attachment b - waratah-wynyard council · 2016-10-12 · location is shown on figure 3. selected...

ATTACHMENT B

ORDINARY MEETING OF COUNCIL

AGENDA OPEN MEETING

17 OCTOBER 2016

Item 7.3 Supporting Documents

DA 157-2015 281 Port Road Boat Harbour Beach

Tasman Geotechnics Pty Ltd ABN 96 130 022 589Level 1, 10 Goodman CourtPO Box 4026, Invermay TAS 7248M 0427 810 534 T 6332 3750E [email protected]

LANDSLIDE RISK ASSESSMENT,PROPOSED EXTENSIONS281 PORT ROAD, BOAT HARBOUR

Prepared for: Ken Ransley

Date: 4 March 2016

Document Reference: TG15110/1 - 02report

Landslide Risk Assessment, 281 Port Road, Boat Harbour

Tasman GeotechnicsReference: TG15110/1 - 02report i

Contents

1 INTRODUCTION 1

2 BACKGROUND INFORMATION 12.1 Regional Setting 12.2 Geology 12.3 Landslide Mapping 22.4 Previous Investigations 22.5 Proposed Development 2

3 FIELD INVESTIGATION 3

4 RESULTS 34.1 Surface Conditions 34.2 Subsurface Conditions 34.3 Laboratory Results 44.4 Slope Stability Analysis 4

5 LANDSLIDE RISK ASSESSMENT 45.1 General 45.2 Potential Hazards 55.3 Risk to Property 5

6 DISCUSSION & RECOMMENDATIONS 66.1 Limitations on Development 66.2 Site Classification 66.3 Footings 66.4 Wind Classification 7

Important information about your report


Tasman GeotechnicsReference: TG15110/1 - 02report ii

FiguresFigure 1 Extract of MRT Geological Mapping

Figure 2 MRT Landslide Map Extract

Figure 3 Site Layout and Borehole Locations

AppendicesAppendix A Engineering Borehole Logs

Appendix B Selected Site Photographs

Appendix C Landslide Risk Matrix

Appendix D Guidelines to Hillside Construction

Version Date Prepared by Reviewed by Distribution

Original 4 March 2016 Emily Bartlett Dr Wayne Griffioen Electronic


Tasman GeotechnicsReference: TG15110/1 - 02report 1

1 INTRODUCTIONTasman Geotechnics was commissioned by Ken Ransley to carry out a Landslide RiskAssessment for proposed extensions and modifications to the existing dwelling at 281 Port Road,Boat Harbour (title reference 75502/2).

The 160m2 site is mapped entirely as a “B landslip area”, as defined under the MineralResources Development Act 1995. The Building Regulations 2014 stipulate that a person mayonly erect, alter or add to a building in a B Landslip area if the total floor area will not exceed200m2 when the building work is completed. The Building Regulations also state that a permitmay be issued for a building with more than 200m2 floor area, if a certificate is given by ageotechnical engineer confirming that:

i) The erection, alteration or addition can be carried out safely; and

ii) The building will be structurally sound; and

iii) The completed building will not affect the stability of the land.

We understand that the existing house is constructed on strip footings and piers. We understandthat the existing house has a footprint of about 60m2, and the proposed development involves anextension to the rear of the house of approximately 47m2. Thus, the footprint of the proposeddevelopment is about 110m2, while the total floor area is 230m2.

This report presents the results of our assessment, including a desk top review of availablereports, site observations, borehole logs and Landslide Risk Assessment. The assessment isconsistent with the Landslide Risk Assessment guidelines published by the AustralianGeomechanics Society (2007).

Our scope of work consisted of:

Carrying out a site walkover to note geomorphological features associated with landslideactivity;

Inspection of the existing house to note any issues associated with landslide movement;

Drilling of one borehole (HA1) to determine subsurface conditions;

Performing a Landslide Risk Assessment.

The assessment is consistent with the Landslide Risk Assessment guidelines published by theAustralian Geomechanics Society (2007).

2 BACKGROUND INFORMATION

2.1 Regional SettingThe site is located at the bottom of a northeast dipping slope along the coast. The site is 50mwest of Jacobs Boat Harbour foreshore. Slopes in the area are up to 30°.

2.2 GeologyThe Mineral Resources Tasmania (MRT) Tasmanian Landslide Map Series, Wynyard – Geologysheet shows the site to be mapped on Quaternary aged “Landslide deposits predominantlyderived from weathered Tertiary rocks”.

An extract of the MRT map is presented on Figure 1.



2.3 Landslide MappingLandslide mapping by MRT has identified two typical scales of landslides for the North-Westcoast area:

i) deep seated rotational landslides and

ii) shallow slides (this includes earth or debris flows).

Extracts of the two landslide susceptibility maps is shown in Figure 2.

The MRT Tasmanian Landslide Map Series, Wynyard – Deep-Seated Landslide Susceptibilitymap shows the site is mapped near the toe of a large landslide complex of unknown activity. Thelandslide is about 300m wide and extends about 350m upslope from the shoreline. Severalsprings are associated with the landslide complex: a number of them have been mapped at thelandslide toe and several at the head scarp.

The susceptibility map shows the site to be mapped as a possible source area associated withdeep-seated landslides. The source area is mapped based on a slope angle of at least 14° forbasaltic colluvium.

The MRT Tasmanian Landslide Map Series, Wynyard – Shallow Slide and Flow Susceptibilitymap shows a small zone of “high” susceptibility near Port Road and “moderate” susceptibility onthe slopes above Port Road (which includes the present site).

2.4 Previous InvestigationsA search was made of the MRT online database of previous reports in the vicinity of the site. Anumber of reports were identified discussing landslides in the Boat Harbour area, although nonespecifically relate to this site.

A report by Matthews (1974) discusses the slope stability along the entire foreshore of JacobsBoat Harbour. Figure 32 of the report shows 281 Port Road mapped as “Basalt talus, slipmaterial and weathered basalt”. The basalt is said to be deeply weathered, with most of theslopes covered in basalt talus derived from the weathering. Figure 32 shows the majority of theforeshore to be mapped as an “Area where there is a danger of further movement”. While 281Port Road is not mapped in this area, it is mapped as a steep zone.

Several geotechnical investigations have been carried out by Coffey Geotechnics and BFPConsultants for properties in the Boat Harbour area. An investigation by Coffey Geotechnics at 4Moore Street in 2007 is particularly relevant. The site is 60m north west of the present site, andthe topography is similar to the current site: on the toe of a large landslide. The investigationinvolved drilling two boreholes: the borehole at the base of the slope encountered slightlyweathered to fresh quartzite rock from 2m depth; the borehole on the landslide toe encounteredTertiary sediments (talus) to 6m depth, overlying quartzite rock. Triaxial testing on anundisturbed sample from the talus showed the clay has a friction angle of 43°, and cohesion of1kPa. The high friction angle was attributed to the presence of rock (gravel) in the sample.

2.5 Proposed DevelopmentThe proposed development involves extending the existing dwelling to the south: about 1m at thesub-floor level for a lift and up to 7m at the ground floor level for 2 bedrooms. Furthermodifications include construction of a first floor and installation of a lift well to access all 3 levelsof the dwelling.

The proposed construction materials are light weight: colorbond roof and cement sheet cladding.

Retaining walls are proposed along the southern boundary and half of the western boundary.Based on our understanding of the natural ground levels, the retaining wall along the southernboundary will vary from 2.5m high in the south-west corner to 1.1m in the south east corner. Theretaining wall along the western boundary will vary from 2.5m high (in the south-west corner) to0m. We assume that the ground levels behind the retaining walls will be re-instated to pre-excavation levels where possible, after the retaining walls have been constructed.

A second cut of approximately 2.5m is proposed in the middle of the building for the lift. This cutwill be retained as part of the house construction.



3 FIELD INVESTIGATIONThe fieldwork was carried out by a Geotechnical Engineer and an Environmental Engineer fromTasman Geotechnics on 6 October 2015. The fieldwork involved a site walkover notinggeomorphological features associated with landslides, and inspecting the existing house andneighbouring house.

One borehole (HA1) was carried out by hand auger near the base of the existing excavation(discussed in Section 4.1). The borehole log is presented in Appendix A and the boreholelocation is shown on Figure 3. Selected site photographs are presented in Appendix B.

A soil sample from 1m depth in HA1 was analyzed by Tasman Geotechnics for Atterberg Limits.The results are presented in Section 4.3.

