The Proposed Auckland Unitary Plan - Chapter H4.14: Stormwater Management

PART3­REGIONALANDDISTRICTRULES»ChapterH:Auckland­widerules»4Naturalresources»

4.14StormwatermanagementIntroduction

Thissectionprovidesthreesetsofrulesformanagingstormwaterthatarisesfromthedevelopmentorredevelopmentofimperviousareasandassociatedactivities.Oneormorerulesmayapply,dependingonthenatureoftheactivityanditslocation.

Stormwaterdiversionanddischargerules

Theserulescontrolthediversionanddischargeofstormwaterfromimperviousareas,pursuanttos.14and15oftheRMA.Therearefourcategoriesofstormwaterdischarge:

a.frompublicstormwaternetworksbyastormwaternetworkdischargeconsent(thesemayincludepublicroads)

b.frompublicroadsoperatedbyroadcontrollingauthorities(wherenotcoveredbyastormwaternetworkdischargeconsent)

c.directedtogroundsoakageortomaintainmoisturelevelsinpeatsoils;

d.fromimperviousareasotherthanthoseconnectedtopublicstormwaternetworks,publicroads,ordischargestogroundsoakage.

Toavoiddoubt,stormwaterfromaprivatesitedirectedtoareticulatedpublicstormwaternetworkisconsideredpartofthestormwaternetworkdischargeprovideditmeetstherequirementsofanyrelevantstormwaternetworkdischargeconsent.Onlyprivatedischargesthatdonotenterapublicstormwaternetworkrequireauthorisationunderclausec.ord.above.

ThediversionanddischargeofstormwaterfromimperviousareasexistingatthedateofnotificationoftheUnitaryPlanarepermittedprovidedthattheyandtheirassociatedeffectsdonotincreaseabovethosethatexistedonthatdate;

Stormwaterdiversionanddischargefromnew/additionalimperviousareasaremanagedbybothdischargeandlanduserules.

Stormwatermanagement–flowrules

Thesearelanduserulesformanagingstormwaterrunofffromimperviousareas,pursuanttos.9(2)ands.30oftheRMA,applyingto:

a.StormwaterManagementArea–Flow1and2overlayareas

b.landusezonesinaccordancewithzoneimperviousareathresholds

c.areasdischargingtothecombinedsewernetwork

d.sitesnotconnectedtothepublicstormwaternetwork.

Stormwatermanagement–qualityrules

Thesearelanduserulesformanagingstormwaterrunoffqualityfromimperviousareaspursuanttos.9(2)ands.30oftheRMA.Theyapplytothefollowinghighcontaminantgeneratingactivities:

a.uncoveredparkingorparkingareas

b.highcontaminantyieldingroofing,spouting,claddingandarchitecturalfeatures

c.highuseroads.

DischargesofstormwaterfromanindustrialortradeactivityareaareaddressedinaseparatesectionoftheUnitaryPlan.The‘industrialortradeactivityarea’isalsodefinedintheplan.

Landusecontrolsareusedtoensurethesamestormwatermanagementrequirementsapply,asappropriate,toactivitieswithaprivatestormwaterdischargeandthosedischargingtoapublicstormwaternetwork.Whereasitealsohasastormwaterdischargetolandorwater,otherthanviaapublicstormwaternetwork,astormwaterdischargeconsentmayalsoberequired.

RulesapplyingspecificallytostormwaterrunofffrompublicroadsoperatedbyroadcontrollingauthoritiesincludebothdischargerulesandlandusecontrolsforhighuseroadsandwithinStormwaterManagementAreas–Flow1and2anddischargestothecombinedsewernetwork.

ThereportAucklandUnitaryPlanStormwaterManagementProvisions:TechnicalBasisofContaminantandVolumeManagementRequirements(AucklandCouncil2013)providesguidanceformeetingthestormwatermanagementrequirementswithinStormwaterManagementArea–Flow1and2andrequirementsapplyingtoHighContaminantGeneratingActivities.

1.Stormwaterdischarges

1.1Activitytable

[rcp/rp]

Diversionanddischargeofstormwatertoland,waterortheCMAincludingthediversionofsurface
waterfromimperviousareas
Activity / ActivityStatus
Existingimperviousareas
ImperviousareasexistingatthedateofnotificationoftheUnitaryPlan / P
ImperviousareasexistingatatthedateofnotificationoftheUnitaryPlanthatdonotmeetthe
permittedactivitycontrols / RD
Stormwater Networks
Stormwaterfromastormwaternetworkoperatedbyastormwaternetworkutilityoperator / C
Stormwaterfromastormwaternetworkoperatedbyastormwaternetworkutilityoperatorthat
doesnotmeetthecontrolledactivitycontrols / RD
Publicroadsoperatedbyaroadcontrollingauthority
Newimperviousareaslessthanorequalto5,000m2,includingancillaryimperviousareas,that
arepartofapublicroad / P
Newimperviousareas,includingancillaryimperviousareas,thatarepartofapublicroadthat
donotmeetthepermittedactivitycontrols / RD
Groundsoakageandpeatsoils
Newimperviousareasdischargingtogroundsoakageandpeatsoilareas / P
Newimperviousareasdischargingtogroundsoakageandpeatsoilareasthatdonotmeetthe
permittedactivitycontrols / RD
Imperviousareasnototherwiseprovidedforbystormwaternetwork,publicroad,groundsoakage
andpeatsoilrules
Newimperviousareasinaruralarea,includingruralzones,openspacezonesandspecialpurposezonesoutsidetheRUBwheretheimperviousareaislessthanorequalto5,000m2
andwhichdoesnotincreasethetotalimperviousareaofthesitetomorethan5,000m2 / P
Newimperviousareasinanurbanarea,includingopenspacezonesandspecialpurposezoneswithintheRUBwheretheimperviousareaislessthanorequalto1,000m2andwhich
doesnotincreasethetotalimperviousareaofthesitetomorethan1,000m2 / P
Newimperviousareasinanurbanarea,includingopenspacezonesandspecialpurposezoneswithintheRUBwherethetotalsiteimperviousareaisincreasedtogreaterthan
1,000m2butlessthanorequalto5,000m2 / RD
Newimperviousareaswherethedevelopmenthasbeensubjecttostructureorframework
planningthatincludesintegratedlanduseandstormwaterplanning / C
Allotherdiversionanddischargeofstormwaterfromimperviousareas
Thediversionanddischargeofstormwaterfromimperviousareasnototherwiseauthorisedby
stormwaterdischargeanddiversionrules / D

1.2Controls

1.2.1Permittedactivities

1.General

a.thedischargemustnotcauseorincreasescouringorerosionatthepointofdischargeordownstream.

b.thedischargemustnotresultin,orincrease,floodingofotherpropertiesineventsuptothe10percentAEPortheinundationofbuildingsineventsuptothe1percentAEP.

c.thedischargemustnotcausenuisanceordamagetootherproperty.

