Shoalhaven City Council has added new water testing sites at four popular swimming locations at Lake Conjola.
Recent community concern, including an online petition signed by more than 10,000 people, outlines fears of poor water quality and has called on council to dredge the lake.
A council spokesperson said it now tests water quality at seven sites on the southern shore of the lake.
“Test results, from May until now, have consistently shown that the water quality is suitable for swimming,” a council spokesperson said.
Given the recent debate around the issue of smell and algae blooms on the lake, council has reminded residents and visitors that Lake Conjola is an ICOLL - an Intermittently Closed and Open Lake or Lagoon.
Under the NSW Coastal Management Act 2016, the preference for this type of lake is to maintain natural processes and not modify ICOLL entrances, a council spokesperson said.
“ICOLLs are complex systems adapted to varying conditions, including water level and degree of salinity. They are very sensitive to human disturbance,” the spokesperson said.
“Natural processes are considered to be the best processes for an ICOLL and also a closed lake is not necessarily an unhealthy lake.”
Council has monitored Lake Conjola weekly at three locations since it closed in April. This is in addition to the regular quarterly testing at 10 other sites within the lake.
Water rating categories are derived from the microbial assessment categories used in the National Health & Medical Research Council (2008) Guidelines. The guidelines rate water quality as good, fair, poor and bad.
Both good and fair results indicate that it’s suitable for swimming. Lake Conjola has consistently rated as good, the spokesperson said.
If test results fall to a “poor” level, the community will be notified immediately that it is unsuitable for swimming.
The Lake Conjola Interim Entrance Management Policy (August 2013), which was adopted by Council and the NSW Government following extensive community consultation, says the lake is only to be opened when the lake water level is at, or exceeding, one-metre AHD.
“If the lake is opened at a lower level than the trigger, it’s likely to close again very quickly, unless it’s followed by heavy rain,” the spokesperson said.
“This is due to the fact that the volume of onshore sand transported into the lake entrance from the ocean, is greater than the volume of water moving out of the lake catchment.
“Opening the lake before there are sufficient volumes of water in the lake can cause significant and long-lasting environmental impacts on the ecosystems in and around the lake.”
State government agencies would have to approve any actions to artificially open the lake outside the adopted conditions.
“Given that this would be acting outside of the agreed entrance management plan and the potential environmental impacts of artificially opening the lake, it is highly unlikely that Council would be successful in gaining such approval,” the spokesperson said.