4 RESULTS

4.1 Surface ConditionsThe 160m2 site is located within the Boat Harbour residential area and the site is predominantlyoccupied by the existing house. The natural slope at the site is estimated to be 25°, flattening toaround 7° uphill (to the south west) of the site and at Port Road below the site. A playground islocated to the north of the site and a restaurant is located between Port Road and the beach.

We understand that the existing house was constructed in the 1950s. The house is ofweatherboard construction with concrete footings (see Photo 1).

The house is situated on the toe of a large landslide. The location of the house on the toe is suchthat the steepest slope is located near the south-east corner of the site (toward Port Road) andflattens to around 10° at the north-east corner (see Figure 3).

The top of the toe is a relatively flat bench, located about 7m above the playground area. Thenorthern boundary of the property is near the junction between the flat ground and the steepslope. The access road to the playground has a slope of around 5°.

According to Mr Ransley, a laundry and bathroom at the rear of the house were demolishedabout 2 years ago (Photo 2), at which time the slope to the south was also excavated to itspresent geometry. The cut is near vertical, with a maximum height of 2.7m (see Photo 3). Thecut slope did not show signs of slumping, nor were any tension cracks noted upslope. The soilprofile exposed in the cut is discussed in Section 4.2.

A public footpath is located on the top side of Port Road with a low timber retaining wall along theuphill side of the path. The footpath (bitumen seal) and retaining wall are in a good condition.

Concrete steps are located on the east side of the house (Photo 4) and provide access to therear of the dwelling. The existing house and concrete footpath showed no signs of activelandslide movement: no cracks were noted throughout the building, and all windows and doorswere aligned. The house upslope of the cut also showed no signs of movement.

4.2 Subsurface ConditionsThe cut exposes up to 1m of fill (near the east end, see Photo 3), which comprises 0.5m oftopsoil, overlying 0.2m of cobbles, overlying 0.3m of cobbles in a clay matrix, with some steel andrubbish. The fill is underlain by basalt talus. The talus comprises angular basalt cobbles andboulders up to more than 1m diameter. In some areas, the basalt appears to present as largeblocks with remnant weathering fabric. The talus is underlain by very stiff basalt clay (lightbrown/red).

HA1 encountered high plasticity, reddish brown silty clay, and was still going at 1.0m belowground level. The silty clay was assessed to be stiff. HA1 generally confirmed the clay matrixobserved in the base of the cut.

Further augering of the borehole might have terminated on cobbles/boulders embedded in theclay.



No groundwater seepage was noted in the cut.

The drilling at 4 Moore Street indicates the presence of shallow quartzite rock. This rock ispresent below the playground to the north of the site, and likely to extend below the talus at thehouse.

4.3 Laboratory ResultsLaboratory testing by Tasman Geotechnics on a soil sample from HA1 at 0.9-1.0m below groundlevel found the following Atterberg Limits:

Liquid Limit = 53%

Plastic Limit = 35%

Plasticity Index = 18%

Linear Shrinkage = 10%.

These results are considered high. Based on these results, the soil is classified according to theUnified Soil Classification system as a high liquid limit silt (MH).

4.4 Slope Stability AnalysisIn order to assess the stability of the slope between the house and Port Road, we carried outsome preliminary stability analysis.

The numerical value for the Factor of Safety (FOS) is a ratio of the sliding (activating) forces toresisting forces along a failure plane. FOS = 1.0 represents a condition of incipient failure orlimiting equilibrium. The acceptable design value for the FOS of any failure surface is not a fixednumber but depends on the type of theoretical analysis and the perceived acceptable risk. Ananalysis based on assumed values, not backed up by material testing, may require a FOS of 1.5or greater. In this case, a FOS of 1.5 is desirable.

For an infinite drained slope of a (homogeneous) frictional material, the Factor of Safety (FOS)against failure is calculated as:

FOS = tan / tan,

Where is the friction angle of the material and

is the angle of the slope

The slope between the house and Port Road comprises layers of cobbles and clay, so that thefriction angle can vary from 43°, as reported by Coffey Geotechnics for 4 Moore Street, to about30°, which is typical for Tertiary basalt clay. For a maximum slope angle of 25° below the house,the corresponding FOS ranges from 2.0 to 1.24.

It should be noted that the above calculation for FOS does not take in account the contribution of(apparent) cohesion, existing vegetation and the limited length of the slope. These factors wouldincrease the FOS. The presence of a building at the top of the slope would decrease the FOS,but is offset by the quantity of soil removed by excavation. In conclusion, the above calculationhas shown that the FOS for the existing slope is greater than 1.2, but could be less than 1.5.

5 LANDSLIDE RISK ASSESSMENT

5.1 GeneralRisk assessment and management principles applied to slopes can be interpreted as answeringthe following questions;

What might happen? (HAZARD IDENTIFICATION).

How likely is it? (LIKELIHOOD).

What damage or injury might result? (CONSEQUENCE).



How important is it? (RISK EVALUATION).

What can be done about it? (RISK TREATMENT).

The risk is a combination of the likelihood and the consequences for the hazard in question. Thusboth likelihood and consequences are taken into account when evaluating a risk and decidingwhether treatment is required.

The qualitative likelihood, consequence and risk terms used in this report for risk to property aregiven in Appendix C and are based on the Landslide Risk Management Guidelines, published byAustralian Geomechanics Society (AGS, 2007). The risk terms are defined by a matrix thatbrings together different combinations of likelihood and consequence. Risk matrices help tocommunicate the results of risk assessment, rank risks, set priorities and develop transparentapproaches to decision making.

5.2 Potential HazardsBased on the available information, previous investigations and our site observations thefollowing landslide hazards are identified for this site:

Reactivation of the large-scale landslide mapped on the MRT Deep-Seated Landslidemap. Landslides of this scale are likely to have occurred when sea levels or rainfall weremuch higher. The likelihood of the proposed development reactivating a large scalelandslide is assessed to be Barely Credible as the development will have negligible effecton the entire slope.

Translational failure of the natural slope below the house. The steepest part of theslope below the house is near the south-east corner of the site (ie not directly down slopeof the house). A slide below the house would affect the public footpath and possibly thesteps adjacent to the house, with minimal damage to the house. While our calculationsabove indicate the FOS for the slope may be as low as 1.2, it is our assessment that forthe short length of the slope the likelihood of a failure is assessed to be Unlikely.

Failure of cut slope above house. The likelihood of a small-scale translation failure inthe existing cut is assessed to be Likely, as the exposed soil continues to be exposed tothe weather (rain and wind erosion). This will be reduced to Barely Credible if anengineer-designed retaining wall is constructed to support each cut slope.

The identification of the potential hazards considers both the site and nearby properties, and isnecessary to address the stability issues that may impact upon the site and influence the risk toproperty.

5.3 Risk to PropertyThe following table summarizes the risk to property of the landslide events in relation to theproposed development as described in Section 2.5, assuming limitations in Section 6 areincorporated.

Table 2. Landslide risk profilesScenario Likelihood Consequence Risk Profile

Reactivation of large-scale landslide

Barely Credible: Developmenthas negligible effect onmapped landslide.

Catastrophic: A large-scalelandslide would affect severalhouses and Port Road

Low

Small-scale translationalfailure in slope belowhouse

Unlikely: due to short length ofslope

Minor: footpath would bedamaged, but minor damage tohouse

Low

Failure in cut slopesabove house

Likely: present condition Medium: Could affect houseupslope, or proposed extension

High

Barely Credible: If cut slopesare retained with engineer-designed retaining wall

Medium: Could affect houseupslope, or proposed extension

Very Low



The assessment shows that the proposed development presents a Low level of risk, providedthe limitations listed in Section 6 are incorporated in the design.

6 DISCUSSION & RECOMMENDATIONS

6.1 Limitations on DevelopmentIn order to ensure the proposed development does not change the risk profile above Low for thesite, it is recommended that the following limitations be enforced:

The proposed extension should be light weight, articulated and flexible.

All cut slopes should be retained by engineer-designed retaining walls. Design of theretaining walls should make allowance for sloping backfill and possible future loading.

Stormwater from roofs and paved areas should be diverted to council’s stormwatersystem.

Where possible, vegetation should be maintained on the slopes to prevent erosion ofsurface soils. As a minimum, vegetation should comprise grass. If trees are planted onthe slope, then the site should be managed such that when the trees reach maturity andare removed, they are replaced with new (young) trees.