2.Existingimperviousareas

a.theimperviousareawasexistingonthedateofnotificationoftheUnitaryPlan.

b.stormwaterflowsandvolumesfromexistingimperviousareasmustnotbeincreasedabovethoseatthedateofnotificationoftheUnitaryPlan,includingasaresultofachangeinlanduseorremovalofexistingstormwatermanagementmeasures.

c.theconcentrationandloadofcontaminantsinstormwaterflowsfromexistingimperviousareasmustnotbeincreasedabovethoseatthedateofnotificationoftheUnitaryPlan,includingasaresultofachangeinlanduseortheremovalofexistingstormwatertreatmentmeasures.

d.anyroadancillaryareamustnotbenotusedfor:

i.

ii.iii.

storageofroadingandbuildingmaterialsformorethan14dayscontinuouslystorageofhazardousmaterial

works/buildingyards

e.thediversionanddischargemustnotbeotherwiseauthorisedbyanetworkdischargeconsent.

f.anyredevelopmentofexistingimperviousareasmustmeettheStormwaterManagement–FlowandQualityrequirementsoftheUnitaryPlan

g.themethodoftreatment,diversionandlocationofthedischargemustnotchange.

3.Publicroadsoperatedbyaroadcontrollingauthority

a.thenewimperviousarea,includingfootpaths,cyclewaysandancillliaryareas,mustbelessthanorequalto5,000m2.

b.ataminimum,stormwatertreatmentmustbeappliedtocatchpitsforconcentratedflows,orbydirectingsheetflowsacrossvegetatedareaswhereflowsarenotconcentrated

c.thedrainagenetwork,includingroadsidedrainages,swalesandcatchpitsmustbemanagedandmaintainedtoensureeffectiveoperationandpreventerosion,sedimentgenerationanddischarge

d.wherestormwaterisdischargedtoland,itmustbedispersedtopreventscouranderosion.

e.anyroadancillaryareamustnotbeusedfor:

i.

ii.iii.

storageofroadingandbuildingmaterialsformorethan14dayscontinuouslystorageofmaterialthatmaybehazardoustotheenvironment

works/buildingyards.

4.Groundsoakageandpeatsoils

a.thetotalimperviousareaonthesite,includinganynewareas,mustnotexceedthelesserof:

i.

ii.

theimperviousareathresholdfortherelevantzone;or1,000m2

b.anydevelopmentrequirementsforgroundsoakage,includingdevicestotreatdischargesorsoakagedesign,mustbecompliedwith

c.anyflowsinexcessofsoakagecapacityorfromsoakagefailuremustbedirectedtoastormwaternetworkordischargedwithoutcausingscour,erosionorincreasingriskoffloodingtopeopleandpropertyupordownstream

d.anynewimperviousareamustmeettherelevantrequirementsoftheStormwaterManagement–FlowandQualityrequirementsoftheUnitaryPlan,includinginaccordancewitharesourceconsentgrantedunderthoserules.

5.Newimperviousareaslessthanorequalto5,000m2inaruralareas,includingruralzones,openspacezonesandspecialpurposezonesoutsidetheRUB

a.thetotalimperviousareaonthesite,excludingunsealedorgraveledtracks,mustbelessthanorequalto5000m2.

b.theremustbenoconnectiontothestormwaternetworkavailable.

c.thedischargemustbefromanimperviousareawithinaruralarea,includingruralzones,openspacezonesandspecialpurposezonesoutsidetheRUB.

d.stormwatermustbedischargedtolandinamannerthatdispersestheflowandpreventsscourandpointdischargesforming.

6.Newimperviousareaslessthanorequalto1,000m2inanurbanarea,includingopenspacezonesandspecialpurposezoneswithintheRUB(excludingpublicroads)

a.thetotalimperviousareaonthesite,includinganynewimperviousarea,mustbelessthanorequalto1000m2.

b.theremustbenoconnectiontothestormwaternetworkavailable.

c.thedischargemustbefromanimperviousareathatiswithinanurbanarea,includingopenspacezonesandspecialpurposezoneswithintheRUB.

d.thenewimperviousareamustmeettherelevantrequirementsofStormwaterManagement–FlowandQualityrulesoftheUnitaryPlan,includinginaccordancewitharesourceconsentunderthoserules.

1.2.2Controlledactivities

1.General

Thesecontrolsapplytoallcontrolledactivitiesotherthandischargesfrompublicstormwaternetworks

a.Thedischargemustnotcauseorincreasescouringorerosionatthepointofdischarge.

b.Thedischargemustnotresultin,orincrease,thefloodingofotherpropertiesineventsuptothe10per

centAEPortheinundationofbuildingsineventsuptothe1percentAEP.

c.Thedischargemustoccurwiththeminimumofnuisanceanddamageandinparticularavoidsmorethanminoradverseeffectsonanyotherproperty.

d.AnyneworredevelopmentofexistingimperviousareasmustmeettherelevantrequirementsofStormwaterManagement–FlowandQualityrulesoftheUnitaryPlan,includinginaccordancewitharesourceconsentunderthoserules.

e.Thediversionanddischargemustbemanaged,andwherepossibledispersed,tominimiseerosionandsedimentgeneration.

2.Stormwaternetworks

a.TheapplicationmustincludeanassessmentofadverseeffectsthataddressesthemattersidentifiedinTable1.

3.Newimperviousareaindevelopmentsthathavebeensubjecttoanintegratedstructureplanprocess

a.Thedevelopmenthasbeensubjecttoanintegratedlanduseandstormwatermanagementstructureplanningprocessthataddressestheintegratedmanagementstormwater,freshwaterandwaterqualityobjectivesandpoliciesofthisUnitaryPlan.

1.3Assessment­Controlledactivities

1.3.1Mattersofcontrol

Thecouncilwillreserveitscontroltothemattersbelowfortheactivitieslistedascontrolledintheactivitytable.

