategy that demonstrates flood impacts at the site and adjoining the site are managed in accordance with the requirements of the Growth Centres SEPP Amendment (Riverstone West Precinct) 2009, the Growth Centres Development Code and the development controls in Section 4.3 of this DCP
4) Ensure that the Floodplain Management Strategy is supported by a Flood Emergency Response Plan and a Cut and Fill plan [emphasis added]
5) Ensure that the Floodplain Management Strategy addresses the specific requirements listed in Strategy Formulation Requirements in the Appendix of this DCP.
Amongst other things, the Strategy Formulation Requirements 2, 3 and 4 require studies of a wide range of possible flood events including as a minimum the 2 year ARI, 5 year ARI, 20 year ARI, 100 year ARI, 200 year ARI (approximate HHF [defined as the highest historical backwater flood recorded in the Hawkesbury/Nepean Catchment, being the 1867 flood with a recorded level of 19.7 m AHD or 2.4 m above the current 100 year backwater level of 17.3 m AHD for that catchment]), 500 year ARI and PMF [probable maximum flood - the largest flood that could conceivably occur at a particular location] events. In addition, the flood studies are to consider backwater flooding from the Hawkesbury River, flooding of Eastern Creek and any relevant tributaries. The requirements specify the combination of flooding events to be investigated.
Requirements 5-7 specify the use of 2-D flood modelling and list other parameters/ factors.
Requirement 8 requires that the flood studies shall investigate the cumulative effects of flooding - in accordance with the NSW Floodplain Development Manual, 2005. The developed scenario flood study must also include all proposed redistribution of flood flows on account of the proposed building platforms and other earthworks. Requirement 9 considers the impact of climate change.
Requirement 10 states:
For the proposed scenario and associated mitigation proposal relying on cut and fill in the floodplain, the proposed cut and fill extent and volumes shall be based broadly on Figures C2, C3 and C4, with minor adjustments to satisfy the performance specifications defined in the Growth Centres SEPP Amendment (Riverstone West Precinct) 2009, the Growth Centres Development Code and the development controls in Section 4.3 of this DCP
Requirement 11 states that a Staging Plan must be prepared to outline the staging of the earthworks for the precinct.
Requirement 11 specifies:
The flood studies shall investigate the impact of staging of the development and earthworks, and demonstrate compliance with the Growth Centres SEPP Amendment (Riverstone West Precinct) 2009,and the development controls in Section 4.3 of this DCP for each stage.
Figure C1 - shows the land to which the strategy applies - it includes the Riverstone West Precinct and Lot 11. Figure C2 shows preliminary cut and fill. Lot 11 is shown as primarily cut. Figure C3 depicts preliminary earthworks levels, and Figure C4 illustrates the preliminary cut and fill contours.
While the table in s 1.7.3 of RWDCP does not indicate a requirement for a Cut and Fill Plan for precinct-wide earthworks development applications, objective 4 in Appendix 3 [Flood Management Strategy] requires that the Floodplain Management Strategy to be prepared by an applicant be supported by a Flood Emergency Response Plan and a Cut and Fill Plan.
The objectives and controls for cut and fill are found in Section 4 of the DCP - Environmental Management under s 4.2 - Cut and Fill. Relevantly the objectives of cut and fill are to: provide a platform capable of supporting a range of business and industrial uses; minimise the impacts of earthworks on stormwater salinity and groundwater; manage flooding impacts in accordance with the requirements of the Growth Centres SEPP Amendment (Riverstone West Precinct) 2009; and ensure that any cut and fill does not adversely affect the conservation and rehabilitation of the riparian corridors.
In regards to the controls, they include:
1) A Cut and Fill Plan must be prepared in accordance with Table 4 in Section 1.7.3 [This is not specified in Table 4]
2) Earthworks within the Subject Land (as shown in Figure C1 of Appendix C Floodplain Management Strategy of this DCP) are to be undertaken to achieve a balance between cut and fill in accordance with the Floodplain Management Strategy (FMS) as described in Appendix C of this DCP. The FMS will confirm the final Cut and Fill Plan, which is based on the Preliminary Cut and Fill diagram shown in Figure C2 of Appendix C.
3) The finished earthworks levels are to be generally in accordance with the Preliminary Cut and Fill contours shown in Figure C3 of Appendix C. The FMS will confirm the final cut and fill levels.
