Ūawa River
| Ūawa River | |
|---|---|
The Ūawa River mouth at Tolaga Bay | |
Route of the Ūawa River | |
Mouth of the Ūawa River Ūawa River (North Island) | |
| Native name | Ūawa-nui-a-Ruamatua (Māori)[1] |
| Location | |
| Country | New Zealand |
| Island | North Island |
| Region | Gisborne |
| Physical characteristics | |
| Source | confluence of Mangatokerau River and Hikuwai River |
| • location | Mangatuna |
| • coordinates | 38°22′28″S 178°18′23″E / 38.3744°S 178.3065°E |
| Mouth | Tolaga Bay |
• location | Tolaga Bay |
• coordinates | 38°22′28″S 178°18′23″E / 38.3744°S 178.3065°E |
• elevation | 0 m (0 ft) |
| Basin size | 539 km2 (208 sq mi)[2] |
| Discharge | |
| • average | 15 m3/s (530 cu ft/s)[2] |
| Basin features | |
| Progression | Ūawa River → Tolaga Bay → Pacific Ocean |
| River system | Ūawa River System |
| Tributaries | |
| • left | Mangahoui Stream, Mangaopeka Stream, Ihunui Stream |
| • right | Tapuae Stream, Mangaheia River, Waimaunu Stream |
| Bridges | Ūawa River Bridge |
The Ūawa River is a river in the Gisborne District of New Zealand. The river drains an area of consisting of predominately managed forestry land northwest of Tolaga Bay. The river flows out into the Pacific at Tolaga Bay. The river is prone to flooding and has had significant issues with forestry slash.
Geography
The Ūawa River begins at the confluence of the Mangatokerau and Hikuwai rivers. The river and meanders south for about 10 kilometres (6 mi) passing the settlement of Wharekaka before flowing into the sea at Tolaga Bay.[3][4] Much of the catchment area of the Ūawa River is land formed during the Pleistocene.[4]
The larger Ūawa River System includes the Hikuwai River and Waiau River, and drains a total catchment area of 539 km2 (208 sq mi).[2] The ultimate source of the river is at the head of the Pangopango Stream near Tauwharepārae. The stream initially flows north and where it is joined by Ngapunarua Stream it becomes the Waiau River. The river meanders in a northerly direction through large areas of managed forestry before bending eastwards towards the settlement of Hikuwai. The Hikuwai River begins at the confluence of the Waiau River and Mangarākai Stream. The rivers flow south through this section, meandering through an area of farmland and the settlements of Arero and Mangatuna. State highway 2 follows the river valley through this section crossing the river four times.
Biodiversity
The river mouth area is a wetland dominated by Typha orientalis.[4]
Flooding
Flooding in the Ūawa River System is frequent, especially in the Mangaheia River valley.[4] The area is prone to high rain falls when easterly weather systems make landfall from the Pacific Ocean. During Cyclone Gabrielle the monitoring river level at Willow Flat rose from an average 2 m (6 ft 7 in) height to a height of over 14 m (46 ft).
Gallery
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Image of a bridge over the Ūawa River, circa 1915
-
River mouth in the early 20th century
See also
References
- ^ "Place name detail: Ūawa-nui-a-Ruamatua". New Zealand Gazetteer. Land Information New Zealand. Retrieved 23 March 2026.
- ^ a b c Biggs, Hamish; Haddadchi, Arman; Brasington, James; Bind, Jochen; Stout, Justin (August 2025). "The impact of riparian vegetation on bank erosion during extreme weather events". Earth Surface Processes and Landforms. 50 (10). doi:10.1002/ESP.70136. ISSN 0197-9337. Wikidata Q135912689.
- ^ "Place name detail: Ūawa River". New Zealand Gazetteer. Land Information New Zealand. Retrieved 23 March 2026.
- ^ a b c d Horrocks, Mark; Smith, Ian W. G.; Nichol, Scott L.; Shane, Phil A.; Jackman, Gordon (22 February 2010). "Field survey, sedimentology and plant microfossil analysis of sediment cores from possible cultivation sites at Tolaga Bay, eastern North Island, New Zealand". Journal of the Royal Society of New Zealand. 38: 131–147. doi:10.1080/03014220809510551.