1.General

a.Monitoringandreporting,includingonanetworkwidebasisforstormwaternetworks.

b.Operationsandmaintenancerequirements.

2.Stormwaternetworks

a.TheimplementationofmeasuresrequiredtoachievetheBPOforpreventingorminimisingtheadverseeffectsofstormwaterdischargesfrombothexistingand,whererelevant,futuredischarges.

b.AnyprogrammeoffurtherinvestigationsandworksrequiredtogiveeffecttotheBPO.

c.TheimplementationofanyprogrammesrequiredtogiveeffecttotheBPO.

3.Newimperviousareasindevelopmentsthathavebeensubjecttoanintegratedstructureorfarmeworkplanprocessthatincludesintegratedlanduseandstormwaterplanning

a.Thelocationofthedischargepoint(s)

b.Measurestoavoiderosion,scourandfloodrisk.

4.Theimplementationandmaintenanceofmeasurestomeetthestormwaterdiversionanddischargerequirementsoftheintegratedlanduseandstormwatermanagementassessment.

a.ConsistencywithanyrelevantnetworkdischargeconsentorpubliclyavailableandcurrentAucklandCouncilstormwatermanagementplans/analysis.

1.3.2Assessmentcriteria

Thecouncilwillconsiderthereleventassessmentcriteriabelowforthecontrolledactivitieslistedabove.

1.Stormwaternetworks

a.WhethertheconsentapplicationadequatelyaddressesthematterslistedinTable1.

b.TheextenttowhichtheproposedmanagementofstormwaterrepresentstheBPOforthereticulatedcatchment,takingaccountofmattersassessedaslistedinTable1.

2.Newimperviousareaswherethedevelopmenthasbeensubjecttostructureorframeworkplanningthatincludesintegratedlanduseandstormwaterplanning

a.WhetherstormwatermanagementisconsistentwithanyrelevantnetworkdischargeconsentorpubliclyavailableandcurrentAucklandCouncilstormwatermanagementplansand/analysis.

b.Theextenttowhichthestructureorframeworkplanandassociatedplanchangeorresourceconsenthasachievedintegratedandeffectivestormwatermanagementacrosstheproposeddevelopmentareaandinparticular:

i.

ii.iii.

adoptswatersensitivedesignandgreeninfrastructure;minimiseshydrologicalchange;

minimises contaminants.

c.Whetherthestructureorframeworkplanandassociatedplanchangeorresourceconsent providesclearrequirementsforstormwatermanagementatbothasiteandsub­catchmentlevelasrelevant.

d.Whetherthereareprocessesinplacetoensurethatstormwatermanagementwillbeimplementedinaccordancewiththestructureplanorframeworkplanrequirements.

e.WhetherthereisclearidentificationofthoseelementsthataretobevestedinCouncilandthattheymeetthecouncilrequirementsforvestedinfrastructure.

f.Theextenttowhichadverseeffectsofstormwaterdiversionsanddischargesarepreventedormitigated,withparticularregardto:

i.

ii.

iii.iv.

v.

thenature,quality,volumeandpeakflowofthestormwaterrunoff

thesensitivityofnaturalfreshwatersystemsandcoastalwaters,includingtheHaurakiGulfMarinePark,totheadverseeffectsofstormwatercontaminantsandflows

thepotentialforthediversionanddischargetocreateorexacerbatefloodrisks

optionstomanagestormwateron­siteortheuseofcommunalstormwatermanagementmeasures

practicallimitationsinrespectofthemeasuresthatcanbeapplied.

g.Theextenttowhichfloodplains,foodsensitiveandfloodproneareasanddevelopmentareamanagedandwhetheroverlandflowpathshavebeenidentifiedandprotected.

1.4Assessment­Restricteddiscretionaryactivities

1.4.1Mattersofdiscretion

1.ExistingImperviousAreas

a.themanagementoftheadverseeffectsofthestormwaterdiversionanddischargeonreceivingenvironments,buildingsandproperty

b.consistencywithanyrelevantnetworkdischargeconsentorpubliclyavailableandcurrentAucklandCouncilstormwatermanagementplans/analysis

c.operationsandmaintenancerequirements.

d.monitoringandreporting.

2.Stormwaternetworks

a.theBPOforthemanagementoftheadverseeffectsofthestormwaterdiversionanddischargeonreceivingenvironments,buildingsandpropertydischarges

b.monitoringandreporting,includingonanetworkwidebasis

c.operationsandmaintenancerequirements

d.theimplementationofstormwatermanagementdevicesandothermeasurestogiveeffecttotheBPOforpreventingorminimisingtheadverseeffectsofstormwaterdischargesfrombothexistingand,whererelevant,future

e.anyprogrammeoffurtherinvestigationsandworksrequiredtogiveeffecttotheBPO

f.theimplementationofanyprogrammesrequiredtogiveeffecttotheBPO.

3.Publicroadsoperatedbyaroadcontrollingauthority

a.theadoptionoftheBPOtopreventorminimiseadverseeffectsofthestormwaterdiversionanddischargeonreceivingenvironments,buildingsandproperty

b.consistencywithanyrelevantnetworkdischargeconsentorpubliclyavailableandcurrentAucklandCouncilstormwatermanagementplans/analysis

c.themanagementandmitigationoffloodeffects,includingonbuildingsandproperty

d.operationsandmaintenancerequirements

e.monitoringandreporting,includingmonitoringandreportingonanetworkwidebasis.

4.Groundsoakageandpeatsoils

a.methodsofsoakage

b.measurestominimisethedischargeofcontaminantstogroundwateraquifers

c.measurestomaintainsoilmoisturelevelsinpeatsoils

d.disposalofstormwaterinexcessofdevicecapacityandthemanagementofassociatedadverseeffects

e.themanagementandmitigationoffloodeffects,includingonbuildingsandproperty

f.operationsandmaintenancerequirements

g.monitoringandreporting,includingmonitoringandreportingonanetwork­widebasis.

5.Imperviousareasnototherwiseprovidedforbystormwaternetwork,publicroad,groundsoakageandpeatsoilrules

a.thelocationandmethodofthedischarge

b.methodsandmeasurestoavoidlandinstability,erosion,scourandfloodrisk

c.themanagementofstormwaterflowandvolumeformaintainingorenhancingstreamchannelsandstreamhealth

d.themanagementoftheadverseeffectsofthestormwaterdiversionanddischargeonreceivingenvironments,buildingsandproperty,includingcumulativeeffects

e.operationsandmaintenancerequirements

f.monitoringandreporting.

