Wattamolla Upgrade, Royal National Park
Complete with breathtaking coastal views, estuarine lagoon, beach and waterfalls, Wattamolla attracts over 300,000 visitors each year! As part of a Master Plan, works were proposed to help NSW Parks address some of the challenges that go hand-in-hand with managing such a popular site - visitor safety, increasing recreational value and improving operational efficiency, all whilst protecting and conserving the park’s natural, cultural, social and aesthetic values.
Over the course of five years Northrop worked closely with Landscape Architects (Context) and NSW National Parks and Wildlife Services to help undertake extensive upgrade works including upgrade of existing picnic facilities and amenities infrastructure, improved bus access and safety measures, new walking paths and boardwalks and extensive stormwater infrastructure upgrades (including Water Sensitive Urban Design best practices).
Creating Opportunities for Innovation
Redevelopment works in this steep, remote and highly constrained site required unconventional and bespoke engineering designs - where possible we tried to view these constraints as an opportunity to be innovative! We also ensured our designs were sympathetic to the pristine environment, treated the root cause of the site issues (such as stabilising upstream catchments to reduce the impacts of erosion) and incorporated a holistic whole-of-life approach to address ongoing maintenance and long-term cost savings for the client.
Location, Location, Location
The coastal clifftop location meant carefully designing around steep gradients, to minimise disruption to the natural bushland. The existing established trees formed key constraints in our design, with every effort made to grade the site and align stormwater pipes to enable the retention of high value trees. Where there were areas of fill near existing trees, we worked with NPWS to design a bespoke “tree aeration detail” using subsoil pipes under rock fill to ensure airflow to the roots.
The sandy nature of the site and the sensitivity of the receiving waters also required careful consideration of stormwater treatment methods. Drainage was managed predominantly through low maintenance swales, utilising a gapped kerb around the carpark to allow runoff to sheet flow into the swales. A bioretention basin treats the majority of the upstream carpark, and has additional capacity for a possible 130 space carpark that may be constructed in the future. The bioretention basin has been designed with a high flow bypass to ensure the system is not damaged during the high rainfall events that are characteristic to the site, and a custom oil shroud is fitted to the overflow weir to ensure oils and hydrocarbons from the carpark are not discharged into the pristine receiving waters.
Wattamolla is a great example of a Civil-led design, showcasing our environmental design capabilities and our ability to “think outside of the box”. The new amenities facilities, walking tracks and improved car park greatly enhances the overall visitor experience and the innovative stormwater solutions will help protect and preserve a much-loved recreational area for future generations.
Speak to our civil engineers about environmental design - on 02 9241 4188. We have particular expertise in soft engineering/ environmental design and what’s more, we have a passion for these types of projects!