Maintenance of surface runoff, vegetation, retaining structures and other measuresdescribed above are the responsibility of the site owner.

Good hillside construction practices should be followed. A copy of Some Guidelines forHillside Construction are presented in Appendix D.

6.2 Site ClassificationAfter allowing due consideration of the site geology, drainage and soil conditions, the site hasbeen classified as follows:

CLASS H1 (AS 2870 – 2011)Foundation designs in accordance with this classification are to be subject to the overridingconditions of Section 6.3 below.

This Classification is applicable only for ground conditions encountered at the time of thisinvestigation.

6.3 FootingsAn allowable bearing pressure of 200 kPa is available for edge beams, strip and pad footingsfounded on the natural soil.

If footings for the sub-floor retaining wall are constructed and backfilled within 4 weeks ofexcavation, then no change in soil moisture is likely to occur and the above site classification canbe assumed to remain unchanged. If the excavation is left exposed for more than 4 weeks, thefootings for the sub-floor retaining wall should be designed based on first principles.

It is recommended that no structure be founded across fill without the footings extending throughthe fill to the natural soils, allowance made in the structural design for differential settlements orengineer designed pier or pile foundations adopted.

Bored piers founded at least 1m in the natural soil may be proportioned for an allowable endbearing pressure of 300kPa, even if founded on the underlying rock. The base of bored piersshould be inspected to ensure they are clean and free of loose soil prior to pouring concrete.

The site classification presented in Section 6.2 assumes that the current natural drainage andinfiltration conditions at the site will not be markedly affected by the proposed site developmentwork. Care should therefore be taken to ensure that surface water is not permitted to collectadjacent to the structure and that significant changes to seasonal soil moisture equilibria do notdevelop as a result of service trench construction or tree root action.



Attention is drawn to Appendix B of AS 2870 and CSIRO Building Technical File BTF18“Foundation Maintenance and Footing Performance: A Homeowner’s Guide” as a guide tomaintenance requirement for the proposed structure.

Variations in soil conditions may occur in areas of the site not specifically covered by the fieldinvestigation. The base of all footing or beam excavations should therefore be inspected toensure that the founding medium meets the requirements discussed above.

6.4 Wind ClassificationThe wind classification for the site is as follows:

N2 (AS 4055 - 2012)Based on region, terrain, shielding and topography as follows:

Region Terrain category Topography Shielding

A TC1.5 T0 NS

TASMAN GEOTECHNICS Rev 01, May 2008

Important information about your report

These notes are provided to help you understand the limitations of your report.

Project Scope

Your report has been developed on the basis of your unique project specific requirements as understood by Tasman Geotechnics at the time, and applies only to the site investigated. Tasman Geotechnics should be consulted if there are subsequent changes to the proposed project, to assess how the changes impact on the report’s recommendations.

Subsurface Conditions

Subsurface conditions are created by natural processes and the activity of man.

A site assessment identifies subsurface conditions at discreet locations. Actual conditions at other locations may differ from those inferred to exist, because no professional, no matter how qualified, can reveal what is hidden by earth, rock and time.

Nothing can be done to change the conditions that exist, but steps can be taken to reduce the impact of unexpected conditions. For this reason, the services of Tasman Geotechnics should be retained throughout the project, to identify variable conditions, conduct additional investigation or tests if required and recommend solutions to problems encountered on site.

Advice and Recommendations

Your report contains advice or recommendations which are based on observations, measurements, calculations and professional interpretation, all of which have a level of uncertainty attached.

The recommendations are based on the assumption that subsurface conditions encountered at the discreet locations are indicative of an area. This can not be substantiated until implementation of the project has commenced. Tasman Geotechnics is familiar with the background information and should be consulted to assess whether or not the report’s recommendations are valid, or whether changes should be considered.

The report as a whole presents the findings of the site assessment, and the report should not be copied in part or altered in any way.

drawn EB client: Ken Ransley

approved WGproject: Landslide Risk Assessment,

281 Port Road, Boat Harbourdate 8/10/2015

scale NTS title: Extract of MRT Geological Mapping

original size A4 project no: TG15110/1 – 02report figure no: FIGURE 1

NORTH

Prjs

Qxt

Prj

Qxt: Quaternary aged “Landslidedeposits predominantly derived fromweathered Tertiary rocks”.

Tbw: Tertiary aged deeply-weatheredbasalt

Ts: Tertiary aged “Terrestrial sand,gravel and minor lacustrine deposits”

Prjs: Proterozoic aged “Interbeddedshaly black siltstone and thinly beddedquartzite”

Prj: Proterozoic aged “Well-bedded,cross-bedded, mostly medium tocoarse-grained orthoquartzite” (JacobQuartzite)

Tbw

Ts

Extract from MRT Geological map

Extract from MRT Deep-Seated Landslide Susceptibilitymap

281 Port Road

281 Port Road


approved WGproject: Landslide Risk Assessment,


scale NTS title: Extract of MRT Landslide Susceptibility Maps


NORTH

Extract from MRT Deep-Seated Landslide Susceptibility map 281 Port Road

281 Port Road

Extract from MRT Shallow Slide and Debris Flow Susceptibility Map

281 Port Road


approved WGproject: Landslide Risk Assessment


scale NTS title: Site Layout and Borehole Location


NORTH

Existing shack footprint

Demolishedsection of shack

Proposed lift

Stairs

Access Road

Cross Section

Cut slope (2years old)

Maximum height2.7m

1.1m high

283 Port Road

Proposed retainingwall for groundfloor extension

Ground slope~7°

Stairs

SITE LAYOUT

SCHEMATIC CROSS SECTION

Existing sub-floor

Existing ground floor

Proposed groundfloor extension

Existing cut

New retaining walls

Proposedfirst floor

Demolished bathand laundry

Estimated naturalground level

Port Road

Proposed 2.5mcut for sub-floorretaining wall

Ground slope~25°

HA1

HA1 (1m depth)Proposed sub-floor extension

Ground slope~10°

Ground slope~5°


Tasman GeotechnicsReference: TG15110/1 - 02report

Appendix AEngineering Borehole Logs

SOIL DESCRIPTIONEXPLANATION SHEET

Soils are described in accordance with the Unified Soil Classification System (USCS), as shown in the following table.

FIELD IDENTIFICATIONGW

GP

GM

GC

SW

SP

SM

SC

DILATANCY TOUGHNESS

ML Quick to slow None

CL None to very slow Medium

OL Slow Low

MH Slow to none Low to medium

CH None High

OH None to very slow Low to medium

Pt

Particle size descriptive terms Consistency of cohesive soilsSize

Boulders >200mmCobbles 63mm to 200mm Very soft VS <12kPa A finger can be pushed well into soil with little effortGravel coarse 20mm to 63mm Soft S 12 - 25kPa Easily penetrated several cm by fist

medium 6mm to 20mm Firm F 25 - 50kPa Soil can be indented about 5mm by thumbfine 2.36mm to 6mm Stiff St 50-100kPa Surface can be indented but not penetrated by thumb

Sand coarse 600µm to 2.36mm Very stiff VSt 100-200kPa Surface can be marked but not indented by thumbmedium 200µm to 600µm Hard H >200kPa Indented with difficulty by thumb nailfine 75µm to 200µm Friable Fb - Crumbles or powders when scraped by thumb nail

Moisture Condition Density of granular soilsDry (D)

Moist (M)

Wet (W)

Cohesive soils can also be described relative to their Minor Componentsplastic limit, ie: <Wp, =Wp, >Wp Term Observed properties

Trace of Coarse grained: <5%Fine grained: <15%

With some Coarse grained: 5-12%Fine grained: 15-30%

CO

ARSE

GR

AIN

ED S

OIL

S

mor

e th

an 5

0% o

f mat

eria

l les

s th

an 6

3mm

isla

rger

than

0.0

75m

m

GR

AVEL

S Well graded gravels and gravel-sand mixtures,little or no finesPoorly graded gravels and gravel-sandmixtures, little or no fines

GR

AVEL

LYSO

ILS

Silty gravels, gravel-sand-silt mixtures, non-plastic finesClayey gravels, gravel-sand-clay mixtures,plastic fines

SAN

DS

Well graded sands and gravelly sands, little orno finesPoorly graded sands and gravelly sands, littleor no fines

SAN

DY

SOIL

S Silty sand, sand-silt mixtures, non-plastic fines

Clayey sands, sand-clay mixtures, plastic fines

DRY STRENGTH

FIN

E G

RAI

NED

SO

ILS

mor

e th

an 5

0% o

f mat

eria

l les

s th

an63

mm

is le

ss th

an 0

.075

mm

SILT

& C

LAY,

liqui

d lim

it le

ssth

an 5

0%

Inorganic silts, very fine sands or clayey finesands None to low

Inorganic clays or low to medium plasticity,gravelly clays, sandy clays and silty clays Medium to high

Organic silts and organic silty clays of lowplasticity Low to medium

SILT

& C

LAY,

liqui

d lim

it gr

eate

rth

an 5

0%

Inorganic silts, micaceous or diatomaceousfine sands or silts Low to medium

Inorganic clays of high plasticity, fat clays High

Organic clays of medium to high plasticity Medium to high

PEAT Peat muck and other highly organic soils

Name Subdivision Term Undrainedstrength Field guide

Looks and feels dry. Cohesive soils are hard,friable or powdery. Granular soils run freelythrough fingers.

