Lake Rotoiti (Bay of Plenty)
{{Short description|Lake in the North Island of New Zealand}}
{{For|the lake in the South Island|Lake Rotoiti (Tasman)}}
{{Use New Zealand English|date=April 2024}}
{{Infobox body of water
| name = Lake Rotoiti
| image =Jetty on Lake Rotoiti.jpg
| alt = Lake Rotoiti
| caption = Lake Rotoiti
| image_bathymetry = Rotoiti Bathymetry.png
| alt_bathymetry = Bathymetric map of Lake Rotoiti
| caption_bathymetry = Bathymetric map of Lake Rotoiti{{cite journal |last1=de Ronde |first1=Cornel E.J. |last2=Caratori Tontini |first2=Fabio |last3=Black |first3=Jenny |title=Bathymetric map of Lake Rotoiti, New Zealand |date=2021 |doi=10.21420/8123-EA25 |url=https://shop.gns.cri.nz/rl-rotoiti-pdf/ |access-date=31 August 2023| journal=GNS Science Rotorua Lakes Map Series}}
| image_map =
|pushpin_map=North Island
| pushpin_map_alt = Location of Lake Rotoiti
| location = Rotorua Lakes, Bay of Plenty Region, North Island
| coords = {{coord|-38.0390|176.4277|region:NZ-BOP_type:waterbody|display=inline,title}}
| type = crater lake
| inflow =
| outflow = Kaituna River
| catchment =
| basin_countries = New Zealand
| length = {{convert|15|km|abbr=on}}
| width = {{convert|3.6|km|abbr=on}}
| area = {{convert|34.3|km2|abbr=on}}
| depth = {{convert|33|m|abbr=on}}
| max-depth = {{convert|100.0|m|abbr=on}}
| volume =
| residence_time =
| shore =
| elevation = {{convert|279|m|abbr=on}}
| islands =
| cities =
}}
Lake Rotoiti is a lake in the Bay of Plenty region of New Zealand.{{LINZ|42353|Lake Rotoiti|2009-03-18}} It is the northwesternmost in a chain of lakes formed within the Ōkataina Caldera. The lake is close to the northern shore of its more famous neighbour, Lake Rotorua, and is connected to it via the Ohau Channel. It drains to the Kaituna River, which flows into the Bay of Plenty near Maketu.
The full name of the lake is Te Rotoiti-kite-a-Īhenga,
{{cite web
| url=http://www.TeAra.govt.nz/en/volcanic-plateau-places/3
| title= Volcanic Plateau places - Lake Rotoiti to Lake Rotomā
| last= McKinnon
| first= Malcolm
| publisher=Te Ara New Zealand
| date= 2 March 2009
| accessdate = 19 September 2012
}} which in the Māori language means "The Small Lake Discovered by Īhenga", the Māori explorer also credited with discovering Lake Rotorua. Legend says that the lake was named as such because when Ihenga first saw it, he could only see a small part of it and thought the lake was a lot smaller.
Since the 1960s, the quality of lake water has been negatively affected by inflows of nitrogen rich water from Lake Rotorua, agricultural run-off from surrounding farms and seepage from domestic septic tanks.{{cite web |url=http://www.boprc.govt.nz/media/97587/ohauchanneldiversionwallmonitoringreportjune2011final.doc |title=Ohau Channel Diversion Wall Monitoring |date=June 2011 |accessdate=2013-01-03 |archive-url=https://web.archive.org/web/20130212175221/http://www.boprc.govt.nz/media/97587/ohauchanneldiversionwallmonitoringreportjune2011final.doc |archive-date=2013-02-12 |url-status=dead }} The effects of this included an almost permanent algal bloom in the Okere arm of the lake and choking lake weed growth in other still areas of the lake. A barrier to divert the nutrient rich waters of Lake Rotorua into the Kaituna River was completed in late 2008.
