Council to act on lagoon plan, seven years later

Central Coast Council is planning to implement three of nine actions in the Pearl Beach Lagoon Coastal Zone Management Plan, seven years after it was developed in 2013.

The Plan found that there had been a decline in water quality and ecological integrity within and around the lagoon, and that this was mostly due to urban development in the catchment.

Council is currently seeking comment on the three actions: to improve stormwater quality, and possibly to modify the weir and to remove sediment from the lagoon.

It has engaged a team led by coastal and environmental consultants Salients to undertake detailed site investigations, including surveying the ecology around the lagoon, surveying the depths of the lagoon and collecting sediment samples from the bed of the waterway.

The study team is now seeking input from the community to understand how it would like to see the lagoon managed to address the three actions being investigated.

Stormwater drains from the catchment into the western edge of Pearl Beach Lagoon.

"We are presently looking at different options for treating stormwater before it enters the Lagoon to work out which one would be best," said Salients director Mr David Wainwright.

"We are interested in understanding the community's desires and preferences for stormwater treatment."

The team wants to know visual, odour or environmental impacts are most concern to the community and what options residents would like considered.

Options could include upstream, decentralised sediment and litter collection, or sediment basins at the end of pipes.

A swale or shallow wetland could be planted out at pipe outlets "to formalise a vegetated treatment system".

"It's important to remember the space available for installing stormwater treatment options near the lagoon is limited and contains mature trees.

"These constraints will affect what can be achieved."

Mr Wainwright said: "Our study is considering options for future management of the Pearl Beach Lagoon weir.

"The weir in the lagoon entrance channel was installed around 1990.

"It stops the lagoon from completely emptying when it is opened to the ocean (draining across the beach).

"The issues surrounding the weir are complicated and we'd like to further understand the community's desires and preferences relating to future management."

The team wants to know whether there is a preference that the weir remain or be removed, or whether it should be modified in some way.

"Our study is considering options for managing the build-up of sediment in the Pearl Beach Lagoon.

"Alongside installing stormwater treatment measures to slow the rate at which sediment accumulates in the lagoon, we are also considering physically removing sediment from the bed of the lagoon.

"The removal of sediment is complicated by some low-level contamination from stormwater, the widespread presence of naturally occurring acid sulphate soils and restricted access for construction equipment to excavate the sediments.

"We'd like to further understand the community's desires and preferences relating to managing sediments that have built up in the lagoon."

Due to current Covid-19 restrictions, Council is conducting community consultation online through its website where there is an interactive map and online forum.

Details about other options to provide written input are also on the website.

The consultant's work is expected to be completed by the end of this year.

However, this is just the initial phase of the project and work will be ongoing throughout 2021.

Comment may be made until 5pm on Thursday, June 18, at https://www.yourvoiceourcoast.com/pearlbeachczmp.

Website, 27 May 2020

Pearl Beach Lagoon project, Central Coast Council