Sabai Consulting recently completed the Development Application stage design for a residential/commercial townhouse development, located in Bonnells Bay on the Central Coast of NSW. The development included the design of a large carpark which services the local shopping centre complex, upgrade of the stormwater system, a number of new roads/driveways, water and sewer design as well turn path analysis of the driveways due to the tricky topography.

Sabai also prepared the structural design of the retaining walls and the waste management plan. The retaining walls spanned for over 400m and ranged from 3-4m high, including a standard cantilever design as well as a pile wall.

For the stormwater drainage component, Sabai undertook a holistic design process which covered all aspects of Water Sensitive Urban Design (WSUD) and Water Cycle Management process, including design of the on-site detention (OSD) system and water quality facilities such as raingardens, gross pollutant traps (GPTs) and proprietary filtration systems.

The drainage was a particular concern for Council as the system connected via a large downstream inter-allotment pipe which passed through private property before connecting to the downstream network. Through hydrologic modelling, utilising DRAINS software, we managed to demonstrate that our OSD system would detain all incoming flows and slowly release them once the storm’s peak had passed.

If your development needs advice or input from an experienced civil engineer then feel free to contact us for a no obligation discussion on how we can help you with your development.