The Avoca Lake is fed by stormwater runoff into Saltwater Creek that gathers on the slopes within Kincumber Mountain Reserve to the northwest above Pickets Valley. The lake has a surface area of approximately 70 hectares (170 acres) and a catchment area of 10.8 square kilometres (4.2 sq mi).[2] Its outflow is into Bulbararing Bay in the Tasman Sea of the South Pacific Ocean. The outflow is generally closed, and water levels inside the lake are not usually influenced by ocean tides.