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  Council » Policies and Plans » Rules and regulation » Waikato Regional Plan » Waikato Regional Plan (online version) » 3.5 Discharges* » 3.5.11 Implementation Methods - Stormwater Discharges

3.5.11 Implementation Methods - Stormwater Discharges

3.5.11.1 Good Practice

Waikato Regional Council will, in conjunction with territorial authorities, organisations, industry groups and individuals discharging stormwater, provide guidance to develop and implement good practices or appropriate codes of practice.

3.5.11.2 Integration with Territorial Authorities

Waikato Regional Council will work with territorial authorities to ensure the integrated management of stormwater in the Region by:

  1. Ensuring territorial authorities inform Waikato Regional Council of significant resource consent applications that are likely to adversely affect the quality of stormwater discharges.
  2. Ensuring Waikato Regional Council has input into district plan development and reviews.
  3. Working with territorial authorities to identify and manage contaminated sites.

3.5.11.3 Stormwater Management

Waikato Regional Council will work with resources users (including territorial authorities) to:

  1. Find ways to mitigate adverse effects of existing stormwater discharges;
  2. Promote the development of stormwater management plans which record the way in which the stormwater network is operated, including methods to avoid, remedy or mitigate the adverse effects of stormwater discharge; and
  3. Promote alternative methods for the treatment and disposal of stormwater from existing and new subdivisions and development.

Advisory Note:

  • For stormwater discharges in the Lake Taupo Catchment, refer to Policy 13 in section 3.10.3 and Method 7 in section 3.10.4.

3.5.11.4 Permitted Activity Rule – Discharge of Stormwater to Water

Exception

This Rule does not apply to:

Plantation forestry activities as from 1 May 2018 these activities are regulated under the National Environmental Standards for Plantation Forestry Regulations 2017(external link). 

The discharge of stormwater to surface water (including geothermal water) is a permitted activity subject to the following conditions:

  1. The discharge shall not originate from a catchment that includes any high risk facility1, contaminated land*, operating quarry or mineral extraction site unless there is an interceptor system* in place.
  2. Any erosion occurring as a result of the discharge shall be remedied as soon as practicable.
  3. The catchment shall not exceed one hectare for discharges that originate from urban areas.
  4. There shall be no adverse increase in water levels downstream of the discharge point which causes flooding on neighbouring properties, as a result of the discharge.
  5. The discharge shall comply with the suspended solids standards in Section 3.2.4.6.
  6. The discharge shall not contain any material which will cause the production of conspicuous oil or grease films, scums or foams, or floatable suspended materials at any point downstream that is a distance greater than three times the width of the stream at the point of discharge.
  7. The discharge shall not contain concentrations of hazardous substances that may cause significant adverse effects on aquatic life or the suitability of the water for human consumption after treatment.
  8. There shall be no discharge to any Significant Geothermal Feature.

For the purposes of conditions a) and g) levels of hazardous substances in stormwater or sediments that comply with the following guidelines and standards, in relation to the substances that they address will be deemed to be complying with the conditions:

  1. Licences under the Hazardous Substances and New Organisms Act 1996 for the use of the substance in New Zealand specifying discharge and receiving water standards for the substance.
  2. Health and Environmental Guidelines for Selected Timber Treatment Chemicals (Ministry for the Environment, Ministry of Health, 1997).
  3. Environmental Guidelines for Water Discharges from Petroleum Industry Sites in New Zealand (Ministry for the Environment, 1998).
  4. Guidelines for Assessing and Managing Contaminated Gasworks Sites in New Zealand (Ministry for the Environment, August 1997).
  5. Australian/New Zealand Water Quality Guidelines For Fresh And Marine Waters, (Australian & New Zealand Environment & Conservation Council, 2001).

For the purposes of this Rule, ‘urban area’ includes the inner city or town and built up environments, irrespective of local body administrative boundaries, that are serviced by roads where the speed limit is 80 kilometres an hour or less.

Advisory Note:

  • Rules controlling discharge structures are set out in Section 4.2.10.
  • Significant Geothermal Features are defined in the Glossary, and in Development and Limited Development Geothermal Systems, identified on maps in Section 7.10 of this Plan.

3.5.11.5 Permitted Activity Rule – Discharge of Stormwater Onto or Into Land

The discharge of stormwater (including geothermal water) onto or into land is a permitted activity subject to the following conditions:

  1. The discharge shall not originate from a catchment that includes any high risk facility2 or contaminated land* unless there is and interceptor system* in place.
  2. The discharge shall be below a rate that would cause flooding outside the design discharge soakage area, except in rain events equivalent to the 10% Annual Exceedence Probability design storm or greater. Any exceedence shall go into designated overland flow paths.
  3. There shall not be any overland flow resulting in a discharge to surface water, except in rain events equivalent to the 10% Annual Exceedence Probability design storm or greater; then there shall be no adverse surface water effects as a result of the discharge.
  4. Any erosion occurring as a result of the discharge shall be remedied as soon as practicable.
  5. The discharge shall not contain concentrations of hazardous substances that may cause significant adverse effects on aquatic life or the suitability of the water for human consumption after treatment.

For the purposes of conditions a) and e) of this rule, the levels of hazardous substances in stormwater or sediments that comply with the following guidelines and standards, in relation to the substances that they address will be deemed to be complying with the condition:

  1. Licences under the Hazardous Substances and New Organisms Act 1996 for the use of the substance in New Zealand specifying discharge and receiving water standards for the substance.
  2. Health and Environmental Guidelines for Selected Timber Treatment Chemicals (Ministry for the Environment, Ministry of Health,1997).
  3. Environmental Guidelines for Water Discharges from Petroleum Industry Sites in New Zealand (Ministry for the Environment, 1998).
  4. Guidelines for Assessing and Managing Contaminated Gasworks Sites in New Zealand (Ministry for the Environment, August 1997).
  5. Australian/New Zealand Water Quality Guidelines For Fresh And Marine Water, (Australian & New Zealand Environment & Conservation Council, 2001).