The Bay of Plenty Regional Council is expected to see improvement in lake water quality within five years.{{Cite web |url=http://www.boprc.govt.nz/environment/water/rotorua-lakes/ohau-channel-diversion-wall/ |title=Ohau Channel Diversion Wall |access-date=2013-01-03 |archive-url=https://web.archive.org/web/20151124074623/http://www.boprc.govt.nz/environment/water/rotorua-lakes/ohau-channel-diversion-wall/ |archive-date=2015-11-24 |url-status=dead }} The Rotorua Te Arawa Lakes Program reported in 2013 that the intervention has significantly improved water quality. Water quality is the highest it has been in decades, and it is on track to meet targets set by the Program to meet community expectations.{{cite web|url= http://www.rotorualakes.co.nz/lake_rotoiti_water_quality_status |title=Rotorua Te Arawa Lakes Program, Lake Rotoiti Water Quality Status |accessdate=2015-04-30}}
Lake Rotoiti has thermal hot-spring baths on the southern shore which are accessible by boat.{{cite web |url= http://www.rotorua.nz.com/lake-rotoiti.aspx |title= Lake Rotoiti, Lake Rotoehu and Lake Rotoma |accessdate= 2013-01-03 |archive-date= 2012-11-15 |archive-url= https://web.archive.org/web/20121115030952/http://www.rotorua.nz.com/lake-rotoiti.aspx |url-status= dead }}
Geology
Its joint drainage with Lake Rotorua through the Ohau Channel depends upon the sinking Tikitere graben which is also very geothermally active on the south eastern margins of the lake. There appear to have been Rotoiti eruptive vents at the eastern end of the lake and although these are part of the Ōkataina Volcanic Centre they are believed to be in an area of collapse subsidence outside the north western margins of the Ōkataina Caldera itself.{{cite journal|first1=Ery C. |last1=Hughes |first2=Sally |last2=Law |first3= Geoff |last3=Kilgour |first4= Jon D. |last4=Blundy |first5= Heidy M. |last5=Mader |title=Storage, evolution, and mixing in basaltic eruptions from around the Okataina Volcanic Centre, Taupō Volcanic Zone, Aotearoa New Zealand |journal=Journal of Volcanology and Geothermal Research |volume=434 |year=2023 |issue=107715 |page=107715 |issn=0377-0273 |doi=10.1016/j.jvolgeores.2022.107715 |bibcode=2023JVGR..43407715H |s2cid=253783414 |url=https://www.sciencedirect.com/science/article/pii/S0377027322002463)|hdl=20.500.11820/9f5c151c-1f2e-47ed-a264-7649eacdf669 |hdl-access=free }}{{efn|Technically significant surface vents can be well separated from a magma chamber and its associated area of caldera collapse immediately above. A recent extreme example with a basalt eruption was in Iceland where the significant vent was over {{cvt|40|km}} from the caldera collapse that drove the eruption.{{cite journal|last1 =Riel|first1 =B.|last2 =Milillo|first2 =P.|last3 =Simons|first3 =M.|last4 =Lundgren|first4 =P.|last5 =Kanamori|first5 =H.|last6 =Samsonov|first6 =S.|year =2015|title =The collapse of Bárðarbunga caldera, Iceland|journal =Geophysical Journal International|volume =202|issue =1|pages =446–453|doi =10.1093/gji/ggv157|doi-access=free}}}}
This region of the caldera was at one time termed the Haroharo Caldera, but has been renamed in the more standard major event fashion to the Rotoiti Caldera. As postulated, this caldera does not house the lake. The age of this large eruption of more than {{convert|100|km3}} of magma{{cite journal
|last1=Shane
|first1 =Phil
|last2= Nairn
|first2= I.A.
|last3=Smith
|first3=Victoria C.
|year=2005
|pages=295–313
|title=Magma mingling in the ~50 ka Rotoiti eruption from Okataina Volcanic Centre: Implications for geochemical diversity and chronology of large volume rhyolites
|volume=139
|doi=10.1016/j.jvolgeores.2004.08.012
|journal=Journal of Volcanology and Geothermal Research
|issue =3–4
|bibcode =2005JVGR..139..295S
|url=https://www.researchgate.net/publication/223779165
}} was historically ill-defined due to several complexities and the literature gives a range from 40,000 years to 64,000 years ago with 47,400 ± 1500 years ago being recently quoted.{{cite journal|
last1=Flude
|first1=S.
