Stormwater Solution for New World Commercial Site, Richmond, Nelson

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Description: Foodstuffs (SI) Ltd required our stormwater expertise to support a plan change for the proposed site and to obtain the necessary resource consents. While our stormwater solution was fairly conventional in terms of low impact technologies, the design was constrained by a limited land area, a history of flooding, and a discharge point already near capacity.

 

Our expertise: The proposed commercial development includes a New World, ancillary retail units, and associated hardstand carparking. To mitigate any environmental impact from the carpark runoff, our stormwater solution needed to include surface water treatment prior to discharging to the environment. As the site had a history of flooding our solution also had to allow for secondary flow paths through the site.

 

Due to the constrained nature of the site, our solution utilises landscaping and carparking areas as dual purpose raingardens and detention basins. The raingardens discharge to the ground via soakage; providing treatment, recharging the groundwater, and reducing the volume of discharge to the Council stormwater network.

 

e2Environmental completed the initial stormwater impact assessment and conceptual design to support the application to rezone the site from residential to commercial use. This included expert witness services at the rezoning hearing. We also provided preliminary stormwater design services as part of our preparation for the multiple Resource Consent applications.

 

The history of flooding in the area required a detailed 1d hydraulic model of the adjacent Council stormwater network to assess the impact of the proposed development. A hydrological model was used to assess the likely increase in runoff.

 

Outcome: The plan change has been granted and the resource consent applications have been efficiently lodged in consultation with Tasman District Council staff. The applications will be processed on a non-notified basis.