1. Stormwater – Amber Carter

2. Focus of this presentation
What is stormwater?
How stormwater networks function
Stormwater vs discharges of contaminants that are not stormwater
The proposed Plan’s framework for stormwater
Key issues and recommendations

3. What is stormwater?
Runoff that has been intercepted, channelled, diverted, intensified or accelerated by human modification of a land surface, or runoff from the external surface of any structure, as a result of precipitation and including any contaminants contained therein.
The plan draws a distinction between stormwater & the discharge of sediment associated with earthworks – largely for practical reasons in terms of managing the effects. Paul Denton has recommended changes to the earthworks and vegetation clearance rules to make this clearer and replace ‘stormwater’ in these rules with ‘the associated discharge of sediment’. There is a cross referencing note in the stormwater rules directing plan users to the earthworks and vegetation clearance rules for this type of discharge.

4. Stormwater effects: water quality
Sediment
Litter
Hydrocarbons and oil products
Pesticides, herbicides and fungicides from gardens
Heavy metals
Animal faecal matter.
I have briefly discussed some of the adverse effects of stormwater at section of my report, starting at paragraph 26.
[26] Stormwater affects water quality as it contains contaminants that are carried by or dissolved in rainfall runoff. Stormwater then carries these contaminants into waterways and the coastal environment.
[27]Such contaminants in stormwater can cause adverse effects on aquatic ecosystems, human health, mauri (life force), amenity values, and the suitability of water for recreation and shellfish gathering. For example, one major source of copper in aquatic environments is from vehicle brake pad use, carried into waterways via stormwater from roads. At high concentrations, copper can be lethal or have sub-lethal effects (causing reduced growth and/or deformities) on aquatic organisms.

5. Stormwater effects: water quantity
[28] Stormwater affects water quantity in several ways. Stormwater networks can increase the speed and quantity of water discharging to streams and the coast during rainfall events. Urban catchments with a high percentage of impermeable/impervious surfaces increase stormwater discharges (because less water can directly infiltrate the ground) and cause ‘flashy’ streams with higher peak flows. Increased stormwater discharges can cause erosion, scour, and flooding, and can also adversely affect aquatic ecosystems as a result of increased water volumes and increased velocities.

6. Stormwater networks: key concepts
Stormwater in the Wellington Region is untreated.
Stormwater networks discharge directly to streams and/or the coast.
There is variable information about stormwater networks across the region i.e. where all the pipes go, location of overflows etc.

7. How stormwater networks function – an example
STREAM X
STORMWATER DRAINS
This is just to illustrate the nature of the stormwater network in Wellington. This is a stream I’m familiar with in South Karori for reasons unrelated to this report – a tributary to the Karori Stream. I’ve highlighted the location of stormwater drains and the stream they drain into on the aerial.

8. This is what the stormwater drains look like on the surface.

9. I’ve circled the stormwater pipe discharges into the stream, approximately 70m away from the stormwater drains on the road. This is a fairly typical example of a piece of the stormwater network – kerb and channel that drains to a pipe which discharges straight into a nearby stream. Anything that goes into a stormwater drain comes out into a stream / the coast.

10. I would also make the point that a lot of the stormwater network is reasonably old and there is incomplete information about where all the pipes go.

11. Stormwater vs other discharges of contaminants
The PNRP definition of stormwater includes contaminants but only those picked up by runoff as a result of rainfall.
However many contaminants are discharged to streams / the coast via stormwater drains during dry weather. These discharges are managed under separate provisions (because they are not considered stormwater).
Discharges of contaminants to land that may enter water (via the stormwater network) are currently Discretionary Activities under Rule 2 of the operative Discharges to Land Plan.
Under the proposed Plan, these discharges would fall under a wider range of rules, with some permitted (such as by Rule R42), but most would fall under catch-all discretionary (Rule R68) or non-complying rules (e.g. Rule R57: Discharge of hazardous substances).
The proposed new non-complying rule in Ms Conland’s evidence would cover these types of discharges explicitly.

12. Contaminant discharges that are not stormwater
This is a photo of an oil spill in the Wellington Harbour and some paint that has been discharged to a stream in the Botanic Garden. I do not know the details but the Botanic Gardens one may have entered the stream via the stormwater network.
James Snowdon will be presenting more examples of discharges of contaminants from a compliance persepective.
Currently this kind of discharge would be a DA under the operative plans.

