Waioeka-Otara Rivers Scheme

The scheme comprises two main branches, the Waioeka and Otara Rivers. The Waioeka catchment covers 825 km2 extending 60 km, while the Otara covers 350 km2 and extends 30km. Both the catchments are relatively steep with extensive bush cover. The lower reaches of both rivers meander across flood plains before joining at Opotiki and flowing out to sea. Intensive rainstorms occur in both catchments with associated flooding and gravel movement being difficult to control.

A full analysis of the hydrology of both rivers was carried out by the East Coast Catchment Board in 1988. This concluded that, from continuous river stages recorded over the period 1958-85, the one hundred year flow for the Waioeka River as measured at the Cableway recorder, is 2100 cumecs (cubic metres per second). Similarly, based on records for the period 1964-86, the one hundred year flow for the Otara River at the Browns Bridge recorder is 1000 cumens. Mean flows for the Cableway and Browns Bridge sites are 32 and 11 cumens respectively.

Overview
The Waioeka-Otara Rivers Scheme includes substantial stopbanking of both the town and rural sections of both rivers, one pump station (Duke Street) and considerable bank edge protection works including riprap, rubble and plantings. The scheme also includes flood protection to the land adjoining Mill Stream and minor drainage works.