3.5.11.6 Controlled Activity Rule – Discharge of Stormwater Onto or Into Land

The discharge of stormwater (including geothermal water) onto or into land that does not comply with Rule 3.5.11.5 is a controlled activity (requiring resource consent) subject to the following standards and terms:

  1. The discharge shall be below a rate that would cause overland flow leading to a discharge to surface water, except in rain events equivalent to the 10% Annual Exceedence Probability design storm or greater. Any exceedence shall go into designated overland flow paths.

Waikato Regional Council reserves control over the following matters:

  1. Measures used to control erosion or flooding.
  2. Measures to avoid, remedy or mitigate the effects of the discharge on groundwater quality.
  3. Measures (including contaminant loading rates) to ensure that the soil at the site is not contaminated by the discharge to a level that will affect the range of existing and foreseeable uses of the site.
  4. Measures for avoiding, remedying or mitigating the effects of maintaining stormwater treatment systems.
  5. Information and monitoring requirements.
  6. Measures to avoid, remedy or mitigate the effects of the discharge on surface water bodies.
  7. Measures to avoid, remedy or mitigate adverse effects on neighbouring property.

3.5.11.7 Controlled Activity Rule – Discharge of Stormwater Into Water

The discharge of stormwater to surface water (including geothermal water) that is lawfully established at the time of notification of this Plan (28 September 1998) and does not comply with Rule 3.5.11.4 is a controlled activity (requiring resource consent) subject to the following standards and terms:

  1. The discharge shall not contain concentrations of hazardous substances that are causing significant adverse effects on aquatic life or the suitability of the water for human consumption after treatment.

Waikato Regional Council reserves control over the following matters:

  1. Measures used to control erosion or flooding.
  2. Measures to avoid, remedy or mitigate the effects of the discharge on the receiving water bodies.
  3. Measures for avoiding, remedying or mitigating the effects of maintaining stormwater treatment systems.
  4. Information and monitoring requirements.
  5. The degree of compliance with discharge or receiving water standards for any hazardous substance in relevant New Zealand Standards, Guidelines or licences issued under the Hazardous Substances and New Organisms Act 1996.

 

3.5.11.8 Discretionary Activity Rule – Discharge of Stormwater

The discharge of stormwater into water, and/or into or onto land which does not comply with Rules 3.5.11.4, 3.5.11.5, 3.5.11.6 and 3.5.11.7 is a discretionary activity (requiring resource consent).

Advisory Notes:

  • Information requirements to enable the assessment of any application under this Rule are set out in Section 8.1.2.2 of this Plan. In addition, assessment shall also take into account the matters identified in the policies of Section 3.2.3 of this Plan.
  • Rules controlling discharge structures are set out in Section 4.2.10 of this Plan.

 

Explanation and Principal Reasons for Adopting Methods 3.5.11.1 to 3.5.11.8
The non-regulatory methods for stormwater management implement Policy 7 by encouraging at-source management and treatment of stormwater prior to its discharge to receiving waters. Method 3.5.11.1 supports initiatives to develop, implement and manage stormwater discharges, for example, codes of practice, guidelines, environmental management systems, best practicable options and good practices. The oil industry is one that has produced a detailed code of practice that addresses management of stormwater discharges from service stations. Other treatment options for stormwater include the use of grassy swales, sumps or artificial wetlands, and the diversion of the ‘first flush’ into trade waste systems.

Methods 3.5.11.2 and 3.5.11.3 promote the need for integrated management of stormwater with territorial authorities. Given that territorial authorities own and manage the large majority of stormwater systems in the Region, they are clearly very influential in terms of the standards and technology adopted. If Waikato Regional Council wishes to bring about improvements in these areas, it needs to work with territorial authorities and have regard to the practical constraints which exist and the communities’ ability to pay for improvements.

Under the RMA, the discharge of stormwater to water may only occur if it is expressly allowed by a rule in a regional plan or by a resource consent. In accordance with Policy 1, Rule 3.5.11.4 allows the discharge of stormwater only from area that are not likely to cause contamination. The nature of the catchment from which stormwater is derived is an important factor influencing the risk of adverse effects from discharges. Consequently, discharges from contaminated land and those high risk facilities identified in Section 3.2.4.5, are not permitted activities unless there is an interceptor system in place.

In accordance with Policies 2 and 3, Rule 3.5.11.5 provides for the discharge of stormwater to land provided that the stormwater is not sourced from either contaminated land or high-risk facilities unless there is an interceptor system in place. Land-based disposal is promoted in preference to water-based disposal as a way to ensure that accidental spills of contaminants are not directly discharged into water bodies. Land-based disposal is also consistent with tangata whenua views.

Rule 3.5.11.6 allows the discharge of stormwater onto land from stormwater catchments draining high risk facility sites, provided the specific standard and term is complied with. Waikato Regional Council has reserved its control over issues relating to the effects of the discharge on the natural and human uses and values of the water, flooding, erosion, soil contamination and change in water levels downstream from the discharge.

Rule 3.5.11.7 identifies that consent applications for existing discharges of stormwater will not be declined by Waikato Regional Council, despite the fact that they have potential to have adverse effects on the environment from the contaminants present. Control is reserved over a number of matters related to environmental effects, so that conditions can be placed on the consent, which will ensure any effects are minor.

Any stormwater discharge into water or onto and/or land that does not comply with the permitted or controlled activity rules is a discretionary activity under Rule 3.5.11.8. This allows for any adverse effects to be assessed against the criteria set out in the RMA.

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