Term Density indexVery loose <35%

Loose 15 to 35%Soil feels cool, darkened in colour. Cohesivesoils are usually weakened by moisturepresence, granular soils tend to cohere.

medium dense 35 to 65%Dense 65 to 85%

Very dense >85%As for moist soils, but free water forms onhands when sample is handled

ProportionsThe plastic limit is defined as the minimum water content atwhich the soil can be rolled into a thread 3mm thick.

Presence just detectable by feel or eye. Soilproperties little or no different to generalproperties of primary component.Presence easily detected by feel or eye. Soilproperties little different to general properties ofprimary component.

ENGINEERING BOREHOLE LOG Borehole no. HA1

Sheet no. 1 of 1Job no. TG15110/1

Client : Ken RansleyProject : LRA Date : 6/10/2015

Location : 281 Port Road, Boat Harbour Logged By : EB

Drill model : Hand Auger Slope : deg RL Surface :Hole diameter : 60mm Bearing : deg Datum :

1 2 3 4

CH SILTY CLAY, high plasticity, reddish brown D/M St

Terminated at 1.0m, still going

1.50

1.75

2.00

Cla

ssifi

catio

n

Material Description

Gra

phic

Log

1.00

1.25

Met

hod

Pene

tratio

n

NotesSamples

Tests Wat

er

Auge

r

D

Con

sist

ency

dens

ity, i

ndex

Structure, additionalobservations

0.25

0.50

0.75M

oist

ure

Con

ditio

n



Appendix BSelected Site Photographs



Photo 1. View of building footings and weatherboard exterior.

Photo 2. Rear of dwelling at time of fieldwork.

Footprint of formerlaundry and bathroom

Approximate alignment forsub-floor retaining wall



Photo 3. View of cut along southern boundary.

2.7m high cut

1m fill Talus



Photo 4. Concrete steps leading to rear of existing dwelling.



Appendix CLandslide Risk Matrix

TASMAN GEOTECHNICS Rev 01, June 2008

Terminology for use in Assessing Risk to Property

These notes are provided to help you understand concepts and terms used in Landslide Risk Assessment and are based on the “Practice Note Guidelines for Landslide Risk Management 2007” published in Australian Geomechanics Vol 42, No 1, 2007.

Likelihood Terms

The qualitative likelihood terms have been related to a nominal design life of 50 years. The assessment of likelihood involves judgment based on the knowledge and experience of the assessor. Different assessors may make different judgments.

Approximate Annual

Probability

Implied indicative Recurrence Interval

Description Descriptor Level

10-1 10 years The event is expected to occur over the design life

Almost Certain

A

10-2 100 years The event will probably occur under adverse conditions over the design life

Likely B

10-3 1000 years The event could occur under adverse conditions over the design life

Possible C

10-4 10,000 years The event might occur under very adverse conditions over the design life

Unlikely D

10-5 100,000 years The event is conceivable but only under exceptional circumstances over the design life

Rare E

10-6 1,000,000 years The event is inconceivable or fanciful for the design life

Barely Credible

F

Qualitative Measures of Consequence to PropertyIndicative

Cost of Damage

Description Descriptor Level

200% Structure(s) completely destroyed and/or large scale damage requiring major engineering works for stabilisation. Could cause at least one adjacent property major consequential damage.

Catastrophic 1

60% Extensive damage to most of structure, and/or extending beyond site boundaries requiring significant stabilisation works. Could cause at least one adjacent property medium consequential damage

Major 2

20% Moderate damage to some of structure, and/or significant part of site requiring large stabilisation works. Could cause at least one adjacent property minor consequential damage.

Medium 3

5% Limited damage to part of structure, and/or part of site requiring some reinstatement stabilisation works

Minor 4

0.5% Little damage. Insignificant 5

The assessment of consequences involves judgment based on the knowledge and experience of the assessor. The relative consequence terms are value judgments related to how the potential consequences may be perceived by those affected by the risk. Explicit descriptions of potential consequences will help the stakeholders understand the consequences and arrive at their judgment.

TASMAN GEOTECHNICS Rev 01, June 2008

Qualitative Risk Analysis Matrix – Risk to PropertyLikelihood Consequences to Property

Approximateannual

probability

1:

Catastrophic

2:

Major

3:

Medium

4:

Minor

5:

Insignificant

A: Almost Certain 10-1 VH VH VH H L

B: Likely 10-2 VH VH H M L

C: Possible 10-3 VH H M M VL

D: Unlikely 10-4 H M L L VL

E: Rare 10-5 M L L VL VL

F: Barely credible 10-6 L VL VL VL VL

NOTES:

1. The risk associated with Insignificant consequences, however likely, is defined as Low or Very Low

2. The main purpose of a risk matrix is to help rank risks and set priorities and help the decision making process.

Response to Risk

In general, it is the responsibility of the client and/or regulatory and/or others who may be affected to decide whether to accept or treat the risk. The risk assessor and/or other advisers may assist by making risk comparisons, discussing treatment options, explaining the risk management process, advising how others have reacted to risk in similar situations and making recommendations. Attitudes to risk vary widely and risk evaluation often involves considering more than just property damage (eg environmental effects, public reaction, business confidence etc).

The following is a guide to typical responses to assessed risk.

Risk Level Example Implications

VH Very High Unacceptable without treatment. Extensive detailed investigation and research, planning and implementation of treatment options essential to reduce risk to Low; may be too expensive and not practical. Work likely to cost more than the value of the property.

H High Unacceptable without treatment. Detailed investigation, planning and implementation of treatment options required to reduce risk to Low. Work would cost a substantial sum in relation to the value of the property.

M Moderate May be tolerated in certain circumstances (subject to regulator’s approval) but requires investigation, planning and implementation of treatment options to reduce the risk to Low. Treatment options to reduce to Low risk should be implemented as soon as practicable.

L Low Usually accepted by regulators. Where treatment has been required to reduce the risk to this level, ongoing maintenance is required.

VL Very Low Acceptable. Manage by normal slope maintenance procedures



Appendix DGuidelines to Hillside Construction

PLANNING REPORT

APPLICANT Ken & Sue RANSLEY

ADDRESS 281 Port Road, Boat Harbour Beach

DATE 28.07.2016

PROJECT NUMBER 15044‐P

PID 7086740

CT REF 171021/1

PROPERTY SIZE 171m2

PROPOSAL Dwelling Extension

PROPOSED USE Residential

ZONING Low Density Residential

USE STATUS Permitted

DEVELOPMENT STATUS Discretionary

REPORTING PLANNER Jayne Newman

ABN: 27 165 669 278 PO Box 428 Somerset

TAS 7322 Ph: 0407 532 435

Email: [email protected]

1 | P a g e K e n R a n s l e y

Dwelling Extension 281 Port Road, Boat Harbour Beach

12.1.1 Zone Purpose Statements

12.1.1.1 To provide for residential use or development on larger lots in residential areas where there are infrastructure or environmental constraints that limit development.

12.1.1.2 To provide for non‐residential uses that are compatible with residential amenity.

12.1.2 Local Area Objectives

(a) Land is available for residential use in urban and semi‐urban settings;

(b) Low density residential areas make efficient use of land and optimise available infrastructure provision through a balance between infill and redevelopment of established residential areas and by incremental release of new land;

(c) The type, scale, and intensity of use or development are consistent with the level of permanent constraint on residential use at suburban densities.