8) Earthworks associated with filling within the Precinct may be undertaken in accordance with the Staging Plan as required in Appendix C. DAs are to be lodged for each stage of the earthworks, and shall be supported by documentation that demonstrates conformance with the requirements of Appendix C.
10) The Staging Plan in the Floodplain Management Strategy must be updated if there is a deviation from the most recent staging plan in Appendix C.
11) Minimum cut and fill levels must comply with Figure 20. The slope between the designated levels shall be a maximum of three per cent.
Figure 20, referred to in cut and fill control 11, shows the boundaries of the Precinct and does not include Lot 11. The indicative cut level is +RL 33.5. The indicative extent of fill platforms shown in Figure 20 does not correspond to the preliminary cut and fill diagram in Figure C2 - Appendix C.
[7]
The hearing and evidence
The hearing commenced on site. The Court had the opportunity to hear from representatives of three local groups.
The Riverstone Chamber of Commerce supports the proposal on the basis that Riverstone needs investment and employment opportunities to avoid its demise, especially given the planned significant increase in the area's population.
The Blacktown and District Environmental Group and the Friends of Knudson Reserve raised concerns about the impacts that narrowing the floodplain and changes in velocity of flood waters may have on the riparian zone along by Eastern Creek. Amongst other things, the representatives discussed the absence of any designated conservation or wildlife corridor along the western boundary of the site, the loss of Endangered Ecological Communities from this and other nearby sites and the known history of flooding in the area.
The site was inspected. The topography, existing infrastructure and other site features were observed.
The primary issue in this matter is the impact of the proposed earthworks on flood levels on adjoining properties in the locality, and within the wider catchment.
The parties' experts prepared joint reports: Mr Christopher Thomas, civil engineer and hydrologist with Worley Parsons prepared the applicant's Floodplain Management Strategy (the FMS) (Exhibit D) and Flood Impact Assessment (the FIA) (Exhibit C); Mr Andrew Bewsher, a hydrological and flooding expert, engaged by Blacktown City Council to review the relevant documentation and provide 'Floodplain Development Advice' (Exhibit 4); Mr Rhys Hardwick-Jones, an Associate of WMAwater Pty Ltd, a specialist in flood modelling, engaged by council to provide a 'Review of RMA-2 Modelling and Impact Assessment' (Exhibit 6); and Mr Steven Molino of Molino Stewart Pty Ltd, an expert in floodplain management, engaged by council to prepare a statement of evidence in regards to flood damages and flood emergency planning (Exhibit 2).
Mr Molino and Mr Thomas prepared a joint report on flood emergency response management issues (Exhibit 3). Mr Molino was not required to give oral evidence.
Mr Thomas, Mr Bewsher and Mr Hardwick-Jones prepared a joint report (Exhibit 9) on what they considered to be the key issues of: free drainage of cut areas, the significance of the local flood impacts, the quantum of the predicted increase in regional 100 year ARI flood level, the consequences of the regional flood impacts, and the methodology for assessing the cumulative flood impacts. These experts gave concurrent oral evidence. The joint report discussed below refers to Exhibit 9. Mr Hardwick-Jones' evidence was limited to questions of modelling.
Apart from the individual and joint reports prepared by the parties' experts, Exhibit F is a report to council from council's Director - City Strategy & Development - Planning & Development in regards to the appeal before the Court. It provides some background to the assumptions made and positions taken by the parties' experts. Section 2.5 clauses a. and b. are particularly useful.
a. The DCP provides floodplain management controls in Appendix C and shows indicative sketches of the areas of cut and fill in Figures C2 to C4. These sketches are shown as contour plans and are not supported by indicative volumes of cut and fill. However they form the basis for filling of the floodplain as adopted by the Department of Planning and Environment for the site. The strategy in the DCP proposed the provision of compensatory flood storage within Lot 11 which adjoins the development site. Lot 11 is now owned by a separate owner to the subject land.
b. Council was provided with a copy of the surface modelling used to establish the basis of Figures C2 to C4. An analysis of this information indicates there will a loss of about 2,650,000 m3 of flood storage for development of the full site. This loss of flood storage is a development principle that now underpins the Precinct Plan and DCP for the site. This means that this loss of flood storage has been accepted by the NSW Government, in principle, as a first layer of assessment of the proposal. However, the overall impact on the floodplain external to the site is the second layer of assessment.
