The Waitakaruru River is a river of the Waikato Region of New Zealand's North Island. It flows initially north before turning northwest across the northwestern corner of the Hauraki Plains, reaching the southwestern corner of the Firth of Thames close to the settlement of Waitakaruru.

Waitakaruru River
Map
Location
CountryNew Zealand
Physical characteristics
Source 
 • locationHapuakohe Range
Mouth 
 • location
Firth of Thames
Length15 km (9.3 mi)

Grey mangrove, or mānawa, has rapidly colonised the estuary since 1940, due to sediment deposited by the rivers and climate change.[1]

The river should not be confused with the similarly named Waitakaruru Stream, which is also in the Waikato Region, near Morrinsville.

Pollution

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In its lower reaches the river is not fit for swimming,[2] as the nitrogen and phosphorus pollution levels are many times those of the natural river.[3]

Pollution has generally been worsening, as shown in this table -

Relative seasonal Kendall slope estimator (RSKSE) trends (% per year). Important (i.e. slope direction probability over 95% and RSKSE over ±1% pa) improvements, or deteriorations in bold.
Conductivity Turbidity Visual clarity Total nitrogen Nitrate-N Ammonia Total phosphorus (provisional) Dissolved reactive P Escherichia coli
1993–2017 1.1 –1.8 1.9 –1.5 –1.8 –3.6 –1.6 –0.7 –2.0
2008–2017 –0.4 –4.2 7.6 –2.6 –1.5 –3.0 –3.9 –2.3 –7.3

Monthly records are flow-adjusted using a Lowess curve fit with 30% span.[4]

See also

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References

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  1. ^ "Mangrove Habitat Expansion in the Southern Firth of Thames: Sedimentation Processes and Coastal Hazards Mitigation". Waikato Regional Council. Retrieved 29 December 2018.
  2. ^ "Waitakaruru River at Coxhead Rd Bridge". Waikato Regional Council. Retrieved 29 December 2018.
  3. ^ Vant, Bill (November 2016). "Water quality and sources of nitrogen and phosphorus in the Hauraki rivers, 2006–15" (PDF). Waikato Regional Council.
  4. ^ Vant, Bill. Waikato Regional Council Technical Report 2018/30 Trends in river water quality in the Waikato region, 1993-2017.

"Place name detail: Waitakaruru River". New Zealand Gazetteer. New Zealand Geographic Board. Retrieved 12 July 2009.

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37°14′S 175°24′E / 37.233°S 175.400°E / -37.233; 175.400