(d) New or intensified use or development is restricted if the limit of a known constraint on residential use is uncertain;

(e) Low density residential areas provide equivalent opportunity for single dwelling and multiple dwelling developments and for shared and supported accommodation through private, public, and social investment.

(f) Low density residential areas enable opportunity for convenient access to basic level services and facilities for education, health care, retail, social, and recreation purposes;

(g) Low density residential areas provide small‐scale employment opportunities in home occupation and home based business.

(h) The amenity and character of low density residential areas is commensurate with the location of housing and support activity within a shared urban or semi‐urban living space, and is to take into account –

(i) the likely impact on residential use from the occurrence and operation of non‐housing activity;

(ii) suitable of a site for intended use;

(iii) possible absence in provision or capacity of community services, transport infrastructure and utilities;

(iv) restriction imposed by an environmental constraint;

(v) the level of risk from exposure to a natural hazard; and

(vi) the effect of location and configuration of buildings within a site on ‐

a. apparent bulk and scale of buildings and structures;

b. opportunity for on‐site provision of private open space and facilities for parking of vehicles;

c. opportunity for access to daylight and sunlight;

d. visual and acoustic privacy between adjacent dwellings; and

e. consistency of the streetscape; and

f. the relationship between new sensitive use and the use of land in an adjoining zone

Comment: In response to additional information request, dated 9 December 2015, we now provide a full report. The application relates to the extension of an existing dwelling at 281 Port Road, Boat Harbour Beach. The extension consists of a small extension to the subfloor to meet the existing retaining wall, an extension to the existing ground floor plan to be built 900mm from the western boundary and 300mm from the southern boundary, with a new retaining wall bounding the building on the southern and western sides, 300mm from the boundary. Additionally there is a new first floor proposed, containing a master bedroom, ensuite and robe.


Development Standards

12.4.1 Suitability of a site or lot on a plan of subdivision for use or development

The minimum properties of a site and of each lot on a plan of subdivision are to –

(a) provide a suitable development area for the intended use;

(b) provide access from a road; and

(c) make adequate provision for a water supply and for the drainage and disposal of sewage and stormwater

A1 P1

A site or each lot on a plan of subdivision must –

(a) have an area of ‐

(i) not less than 500m2 excluding any access strip; or

(ii) if in a locality shown in the Table to this clause, not less than the site area shown for that locality; and

(b) if intended for a building, contain a building area of not less than 10.0m x 15.0m ‐

(i) clear of any applicable setback from a frontage, side or rear boundary;

(ii) clear of any applicable setback from a zone boundary;

(iii) clear of any registered easement;

(iv) clear of any registered right of way benefitting other land;

(v) clear of any restriction imposed by a utility;

(vi) not including an access strip;

(vii) accessible from a frontage or access strip; and

(viii) if a new residential lot, with a long axis within the range 30º east of north and 20º west of north

A site or each lot on a plan of subdivision must

(a) be of sufficient area for the intended use or development without likely constraint or interference for –

(i) erection of a building if required by the intended use;

(ii) access to the site;

(iii) use or development of adjacent land;

(iv) a utility; and

(v) any easement or lawful entitlement for access to other land; and

(b) if a new residential lot, be orientated to maximise opportunity for solar access to a building area

COMMENT: The lot has an area of 171m2 providing constraint in development area. With the existing development on the site, it is demonstrated that the site is suitable for the existing residential use. The proposal does not impact access to the site or any development on adjacent sites. There are no utilities directly adjoining this lot or easements benefiting any other land effected.


A2 P2

A site or each lot on a subdivision plan must have a separate access from a road –

(a) across a frontage over which no other land has a right of access; and

(b) if an internal lot, by an access strip connecting to a frontage over land not required as the means of access to any other land; or

(c) by a right of way connecting to a road ‐

(i) over land not required as the means of access to any other land; and

(ii) not required to give the lot of which it is a part the minimum properties of a lot in accordance with the acceptable solution in any applicable standard; and

(d) with a width of frontage and any access strip or right of way of not less than –

(i) 3.6m for single dwelling development; or

(ii) 6.0m for multiple dwelling development or development for a non‐residential use; and

(e) the relevant road authority in accordance with the Local Government (Highways) Act 1982 or the Roads and Jetties Act 1935 must have advised it is satisfied adequate arrangements can be made to provide vehicular access between the carriageway of a road and the frontage, access strip or right of way to the site or each lot on a proposed subdivision plan.

(a) A site must have a reasonable and secure access from a road provided –

(i) across a frontage; or

(ii) by an access strip connecting to a frontage, if for an internal lot; or

(iii) by a right of way connecting to a road over land not required to give the lot of which it is a part the minimum properties of a lot in accordance with the acceptable solution in any applicable standard; and

(iv) the dimensions of the frontage and any access strip or right‐of‐way must be adequate for the type and volume of traffic likely to be generated by –

a. the intended use; and

b. the existing or potential use of any other land which requires use of the access as the means of access for that land; and

(v) the relevant road authority in accordance with the Local Government (Highways) Act 1982 or the Roads and Jetties Act 1935 must have advised it is satisfied adequate arrangements can be made to provide vehicular access between the carriageway of a road and the frontage, access strip or right of way to the site or each lot on a subdivision plan; or

(b) It must be unnecessary for the development to require access to the site or to a lot on a subdivision plan.

COMMENT: The site has an existing approved access via a right of way. No changes are proposed to this access.

A3 P3

A site or each lot on a plan of subdivision must be capable of connecting to a water supply– (a) provided in accordance with the Water and Sewerage

Industry Act 2008; or (b) from a rechargeable drinking water system R31 with a

storage capacity of not less than 10,000 litres if– (i) there is not a reticulated water supply; and (ii) development is for –

a. a single dwelling; or b. a use with an equivalent population of not more than

10 people per day

(a) There must be a water supply available for the site or for each lot on a plan of subdivision with an adequate level of reliability, quality, and quantity to service the anticipated use of the site or the intended use of each lot on a plan of subdivision; or

(b) It must be unnecessary to require a water supply

COMMENT: A 10,000 litres water storage tank is proposed for domestic water supply, see drainage plan 15044‐07.


A4 P4

A site or each lot on a plan of subdivision must be capable of draining and disposing of sewage and liquid trade waste – (a) to a sewerage system provided in accordance with the Water and Sewerage Industry Act 2008; or (b) by on‐site disposal if – (i) sewage or liquid trade waste cannot be drained to a reticulated sewer system; and (ii) the development a. is for a single dwelling; or b. provides for an equivalent population of not more than 10 people per day; or

(iii) the site has capacity for on‐site disposal of domestic waste water in accordance with AS/NZS1547:2012 On‐site domestic‐wastewater management clear of any defined building area or access strip

(a) A site or each lot on a plan of subdivision must drain and dispose of sewage and liquid trade waste –

(i) in accordance with any prescribed emission limits for discharge of waste water;

(ii) in accordance with any limit advised by the Tasmanian Environmental Protection Agency;

(iii) without likely adverse impact for the health or amenity of the land and adjacent land;

(iv) without compromise to water quality objectives for surface or ground water established under the State Policy on Water Quality Management 1997; and

(b) It must be unnecessary to require arrangements for the drainage and disposal of sewage or liquid trade waste

COMMENT: The site has an existing connection to a reticulated sewerage system.

A5 P5

A site or each lot on a plan of subdivision must be capable of draining and disposing of stormwater –

(a) to a stormwater system provided in accordance with the Urban Drainage Act 2013; or

(b) if storm water cannot be drained to a stormwater system –

(i) for discharge to a natural drainage line, water body, or watercourse; or

(ii) for disposal within the site if –

a. the site has an area of not less than 5000m2;

b. the disposal area is not within any defined building area;

c. the disposal area is not within any area required for the disposal of sewage;

d. the disposal area is not within any access strip; and

e. not more than 50% of the site is impervious surface; and

(iii) the development is for a single dwelling

(a) A site or each lot on a plan of subdivision must drain and dispose of stormwater –

(i) to accommodate the anticipated stormwater –

a. currently entering from beyond its boundaries; and

b. from the proposed development;

(ii) without likelihood for concentration on adjacent land;

(iii) without creating an unacceptable level of risk for the safety of life or for use or development on the land and on adjacent land;

(iv) to manage the quantity and rate of discharge of stormwater to receiving waters;

(v) to manage the quality of stormwater discharged to receiving waters; and

(vi) to provide positive drainage away from any sewer pipe, on‐site sewage disposal system, or building area; or

(b) It must be unnecessary to require the drainage and disposal of stormwater

COMMENT: The application does include a new connection point to an urban drainage system. A pre‐approval has been provided by council engineering department via email dated 26 October 2015.