6.Infringementofzonemaximumimperviousareacontrolandinfringementofzonemaximumimperviousareawithinariparianyard.

a.thelocationandmethodofthedischarge

b.methodsandmeasurestoavoidlandinstability,erosion,scourandfloodrisk

c.themanagementofstormwaterflowandvolumeformaintainingorenhancingstreamchannelsandstreamhealth

d.themanagementoftheadverseeffectsofthestormwaterdiversionanddischargeonreceivingenvironments,buildingsandproperty,includingcumulativeeffects

e.operationsandmaintenancerequirements

f.monitoringandreporting.

1.4.2Assessmentcriteria

1.Allrestricteddiscretionaryactivities(excludingstormwaternetworksandpublicroadsandinfringingthezonemaximumimperviousareawithinariparianyard)

a.theextenttowhichtheproposalpreventsorminimisestheadverseeffectsofthedischarge,includingcumulativeeffects,totheextentpossiblehavingregardto:

i.

ii.iii.iv.

v.

vi.vii.viii.

thenature,volumeandpeakflowofthestormwaterdischarge

thesensitivityofthereceivingenvironmenttostormwatercontaminantsandflowsavoidingthecreationorincreaseoffloodrisktootherproperties

optionsformanagingstormwateron­siteorthroughcommunalmanagementdevicespracticallimitationsonthemeasuresthatmaybeused

maintainingwaterlevelsinunderlyingpeatsoilsandgroundstability(whererelevant)theadoptionofwatersensitivedesignandgreeninfrastructurewherepracticable

vManaWhenuaandcommunityvaluesanduses

b.optionsfordischargewherethereisnoavailablestormwaternetwork

c.consistencywithanyrelevantnetworkdischargeconsentorpubliclyavailableandcurrentAucklandCouncilstormwatermanagementplans/analysis

d.opportunitiestoreduceexistingadverseeffectsandenhancereceivingenvironments

e.theeffectsonmarinesedimentquality,inaccordancewithCoastalZoneDischargesPolicy10

andassociatedTable1.

2.Infringingthezonemaximumimperviousareawithinariparianyard

a.Developmentthatdoesnotcomplywiththeriparianorcoastalyardcontrolswillneedtodemonstratethat:

i.

ii.iii.iv.

v.

vi.

adverseeffectsonthefunctionoftheyardinmanagingflooding,erosion,orwaterquality,willbeminimised

thecontinuityofanyvegetationcorridorwillbemaintained

Siteworksandassociatedvehiclemovementsareminimisedinthewithintheyard

thereisnopracticablealternativetodevelopmentwithintheyardandthatthedevelopmentislocatedasfarfromtheCoastalMarineArea,orstreamaspossible

locatingdevelopmentwithintheyardisrequiredforthereasonableuseanddevelopmentofthesite,includingfortheprovisionofpublicaccessorinfrastructuresuchasrecreationaltrails,bridges/culverts,undergroundutilities,wastewaterorstormwaterinfrastructure

theadverseeffectsofdevelopmentwithintheyardaremitigatedbyplantingwithnativeplantsand/orprovidingawidersetbackelsewherethatwillenhancethefunctionoftheyard

3.StormwaterNetworksandPublicRoads

a.theextenttowhichtheBPOaddressesthemattersforstormwaternetworksandroadsinAuckland­wide­WaterqualityandintegratedmanagementPolicy10andTable1.

b.theeffectsonmarinesedimentquality,inaccordancewiththeCoastalzone­DischargesPolicy10andassociatedTable1.

1.5Requirementsforstormwaternetworkdischargeconsents

Table1:

A / Theissuesarisingfromstormwaterandwastewaterdischarges,diversionsandassociated
activitiesfacingthecatchmentordistrict,including:
i / descriptionofthedrainagenetworksandtheircurrentandpredictedfutureperformanceunderlikelygrowth
scenarios
ii / assessmentofthereceivingenvironmentandtheactualandpotentialeffects,includingcumulativeeffects,
ofdiversionsanddischargesfromthenetwork
iii / identificationofpotentialurbangrowth,landuseintensificationandredevelopmentandtheconsequenceof
thisforthenetworkanddischarges
iv / managementresponsibilitiesforstormwaterandwastewaternetworksandassociateddischarges
v / significantnon­networklanduseanddischargeactivitiesthatmayhaveamaterialeffectonenvironmental
andstormwatermanagementoutcomes
B / Adescriptionoftheobjectivessoughtforthestormwaterandwastewaterdischargesand
diversionsincluding:
i / social,ecological,economic,amenityandculturalobjectivesincludingthestrategicimportanceofthe
activityandstormwaternetwork
ii / theresultsofanyconsultation
iii / identifiedmilestonesrequiredtoachievethoseobjectives
C / Theproposedapproachtomanagingdiversionsanddischargesincluding:
i / identificationoftheBPOforpreventingorminimisingtheadverseeffectsofstormwaterdischargesfromboth
existingand,whererelevant,futuredischarges
ii / prioritiesforfurtherinvestigationintominimisingtheeffectsofthedischargesanddevelopmentof
managementresponsesandassociatedmilestones
iii / proceduresformonitoringandreportingprogressagainstobjectivesandmilestones
iv / aregionallyprioritisedprogrammeforimplementingimprovementprojectsandworks
v / operationandmaintenanceprogrammesandprocesses
vi / otherprogrammestoassistinachievingoutcomesincludingeducationinitiativesandcommunitybased
programmes
vii / consistencywithotherlanduseprocessoutcomessuchasstructureplans,andpubliclyavailableand
currentAucklandCouncilstormwatermanagementplans/analysis
viii / aprocessforreviewingthemanagementapproachbasedonanincreasedunderstandingofenvironmental
responses,publichealthissues,communityaspirationsandnetworkpriorities
D / PublicRoadNetworks(wherenotincludedinwiderstormwaternetworkdischargeconsents)
i / descriptionofthedrainagenetworksandtheircurrentandpredictedfutureperformanceunderlikelygrowth
ii / assessmentofthereceivingenvironmentandtheactualandpotentialeffects,includingcumulativeeffects,
ofdiversionsanddischargesfrom thenetwork
iii / considerationofalternativeoptionswherepotentialadverseeffectsaresignificant
iv / social,ecological,economic,amenityandculturalobjectivesincludingthestrategicimportanceofthe
activityandstormwaternetwork
v / theresultsofanyconsultation
vi / consistencywithotherlanduseprocessoutcomessuchasstructureplans,andpubliclyavailableand
currentAucklandCouncilstormwatermanagementplans/analysis
vii / identificationoftheBPOforpreventingorminimisingtheadverseeffectsofstormwaterdischargesfromboth
existingand,whererelevant,futuredischarges
viii / operationandmaintenanceprogrammesandprocesses
ix / monitoring

2.Stormwater Management ­ Flow

Itisanticipatedthattechnicalguidancewillbeprovidedthroughbestmanagementpracticeguidelinestosupportimplementationofflowrulesinthischapter.