|last2=Storey
|first2=M.
|year=2016
|title=40Ar/39Ar age of the Rotoiti Breccia and Rotoehu Ash, Okataina Volcanic Complex, New Zealand, and identification of heterogeneously distributed excess 40Ar in supercooled crystals
|journal=Quaternary Geochronology
|volume=33
|pages=13–23
|doi=10.1016/j.quageo.2016.01.002
|url=https://strathprints.strath.ac.uk/83832/1/Flude_Storey_QG2016_40Ar_39Ar_age_Rotoiti_breccia_Rotoehu_ash_Okataina_Volcanic_Complex_New_Zealand.pdf
}}{{cite journal|last1=Schmitz |first1=Mark D. |last2=Smith |first2=Ian E. M. |title=The Petrology of the Rotoiti Eruption Sequence, Taupo Volcanic Zone: an Example of Fractionation and Mixing in a Rhyolitic System|journal=Journal of Petrology |volume=45 |issue=10 |pages=2045–2066 |year=2004 |doi=10.1093/petrology/egh047 }} What is not now challenged is that this was a paired eruption with a nearby vent in the Ōkataina Caldera that had a separate magma source and erupted Earthquake Flat breccia.Houghton B F, Wilson C J N, McWilliams M O, Lanphere M A, Weaver S D, Briggs R M, Pringle M S, 1995. [https://pubs.geoscienceworld.org/gsa/geology/article-abstract/23/1/13/206153/Chronology-and-dynamics-of-a-large-silicic Chronology and dynamics of a large silicic magmatic system: Central Taupo Volcano Zone, New Zealand]. Geology, 23: 13-16.
Climate
{{Weather box|width=auto
|metric first=y
|single line=y
|collapsed = Y
|location = Lake Rotoiti (1991–2020)
|Jan high C = 21.2
|Feb high C = 21.2
|Mar high C = 18.9
|Apr high C = 15.4
|May high C = 12.1
|Jun high C = 9.1
|Jul high C = 8.9
|Aug high C = 10.0
|Sep high C = 12.1
|Oct high C = 14.5
|Nov high C = 16.5
|Dec high C = 18.9
| year high C =
|Jan mean C = 14.9
|Feb mean C = 14.8
|Mar mean C = 12.9
|Apr mean C = 9.9
|May mean C = 7.1
|Jun mean C = 4.1
|Jul mean C = 3.7
|Aug mean C = 4.8
|Sep mean C = 6.8
|Oct mean C = 9.0
|Nov mean C = 10.8
|Dec mean C = 13.2
| year mean C =
|Jan low C = 8.7
|Feb low C = 8.5
|Mar low C = 6.9
|Apr low C = 4.4
|May low C = 2.1
|Jun low C = -0.9
|Jul low C = -1.5
|Aug low C = -0.4
|Sep low C = 1.6
|Oct low C = 3.6
|Nov low C = 5.1
|Dec low C = 7.5
| year low C =
|rain colour = green
|Jan rain mm = 131.0
|Feb rain mm = 108.9
|Mar rain mm = 121.0
|Apr rain mm = 90.1
|May rain mm = 116.5
|Jun rain mm = 159.2
|Jul rain mm = 104.0
|Aug rain mm = 139.0
|Sep rain mm = 154.3
|Oct rain mm = 167.8
|Nov rain mm = 149.6
|Dec rain mm = 150.7
|year rain mm =
{{cite web
|url = http://cliflo.niwa.co.nz
|title = CliFlo – National Climate Database : Lake Rotoiti 2
|publisher = NIWA
|access-date = 19 May 2024}}
}}
{{wide image|Lake Rotoiti NZ7 3514 - 32143651807.jpg|800px|Panorama of Lake Rotoiti}}
{{wide image|Lake Rotoiti NZ7 3525 - 47085364681.jpg|800px|Homes and vacation homes nestled in around Lake Rotoiti}}
Notes
{{Notelist}}
References
{{Reflist}}
{{Authority control}}
{{DEFAULTSORT:Rotoiti, Lake, Bay of Plenty}}
Category:Lakes of the Bay of Plenty Region