Letter to Noosa Council - 20 Mitti Street

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Proposed Development
Pursuant to section 78 of the Planning Act 2016, the applicant is making a ‘minor change’ to the
application as shown in Figure 1 (Attachment 2).




Figure 1 – New Proposal Plan

The ‘minor change’ marginally increases the area of Lot 1 to 711m² with Lot 2 having an area of 662m².
The boundary of Lot 1 near the access easement has been shifted towards the north west so that both
allotments can be readily connected to the existing sewer main that traverses the land. No changes
are being proposed to the existing access arrangement or the existing built form on the land, other
than the provision of a kitchen and laundry within the existing extension once the reconfiguration has
occurred.

At this time the stormwater easement has also been removed from Lot 1. This is because it is not clear
what purpose the easement serves given the applicant is responsible for the maintenance of the
property; however, the applicant might accept the imposition of an easement over Lot 1 if the purpose
of the easement can be explained.

This is particularly the case given no further building work is being proposed on Lot 1, with no increase
in stormwater runoff. If it is intended by the easement to prevent further building work on Lot 1, then
the applicant would accept a condition that prevents any further building work within Lot 1. Further,
a property note could also be included advising future owners of the localised stormwater flows across
the site during a 1%AEP event.


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The changes being made do not affect the proposed access and services easement for Lot 1. Further,
it is understood that the applicant has demonstrated that there is adequate onsite maneuvering for
vehicles to enter and leave both allotments in a forward gear and pass one another should that be
necessary; however, in my opinion, this is unlikely given the existing sight lines that are available.

Pursuant to the definition of part (a) of a ‘minor change’ under the Planning Act 2016, the proposal
will not result in a substantially different development under Schedule 1 of the Development
Assessment Rules (i). Further, if the application was remade including the change would not cause any
of the circumstances listed as (A) to (E) under part (ii). Consequently, the proposed development is a
‘minor change’.




Figure 2 – Aerial Photograph

Site and Surrounds
The site is located at 20 Mitti Street, Noosa Heads, has an area of 1,373m² and slopes from Mitti Street
downwards towards the Noosa National Park to the east (refer Figure 2). The site is improved by a
relatively large dwelling having two parts, both being removed from and not clearly visible from the
roadway. The land is generally secluded and has a vegetated and landscaped setting. The land is partly
located in an overland flow path which is predominately maintains a low flow volume but is affected
by localised stormwater flows during a 1%AEP event.

The land is characterised primarily of dwellings on the eastern side of Mitti Street, with several unit
developments located on the western side. To the immediate north is a group housing development
comprising allotments that are about 350m² in area. Adjoining the site to the west is an allotment
having an area of about 600m². To the south is another group housing development comprising

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allotments that are also about 350m² in area. The surrounding land is generally comprised of dwellings
on allotments that are about 600m² in area (Figure 2).

Background
The subject land contains a dwelling with recent addition being approved by Noosa Building Certifiers
(2016-0730), which was subsequently amended on 14 August 2018. The additions are connected to
the existing dwelling by an elevated walkway. The existing dwelling contains one kitchen, laundry and
is otherwise self-contained for the exclusive use of one household, in accordance with the definition
of a dwelling unit and consistent with a Detached House use.

A letter from Noosa Council dated 19 February 2018, was sent to the applicant suggesting that the
dwelling was being used as a dual occupancy; however, the applicant has confirmed that this is not
the case. Given the unique nature of the property the dwelling is made available for short term
accommodation in a range of modes to meet market demand.

While the applicant does rent the main dwelling on proposed Lot 2 for visitor accommodation from
time to time, the applicant does not attend the site while this is occurring. That is, both parts of the
dwelling are not occupied by different households at the same time. Consequently, the use of the
existing dwelling by a single household is consistent with the definition of a Detached House. Further,
it is not unusual for part of rental property to not be available for use by visitors; however, this might
change in the future.