2.1Activitytable

[rp]

Section9(2)RMAlandusecontrolsformanagingstormwaterflows
Activity / Activitystatus
WithinordischargingtoaStormwaterManagementArea–Flow(SMAF)1or2
Imperviousareas(otherthanforapublicroad)oflessthanorequalto25m2inaSMAF1or2 / P
Imperviousareas(otherthanforapublicroad)greaterthan25m2inaSMAF1or2(otherthan
forapublicroad)thatmeethydrologymitigationrequirements / C
ImperviousareasinaSMAF1or2unabletocomplywiththepermittedandcontrolledactivity
controls / RD
PublicroadsoperatedbyaroadcontrollingauthoritywithinaStormwaterManagementArea–Flow
(SMAF)1or2
Imperviousareaslessthanorequalto1000m2withinaSMAF1or2thatmeetthehydrology
mitigationrequirements / P
Imperviousareasgreaterthan1000m2andlessthanorequalto5000m2withinaSMAF1or2
thatmeethydrologymitigationrequirements / C
ImperviousareaswithinaSMAF1or2thatdonotmeetthepermittedandcontrolledactivity
controls / RD
Imperviousareaswherestormwaterisdirectedtothecombinedsewernetwork(includingfrom
publicroads)
Theredevelopmentofexistingimperviousareaswheretheseareasdirectstormwatertothe
combinedsewernetwork / P
Thedevelopmentofnewimperviousareaswheretheseareasdirectstormwatertothe
combinedsewernetwork / C
Thedevelopmentofneworredevelopmentofexistingimperviousareaswheretheseareasdirectstormwatertothecombinedsewernetworkandareunabletomeetthepermittedand
controlledactivitycontrols / D
Imperviousareasinurbanareas(excludingthestrategictransportcorridorandroads)notconnected
tothestormwaternetwork
Thedevelopmentofnewimperviousareaslessthan25m2wherethetotalimperviousareaon
thesitecompriseslessthanorequalto10%ofthetotalsitearea / P
Thedevelopmentofnewimperviousareasgreaterthan25m2wherethetotalpercentage
imperviousareaonthesiteisgreaterthan10% / C
Thedevelopmentofnewimperviousareasthatdonotmeetthepermittedorcontrolledactivity
controls / D
AllzoneswithanImperviousAreaThresholdwherenototherwisecontrolledwithinSMAF1or2,
combinedsewerornotconnectedtostormwaternetwork(excludingtheHaurakiGulfIslands)
Totalimperviousareaonthesiteislessthanorequaltotheimperviousareathresholdforthe
relevantzone / P
Totalimperviousareaonthesiteisgreaterthantheimperviousareathresholdfortherelevant
zoneinallareas / RD

2.2Controls

2.2.1Permittedactivities

1.PublicroadsoperatedbyaroadcontrollingauthoritywithinaStormwaterManagementArea–Flow(SMAF)1or2

a.thenew/redevelopedimperviousarea,includingfootpaths,cyclewaysandancillaryareasmustbelessthan1000m2

b.stormwatervolumesandflowfromtheareamustbemanagedtoachievethehydrologymitigationrequirementspecifiedinTable2forSMAF1andSMAF2

c.thestormwatermanagementdevicemustbecertifiedbyacouncil­approvedcharteredprofessionalengineerasbeingdesignedtomeettherequiredlevelofhydrologymitigationandisconstructed

inaccordancewiththedesignandsoundengineeringpractice.

d.thestormwatermanagementdeviceisfullyoperationalpriortopublicuseofroad.

e.‘asbuilt’plansandanoperationsandmaintenanceplanareprovidedtocouncilwithinthreemonthsofpracticalcompletionoftheworks.

f.anydevicesaremaintainedinaccordancewiththeoperationsandmaintenanceplan.

2.Imperviousareaswherestormwaterisdirectedtothecombinedsewernetwork(includingpublicroads)

a.theredevelopmentdoesnotresultinanincreaseinimperviousareaandstormwaterrunoffdischargingtothecombinedsewernetwork.

b.thereisnoalternativedischargeoption.

3.Imperviousareasinurbanareas(excludingthestrategictransportcorridorandroads)notconnectedtothestormwaternetwork

a.either:

i.

ii.

theincreaseinimperviousareaabovethatexistingatthedateofnotificationoftheUnitaryPlanislessthan25m2;or

thetotalimperviousareaislessthan10percentofthesiteare.

2.2.2Controlledactivities

1.New/redevelopmentofimperviousareaswithinaSMAF1or2(excludingpublicroads)

a.thetotalsiteimperviousareaislessthanorequaltotheImperviousAreaThresholdfortherelevantzone

b.wherethenewimperviousareaortheredevelopmentofexistingimperviousareacompriseslessthan50percentofthetotalsiteareastormwaterfromtheneworredevelopedareaismanagedtoachievetheHydrologymitigationrequirementsspecifiedinTable2foraSMAF1andSMAF2

c.wherethenewimperviousareaortheredevelopmentofexistingimperviousareascomprisesmorethanorequalto50percentofthetotalsitearea:

i.stormwaterfromthetotalsiteimperviousareaismanagedtoachievethehydrologymitigationrequirementsspecifiedinTable2foraSMAF1andSMAF2.

2.PublicroadsoperatedbyaroadcontrollingauthoritywithinaSMAF1or2

a.thenew/redevelopmentimperviousarea,includingfootpaths,cyclewaysandancillaryareasisgreaterthan1,000m2butlessthan5,000m2.

b.stormwaterrunofffromthenew/redevelopedarea,andanyadditionalexistingareadischargingtothesamedischargepoint(s)ismanagedtoachievethehydrologymitigationrequirementsspecifiedinTable2foraSMAF1andSMAF2.

