Waipa River

Waipa River
From Waingaro Rd bridge looking north down Waipa River to Ngaruawahia Point bandstand, the Waikato (coming from right) and the Hakarimata Range in the background (19-9-2012)
Country	New Zealand
Basin features
Main source	Rangitoto Range 703 m (2,306 ft)
River mouth	Waikato River 20 m (66 ft)
Basin size	3,050 km2 (1,180 sq mi)
Tributaries	Left: Wharekiri Stream, Kaama Stream, Waiharakea Stream, Otanetapoto Stream, Mangawhaka Stream, Ngakuratro Stream, Mangawhero Stream, Mangapu River, Orahiri Stream, Waitomo Stream, Mangamahoe Stream, Owaikura Stream, Ongaruhe Stream, Moakurarua Stream, Ngakoaohia Stream, Mangauika Stream, Ngaparierua Stream, Mangawawe Stream, Mangamauku Stream, Mangao Stream, Waikoha Stream, Paratawa Stream, Tunaeke Stream, Karakariki Stream, Mangaotama Stream, Karangatuoro Stream, Timaru Stream, Te Paki Stream, Maroheno Stream, Firewood Creek, Mangarata Stream. Right: Otamaroa Stream, Okahukura Stream, Mata Stream, Tunawaea Stream, Owawenga Stream, Tauraroa Stream, Parapara Stream, Mohoanui Stream, Mangaoronga Stream, Okuri Stream, Okohau Stream, Mangawhero Stream, Puniu River, Mangapiko Stream, Mangakaware Stream, Mangaotama Stream, Mangahia Stream, Koromatua Stream, Ohote Stream.
Physical characteristics
Length	115 km (71 mi)
Discharge	Average rate: 83.9 m3/s (2,960 cu ft/s)

The Waipa River is in the Waikato region of the North Island of New Zealand. The headwaters are in the Rangitoto Range east of Te Kuiti. It flows north for 115 kilometres (71 mi), passing through Otorohanga and Pirongia, before flowing into the Waikato River at Ngaruawahia. It is the Waikato's largest tributary. The Waipa's main tributary is the Puniu River.

In the headwaters upstream of Otorohanga the river can be very clear during low flow conditions. This section of the river flows through rough farmland and patches of native bush. In this clearer part of the river there can be very good fly fishing for trout, but you'll need to ask the land owners permission to access the river.

The Waipa is prone to flooding in its lower reaches as flood flows can be over 100 times—20 to 560 m³/s (710 to 19,780 cu ft/s)—those of dry flows and the river can rise up to 11 m (36 ft).

In 2013 Maniapoto Māori Trust Board and the riparian local councils set up a joint management agreement for the river.

The table below shows the time water takes to flow the 130 km (81 mi) from Te Kuiti to its confluence with the Waikato in times of low flow (15% of days are slower than this) and high flow (15% of days faster) -

In 2003 Hydro Power Ltd was given consent to build a hydro-electric power station, with weirs in the Okahukura Stream, upstream from Owen Falls, and carrying water down the gorge to a station on the west bank 2.5 kilometres (1.6 mi) below the falls. Work was done in 2006, but, in 2007, Hydro Energy (Waipa) Ltd was fined for unconsented damage to native vegetation in building the penstock. The resource was initially estimated to be able to generate 10 to 20MW. Construction halted, though Renewable Power bought the asset in 2010 and estimates potential at 9MW.

In 2017 Nova Energy were given consent to build a 360MW gas-turbine station (connected to the Maui Gas Pipeline) on the Ongaruhe Stream, close to its confluence with the Waipa.