Stormwater Case Studies

Stockyard Falls Bulk Retail Facility, Warkworth
Project management, design, consenting and construction supervision. Document preparation for a Plan Change and Land Use consent application for a 20ha site requiring significant earthworks in a sensitive receiving environment, including a nearby river, a municipal water supply intake and treatment plant. A staged construction methodology was developed to mitigate the effects of the proposed works along with a comprehensive use of the methods presented in TP90 for erosion and sediment control. Engineering solutions included wetland stormwater treatment pond, pedestrian walkways and landscape planting.
Moores Bay Subdivision, Kawau Island
A 20 lot exclusive lifestyle retreat over steep bush clad slopes. Stormwater treatment measures employed the use of low impact devices tailored to site characteristics including water re-use, detention tanks with low energy outlets, grass swales and vegetative filter strips. Benefits of this approach are hydraulic neutrality for the site post-development and collection and treatment of runoff to an efficiency level of 75% plus in accordance with TP10.
Wetland Lake Restoration, Northland
Establishment of two freshwater lakes with surrounding wetland areas and a combined surface area in excess of 8ha, supported by earth dams. The lakes and wetlands provide treatment for the private road network that runs through the site. Stormwater runoff from the roads is collected by grass swales and rock lined channels (for channel gradients greater than 5%). The swales and channels convey the water to the lakes with virtually no use of pipework except for culverts.
Sarah's Cove Lifestyle Development, Coromandel
Preparation of earthworks, stormwater discharge and treatment, and works in watercourse consents for the development of a 60ha rural site. Designed to establish a naturalised system of watercourses connecting a series of wetland areas along the valley floor, and manage a change in character from pastoral land use to a rural lifestyle blocks.
Sandspit Motor Camp Upgrade Works
Construction of a new accessway as part of a site upgrade. Design work included consideration of alternative stream crossing methods, including a bridge, box culvert and twin circular culverts. The commission included catchment and ecological assessments, design of a fish passage, temporary stream diversion, and preparation of consents to both Rodney District Council and Auckland Regional Council (Works in Watercourse and engineering approval).  
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