Stormwater Management June 2018 Andrea Phillips

Effects of development

Effects include MORE water (increased volume and velocity) DIRTIER water (pollution and contaminants) Hitting the same watercourse (if it’s lucky enough to not be piped). Waterways have a large impact on our community – temperature, health and wellbeing. What are we doing about it?

Erosion and lining

Drivers to manage sw National Policy Statement - Freshwater Waikato Vision and Strategy Regional Policy Statement Healthy Rivers: Proposed Regional Plan Change 1 Comprehensive Consent District Plan – ICMPs, WIA, WEM

Management ‘train’ Stormwater Management needs to be addressed at multiple locations: At source stormwater reduction On lot stormwater management Sub-catchment management Watercourse protection and enhancement

Document updates…best practice Initial focus on new management devices to be in line with best practice: At source and on lot reduction and mitigation: WRC Stormwater Guidelines Three Waters Management practice notes Sub-catchment: Updates to Infrastructure Technical Specification. Watercourse Protection: Programme of works within watercourses.

What decides a specific ‘on lot’ requirement? WRC or HCC Consent District Plan – general rule District Plan – through an ICMP District Plan – through WIA HCC SW Bylaw (high risk sites) Implemented through Building Consent.

ICMPs

Rotokauri sw treatment Overview of Stormwater Treatment Train and Total Phosphorous Targets:

On lot: Three Waters Management Practice Notes Created as a means of compliance for the HCC District Plan rule (water efficiency measure). May be specific from Resource Consent or ICMP

HCC02 – Rainwater reuse system (rain tank)

HCC02 – Rain tank below ground

HCC03 - Soakage

HCC04 – Bioretention (raingarden)

HCC04 – Bioretention (raingarden)

HCC06 - Detention

Next steps Currently reviewing the on lot notes – incorporate learnings, understand the risk and liability, make it easy where we can (standard drawings).