At 2.6 a. and b.:
a. DA-13-1845 will result in a loss of floodplain storage of 1,116,255 m3 within the precinct. This is achieved by reshaping and evening out the site to create a suitable development platform and importing material from excavation work for the North West Rail Link.
b. This is the Stage 1 DA for the precinct earthworks. Other DAs will be submitted later. However, the total impact of the net loss of flood storage within the precinct from all DAs should be no greater than the 2,650,000 m3 of lost flood storage endorsed by the DCP.
The basis of the assessment is the 1:100 year flood level of RL 17.3 mAHD.
Amongst other things, the experts considered the FMS. The joint report outlines the potential fill options for the Riverstone West Precinct considered in the FMS.
Option 1 is based on the maximum fill extent defined by the Indicative Layout Plan [Figure 5 RWDCP] approved as part of the rezoning of Lot 211. It involves no cut within Lot 211 and the net loss of floodplain storage below 17.3 mAHD of 3.62M m3.
Option 2 is based on the same layout plan as Option 1 but considers floodway constraints and selective cut within Lot 211. It results in a net loss of floodplain storage below 17.3 mAHD of 3.74 M m3.
Modified Option 2 [considered during conciliation] involves selective cut within Lot 211 and a net loss of floodplain storage below 17.3 mAHD of 2.65M m3. This is the option assessed in the FIA - referred to in that document as the 'updated development layout'.
The FMS modelled the combined probabilities of concurrent flood events required by the RWDCP: Eastern Creek 100 year ARI + Hawkesbury 100 year ARI; Eastern Creek 100 year ARI + Hawkesbury 5 year ARI; and Eastern Creek 100 year ARI with no concurrent flooding of the Hawkesbury. In addition, for completeness, Worley Parsons modelled a combination of a 100 year ARI Eastern Creek flood with a 20 year ARI Hawkesbury flood for option 1.
In order to determine the impacts of the proposal on local and regional flooding, Worley Parsons used an updated RMA-2 model as the primary basis for their calculations. The RUBICON (1999) model was used to compare peak flood levels generated by the RMA-2 model and validate the use of the RMA-2 model. The results of the RUBICON modelling were used to adjust the RMA-2 results (adjusted RMA-2).
In his review of the modelling, Mr Hardwick-Jones states that the Hawkesbury-Nepean system, including its tributaries of Eastern Creek and South Creek, is complex and difficult to model with the available technology. This is primarily due to the size and scale of the floodplain and the nature of the topography in the Richmond - Windsor area. He states that each of the available models -RUBICON and the RMA-2, has limitations when assessing flood behaviour in this region.
The RUBICON model is essentially a one dimensional model developed in the late 1980s/ early 1990s for the length of the Hawkesbury-Nepean River to the Warragamba Dam. The model is composed of a network of flow paths - each of which is represented by surveyed cross-sections. The model is limited in its ability to resolve flow behaviour in areas where complicated cross-flows occur.
The RMA-2 model is a two dimensional model developed in the late 1990s and updated since then to incorporate more of the catchment as more topographic data is collected. While the topographic data is more precise than the surveyed data used in the RUBICON model, the geographic extent of the RMA-2 model is more limited. The limitation of this model is that the impacts of flooding events outside the boundaries of the model, especially downstream, cannot be accurately assessed.
Notwithstanding the limitations of the models, all three experts agree that the modelling undertaken for the FMS and the FIA appears reliable and provides accurate estimates of the impact of the proposed development on flood levels and velocities under local flooding conditions. They agree that the changes in flood velocities due to the three options are likely to be small and consistent with cl. 20(2)(c) of SEPP - SRGC (Exhibit 9- [13]-[14]).
The joint report includes a number of tables summarising the predicted maximum rise in flood levels for both local and regional flooding derived from the three models used for the range of flood events given in paragraph [59].
Mr Bewsher and Mr Thomas agree that the results of the modelling of the three local flood scenarios required by RWDCP indicate that there will be an increase in peak flood level outside Lot 211 of less than 10mm. The modelling for the 100 year ARI Eastern Creek flood with a 20 year ARI Hawkesbury flood (100/20) for option 1 indicates a possible increase of 40mm. It is agreed that the accuracies of flood models are traditionally considered to be 10 to 20mm.
[8]
Submissions
The applicant contends that in view of the strategic aims of SEPP - SRGC, the Court should take a purposive approach in considering cl. 20(2) of SEPP-SRGC.