3.Newimperviousareaswherethestormwaterisdirectedtothecombinedsewernetwork

a.thetotalsiteimperviousareaislessthanorequaltotheImperviousAreaThresholdfortherelevantzone

b.anynewimperviousareadoesnotincreasethetotalimperviousareaorstormwaterrunofffromthesitedirectedtothecombinedsewernetwork.

4.Imperviousareasinurbanareas(excludingthestrategictransportcorridorandroads)notconnectedtothestormwaternetworkorgroundsoakage

a.thetotalsiteimperviousareaislessthanorequaltotheImperviousAreaThresholdfortherelevantzone

b.stormwaterrunoffcanbedischargedfromthesitewithoutgivingrisetosignificantadverseeffects(includingcumulativeeffects)including:

i.

ii.iii.

erosionorscouratornearthepointofdischargefloodingofanyhabitablefloororotherproperty

landinstability,includingcliffandstreambankerosion.

2.3Assessment­Controlledactivities

2.3.1Mattersofcontrol

1.Allcontrolledactivities

a.theimplementationofstormwatermanagementsystemsordevicestoachievestormwaterhydrologymitigationrequirement

b.operationsandmaintenancerequirements

c.monitoringandreporting,includingmonitoringandreportingonanetworkwidebasiswhereapplicable.

2.PublicroadsoperatedbyaroadcontrollingauthoritywithinaSMAF1or2

a.theprovisionofdesignspriortoworkstartingandas­builtplansfollowingcompletionofworks.

3.New/redevelopmentofimpervioussurfacesgreaterthanorequalto1000m2andlessthan5,000m2forapublicroadinSMAF1or2

a.measurestomanagestormwaterrunofftonomorethanexistinglevels.

4.Imperviousareasinurbanlanduses(excludingthestrategictransportcorridorandroads)notconnectedtothestormwaternetwork

a.themethodofstormwatermanagementanddischargemeasuresandtheextenttowhichtheyminimiseormitigateadverseeffects,includingflooding,erosionandlandstability

b.conditionsinrespectofconnectingintoastormwaternetworkshouldonebecomeavailable.

2.3.2Assessmentcriteria

1.Allcontrolledactivities

a.Whetherthesitestormwaterrunoffisdirectedtoanon­sitedeviceand/orviaacommunalorpublicmanagementdevicedesignedandsizedtoaccommodatestormwaterrunofffromthesiteandachievethestormwaterhydrologymitigationrequirements.

2.4Assessment­Restricteddiscretionaryactivities

2.4.1Mattersofdiscretion

1.Allrestricteddiscretionactivities

a.themanagementofeffects,includingcumulativeeffects,onstreams,thecapacityofthestormwaternetwork,andfloodingwithinthecatchment

b.thedesignandimplementationofstormwaterflow/volumemanagementmeasures

c.operationsandmaintenancerequirements

d.monitoringandreporting.

2.Imperviousareaswherestormwaterisdirectedtothecombinedsewernetwork(includingfrompublicroads)

a.measurestomitigatepotentialincreasesinoverflowsfromthecombinedsewernetwork.

3.Imperviousareasinurbanareas(excludingthestrategictransportcorridorandroads)notconnectedtothestormwaternetwork

a.methodsofstormwaterdisposal

b.themanagementofpotentialeffectsonlandstabilityanderosion

c.theconnectiontoapublicstormwaternetworkshouldonebecomeavailable.

2.4.2Assessmentcriteria

1.Allrestricteddiscretionaryactivities

a.theextentofexistingfloodingwithinthecatchmentandavoidingcreatingorincreasingexistingflooding,includingincrementaladverseeffects

b.theextenttowhichtheincrementalandcumulativeadverseeffectsofincreasedstormwaterflowsincludingonstreamchannelsandstreamhealth,naturalcharacter,biodiversity,erosionandstabilityandcommunityandManaWhenuavaluescanbeavoided,orifnotavoidedthenotherwiseadequatelymitigated;

c.theabilitytoreduceexistingadverseeffects

d.whetherastormwaternetworkisavailableanditscapacitytocaterforincreasedstormwaterflows

e.whetherstormwaterflowismanagedon­siteorwhethertherearestormwatermanagementdevicesinthecatchmentandtheirabilitytoacceptandcaterforincreasedstormwaterflowstomeetmitigationrequirements

f.theabilityofmitigationmeasurestodetainthe2,10and100year,24hrrainfalleventpeakflowstothepre­development(grass)conditionfortheexcessimperviousarea(appliestonew/redevelopmentofimperviousareasinexcessofzoneimperviousareathresholdsonly)

Table2:StormwaterManagementArea­Flowhydrologymitigationrequirements

Stormwater
Management Area / Hydrologymitigationrequirement
SMAF1 / •providedetention(temporarystorage)withavolumeequaltotherunoffvolumefromthe95thpercentile,24hrrainfalleventfortheimperviousareaforwhichhydrologymitigationisrequired;and
•provideretention(volumereduction)ofa10mm,24hrrainfalleventforthe impervious
areaforwhichhydrologymitigationisrequired
SMAF2 / •providedetention(temporarystorage)withavolumeequaltotherunoffvolumefromthe90thpercentile,24hrrainfalleventfortheimperviousareaforwhichhydrologymitigationisrequired;and
•provideretention(volumereduction)ofa8mm,24hrrainfalleventforthe impervious
areaforwhichhydrologymitigationisrequired

3.Stormwatermanagement­quality

3.1Activitytable

[rp]