13. The PNRP’s stormwater framework

14. Rule R52: Restricted discretionary
Objective O48
Policy P74
TA Stage-one
Method M15
Rule R50: Controlled
Schedule N: SMS
Policy P75
TA Stage-two
Rule R51: Restricted Discretionary
Policy P78 Large sites
Rule R52: Restricted discretionary
Rule R49 stormwater to land - permitted
All other stormwater
R48 individual properties - permitted
R49 stormwater to land - permitted
R53 all other stormwater - discretionary
Policy P63
Policy P70
Policies P73, P76-P79
Considered in the s42A Report: Stormwater
Considered in the s42A Report: Water Quality
This diagram shows the stormwater provisions, along with two of the most relevant WQ policies. I will briefly go through the framework and then go through each key issue in my report.
The proposed Plan’s primary focus is on managing the adverse effects of stormwater discharges from local authority stormwater networks, as these are the key system for transporting contaminants through our urban spaces into aquatic environments. The proposed Plan adopts a two-staged approach to consenting local authority stormwater networks. The short-term, first-stage controlled activity consents are primarily aimed at collecting information on the quality of stormwater discharges from a network; the longer-term, second-stage restricted discretionary consents are aimed at managing the network as appropriate to address adverse effects identified during the information-collection at stage one and meet water quality outcomes.
The proposed Plan also contains separate provisions for stormwater discharges from ‘large sites’ (being state highways, the port, and airports). Stormwater discharges from individual properties are generally permitted under Rules R48 and Rule R49, subject to meeting the conditions.
[Reasons for the approach to large sites are at p53-p55 of the s32 report: Discharges to water]

15. Provisions in my evidence
Issue
Provisions
Issue 1 – Objective framework
Definition of stormwater, Objective O48
Issue 2 – General stormwater policies
Definition of source control, Definition of water sensitive urban design, P73 and P79
Issue 3 – TA Consenting framework
Definition of stormwater network, Definition of stormwater management strategy, P74, P75, R50, R51, Method M15, Schedule N
Issue 4 – Wastewater and stormwater interactions
P76 and P77 (and amendments to R50/R51)
Issue 5 – Stormwater from new urban areas
Proposed new rules R48A and R52A
Issue 6 – Stormwater from a port, airport or state highway
P78 and R52
Issue 7 – All other stormwater
R48, R49, R53

16. Issue 1: Objective framework
Definition of stormwater
Objective O48
I have covered the definition of stormwater earlier and do not recommend any changes to it.
My key recommendation for this issue is for Objective O48.
[125] Recommendations for Issue 1

17. Objective O48
Stormwater networks and urban land uses are managed so that the adverse quality and quantity effects of stormwater discharges from the network are improved over time.
[110]I recommend that Objective O48 be amended so the objective is not restricted only to the discharge of stormwater from networks. There should be a clear line from objectives to the policies and rules that implement them. The stormwater-specific policies (P73-P79) and rules (R48-R53) should implement Objective O48. Whilst some of these lower-order provisions are specific to stormwater networks (e.g. Policy P74/P75), there are also provisions applying to stormwater from other sources (individual properties and ‘large sites’). If Objective O48 is not amended to be relevant to all stormwater discharges, resource consent applications for the discharge of stormwater from locations other than stormwater networks would not be guided by this objective.

18. Issue 2: General stormwater policies
Definition of water sensitive urban design
Definition of source control
Policy P73
Policy P79
[168] Recommendations for Issue 2
Photo: A bund. Used to prevent spills entering the stormwater network.

19. Officer’s recommendations: Issue 2
Minor wording changes to P79 for clarity
Clause 16 change to P73
Minor clarification to definition of water sensitive urban design
[168] Recommendations for Issue 2
Photo: A rain garden.

20. Issue 3: TA Framework Definition of stormwater network
Definition of stormwater management strategy
Policies P74 and P75
Rules R50 and R51
Method M15
Schedule N

21. First stage consent (Rule R50 / Policy P74)
Controlled activity
Non-notified
Short duration (5 years)
Must be applied for by
Second stage consent (Rule R51 / Policy P75)
Restricted discretionary activity
Must include a Stormwater Management Strategy
Longer duration consent (max 35 years)
The PNRP is a significant shift from the operative plans, in that it explicitly requires all TA networks to gain consent for stormwater discharges on a global basis.
I have a section on the approach in the operative plans at section 6.5 / para [40] of my s42A report.
Under the operative plans, consents for discharges from TA stormwater networks have been granted on an ad hoc basis, either recognising specific high risk catchments (e.g. the Gracefield industrial area under a consent granted to HCC) or taking a network‑based ‘global’ approach (e.g. the network consents granted to WCC).