Mr Clay, for the applicant, asserts there are different standards applied to the relevant sub clauses (2)(b), (c), and (d). In addition, cl. 20(3) identifies another standard. Specifically, cl. 20(2)(b) states 'does not increase', cl. 20(2)(c) limits any increases to 'minor increases', and cl. 20(2)(d) states the proposed development must not result in 'adverse' flood impacts. Clause 20(3) considers minor development that will not result in 'unacceptable adverse' flood impacts.
In Mr Clay's submission, the key question to be answered is - what is the proper construction of the phrase in cl. 20(2)(b) -'does not increase flood levels'. It is his submission that this phrase means an increase in flood levels which is more than nominal, not trivial, not negligible and therefore material. He cites a number of cases to support this contention including Dainford v Lamb (1985) 3 NSWLER 255 at [268] where Powell J said in considering the phrase "affected substantially and adversely":
By adding the word "substantially" to a clause which would otherwise be operated if the relevant effect was anything more than just nominal, the draftsman was intending to indicate that, before the clause could operate, the relevant effect must be shown to be of real substance.
In Manning v Bathurst Regional Council & Others (No 2) [2013] NSWLEC 186, Pepper J at [63] and [71] in regards to the meaning of "unlikely to be affected" said:
[63]…In other words, "affect" is not to be construed to include any and all "effects" no matter how trivial, of a development…
[71]…The only applicable touchstone is one of materiality, or conversely, immateriality or triviality…
In regards to the application of cl. 20(2)(b) to the expert evidence, Mr Clay maintains that this only applies to adjoining properties and not to the broader region and that the agreed position of the experts was that the increase would be about 10mm which falls within the accuracy limits of the flood models. To that extent, the increase must be considered negligible or immaterial and therefore cl. 20(2)(b) is not offended and cl. 20(2)(d) is met. With respect to cl. 20(2)(c), the experts agree that the increase in velocity is likely to be minor and acceptable. While he agrees that the development is more than minor, Mr Clay asserts that the performance outcome of "will not result in unacceptable adverse flood impacts on adjoining properties" in cl. 20(3) is achieved by this proposal. In regards to the 100/20 combination of flood events and a possible increase of 40mm, Mr Clay maintains that the Court should accept Mr Thomas' evidence on the unlikely occurrence of such an event. He submits there is no evidence that this combination should be considered as the design flood level, which he asserts, is Mr Bewsher's view.
Mr Clay maintains that while cl 20(2)(a) requires the proposed development be undertaken in a manner consistent with the Floodplain Management Strategy in RWDCP, this implies broad compliance and a common sense approach that achieves the desires outcomes of the SEPP and DCP. To that end, the proposed cut and fill volumes should be based broadly on the relevant figures in Appendix C of RWDCP.
With respect to the regional flooding impacts of the proposal, Mr Clay contends that this is effectively a diversion as the DCP expects there to be some regional impact as it allows fill within the floodplain. He asserts that the emphasis in the SEPP and the DCP is on local flooding and there is no requirement to consider the cumulative regional impacts. Mr Clay maintains the context must be the regional/strategic level set by the creation of a growth centre and any impacts must be offset against regional and broader community benefits. He contends that the regional impacts of adding 2.65M m3 to a floodplain in excess of 22,000 km2 would have the equivalent impact of adding a few grains of sand to a glass of water.
Similarly, in regards to the cumulative impacts on the floodplain and likely precedent an approval would have, Mr Clay asserts that any approval will not create an expectation elsewhere in the growth centre as the NSW Government will determine what is appropriate for each precinct via a precinct-specific DCP. In this respect, he maintains that the applicant has formulated the development proposal by applying what is permitted by the RWDCP.
In summarising council's contentions, Mr Clay considers that to the extent necessary: contention 1 - impacts on the floodplain and contention 2 - precedent and cumulative impacts have been addressed. The applicant is prepared to accept conditions concerning contention 3 - traffic movements and the Vineyard level crossing and contention 4 - the adequacy of the Flood Emergency Response Plan. In regards to contention 5 - source of the fill, the applicant is prepared to accept a condition that specifies a qualitative condition rather than restricting the applicant to a particular source.
In essence, Mr Clay submits that there are some tensions between the planning instruments and controls, the Court's approach should be flexible and consider the bigger/ more strategic picture.
The applicant accepts that while there are some deficiencies in the Development Application such as the inconsistency between the staging plan shown in the FMS and the application before the Court, these do not warrant refusal of the appeal and could be easily rectified by the imposition of conditions or at worst, by the Court taking an "amber light" approach.