Section9(2)RMAlandusecontrolsformanagingstormwatercontaminantsinrunofffromhigh
contaminantgeneratinglanduseactivities
Activity / Activitystatus
Newandredevelopmentofexistinguncoveredparking(includingthatwhichisaccessorytothe
mainuseofthesite)
Uncoveredparking(includingthatwhichisaccessorytothemainuseofthesite)includingentry/exit(includingthatwhichisaccessorytothemainuseofthesite),whichislessthanor
equal1000m2inareaandwhicharenotlocatedintheIndustrialorTradeActivityarea / P
Uncoveredparking(includingthatwhichisaccessorytothemainuseofthesite)includingentry/exit,whicharegreaterthan1000m2inareaandwhicharenotlocatedintheIndustrialor
TradeActivityarea,wherestormwaterqualitymanagementrequirementsaremet / C
Uncoveredparking(includingthatwhichisaccessorytothemainuseofthesite)including
entry/exit,whichdonotmeetthepermittedandcontrolledactivitycontrols / RD
Newhighcontaminant­yieldingroofing,claddingorarchitecturalfeatures
Theinstallationofhighcontaminantyieldingroofing,spouting,claddingmaterialor
architecturalfeatures,subjecttomeetingmaximumareathresholds / P
Theinstallationofhighcontaminantyieldingroofing,spouting,claddingmaterialor architecturalfeatures,exceedingpermittedactivityareacontrolsandwherestormwaterquality
managementrequirementsaremet / C
Theinstallationofhighcontaminantyieldingroofingspouting,claddingmaterialorarchitectural
featuresthatdoesnotmeetthepermittedandcontrolledactivitycontrols / D
New,andredevelopmentofexisting,high­usepublicroadsoperatedbyaroadcontrollingauthority
Imperviousarealessthanorequalto5000m2 / P
Imperviousareathatdischargesstormwatertoanexistingconsentedstormwaterquality
managementdevice / P
Imperviousareagreaterthan5000m2wherestormwaterqualitymanagementrequirementsare
met / C
Imperviousareathatdoesnotmeetthepermittedactivityandcontrolledactivitycontrols / RD

3.2Controls

3.2.1Permittedactivities

1.New,andredevelopmentofexisting,uncoveredparking(includingthatwhichisaccessorytothemainuseofthesite)

a.Theneworredevelopedparkingincludingentry/exitmustbelessthan1000m2,excludinganyareathatisincludedinanIndustrialorTradeActivityarea.

2.Newhighcontaminant­yieldingroofing,spouting,claddingorarchitecturalfeatures

a.Thetotalareaofhighcontaminantyieldingroofing,spouting,claddingorarchitecturalfeaturesusedonthesitemustnotexceed:

i.

ii.

iii.

25m2inurbanarea

25m2inanyruralzonewherethestormwaterrunofffromtheroofing,spouting,claddingorarchitecturalfeaturesispipeddirectlytoawatercourse

250m2inanyruralzonewherethestormwaterrunofffromtheroofing,spouting,claddingorarchitecturalfeaturesisdirectedtoanyvegetateddrain/swale,wetlandorsimilar.

3.New,andredevelopmentofexisting,highusepublicroadslessthan5000m2

a.Thenew/redevelopedimperviousareaofthehighuseroadmustbelessthanorequalto5000m2

b.Stormwaterrunofffromthenew/redevelopedarea,andanyadditionalexistingareadischargingtothesamedischargepoint(s),mustbemanagedbydevicesthataredesignedtomeetthestormwaterqualitymanagementrequirementsfortherelevantcontaminantsofconcerninTables3and4.

c.Thestormwatermanagementdevicesmustbecertifiedbycouncil­approvedcharteredprofessionalengineerasbeingdesignedtomeetthestormwaterqualityrequirementsandisconstructedinaccordancewiththedesignandsoundengineeringpractice.

d.Thestormwatermanagementdevicesmustbebuiltgenerallyinaccordancewiththecertifieddesignandisfullyoperationalpriortopublicuseofthenew/redevelopedroad.

e.‘Asbuilt’plansandanoperationsandmaintenanceplanmustbeprovidedtocouncilwithinthreemonthsofpracticalcompletionoftheworks.

f.Stormwatermanagementdevicesmustbemaintainedinaccordancewiththeoperationsandmaintenanceplan.

g.Acomplianceprogrammemustbeestablishedandfollowedtoensurecompliancewithallpermittedactivitycontrolsandisprovidedtocouncilbythreemonthsofpracticalcompletionoftheworks.

4.New,andredevelopmentofexisting,high­useroadsthatdischargetoexistingstormwaterqualitymanagementdevices

a.Stormwaterrunofffromthenew/redevelopedareamustbedirectedtoanexistingstormwaterqualitymanagementdevice,requiredbyacurrentstormwaterdischargeconsent,subjectto:

i.

ii.

certificationbyacouncil­approvedcharteredprofessionalengineerthattheexistingstormwatermanagementdeviceisdesignedandsizedtoaccommodatetheincreaseinflowfromthenew/redevelopedimperviousareawithoutreducingdesigntreatmentlevelsorcausingscourorerosion;

stormwatermanagementdevicesaremaintainedinaccordancewithresourceconsentrequirementsoranoperationsandmaintenanceplan

3.2.2Controlledactivities

1.New,andredevelopmentofexisting,uncoveredparking(includingthatwhichisaccessorytothemainuseofthesite)

a.Wheretheneworredevelopmentofexistinguncoveredparkingareas,includingentry/exit,comprisesmorethan1000m2butislessthan50percentofthetotalcarparkarea(excludinganyareathatisincludedinanIndustrialorTradeActivityarea):

i.stormwaterrunofffromthenew/redevelopedparkingmustbemanagedbydevicesthataredesignedtomeetthestormwaterqualitymanagementrequirementsfortherelevantcontaminantsofconcerninTables3and4.

b.Wheretheneworredevelopmentofexistinguncoveredparking,includingentry/exit,comprisesmorethan1000m2andisgreaterthan50percentofthetotalparkingarea(excludinganyareathatisincludedinanIndustrialorTradeActivityarea):

i.stormwaterrunofffromtheentireparkingareamustbemanagedbydevicesthataredesignedtomeetthestormwaterqualitymanagementrequirementsfortherelevantcontaminantsofconcerninTables3and4.

2.Newhighcontaminant­yieldingroofingspouting,claddingorarchitecturalfeatures

a.Thetotalareaofanyhighcontaminantyieldingroofing,spouting,claddingorarchitecturalfeaturesusedonthesiteexceeds:

i.

ii.

iii.

25m2inanyurbanzone.

25m2inanyruralzonewheretherunofffromtheroofing,spouting,claddingorarchitecturalfeaturesispipeddirectlytoawatercourse.

250m2inanyruralzonewheretherunofffromtheroofing,spouting,claddingorarchitecturalfeaturesisdirectedtoanyvegetateddrain/swale,wetlandorsimilar.

b.Stormwaterrunofffromtheroofing,spouting,claddingorarchitecturalfeaturesismanagedbydevicesthataredesignedtomeetthestormwaterqualitymanagementrequirementsfortherelevantcontaminantsofconcerninTables3and4.