The letter also states the applicant … may also wish to investigate the possibility of reconfiguring the
lot into 2 lots. However, goes on to say that … please note though the site is not sufficiently sized to
meet the minimum lot size requirements for a 2-lot subdivision falling below the minimum lot size of a
battle axed shaped lot of 800m². Therefore, were you to proceed with such a proposal the application
would need to demonstrate relevant grounds to Council.

Because of the above suggestion, the applicant lodged the current application in good faith following
a positive prelodgement meeting with the Council. Further, the applicant has provided all information
necessary in support of the proposal. It is hoped that this submission will provide enough information
that the development will be considered favourably.

It should be noted that the applicant has advised should the application not be supported it is likely
the whole of the dwelling will be made available for visitor accommodation in the future. The existing
built form contains a number of large bedrooms and other facilities making the dwelling attractive to
visitors, in particular large groups. It would be reasonably expected the property would be well
occupied by visitors to the area given the desirable location.

Localised Stormwater Flows
The key issue associated with the development is the matter of localised stormwater flow during a
1%AEP event. According to the advice provided by Barlow Shelley in the Flood Hazard Assessment
Report, the following is most relevant:



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    •   the flow across the subject land is intermittent from the Noosa National Park with the site
        being dry most of the time and predominantly containing trickle flows;
    •   about 30% of the total flow from the upstream catchment passes through the site with the
        remaining 70% being within the Noosa National Park;
    •   adjacent to the upstream (southern) boundary the flow depth beside the existing extension in
        the Defined Flood Event (DFE - 1%AEP) is 400-500mm deep;
    •   the maximum flow depth across the driveway low point is about 390mm and the velocity of
        flow complies with the relevant standard being less than 0.45m/s (Table 7.4.5 from QUDM for
        “Vehicle safety: Transverse flow limits (no risk to life) e.g. road intersection”);
    •   the consulting engineers (Barlow Shelley) being structural and civil engineers have designed
        the dwelling extension to withstand the localised stormwater flows and to be substantially
        above the DFE; and
    •   the critical time of concentration for the DFE is 33mins so the 1%AEP event starts as ‘dry’ at
        0mins and peaks at 33mins, the maximum velocity and depth then subsides at approx. 60-
        65mins back to ‘dry’. Therefore, the peak (worst case) flows across the driveway and the site
        for approximately 10-15mins.

Barlow Shelley has provided additional advice which is provided as Attachment 3. This advice
addresses the issues raised in the email from Council to Martoo Consulting on 27 June 2018, and the
following comments are made:
    • the advice confirms approximately 30% of the flow passes through the site west of the new
        extension with the remaining 70% by passing the site within the Noosa National Park;
    • any local increases in flow depth due to debris build-up against the downstream tennis court
        fence will not be significant that would not affect the existing extension to the dwelling. This
        is because the floor level is about 800mm above the 1% AEP at the downstream face and
        580mm above at the upstream face. This provides an adequate factor of safety and complies
        with Council’s codes and policies;
    • Barlow Shelley being structural engineers have confirmed that the residence was designed to
        suit the conditions and accommodates the modelled flows as notated in the reports submitted
        to date; and
    • the modelling already addresses the full catchment and provides enough detail for the
        assessment, particularly considering that the extension is existing and has been designed,
        certified, approved and built to suit the site conditions.

This is unlike an area that is subject to river flooding under the Natural Hazards and Landslide Overlay
(OM6.3), which does not apply to the subject land. Land subject to river flooding in the Noosa Heads,
Noosaville and Tewantin localities can be developed where in accordance with specific outcome O2
of the Detached House Code. In these locations many properties are inundated by flooding for
extended periods and have restricted access, yet development is allowed, subject to meeting relevant
criteria. These same provisions apply, and the existing extension to the dwelling has been designed
and constructed to satisfy these provisions.