Mr Miller for the council submits that the application, when assessed against the requirements of s 79C of the Act, should be refused on a number of grounds.
In regards to cl. 20(2) SEPP-SRGC Mr Miller contends that: subclause (a) is capable of being achieved however the development application falls short; as subclause (b) is not satisfied, the Court must not approve the DA; as any increase in velocity of floodwaters is agreed by the experts as being minor, subclause (c) is met; subclause (d) doesn't specify flood levels and requires consideration of the construction stage, as the applicant has not modelled the impacts of the cut and fill proposed in the DA, satisfaction of this subclause is uncertain.
In considering cl. 20(2)(b) and Mr Clay's submissions, Mr Miller maintains that the phrase "does not increase" does not include any qualification that implies anything other than what it says, unlike subclauses (c) and (d). All experts agreed that the proposal would increase the flood levels on adjoining land. In regards to the cases cited, the words must be read in the context of the matter/ planning instrument being considered and that an adverb cannot be taken out of one clause and grafted onto another.
Council's view is that the development application is deficient in many ways as it does not fully meet the requirements of RWDCP. This includes: no modelling of any fill below the 17.3 mAHD level; no investigation of the impacts of the staging of the earthworks on flood level, and in particular, the impact of the earthworks the subject of the DA; and no current stormwater plan.
Mr Miller maintains that any suggestion that the DCP permits flood impacts is incorrect and elevates the DCP above the SEPP.
In regards to the regional flooding impacts and associated potential damages, Mr Miller contends that this is not a distraction and council's concerns are entirely reasonable and responsible and the issue is an important matter for consideration under s 79C.
[9]
Consideration and findings
The main issue in these proceedings is the impact of the net increase in fill and subsequent loss of flood storage as a consequence of the proposed earthworks on local and regional flood levels.
Section 79C of the EPA Act requires us to take a number of relevant matters into consideration in our determination of this development application.
The starting point of our consideration must be SEPP-SRGC as this is the environmental planning instrument that applies to the site (s 79C(1)(a)(i)). Essentially, the aims of the SEPP are to co-ordinate the release and planning of land for urban development in an orderly and sustainable manner in Sydney's regional growth centres, including the North West Growth Centre.
Clause 20 - Development on and near certain land at Riverstone West -specifically applies to this development application. Clause 20(2) makes it clear that '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 of all four specified matters in subclauses (a), (b), (c) and (d).
Subclause 20(2)(a) requires that the proposed development will be undertaken in a manner that is consistent with the Floodplain Management Strategy which is part of the RWDCP [Appendix C]. Therefore, the SEPP requires the application of the DCP. Notwithstanding the deficiencies in RWDCP (discussed elsewhere), the DCP in turn consistently requires demonstration of compliance with the SEPP. Apart from the exceptions noted below, we are generally satisfied that the applicant's detailed Floodplain Management Strategy, to the extent that this underpins the proposed development, complies with Appendix C of RWDCP. We acknowledge the applicant's acceptance of the deficiencies in the Development Application and council's agreement that most of these deficiencies can be dealt with by way of conditions.
In our view, subclause 20(2)(b) is the key to whether consent can be granted to the proposed development. This subclause requires the consent authority to reach a state of satisfaction that the proposed development 'does not increase flood levels on adjoining properties up to the design 100 year recurrence flood'.
In this regard we prefer Mr Miller's submissions on the interpretation of the subclause (at [85]). In our view 'does not increase' has the same meaning as 'there will be no increase'. The ordinary meaning of 'no' (Macquarie Dictionary) in this context is "not in any degree", and for 'not'- "a word expressing negation, denial, refusal or prohibition". In our view, this subclause prohibits any development that would lead to an increase in flood levels on adjoining properties. There is no qualification of the word 'increase' other than a prohibition through the use of 'not'. This is contrasted with the qualifications of the degree of flooding or level of impact allowed in subclauses (c) and (d).
At [17] of the joint report, and confirmed in oral evidence, the experts agree that the proposed development will increase flood levels outside Lot 211 and therefore on adjoining properties; albeit the increase is less than 10mm for most modelled flood scenarios, a figure acknowledged to be within the sensitivities of the models. While we note the dispute between the experts about the 100 year ARI Hawkesbury flood with a 20 year ARI Eastern Creek flood and its significance, the potential increase of this combination is 40mm. Even if we accept Mr Thomas' considered and reasonable explanation of the rarity of this event and discard this combination, as there will be an increase in flood levels arising from the other modelled events, we cannot grant consent to the development application before us.