3.New/redevelopedimperviousareaforahighusepublicroad

a.Stormwaterrunofffromthenew/redevelopedimperviousarea,andanyadditionalexistingimperviousareadischargingtothesamedischargepoint(s),ismanagedbyadeviceordevicesdesignedtomeetthestormwaterqualitymanagementrequirementsfortherelevantcontaminantsofconcerninTables3and4.

3.3Assessment­Controlledactivities

3.3.1Mattersofcontrol

1.Allcontrolledactivities

a.theimplementationofastormwatermanagementsystemordevicestoachievethestormwaterqualitymanagementrequirements

b.operationsandmaintenancerequirements

c.monitoringandreporting,onanetwork­widebasis.

3.3.2Assessmentcriteria

1.Allcontrolledactivities

a.whetherthesitestormwaterrunoffisdirectedtoanon­sitedeviceand/orviaacommunalorpublicmanagementdevicedesignedandsizedtoaccommodatestormwaterrunofffromthesiteandachievethestormwaterqualitymanagementrequirements.

3.4Assessment­Restricteddiscretionaryactivities

3.4.1Mattersofdiscretion

Thecouncilwillrestrictitsdiscretiontothemattersbelowforrestricteddiscretionaryactivities.

1.Infringementofmaximumimperviousareacontrolwithinriparianyardsorinfringementofthecoastalprotectionyard:

a.adverseeffectsonthefunctionoftheyard

b.thecontinuityofanyvegetation

c.siteworksandassociatedvehiclemovements

d.pacticablealternatives

e.reasonableuseanddevelopmentofthesite

f.mitigation.

2.Newandredevelopmentofexistinguncoveredparkingorparkingareas(includingthatwhichisaccessorytothemainuseofthesite)

a.stormwaterqualitymanagementrequirementsforminimisingadverseeffects

b.implementationofstormwaterqualitymanagementmeasures

c.operationsandmaintenancerequirements

d.monitoringandreporting,includingmonitoringandreportingonanetworkwidebasis.

3.Newandredevelopmentofexistingimperviousareaforahighusepublicroad

a.theimplementationoftheBPOformanagingstormwaterqualityandassociatedadverseeffects

b.Stormwaterqualitymanagementrequirements

c.Operationsandmaintenancerequirements

d.Monitoringandreporting,includingmonitoringandreportingonanetworkwidebasis.

3.4.2Assessmentcriteria

Thecouncilwillconsiderthereleventassessmentcriteriabelowforrestricteddiscretionaryactivities.

1.Allrestricteddiscretionaryactivities

a.thenatureofthedischarge;

b.thesensitivityofthereceivingenvironment,includingcoastalwaters,anditssusceptibilitytotheadverseeffectsofstormwatercontaminants

c.theextenttowhichincrementalandcumulativeadverseeffectsofstormwatercontaminantsonreceivingenvironmentsincludingonbiodiversity,communityandManaWhenuausesandvaluescanbeavoided,orifnotavoidedthenotherwiseadequatelymitigated;

d.theabilitytoreduceexistingadverseeffects

e.whetherstormwatercontaminantsaremanagedon­siteorwhethertherearestormwatermanagementdevicesinthecatchmentthatcanacceptandcaterforincreasedstormwatercontaminantloadstomeetmitigationrequirements

f.theeffectsonmarinesedimentquality,inaccordancewithAucklandwidewaterqualityandintegratedmanagementpolicy10andTable1.

2.Infringementofmaximumimperviousareacontrolwithinriparianyardsorinfringementofthecoastalprotectionyard:

a.developmentthatdoesnotcomplywiththeriparianorcoastalyardcontrolswillneedtodemonstratethat:

i.

ii.iii.iv.

v.

vi.

adverseeffectsonthefunctionoftheyardinmanagingflooding,erosion,orwaterquality,willbeminimised

thecontinuityofanyvegetationcorridorwillbemaintained

siteworksandassociatedvehiclemovementsareminimisedinthewithintheyard,

thereisnopracticablealternativetodevelopmentwithintheyardandthatthedevelopmentislocatedasfarfromtheCoastalMarineArea,orstreamaspossible

locatingdevelopmentwithintheyardisrequiredforthereasonableuseanddevelopmentofthesite,includingfortheprovisionofpublicaccessorinfrastructuresuchasrecreationaltrails,bridges/culverts,undergroundutilities,wastewaterorstormwaterinfrastructure

theadverseeffectsofdevelopmentwithintheyardaremitigatedbyplantingwithnativeplantsand/orprovidingawidersetbackelsewherethatwillenhancethefunctionoftheyard.

3.Newandredevelopmentofexistingimperviousareaforahighusepublicroadunabletomeetrules,permittedactivityandcontrolledactivitycontrols

a.thenatureofthedischarge;

b.thesensitivityofthereceivingenvironment,includingcoastalwaters,anditssusceptibilitytotheadverseeffectsofstormwatercontaminants

c.theextenttowhichincrementalandcumulativeadverseeffectsofstormwatercontaminantson

receivingenvironmentsincludingonnaturalcharacter,biodiversity,communityandManaWhenuausesandvaluescanbeavoided,orifnotavoidedthenotherwiseadequatelymitigated;

d.theabilitytoreduceexistingadverseeffects;

e.theextenttowhichthewaterqualitymattersforstormwaternetworksandroadsinAucklandwidewaterqualityandintegratedmanagementpolicy10andTable1.

f.theeffectsonmarinesedimentquality,inaccordancewithCoastalZonesdischargespolicy10

andTable1.

g.hepracticalityandlimitationsofapplyingstormwaterqualitymanagement,particularlytoexistinghighuseroadnetworks.

Table3:Stormwaterqualitymanagementrequirements

Symbol / Name / Designeffluentqualityrequirementforstormwaterrunofffrom90%oftheannual
rainfall
M / Metals / Totalzinc30µg/L,Totalcopper
10µg/L
S / Sediment / Totalsuspendedsolids20mg/L
T / Temperature / Temperature25°C

Table4:Stormwatercontaminantsofconcern

Receivingenvironment / Landuseactivity
Highuseroads,carpark / Roofingmetal / Industrialsitesactivityarea
RiverorStream / M,S,T / M,T / Appropriatetonatureofactivities,contaminantsandreceiving
environments
Allotherreceivingenvironments / M,S / M

S=sedimentM=metals

T=temperature