In this case having regard to the design of the existing extension, the associated access and the
engineering advice provided, in my opinion, the risk to people and property is minimal. This is because:

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    •   all habitable rooms are located 580mm or more above the DFE, with the planning scheme
        requiring 300mm;
    •   the extension to dwelling has been structurally designed to cater for a 1%AEP storm event;
    •   the depth and rate of flow across the access accords with the level of safety under the relevant
        standard (QUDM) and has a limited duration of 10-15 minutes; and
    •   regardless of the proposal to reconfigure the land, the level of risk remains the same for
        occupants of the extension.

Noosa Plan 2006
The application made is for reconfiguring a lot for the creation of two (2) allotments from a single
allotment. The subject land is located within the Noosa Heads Locality and is included in the Detached
House Zone.

Under the assessment table for development other than Material Change of Use (Table 9.10), the
proposed development is code assessable against the Noosa Heads Locality Code, Reconfiguring a
Lot Code, Landscaping Code and Engineering Works Codes.

Noosa Heads Locality Code
Under Part 9.7.1 of the Noosa Heads Locality Code, the overall outcomes are the purpose of the Code.
Under part 9.7.2 the most relevant overall outcomes include (a) and (nn). Having regard to overall
outcome (a), the dwelling on the new allotment:
   i.  is compatible with other uses and works in the locality;
  ii.  will maintain the safety of people and works;
 iii.  will not have a significant impact upon the amenity enjoyed by users or other premises; and
 iv.   avoids any significant adverse effect on the natural environment.

Having regard to overall outcome (nn), specially for the Detached House Zone:
   i.  the development has a low site impact and is a low-density development form having a
       domestic scale;
  ii.  maintains a high level of residential amenity;
 iii.  the allotment sizes and density are consistent with the character of the neighbourhood;
 iv.   the existing building style will remain unchanged and is befitting of the character of the
       locality, and is integrated with the site characteristics including slope and vegetation; and
  v.   no further building work is being proposed with landscaping provided amongst the existing
       buildings, with some trees and vegetation also being retained.

Under Table 9.11, the most relevant specific outcome is O16 (Flooding and drainage), with buildings
and other works designed and sited:
   a) with flood free habitable rooms being located at least 580mm above the DFE (1%AEP storm
       event) on Lot 1, a vehicle can safely traverse the access should that be necessary given the
       velocity and depth of flow is below the level of safety required and has a limited duration of
       10-15 minutes;
   b) the inundation of Lot 1 is relatively minor, short term and infrequent and does not affect any
       habitable rooms;

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    c) the new carport is located 800mm below the extension and will flood by 50-100mm in a 1%AEP
       storm event; however, is still elevated and will drain by gravity means;
    d) the existing building on Lot 1 is elevated and allows water to flow beneath, with the existing
       driveway not adversely impacting upon other premises, and no new works are being proposed;
       and
    e) no earthworks are proposed, and the existing development does not cause ponding on site or
       nearby land, has not increased flooding or affect the safety or use of any other land, and does
       not adversely affect the flow of water in the overland flow path.

In my opinion, the proposed development complies with specific outcome O16, and does not offend
any of the other specific outcomes for the Detached Housing Zone. Further, the proposed
development is consistent with the overall outcomes and purpose of the Noosa Heads Locality Code.

Reconfiguring a Lot Code
Under part 14.181.1, the overall outcomes are the purpose of the Reconfiguring a Lot Code. Having
regard to part 14.181.2, the following comments are made about the most relevant overall outcomes
(adopting the same numbering):
   a) the lot sizes and dimensions are appropriate for their intended use;
   b) maintain the same residential land uses in the locality;
   c) the proposed lots have suitable, safe and appropriate access;
   d) the proposed development, including the existing buildings and works will not have any
       impact on the existing drainage line or other environmentally sensitive area;
   e) the proposed development does not impact upon the road network;
   f) …;
   g) the proposed lots will not have any impact on the natural environment and landscape, and will
       not worsen the risk to people and property having regard to stormwater flows during a 1%AEP
       event (refer comments above);
   h) the proposed allotments can be readily serviced in an effective and efficient manner;
   i) …
   j) …
   k) the orientation of the allotments is set given the minor nature of the development and the
       location, with buildings already established on the land;
   l) the proposed development is entirely consistent with the developed character of its
       neighbourhood;
   m) … ; and
   n) … .