Table to Clause 12.4.1 A1

Locality Site area per dwelling (m²)

Sisters Beach 800

12.4.2 Dwelling density

Residential dwelling density R15 is to –

(a) make efficient use of land for housing;

(b) optimise utilities and community services; and

(c) be consistent with any constraint on suitability of the land for residential use

A1 P1

The site area per dwelling must –

(a) be not less than 500m2 if the site has –

(i) connection to a reticulated water supply;

(ii) connection to a reticulated sewer system; and

(iii) connection to a stormwater system; or

(b) if the site is in a locality shown in the Table to this clause, not less than the site area for that locality

The number of dwellings on a site must be –

(a) consistent with the capability of the land for residential use in terms of ‐

(i) a suitable building area

(ii) access from a road

(iii) provision of a water supply

(iv) disposal of sewage

(v) disposal of stormwater

(vi) a tolerable level of risk from a natural hazard

COMMENT: The site currently demonstrates that it is of suitable size to accommodate a dwelling. The extension will not impact the existing onsite water supply or access, nor will it impact the existing connection to reticulated sewerage disposal. The disposal of stormwater from the site will be improved with a new connection to a reticulated stormwater system. A report provided by Tasman Geotechnics reference TG15110/1 dated 4 March 2016 concludes that the there is a tolerable level of risk from natural hazards.


Locality Site area per dwelling (m²)

Sisters Beach 800


12.4.3 Location and configuration of development

The location and configuration of development is to –

(a) be consistent with land capability;

(b) provide a consistent separation between the development area on adjacent sites and between development and a road;

(c) provide sufficient site area for open space, service activity and vehicle parking;

(d) provide consistency in the apparent scale, bulk, massing, and proportion of adjacent buildings;

(e) provide for the facade of a residential building to remain the dominant architectural element in the streetscape ; and

(f) separate adjacent buildings to provide reasonable opportunity for daylight and sunlight to habitable rooms and to private open space areas

A1 P1

A building, including any garage, carport or an external car parking area and any area for the display, handling, or storage of goods, materials or waste, must be setback from a frontage –

(a) not less than 4.5m from a primary frontage; and

(b) not less than 3.0m from any secondary frontage; or

(c) not less than and not more than the setbacks for any existing building on each of the immediate adjoining sites;

(d) not less than for any building retained on the site;

(e) in accordance with any building area shown on a sealed plan; or

(f) if the site abuts a road shown in the Table to this clause, the setback specified for that road

The setback of a building from a frontage must be –

(a) consistent with the streetscape; and

(b) required by a constraint imposed by –

(i) size and shape of the site;

(ii) orientation and topography of land;

(iii) arrangements for a water supply and for the drainage and disposal of sewage and stormwater;

(iv) arrangements for vehicular or pedestrian access;

(v) any requirement of a conservation or urban design outcome detailed in a provision in this planning scheme;

(vi) a utility; or

(vii) any lawful and binding requirement –

a. by the State or a council or by an entity owned or regulated by the State or a council to acquire or occupy part of the site; or

b. an interest protected at law by an easement or other regulation

COMMENT: (a) The development is consistent with the streetscape and the adjacent property at 283 Port Road. The frontage to the right of way

is remaining relatively unchanged from the existing apart from a minor extension to the footprint of the existing deck (the current

frontage setback varies from 0.34 to 2.57m). The impact on the elevation will be minimal as the deck is to be open above and below

as per the existing structure.

(b)The small site area of 172m² is the main constraint in not meeting acceptable solution A1. The orientation and topography of the

site provide limited opportunity for outdoor space hence the area between the front of the existing building and the front boundary

is to be utilised by means of a timber deck at the main living floor level. Arrangements for water supply and the drainage & disposal

of sewage & stormwater have also been a consideration (see P3 below).


A2 P2

All buildings must be contained within a building envelope determined by ‐

(a) the applicable frontage setback;

(b) projecting at an angle of 45º from the horizontal at a height of 3.0m at each side boundary and at a distance of 4.0m from the rear boundary to a building height of not more than 8.5m if walls are setback ‐

(i) not less than 1.5m from each side boundary; or

(ii) less than 1.5m from a side boundary if wall height is not more than 3.0m; and –

a. built against the wall of an adjoining building; or

b. the wall or walls ‐

i. have the lesser of a total length of 9.0m or one‐third of the boundary with the adjoining land;

ii. there is no door or window in the wall of the building; and

iii. overshadowing does not result in ‐

a. Less than 2 hours of continuous sunlight to a required minimum private open space area in an adjacent dwelling between 9.00am and 3.00pm on 21st June ; or

b. A further reduction in continuous sunlight to a required minimum private open space area in an adjacent dwelling if already less than 2 hours between 9.00am and 3.00pm on 21st June ; or

(c) in accordance with any building envelope shown on a sealed plan

Building height and location of a building in relation to a frontage and site boundaries must ‐

(a) minimise likelihood for overshadowing of a habitable room or a required minimum area of private open space in any adjacent dwelling;

(b) minimise the apparent scale, bulk, massing and proportion relative to any adjacent building;

(c) be consistent with the streetscape;

(d) respond to the effect of the slope and orientation of the site; and

(e) provide separation between buildings to attenuate impact

COMMENT: (a) Due to the steep slope of the site and adjacent sites the proposed extension does not cause undue shadowing on the adjacent

properties. This is demonstrated by shadow plans on PLA Designs drawing No. 15044‐08. The additional shadowing cast onto

the neighbouring properties at 279 & 283 Port Road is negligible considering the fact that habitable spaces are on the first floor

of these dwellings. The majority of the shadowing shown in the drawing will be to the lower floor of the residence.

(b) The narrow width and overall footprint of the residence (including the proposed extension) help to minimise the scale and bulk.

Consistent with other surrounding properties. The split level building design is to enable it to work with the slope of the site as

much as possible in conjunction with the site cut. These strategies help to reduce bulk and mass proportions of the residence.

(c) The proposed residence is consistent with the beach‐style homes in Boat Harbour which have skillion roofs and decks to the

northern side with split level or two storey construction.

(d) As mentioned under (a) the reduced frontage setback is to allow for useable outdoor space due to the slope of the site and also

enable this outdoor space to be orientated north for greater amenity..

(e) There will still be visual separation between buildings that is consistent with the area; as there is a large amount of open garden

areas and walkways around the residence of surrounding properties. These characteristics surrounding the property at Boat

Harbour enable it to retain a small scale and consistent appearance.


A3 P3

Site coverage must:

(a) not be more than 50%; or

(b) if the site is in a locality shown in the Table to this Clause, not more than the site coverage for that locality; and

(c) not include any part of a site required for the disposal of sewage or stormwater; or

(d) be not more than any building area shown on a sealed plan

Site coverage must –

(a) provide a usable area for private open space, landscaping, and vehicle parking and service activity;

(b) retain capacity in any area required for disposal of sewage or stormwater; and

(c) be consistent with the streetscape

COMMENT: (a) The existing residence has a ground floor coverage of 58%. The proposed extension takes the total site coverage to 90%,

however 25% of this site coverage is for the northerly facing deck which will allow for a useable outdoor space. Vehicle parking

provisions will remain unchanged.

(b) A new stormwater storage tank is to be installed under the deck with overflow to discharge into a new stormwater connection

(refer PLA Designs drawing No.15044‐07). The site has an existing sewer connection to Tas Water infrastructure.

(c) As noted above in P2(e).

A4 P4

A garage, carport or an external car parking area and any area for the display, handling, or storage of goods, materials or waste, must be located behind the primary frontage of a building

A garage, carport or an external car parking area and any area for the display, handling, or storage of goods, materials or waste, must –

(a) not dominate the architectural or visual frontage of the site;

(b) be consistent with the streetscape;

(c) be required by a constraint imposed by size, shape, slope, orientation, and topography on development of the site; and

(d) provide durable physical screening to attenuate appearance of the parking or loading area from a frontage and adjacent land

COMMENT: Not applicable; The application does not involve any carports or garages.