22. TA framework: key points
Stage 1 = information gathering
Stage 2 = stormwater management strategy (Schedule N)
Focused on urban areas (not rural)
‘Global’ approach for efficiency
Monitoring regime in stage 1 is targeted on the basis of risk
Management response in stage 2 proportionate to adverse effects

23. TA Stage 1: Policy P74 and Rule R50
Four matters for control
Non-notified
Deadline in Rule R50 has now passed (no more consents can be applied for under this rule unless the deadline is extended)
Managing acute effects on human health

24. TA Stage 1 – Officer’s recommendations
Extend the deadline to apply under controlled activity Rule R50
(Include wastewater overflows in the rule - Issue 4)

25. TA Stage 2: Policy P75, Rule R50, Schedule N
Restricted discretionary activity
Application must include a stormwater management strategy
Any wastewater contamination must be managed in accordance with P76 & P77

26. TA Stage 2: Officer’s recommendations
Amend Policy P75(d) for clarity
Remove the now-obsolete date reference in Rule R51
(Include wastewater overflows in Rule R51 and add a matter for discretion - Issue 4)
Amendments to Schedule N
Include mana whenua in Method M15
Amendments discussed from paragraph 251 onwards. Schedule N is at page 432 of the plan.
I recommend a number of amendments to Schedule N based on discussions with WWL. I have appended an agreed version between myself and WWL in Appendix A of my report. In my view, these amendments do not change the intent of the Schedule but make the requirements clearer.

27. Issue 4: Wastewater & Stormwater interactions
Policy P76
Policy P77
(amendments to Rule R50/R51)

28. Inflow & Infiltration
Inflow – where stormwater enters the wastewater network and wastewater enters the stormwater network.
Infiltration – where groundwater enters the stormwater and wastewater networks due to faults, cracked pipes, and so on.
[289] Because of infiltration and inflow (I&I), during heavy rainfall, excess water enters the wastewater network, overloads its capacity, and then overflows into the stormwater network. Faecal contamination from stormwater can affect human health (for example, if there are recreational swimmers near a discharge point), and can adversely affect Māori cultural values.
The proposed Plan contains provisions for both wastewater (considered in the s42A Report: Wastewater to water) and stormwater. Stormwater is not wastewater (wastewater does not result from runoff) and the proposed Plan treats wastewater and stormwater networks differently. However, there is a grey area in the proposed Plan where the two networks interact in terms of which provisions apply (such as in the case of constructed wastewater overflows into the stormwater network).

29. Constructed wastewater overflows – some simplified diagrams
Note this is just to illustrate the concept.

30.     Photo Credit: King County

31. Statutory direction: NZCPS Policy 23 (my emphasis)
2. In managing discharge of human sewage, do not allow:
discharge of human sewage directly to water in the coastal environment without treatment; and…
4. In managing discharges of stormwater take steps to avoid adverse effects of stormwater discharge to water in the coastal environment, on a catchment by catchment basis, by:
avoiding where practicable and otherwise remedying cross contamination of sewage and stormwater systems…

32. Policy P76
Sets out how adverse effects of wastewater and stormwater interactions are to be minimised.
Avoid new connections (P76(a))
Reduce existing contamination of stormwater with wastewater (P76(b))
Reduce existing contamination of wastewater with stormwater (P76(c))

33. Policy P76: Officer’s recommendation
(b) ) progressive elimination ofreducing contamination of stormwater from the existing wastewater network, and (c) progressively reducing stormwater and groundwater infiltration and inflow into the wastewater network so that untreated wastewater only overflows to water during heavy rainfall events.
I recommend that Policy P76(b) is amended to make it clear that existing contamination is not simply to be reduced but progressively reduced over time towards the eventual goal of elimination, in accordance with the NZCPS’s direction to ‘not allow’ the discharge of untreated human sewage to the coast and ‘otherwise remedying’ cross contamination between the sewage and stormwater systems.
I consider that the second part of (c) ‘so that untreated wastewater only overflows to water during heavy rainfall events’ is both unnecessary and potentially confusing. This wording could be interpreted to mean that progressive reduction of infiltration and inflow into the wastewater network is not required if wastewater overflows occur only during heavy rainfall. This is counter to the proposed Plan’s intent and would not implement proposed Objective O48 ‘improved over time’ nor the direction of the NZCPS or NPS-FM.
[318] Recommendation on P76

34. Policy P77
Applies to the second-stage consent applications under Rule R51.
Sets out the circumstances in which wastewater can be included in the scope of the second-stage stormwater consent.