We also note the agreement between Mr Bewsher and Mr Thomas at paragraph [69] of this judgment that refining the fill footprint in the south-east corner of Lot 211 would probably reduce the predicted flood level for the 100/20 combination to an acceptable level, no modelling has been undertaken to demonstrate whether that acceptable level is still an increase, and or what the impact may be on the other specified combinations of flood events. Therefore, despite this agreement, we cannot be satisfied to the level required by cl. 20(2).
While modelling has been undertaken for the design 100 year recurrence flood, but not specifically up to that point as required by c. 20(2)(b), we do not see this particular element of the subclause as a matter warranting refusal.
Although we have determined that we cannot grant consent to the proposed development, we have considered the other subclauses and matters to be addressed under s 79C.
As the experts agree that the proposal limits any increases in flood velocities on adjoining properties to minor increases, we are satisfied that subclause 20(2)(c) is met.
On the face of it, the increases in flood levels on adjoining properties appear to be small however, as no modelling has been undertaken of the proposed stage 1 earthworks, we cannot be satisfied there will be any adverse flood impacts on those properties as a consequence of the proposed development. To this end, subclause 20(2)(d) is not met but could be with further modelling and assessment.
In regards to the regional impacts, the focus of cl 20(2) is on adjoining land and therefore local impacts. RWDCP appears to have a broader, more ambiguous focus. While Appendix C requires an FMS to consider local impacts, it must also be prepared in accordance with the NSW Floodplain Development Manual 2005. The Manual does not specify the size of any study area however it provides a range of factors to consider in defining the study area. The Worley Parsons FMS considered it unrealistic to consider the entirety of the Hawkesbury-Nepean system given its massive size. The FMS investigated the impact on an area of about 98km2 being the 'local' floodplain with a consistent 100 year ARI flood level equivalent to 17.3 mAHD'. In our view this is a reasonable approach.
Notwithstanding the disagreement between Mr Thomas and Mr Bewsher about the assessment of the cumulative impacts of the proposal on the floodplain, we note the experts' agreement (paragraph [70] of this judgment) that there will be an increase in flood levels at a more regional level. While this is a relatively minor increase, it will nonetheless have an economic impact and must be considered in the public interest under s 79C(1)(e). The SEPP provides no specific guidance in regards to regional impacts although applying the same logic to regional flooding as is given to local flooding in cl. 20(2)(b), we must similarly refuse the proposal on this basis. We also note the Development Objective (2) in RWDCP which is to "ensure development does not cause offsite flood impacts that are unacceptable to Council". On the evidence before us we cannot be satisfied that the offsite flood impacts would be acceptable.
Both the SEPP and s 79C(1)(a)(iii) require consideration of RWDCP.
It is fair to say that the drafting of RWDCP and to some extent the SEPP, has created challenges for the parties and for the Court. Indeed, there are many inconsistencies in RWDCP that don't engender great confidence in it, starting with the absence of the date of commencement and including others, such as cut and fill plans, that have been mentioned elsewhere in this judgment.
Significantly, RWDCP only applies to the land illustrated in Figure 1 - the Riverstone West Precinct and does not include Lot 11 on the yet to be rezoned precinct to the west. The DCP requires the preparation of precinct-wide plans. However, cl 20 SEPP-SRGC applies to the Riverstone West Precinct and Lot 11 as does Appendix C in RWDCP, (referred to in cl. 20(2)(a) SEPP-SRGC) and presumes cut and fill earthworks - illustrated in Figures C2, C3 and C4 of the DCP. Our reading of cut and fill control (2) in s 4.2 of RWDCP is that the works within the Riverstone West Precinct and Lot 11 are to achieve a balance between cut and fill as indicated in Figure C2 of Appendix 3. The council report considers the loss of 2.65 million cubic metres of floodplain storage within the Riverstone West Precinct as a figure endorsed by the RWDCP and which therefore the council is prepared to accept (see [55]-[56] of this judgment), however, we cannot be so confident.