A5 P5

Total width of openings in the frontage elevation of a garage or carport (whether freestanding or part of any other building) must be the lesser of –

(a) 6.0m; or

(b) half the width of the frontage

The frontage elevation of a garage or carport (whether freestanding or part of any other building) must minimise potential to dominate the streetscape

COMMENT: Not applicable; The application does not involve any carports or garages.


A6 P6

If on a site at Boat Harbour, a building on the lower side of a road must be single storey on the road elevation

The frontage elevation of a garage or carport (whether freestanding or part of any other building) must minimise potential to dominate the streetscape An access strip or shared driveway, including any pedestrian pathway and parking area, must minimise likelihood for impact from over‐viewing and noise disturbance on the amenity of any dwelling

COMMENT: Not applicable; Although located at Boat Harbour Beach, the proposal is not located on the lower side of the road.

Table to Clause 12.4.3 A2 Locality Feature Setback distance (m)

Boat Harbour a reserve under the Crown Lands Act 1976 6

Sisters Beach a reserve under the Crown Lands Act 1976 6

Table to Clause 12.4.3 A3 Locality Site coverage (%) Boat Harbour 30 Sisters Beach 40


12.4.4 Visual and acoustic privacy for residential development

The location and configuration of development is to minimise likelihood for –

(a) overlooking of a habitable room, balcony, deck, or roof garden in an adjacent dwelling;

(b) intrusion of vehicle noise from an access strip or communal driveway

A1 P1

A door or window to a habitable room, or any part of a balcony, deck, roof garden, parking space or carport of a building must –

(a) if the finished floor level is more than 1.0m above natural ground level ‐

(i) be not less than 6.0m from any door, window, balcony, deck, or roof garden in an adjacent dwelling;

(ii) be not less than 3.0m from a side boundary;

(iii) be not less than 4.0m from a rear boundary; and

(iv) if an internal lot, be not less than 4.5m from the boundary abutting a rear boundary of an adjacent frontage site; or

(b) if less than the setbacks in clause A1(a) ‐

(i) be off‐set by not less than 1.5m from the edge of any door or window in an adjacent dwelling;

(ii) a have a window sill height of not less than 1.8m above finished floor level;

(iii) have fixed and durable glazing or screening with a uniform transparency on not more than 25% in that part of a door or window less than 1.8m above finished floor level; or

(iv) have a fixed and durable external screen other than vegetation of not less than 1.8m height above the finished floor level with a uniform transparency of not more than 25% for the full width of the door, window, balcony, deck, roof garden, parking space, or carport

Likelihood for overlooking from a door or window in a habitable room or from any part of a balcony, deck, roof garden, parking space, or carport of a building must be minimised by –

(a) physical separation from the door, window balcony, deck, or roof garden in an adjacent dwelling;

(b) off‐set from a door or window to a habitable room in an adjacent dwelling;

(c) effective use of screening other than vegetation; or

(d) effect of topography and natural features

COMMENT: Floor level is less than 1m above natural ground level on the western elevation, windows on the southern elevation are 1700 above

finished floor level. Windows on the eastern elevation, although within the prescribed setback to the boundary will not result in

overlooking as they are adjacent to a pedestrian walkway and the road located below. Similarly on the northern elevation windows

& deck will only be overlooking the right‐of‐way. The western side of the proposed deck will be screened to prevent overlooking of

the adjacent property (refer drawing No.15044‐05).

A2 P2

An access strip or shared driveway, including any pedestrian

pathway and parking area, must be separated by a distance of not

less than 1.5m horizontally and 1.5m vertically from the door or

window to a dwelling or any balcony, deck, or roof garden in a

dwelling.

An access strip or communal driveway, including any pedestrian pathway and parking area, must minimise likelihood for impact from over‐viewing and noise disturbance on the amenity of any dwelling

COMMENT: Not applicable; The right of way access is existing and no changes are proposed as part of this application.


12.4.5 Private open space for residential use

Private open space is available in development for residential use to meet the reasonable private and communal needs of residents for garden, recreation, service, and storage purposes.

A1 P1

Each dwelling must provide private open space –

(a) if a dwelling with a floor level of not more than 2.5m above finished ground level, a ground level area ‐

(i) located adjoining the rear or side of the dwelling;

(ii) accessible from the dwelling;

(iii) of not less than 25m2;

(iv) with a minimum dimension of 4.0m;

(v) on a single level;

(vi) with a gradient of not more than 1 in 10; and

(b) if a dwelling with a floor level of more than 2.5m above finished ground level, as an alternative to a ground level area, a private balcony, deck, terrace or roof garden –

(i) of not less than 25m2;

(ii) with a minimum dimension of 4.0m; and

(iii) accessible from the dwelling

Private open space must ‐

(a) be of size and dimension appropriate for the projected requirements of the residents of the dwelling; and

(b) be usable taking into account –

(i) the effect of shape, orientation, and topography of the site;

(ii) the availability, accessibility, purpose, and characteristics of –

a. any other recreation and service area within the site;

b. any external communal open space area; and

c. public open space

COMMENT: The deck is not 4m in width as per A1(b)(ii) and is therefore reliant on Performance Criteria P1.

The proposed deck on the northern aspect of the dwelling is designed to provide residents with a useable outdoor open space and

responds to the shape, orientation and topography of the site as well as the limited availability of space on this small site.

A2 P2

The required minimum private open space area must be capable of receiving at least 3 hours of sunlight between 9.00am and 3.00pm on 21st June

Each private open space area must maximise opportunity for access to sunlight having regard for ‐

(a) aspect, orientation, size, shape, slope, and topography of the site;

(b) desirable to retain existing vegetation on the site; and

(c) the impact of overshadowing by existing development on adjacent land

COMMENT: Although the current circumstance and the proposed, the minimum private open space is not met (as addressed above), the space that is available is capable of achieving more than 3 hours of sunlight due to its northern orientation.


A3 P3

Unless there is a ground level private open space area directly accessible at grade to a shared driveway or pedestrian pathway, each dwelling in a multiple dwelling development must have access to a waste storage area –

(a) located behind the applicable frontage setback;

(b) of not less than 1.5m2 per dwelling;

(c) screened to view from the frontage and any dwelling by a wall of height not less than 1.2m above finished ground level; and

(d) not less than 6.0 from a window, door, balcony, deck, roof garden or private open space area of a dwelling

Arrangements must be made for the storage of waste –

(a) with sufficient size and area to serve requirements of the site;

(b) screened to view from the frontage and from dwellings; and

(c) separated from a dwelling to attenuate noise and odour

COMMENT: Not applicable; The application relates to a single dwelling development.

12.4.6 Frontage fences

A frontage fence is to –

(a) assist privacy and security for occupants of a dwelling;

(b) assist to attenuate likely impact from activity on a road, on the site, or on adjacent land;

A1 P1

The height of a fence, including any supporting retaining wall, on a frontage or within a frontage setback must be –

(a) not more than 1.2m if the fence is solid; or

(b) not more than 1.8m provided that part of the fence above 1.2m has openings that provide a uniform transparency of not less than 30%.

The height of a fence on a frontage or within a frontage setback must be reasonably required for security and privacy of the site

Comment: Not applicable;

No fencing is proposed as part of this application.


12.4.7 Setback of development for sensitive use

Development for a sensitive use is to –

(a) Minimize likelihood for conflict, interference, and constraint between the sensitive use and the use or development of land in a zone that is not for a residential purpose; and

(b) Minimize unreasonable impact on amenity of the sensitive use through exposure to emission of noise, fumes, light and vibration from road, rail, or marine transport

A1 P1

A building containing a sensitive use must be contained within a building envelope determined by –

(a) the setback distance from the zone boundary as shown on the Table to this clause; and

(b) projecting upward and away from the zone boundary at an angle of 45º above the horizontal from a wall height of 3.0m at the setback distance from the zone boundary

The location of a building containing a sensitive use must –

(a) minimise likelihood for conflict, constraint or interference by the sensitive use on existing and potential use of land in the adjoining zone; and

(b) minimise likely impact from existing and potential use of land in the adjoining zone on the amenity of the sensitive use

COMMENT: Not applicable, The application is for the extension to an existing sensitive use.

