About the catchment

The Otara catchment encompasses a total area of 3,477 ha drained by 196.7km of open watercourse which discharges to the Tamaki Estuary via Otara Lake. The catchment is within the two political boundaries (50/50) of the Ōtara-Papatoetoe Local Board and Howick Local Board. 

The underlying geology consists of Waitemata group soils which are poorly draining with low surface infiltration during heaving rainfall.

The catchment was once a green and productive land, supporting clean waterways filled with fish and used for drinking, food, transport, portage and recreation.

Today the catchment is home to tens of thousands of people and the land use a diverse mix of housing, commercial, retail, industry, roads, park land, rural properties, closed landfills and sports grounds.  

Streams within the upper catchment are generally modified by rural framing activities but maintain important habitat and migratory pathways for native fish including banded kokopu, connecting to upper headwaters.

The downstream reaches within the urban area are heavily modified with limited capacity and little flood plain area.

The primary receiving environment is Otara Lake, a tidal arm of the Tamaki estuary blocked by a tidal weir to retain water at low tide for use at the (now decommissioned) Otahuhu Power Station.