The inclusion of Lot 11 into some parts of the SEPP and DCP and not others presents great difficulties for a proponent and the consent authority given Lot 11 is in separate ownership and its status is uncertain. Indeed it is not clear that SEPP-SRGC currently applies to Lot 11 as the zoning map Sheet LZH_004 shows Lot 11 as being outside the boundary of the North West Growth Centre (see [24]). In our view, neither the 2009 amendment to the SEPP (occasioned by the creation and rezoning of the Riverstone West Precinct) nor the accompanying RWDCP, have been carefully drafted to avoid anomalies and inconsistencies or, if the anomalies are intended, explain them in any meaningful way.
In considering the submissions made on behalf of the chamber of commerce, we agree that the proposal is largely consistent with the aims and objectives of both the SEPP and the DCP. To the very limited extent to which environmental issues were canvassed, the proposal is unlikely to cause any unacceptable impacts on the riparian zone and the wildlife corridor. We note the proposed setback of any earthworks from Eastern Creek and the very minor increases in velocity of any floodwater. We also note that s. 1.4.3 RWDCP states that 16.3 ha of existing native vegetation is to be retained or offset within the precinct, 4.3 ha of which is to have Biodiversity Certification under the Threatened Species Conservation Act, 1995.
[10]
Orders
As a consequence of our findings, the Orders of the Court are:
1. The appeal is dismissed.
2. Development Application DA-13-1845 for Stage 1 bulk earthworks and associated activities on part of Lot 211, DP 830505, Riverstone is refused.
3. The exhibits except B and 5 are returned.
Judy Fakes
Commissioner of the Court
Ross Spears
Acting Commissioner of the Court
[11]
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Decision last updated: 27 January 2015
The experts disagree about the relevance of the 100/20 combination. Mr Thomas considers this would only result in an increase locally to 13.77 mAHD - well below the adopted 100 year ARI flood level of 17.3 mAHD. He also maintains that such an event is very rare and highly unlikely because the two catchments have significantly different critical durations in that peak flooding of Eastern Creek occurs in about 9 hours and flooding of the Hawkesbury takes about 72 hours. That is, the peak flood from the Hawkesbury would not occur at Riverstone West until approximately 57 hours after the arrival of the peak generated by rainfall falling across the Eastern Creek catchment.
Mr Bewsher is of the opinion that the applicant hasn't demonstrated that this combination is the worst case scenario and that an assessment of rainfall patterns has not been undertaken to consider the impacts of locally heavy rain storms, for example embedded storms associated with an east coast low, across the catchment.
Despite their differences in regards to the significance of local flood impacts, Mr Bewsher and Mr Thomas agree that a small refinement to the south-east corner of the fill footprint within Lot 211 would likely reduce the predicted flood level for the 100/20 combination to an acceptable (but unspecified) level.
With respect to regional flood levels, all three experts agree there will be an increase as a consequence of the proposed development. The increase in levels for option 1 is agreed at no more than 12mm; for modified option 2, the experts consider the range is from 5mm to 9mm.
Mr Thomas and Mr Bewsher agree that the potential consequences of concern associated with an increase in regional flood levels are the number of additional dwellings that would be flooded above floor level as a consequence of a rise, and the resulting increase in flood damages.
Mr Thomas and Mr Molino prepared a joint report in regards to potential damages. The experts agreed that for each rise of 1mm in the regional flood level, there will be, on average, one additional house flooded above floor level with a tangible cost of between $120,000 and $420,000 per 1 mm increase. Mr Bewsher considers a more realistic order of damages to be around $1M for each 1mm rise in the regional flood level.
Mr Thomas and Mr Bewsher agree that cumulative impacts of fill across the floodplain must be considered. The FMS includes an assessment of potential cumulative impacts in response to Item 8 Appendix C RWDCP - "developed flood studies should investigate the cumulative effects of flooding". The FMS tabulated the estimated fill volumes for the development areas within the local floodplain. The development areas considered are Pitt Town, Windsor Downs, Marsden Park, Schofields, St Marys Release, Wilberforce and Riverstone West. The investigation found that the proposed development of the Riverstone West Precinct represents 83% of the total volume of predicted filling. In view of the predicted small increases in flood levels indicated by the flood modelling, the FMS found the cumulative impact of all possible development would be negligible.
Mr Bewsher is of the opinion that the cumulative impacts have not been assessed correctly and are not negligible because the extent of potential development within the Hawkesbury-Nepean floodplain is larger than the zoned land considered by the FMS and the consequences of even small rises in the regional flood level are considerable and cannot be ignored. Mr Bewsher remains concerned that approval of the development would set a dangerous precedent for floodplain management in the Hawkesbury-Nepean Valley.