Merrica River rises on the northern slopes of Mount Nadgee within the Nadgee Nature Reserve; located about 9 kilometres (5.6 mi) southwest of Tumbledown Mountain. The river flows generally northeast before reaching its mouth with the Tasman Sea of the South Pacific Ocean, emptying into Disaster Bay.[3] The river descends 230 metres (750 ft) over its 19 kilometres (12 mi) course.[1]
The catchment area of the river is 60.5 square kilometres (23.4 sq mi) with a volume of 48.5 megalitres (1.71×10^6 cu ft) over a surface area of 0.1 square kilometres (0.039 sq mi), at an average depth of 0.4 metres (1 ft 4 in).[4]
^"Merrica River". Coastal and floodplain management: Coastal zone management: Estuaries of NSW. NSW Environment and Heritage. 27 April 2012. Retrieved 30 May 2013.