Site civils design for Nazareth House – Rest Home and Residential Units, Christchurch

Description: The post-quake rebuild of Nazareth House includes an 80-bed rest home, 20-bed dementia unit, convent, chapel and 62 Licence to Occupy (LTO) units. e2Environmental’s role was the design and construction observation of site civil works including water supply, wastewater, stormwater, roading and earthworks. Stormwater design for the site was particularly challenging due to the site being in a flood hazard area, existing flooding issues downstream and space constraints at the site for the required attenuation of stormwater peak flows of up to 50 year 30 hour storm events.

Our expertise: The stormwater solution for the site was very complex, incorporating multiple types of treatment devices (first flush basin, swale and proprietary devices), detention storage (detention basin, underground storage chambers and garden/car park areas designed to pond) and outlet controls designed to restrict flows so that the storage could be properly utilised. It was a complex engineering problem initially with no obvious solution, and some components required working outside of normal code of practices/standards to come up with a solution, for example one of the proprietary devices was a combination filtration device/raingarden.

e2Environmental prepared the Stormwater Discharge Consent and Works in/near a Waterway Consent applications, which required input from a diverse team including geotechnical engineers, hydrogeologists, a freshwater ecologist, surveyors and other engineers. e2Environmental carried out stormwater modelling to support the application.

Outcome: e2Environmental were able to provide an innovative solution to this complex engineering problem and is currently undertaking construction observation. The first stages of construction have been completed and include the residential units and 80-bed rest home. The chapel and convent are expected to be completed later this year.