35. Policy P77: Officer’s recommendation
Delete (a) as redundant.
Amend (c) to be more consistent with wastewater Policy 80.
Wording changes for clarity.
[325] Recommendation on P77.

36. Rules R50/R51: Officer’s recommendation
Amendment to include ‘stormwater that may be contaminated by wastewater from overflows during heavy rainfall events’ into both Rule R50 and R51.
Additional matter for discretion in Rule R51 for effects on human health.
There has been some confusion during implementation around what is included within the scope of the global stormwater consent applications. I have recommended amendments to the local authority stormwater rules to clarify that the global consents do include some wastewater contamination under certain circumstances. I have set out my reasoning in Issue 4.3 starting at paragraph [326] of my report.
This would not authorise, for example, illegal cross-connections (such as when an individual property discharges wastewater directly into the stormwater network).
Rule R50 as notified already include effects on human health as a matter for control, and Schedule N as notified already requires a plan for minimising the adverse effects of wastewater interaction with stormwater in accordance with the two policies I just ran through – Policies P76 and P77.
I also recommend that Rule R51 is amended to include an additional matter for discretion for effects on human health.

37. Issue 5: Stormwater from new urban areas
This is an issue that I cover in my report under Issue 5, beginning at paragraph 337. In effect, this is about a gap in the plan about how new stormwater networks will be managed. It’s been raised by both Ereg and submitters requesting clarification.
Taking a source control and treatment train approach to new activities and land uses (Policy P73(b))
Implementing water sensitive urban design in new subdivision and development (Policy P73(c))
Retaining pre-development hydrographs and overland flow paths as far as practicable in new subdivision and development (Policy P79)
How will water sensitive urban design / maintaining pre-development hydrographs be considered in new subdivision and development as per Policy P73 / P78?
How will new stormwater networks be managed before they vest in the local authority? Do they require resource consent individually or will they be covered by the local authority’s ‘global’ stormwater network consents?

38. Concerns
How are policies P73 and P79 implemented for new subdivision and development (water sensitive urban design, hydraulic neutrality)?
Do stormwater discharges from new networks need resource consent? Are they included in the TA global consents?
These are concerns raised by both submitters and Environmental Regulation officers during implementation.
Directions in P73 and P79:
Taking a source control and treatment train approach to new activities and land uses (Policy P73(b))
Implementing water sensitive urban design in new subdivision and development (Policy P73(c))
Retaining pre-development hydrographs and overland flow paths as far as practicable in new subdivision and development (Policy P79)
These policies draw from RPS Policy 14: Minimising contamination in stormwater from new development – regional plans
Regional plans shall include policies, rules and/or methods that protect aquatic ecosystem health by minimising ecotoxic and other contaminants in stormwater that discharges into water, or onto or into land that may enter water, from new subdivision and development.
Based on Council’s s32 report: Discharges to Water, discussions with Council officers, and the requirements of Schedule N, I believe that the proposed Plan’s intent is that any new development that will eventually discharge into or be owned or managed by a local authority is part of the local authority stormwater network. In other words, the proposed Plan does not intend for new developments discharging stormwater into the local authority network to seek resource consent for their stormwater discharges under the proposed Plan; these will fall within the scope of the local authority global consents.
Unintended consequence – stormwater from multiple properties that would otherwise meet the PA conditions that is NOT part of the TA network requires consent but much bigger ones that will be owned by TA do not.
Stormwater Management Strategy condition (h) requires TAs to describe how stormwater discharges from new impervious surfaces will be managed.
Second stage consent will have conditions on quality of discharges that TAs must meet.
Local authorities take actions as needed in order to meet their second-stage consent conditions. This may include introducing regulations.
New developments need permission to connect to the local authority network via mechanisms outside the proposed Plan (e.g. bylaws)
Local authorities are responsible for approving subdivision designs
This framework is not clear to submitters – many requests for amendments and clarification, including requests for new rules.
In the medium-longer term, these combined with the proposed Plan’s framework for the second-stage consents under Rule R51/Schedule N should provide an efficient and effective approach to managing the adverse effects of stormwater discharges.
However, I am concerned that in the short-medium term, before the Stormwater Management Strategies are developed, that there is a regulatory ‘gap’.
To address the many requests for amendments to clarify how the proposed rules apply to new developments, I recommend that a new rule is introduced that explicitly clarifies the activity status of new developments’ stormwater discharges and that it should also directly implement Policy P73 and P79 and so resolve submitters’ concerns on how these policies are to be implemented.

