Lake Curalo was manually opened to the ocean on Sunday after it reached a critical 1.1 metre mark, a trigger used by Bega Valley Shire Council to determine the action.
There was much excitement about this finally taking place, as the last manual opening occurred in December 2014 and the lake remained open until around mid-November 2016.
There has been criticism of management of the lake for years. Many Eden residents believe the central position of the lake and the urban development surrounding its catchment area have caused the lake to fill with sediment and it has consequently become shallower over time.
In March this year a meeting was held by a group of 60 residents concerned about the health of the lake, to explore options for improving its appeal, with multiple reports of bad odours, dead fish and pollution and excess nutrient being brought to the lake by stormwater.
Council's coastal management officer, Rachel Duczynski, said many Bega Valley estuaries are "intermittently closed and open lakes and lagoons" (ICOLLS), "and there is often community concern over closed ICOLLS such as perceived 'poor' water quality, odour, flooding of low lying areas and concerns over fish stocks".
"However, many ICOLLS retain good water quality for long periods of closure with openings not guaranteed to improve water quality due to the limited tidal movement they tend to experience."
The NSW state policy for entrance management is for minimal interference and advocates natural processes being able to operate to the greatest extent possible.
"Entrances are managed to mitigate and reduce flooding impacts on key public and private infrastructure, assets and access around water heights with openings based on trigger heights determined by these factors," Ms Duczynski said.
"By maximising trigger heights we ensure the best chance of an effective opening and scour of the entrance channel, enhancing chances of a longer lasting opening. The length of time estuaries remain open is dependent on catchment inflows and wave activity at the entrance.
"We have had three consecutive years of below average rainfall which has been a contributing factor to the extended closure."