Avoca and Terrigal lagoons and Kincumber Creek are three of the least healthy estuarine waterways on the Central Coast. Central Coast Council’s first combined Waterways report card, released on December 12, lists the water quality in Terrigal Lagoon as only fair, and Kincumber Creek as poor, while Avoca Lagoon scored the report’s only very poor rating.
The report examines the ecological health of Southern Lake Macquarie, Tuggerah Lakes, Brisbane Water and the coastal lagoons over the 2017- 18 year, providing a clear picture of the estuarine sections of the entire region’s waterways network. Turbidity exceeded trigger values in Terrigal Lagoon throughout the entire sampling period, and chlorophyll-a levels were considered poor.
At Avoca Lagoon, both turbidity and chlorophyll-a clearly exceeded trigger values on all sampling occasions throughout 2017-18. Kincumber Creek suffered regular high turbidity due to its shallow nature, but chlorophyll-a was generally good with some exceedances recorded. Turbidity is a measure of water clarity or cloudiness and chlorophyll-a is an indicator of levels of microalgae and nutrients in the water, which can lead to algal blooms and a decline in water quality.
Seagrass depth range is also assessed as a biological indicator of water clarity over longer time periods. Council’s Environment and Planning Director, Scott Cox said that while the report showed overall positive results it also provided a valuable tool to help Council identify areas for further investigation. “Council uses a recognised monitoring program to assess the ecological health of our waterways, allowing us to monitor the condition, monitor changes over time and target investment and on ground works to improve ecosystem health, ” Cox said.
“For the 2017-18 year we have seen good results in all of the southern Lake Macquarie, Cockrone and Wamberal Lagoon sites, plus the majority of sites in Tuggerah Lakes, Lake Munmorah and Brisbane Water. “Other sites that have shown a mix of poorer results include Budgewoi Lake, Terrigal and Avoca lagoons, and some other sites where creek systems enter larger waterways.
“These results will allow Council to review our management actions and plan for on ground works to help improve waterway health over time. ” The report noted reduced water quality at Narara Creek, Erina Creek and Kincumber Creek, highlighting concerns for water quality entering from the catchments. Cox said Brisbane Water main basin sites at Woy Woy Bay, Cockle Bay and Booker Bay were considered excellent for the 2017-18 year.
“The naturally well flushed nature of the main sites within Brisbane Water is reflected in the excellent results, ” he said. “Reduced water quality coming from the Narara, Erina and Kincumber Creek catchments have highlighted some concerns, with turbidity being the main concern. ” He said Council had some work to do in the Terrigal and Avoca lagoon catchments to understand what is going on and how results can be improved over time. Council’s program is delivered in partnership with the NSW Department of Planning, Industry and Environment, using a scientifically robust methodology and is the most comprehensive program of its kind provided by local government in NSW. Mayor, Lisa Matthews, said:
“Our local waterways make up 13% of the total area of the Central Coast so it is important to understand the state that they are in, so that we can make informed decisions. “This report will enable a greater understanding of our waterways and allow the community to take a role, in partnership with Council, to help maintain and improve the health or our rivers and lakes. ”
The report also outlines the actions Council has taken to target improvements in waterway health including: rehabilitation of natural wetlands at Erina, Davistown, Saratoga, Bensville, Point Clare and Tascott; protection and rehabilitation of coastal saltmarsh and foreshore bushland along the shores of Tuggerah Lake and Brisbane Water; maintenance of a network of over 418 stormwater quality improvement devices throughout the estuary catchments to improve water quality; and, removal of 967 tonnes of sediment and pollutants from stormwater quality improvement devices.
Source: Media release, Dec 12 Central Coast Council The Central Coast Waterways Report Card