Having regard to the above, the proposed development is entirely consistent with the overall
outcomes and purpose of the Reconfiguring a Lot Code.

With respect to Table 14-66, the following comments are made about the most relevant specific
outcomes:




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Lot Size and Dimensions:
O1 Lots have the appropriate area and dimensions for (adopting the same numbering):
   a) the intended use for Detached Housing with no further building work being proposed. The
       existing structures have adequate building setbacks, private open space and on site
       manoeuvring for vehicles. While the proposed allotments technically do not meet the
       minimum allotment size of 800m² under Table 14-68, the allotment sizes are well above the
       minimum lot size of 600m² for the Detached Housing Zone and are adequate for the intended
       use;
   b) while the proposed residential development on Lot 1 is not above the 1%AEP storm event
       level:
           a. the extension to the dwelling is existing;
           b. all habitable rooms are located at least 580mm above the stormwater flow level;
           c. the overland flow path provides for intermittent and irregular flows only;
           d. the maximum depth and volume of flow across the access has a limited duration and
               complies with the relevant safety standard (QUDM); and
           e. the proposed development does not change the level of risk to people and property
               with the existing development remaining unchanged;
   c) the development proposed is not a community title;
   d) the existing built form has been sited, designed and constructed to minimise the risk from
       stormwater flow;
   e) the proposed development will not have any impact upon water quality with limited works for
       the provision of services being required;
   f) the proposed development does not require further building work with no loss of the natural
       environmental values, including native vegetation;
   g) … ;
   h) no earthworks are proposed with no further development being intended other than to
       provide for some services;
   i) the private open space areas within the proposed allotments are to be landscaped and
       maintained; and
   j) convenient vehicle access, onsite manoeuvring and parking is provided for both dwellings on
       the proposed allotments.

Having regard to the above, the proposed development either complies with or meets the intent of
the overall outcomes. To the extent there is any deemed non-compliance with this specific outcome,
in my opinion, this is minor and of technical nature only.

Lot Layout:
O4 Subdivision of land for residential development provides for a neighbourhood with a strong and
positive identity. To the extent relevant, the proposed development does not offend any of the specific
outcomes and is entirely consistent with the nature and character of the locality.

O5 Having regard to house site areas, while the extension to the dwelling on Lot 1 is not located 50m
from the Noosa National Park, the extension exists and no further building work is proposed. Further,



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the development has no impact upon the environmental values and is not at risk from bushfire
according to the mapping provided.

O6: The proposed development is for residential purposes and provides for a variety of lot sizes in
keeping with the character of the area.

Infrastructure:
O15: Each of the proposed lots is capable of being serviced by appropriate levels of infrastructure,
including water supply, reticulated sewerage, power supply and telecommunications. The matter of
stormwater drainage is not relevant given that each dwelling as constructed drains by overland flow
to the natural drainage line.

O17: The proposed infrastructure to service the additional lot can be designed to maintain effective
function during and immediately after a storm event.

Earthworks and stormwater management
O19: Stormwater runoff from the proposed development is not an issue given no further building
work is being proposed on the land. The existing development will not be changed and there is no
adverse impact upon the natural environment.

O20: No filling or excavation work is proposed, and the development does not impact upon the
existing drainage line, is not mapped as containing protected vegetation under the Biodiversity
Overlay (Map OM6.1) and does not affect water levels on properties elsewhere.

Landscaping and visual amenity:
O21, O22 & O23: The proposed development responds to the distinctive landscape character with
the existing built form being integrated within the natural features on the site and will not result in
the removal of any significant trees or vegetation that would impact upon the views of the locality.

Access Easements:
O32: It is proposed to provide a services and access easement over Lot 2 in favour of Lot 1. The
easement is in an appropriate location to provide safe access and egress and has enough width to
service both allotments. Further, it is understood that there is an agreement in place for the sharing
of maintenance of the footpath crossover, which also serves 22 Mitti Street.