39. New permitted activity Rule R48A
Applies to stormwater from new urban subdivision or developments
Permitted threshold linked to permitted bulk earthworks size – 3000m2
Must still meet the other permitted activity conditions of Rule R48 e.g. TSS standards
I have recommended a new PA rule to explicitly clarify the status of stormwater discharges from new subdivision and development activities.
The ‘trigger’ point is linked to the same size of residential subdivision that currently requires a consent for sediment associated with bulk earthworks over 3,000m2 under Rule R101.
I have set out my reasons at paragraph [380]
Council knows what kinds of developments hit this trigger point
Developers already aware this scale of development needs regional RC
Inefficient not to consider adverse effects of things Council already ‘sees’
Developments smaller than this threshold better picked up by other processes (need technical PA standards if wanted to regulate below this)
Introducing substantial new requirements inequitable at this stage in the Schedule 1 process

40. New RD Rule R52A Matters for discretion linked to Policy P73 and P79
Only applies to areas where there is no stormwater management strategy in place (i.e. for the duration of the first-stage consents).
Photos: Permeable pavement and a stormwater detention tank.

41. Issue 6: Stormwater from ‘large sites’ = a port, airport, or state highway
Photo by Phillip Capper [CC BY-SA ]
State highways - fuels, additives, oil, brake and tyre residues, heavy metals (copper, zinc).
Airports - hydrocarbons (oil and fuel), fuel additives, metals, biocides (herbicides/pesticides), anti-freeze agents, flame retardants, sediment.
Centreport - wood debris, high total suspended solids, dissolved metals (copper, zinc), dissolved humic material, nutrients, acidic resins and tannins, PAHs, organic enrichment, and microbial contaminants washed off logs.
Ecotoxicity effects. Adverse effects of heavy metal exposure may include reduced growth, diminished reproduction, and declining biodiversity over time.
s70 tests for PAs
Photo by By Clilly4 (Own work) [CC BY-SA 4.0 ( via Wikimedia Commons

42. Large site framework ‘Large site’ = ‘a port, airport or state highway’
Restricted discretionary Rule R52 implements Policy P78
Discharges to land are permitted under Rule R49

43. Large sites: Officer’s recommendation
Change titles of Rule R52 / P78 to refer to ‘a port, airport or state highway’
Amend Rule R52 to refer to ‘a surface water body or coastal water’ so it is clear that discharges to land can be permitted under Rule R49
Wording improvements to Policy P78
Large sites = the state highways, the port, and the airports
Discharges to land don’t require resource consent – which I understand would apply to Masterton Hood Aerodrome
I’ve recommended a number of changes to Policy P78, mainly to clean up the wording which is currently quite clumsy – particularly clause (a). In my view, the changes do not change the policy’s intent but make that intent clearer.
[442] Recommendations on Issue 6
Claire Conwell has prepared technical evidence regarding contaminants in stormwater from ‘large sites’

44. Issue 7: All other stormwater
Rule R48
Rule R49
Rule R53
68g/m3
225g/m3
7260g/m3
14900g/m3

45. Rule R48: Officer’s recommendations
Align TSS standards with those in Rule R42.
Allow some discharges into Schedule A sites (subject to meeting the other conditions).
Include Schedule C sites in the stricter TSS condition.

46. Rule R49: Officer’s recommendation
Additional condition: ‘the discharge is not located within 20m up-gradient of a bore used for water abstraction for potable supply or stock water.’
Paragraph 493
David Wilson (S70/003) submits that Rule R49 does not provide protection to groundwater drinking sources and requests amendments to address this. I agree with this submitter’s concern, as stormwater may pick up surface contaminants that could contaminate drinking water if it comes into contact with a bore (such as animal faeces). To manage this risk, I recommend that an additional condition is added to specify a setback distance from bores used for drinking water. I have used the setback distance for discharge of greywater in Rule R73.