A2 P2

Development for a sensitive use must be not less than 50m from –

(a) a major road identified in the Table to this clause;

(b) A railway;

(c) Land designated in the planning scheme for future road or rail purposes; or

(d) a proclaimed wharf area

Development for a sensitive use must –

(a) have minimal impact for safety and efficient operation of the transport infrastructure; and

(b) incorporate appropriate measures to mitigate likely impact of light, noise, odour, particulate, radiation or vibration emissions; or

(c) be temporary use or development for which arrangements have been made with the relevant transport infrastructure entity for removal without compensation within 3 years

COMMENT: The site is not within 50 metres of the Bass Highway, a railway or a proclaimed wharf area.

Table to Clause 12.4.7 A1 Adjoining Zone Setback (m)

General Business 4.0

General Industrial 4.0

Rural Resource (a) 50.0; or

(b) 4.0 if the site is a lot approved for residential use on a plan of subdivision sealed before this planning scheme came into effect

Utilities 10.0



Road Setback (m)

Bass Highway 50

CODES E1 – Bushfire‐Prone Areas Code N/A

The application is not for a vulnerable or hazardous use, nor does it involve the subdivision of land.

E2 Airport Impact Management Code N/A

This site is not within the obstacle limitations of the Burnie/Wynyard Airport.

E3 – Clearing and Conversion of Vegetation Code N/A

The proposed development does not invoke E3.2.1 (a) through to (f).

E4 Change in Ground Level Code Yes

Change in the existing ground level or the natural ground level by cut or fill is to minimise –

(a) likely adverse impact on the physical, environmental, cultural, aesthetic, and amenity features of land; and

(b) risk from a natural hazard

A1 P1

Cut or fill must ‐

(a) not be on land within the Environmental Living zone or the Environmental Management zone;

(b) be required to ‐

(i) provide a construction site for buildings and structures;

(ii) facilitate vehicular access;

(iii) mitigate exposure to a natural or environmental hazard;

(iv) facilitate provision of a utility;

(v) assist the consolidation or intensification of development; or

(vi) assist stormwater management

(c) not result in a modification of surface stormwater water flow to increase –

(i) surface water drainage onto adjacent land;

(ii) pooling of water on the site or on adjacent land; or

(iii) the nature or capacity of discharge from land upstream in a natural or artificial drainage channel;

(d) not destabilise any existing building or increase the requirements for construction of any potential building on adjacent land;

(e) manage disposal of intersected ground water;

(f) safeguard the quality of receiving waters through measures to minimise erosion and release of sediments and other contaminants during each of the site preparation, construction and rehabilitation phase in accordance with Soil and Water Management on Building and Construction Sites 2009;

(g) Not require a retaining or support structure that would result in an area of influence within the boundary of adjacent land; and

Cut or fill must ‐

(a) make arrangements for the drainage and disposal of stormwater;

(b) make arrangements to stabilise any existing building or to increase the requirements for construction of any potential building on adjacent land;

(c) manage drainage and disposal of intersected ground water;

(d) safeguard the quality of receiving waters;

(e) not require a retaining or support structure that would result in an area of influence within the boundary of adjacent land unless the owner of adjacent land has provided written consent to enter into an agreement under Part 5 Land Use Planning and Approvals Act 1993 registered on the title of adjacent land providing for the level of constraint; and

(f) not encroach upon or expose, disturb, or reduce cover over an underground utility to less than 1.0m unless the relevant regulatory entity has advised –

(i) it is satisfied the cut or fill will not result in harm to the utility; and

(ii) any condition or requirement it determines are appropriate to protect the utility


(h) not encroach upon or expose, disturb, or reduce cover over an underground utility to less than 1.0m unless the relevant regulatory entity has advised –

(i) it is satisfied the cut or fill will not result in harm to the utility; and

(ii) any condition or requirement it determines are appropriate to protect the utility

Comment: (a) Stormwater overflow is to discharge into new stormwater connection (refer drawing No.15044‐07).

(b) Retaining structures are required to stabilise adjacent land and will be designed & certified by a structural engineer prior to a building application being submitted (refer confirmation letter by Pitt & Sherry dated 19 November 2015). In relation to

the additional information request, point 1 – The plan has been altered to ensure that there is no line of influence in relation

to the adjoining Crown Land.

(c) Intersected ground water will be managed via drains placed behind retainer walls and connected into stormwater overflow

line via a stormwater pit with silt arrestor (refer to drawing number 15044‐08).

(d) See response to (c) above. (e) The line of influence does extend into 279 (CT.171021/2) & 283 (CT.75502/1) Port Road, Boat Harbour Beach. A copy of the

Part 5 agreements are provided with this documentation. The retaining walls are to be designed by a structural engineer

as per Pitt & Sherry letter dated 19 November 2015.

(f) There are no underground utilities in the vicinity of the existing or proposed excavations.

E5 Local Heritage Code N/A

The lot is not listed within the Heritage Code or listed on the Tasmanian Heritage Register.

E6 Hazard Management Code Yes

E6.6.2 Development on land exposed to a natural hazard

Objective:

The level of likely risk from exposure to a natural hazard is to be tolerable for the type, form, scale and duration of

each development

A1 P1

If the site is within an area of unacceptable risk shown on

a natural hazard map forming part of this planning scheme –

(a) a hazard risk assessment must determine ‐ (i) there is an insufficient increase in risk to warrant

any specific hazard reduction or protection

measure; or

(ii) a tolerable level of risk can be achieved for the

type, form, scale and duration of the

development; and

(b) if a hazard risk assessment established need to involve

land on another title for hazard management consistent

with the objective, the consent in writing of the owner of

that land must be provided to enter into a Part 5

agreement to be registered on the tile of the land and

providing for the effected land to be managed in

accordance with recommendations for hazard

management

There is no performance criteria

Comment: The site is on an area declared as a medium hazard. Retaining walls are proposed as part of this application to mitigate issues detailed in the landslide risk assessment provided by Tasman Geotechnics ref number TG15110/1‐01 and amended report TG15110/1‐02. A letter provided from Pitt and Sherry dated 19 November 2015, confirms the structural integrity of the works will be provided during the building application process.


E7 Sign Code N/A

There are no signs proposed as part of this application.

E8 Telecommunication Code N/A

The application does not propose any telecommunication facilities.

E9 Traffic Generating Use and Parking Code

Yes

Objective: Provision is to be made for convenient, accessible, and usable vehicle parking to satisfy requirements for use or development without impact for use or development of other land or for the safety and operation of any road

A1

Provision for parking must be ‐ (a) the minimum number of on‐site vehicle parking spaces must

be in accordance with the applicable standard for the use class as shown in the Table to this Code;

(b) motor bike parking at a rate of 1 space for every 20vehicle parking spaces;

(c) parking spaces for people with disabilities at the rate of 1 space for every 20 parking spaces or part thereof; and

(d) bicycle parking at the rate of 1 space for every 20 vehicle parking spaces or part thereof

P1

(a) It must be unnecessary or unreasonable to require arrangements for the provision of vehicle parking; or

(b) Adequate and appropriate provision must be made for vehicle parking to meet ‐ (i) anticipated requirement for the type, scale, and intensity

of the use; (ii) likely needs and requirements of site users; and (iii) likely type, number, frequency, and duration of vehicle

parking demand

Comment:

It is unreasonable to require arrangements for the provision of vehicle parking. The site does not currently have any car parking

provisions and the size, location & topography of the site would prohibit the addition of any regardless of the proposed development.

Council car parking spaces that are in the vicinity of the development will be utilised.

E10 Water and Waterways Code N/A

The site is not within 30m of any water body, water course, or wetland.

From: Peter and Elaine KeatsTo: councilSubject: FW: Planning Permit Application DA 157/2016 281 Port Road Boat Harbour BeachDate: Tuesday, 27 September 2016 9:13:33 PM

The General ManagerWaratah-Wynyard CouncilPO Box 168Wynyard 7325 Dear Sir As part owners of the property 238 Port Road Boat Harbour Beach we thank you for theopportunity to make representation on the above planning application. In the comments following “Development Standards”p62 and p67 the impact on adjacent land isdiscussed. Shadowing is dealt with. We value the view which we have of Table Cape and thisproposed extension blocks that outlook . This is our concern. Is it reasonable for visual separation to be only provided by the neighbours? (p67(e)). In the photos p47, existing construction material is said to be concrete and weatherboard. Webelieve there is also cement/asbestos sheet cladding which is not mentioned, though this maynot be relevant at this stage. Yours faithfully, Elaine KeatsDorothy Cunningham

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