Traffic:
O33: The traffic generated by the proposed development will have a negligible impact upon the
external road network.

In summary, the proposed development meets the overall outcomes and the purpose of the
Reconfiguring a Lot Code. Further, the proposed development either complies with or meets the
intent of the specific outcomes under Table 14-66.




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Other Provisions
In terms of the other codes including the Landscaping Code and Engineering Works Codes, the
proposed development either complies with or could be conditioned to comply.

The subject land is located within the Urban Footprint under the South East Queensland Regional Plan
2017 and makes use of available residential land which can be readily serviced in an efficient and
effective manner at minimum cost.

Having regard to the State Planning Policy 2017 (SPP), the proposed development is not within an
area mapped as being subject to flooding (refer OM6.3); however, the land is subject to localised
storm water flows during a 1%AEP event. For reasons given above, the proposed development does
not pose a significant risk to people or property.

Conclusion
The proposed development seeks to reconfigure land to create two allotments. The land contains a
Detached House which is in two parts connected by an elevated walkway. The existing structures are
to be retained and will become two dwellings, with internal modifications only being required for the
extension over proposed Lot 1. The current access, on site carparking and manoeuvring is adequate
to service both dwellings. Services and infrastructure can be readily provided for the proposed
allotments.

While technically both allotments are battle-axe in shape and don’t meet the minimum allotment size
of 800m², the area of both allotments is well over the minimum 600m² for the Detached House Zone.
Further, adequate building setbacks and private open space are provided ensuring a high level of
residential amenity and having enough area to meet the needs of users. The proposed development
is also consistent with the existing residential character of the locality.

The key issue in the assessment is the matter of localised stormwater flows over Lot 1 during a 1%AEP
event. In this case Lot 1 already contains an extension to the existing dwelling and has separate access
and parking. No other building work is required or intended other than internal modifications to
provide a kitchen and laundry and make this part of the dwelling self-contained once the
reconfiguration occurs.

The stormwater flows over Lot 1 during a 1%AEP event are intermittent and for a limited duration
unlike other parts of Noosa that are subject to river flooding (OM6.3). The existing extension is located
at least 580mm above the stormwater flow level and the velocity and depth of flow across the access
does not exceed the level of safety required under the relevant standard (QUDM). Consequently, the
existing development does not present a significant risk to people and property and the proposed
reconfiguring does not change the level of risk.

The proposed development is no different to a dwelling being established in the low-lying areas of
Tewantin, Noosaville or Noosa Heads where significant river flooding can occur. Development is
allowed in these locations subject to attaining minimum floor heights for habitable rooms. Access in



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these locations is also significantly restricted by flooding generally having a greater duration and
severity when compared to the subject land.

In this case the built form exists and there is no added risk to people and property caused by the
reconfiguration. The proposed development either complies with or meets the intent of the planning
scheme. In my opinion, given the extension to the dwelling is consistent with the planning scheme
then the reconfiguration should also be allowed.

Should it be found that there is conflict with the planning scheme, which in my opinion is minor and
of a technical nature only, there are grounds that warrant approval, including:

1. The circumstances are unusual with the site having been developed with the level of risk to people
   and property from a 1%AEP storm event being minimal, and the proposed reconfiguration does
   not change the level of risk.

2. The proposed development makes use of available residential land in a highly desirable location
   and makes effective and efficient use of existing services and infrastructure.

3. The proposed development is not out of character, with the area of the allotments being adequate
   for the intended use and maintain a high level of residential amenity.

4. The proposed development is consistent with the reasonable expectations of local residents and
   is of benefit to the general community.

The applicant also requests that should the recommendation be for refusal, that the application be
decided by the Council.

Should you have any questions with respect to the above, please contact me.

Yours faithfully




Shane Adamson (BEngTech, GDURP, MPIA, MQELA)
Town Planning Specialist
Director - Adamson Town Planning Pty Ltd




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