DOCSLIB.ORG

Proc. 10Th New Zealand Geothermal Workshop 1988 GEOPHYSICAL EXPLORATION for PROSPECTIVE GEOTHERMAL RESOURCES in the TARAWERA

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Proc. 10Th New Zealand Geothermal Workshop 1988 GEOPHYSICAL EXPLORATION for PROSPECTIVE GEOTHERMAL RESOURCES in the TARAWERA 123 Proc. 10th New Zealand Geothermal Workshop 1988 GEOPHYSICAL EXPLORATION FOR PROSPECTIVE GEOTHERMAL RESOURCES IN THE TARAWERA FOREST C. J. BROMLEY2, J. J. BOTTOMLEY1, C.F. PEARSON2 1. FLETCHER CHALLENGE LTD 2. GEOPHYSICAL CONSULTANT (formerly KRTA LTD) ABSTRACT An integrated geophysical survey, involving GEOLOGY resistivity, gravity and magnetic measurements, was conducted early in 1987 over a 300km2 area Geological inferences suggest that the most within and north of the Tarawera Forest, to promising geothermal prospects are located along investigate potential geothermal resources for the north-eastern boundary of Haroharo Caldera, Fletcher Challenge Ltd. Two significant which lies within the Okataina Volcanic Centre. anomalies have been delineated. The first is the The Haroharo and Tarawera complexes have been Tikorangi resistivity and magnetic low, sporadically active for the last 250,000 years, associated with the north-eastern boundary of the most recently in 1886. This suggests that a magma Haroharo Caldera and centered south of the chamber still underlies the caldera (Nairn, 1981). Tikorangi solfataras. The second anomaly, which Important structural features of the caldera in- is situated within the Puhipuhi Basin, east of clude its margin and the Haroharo and Tarawera the caldera, is postulated to represent a vent lineations. As a result of multiple, shallow separate but cooling geothermal system, with dip slumping, associated with the caldera margin, implications of possible epithermal enhanced vertical permeability in the upper mineralisation. kilometre may be distributed over a broad zone. In addition, the underlying ring fault probably Interpretation of the gravity measurements has creates a deep zone of substantial permeability. led to identification of a north-east trending Recent vents form two broad parallel lineations graben passing through Lake Rotoma, and orientated at 50° which are probably associated intersecting the Haroharo Caldera near with deep-seated basement fractures. The Haroharo Tikorangi. combined interpretation Of all vent lineation intersects the caldera boundary, at available data resulted in a pre-drilling a position marked by Tikorangi, a small 5,000 year conceptual hydrological model for the Tikorangi old rhyolite dome. Within the caldera there are system and a target for future exploration very few mapped faults which is probably a drilling. function of the relatively young age of the surficial volcanics. However, outside the INTRODUCTION caldera, numerous north-east trending faults have This paper presents the results of a geophysical been mapped, and many of these may also pass investigation of prospective geothermal resources through the caldera, providing vertical in and near the Tarawera Forest (between Rotorua permeability beneath the surficial volcanics. and Kawerau) for Fletcher Challenge Ltd. Previous studies (Nairn, 1981, Yamada, 1985) The near surface geology of the Haroharo Complex provided encouraging evidence for the possible consists of a relatively thick sequence of recent existence of a geothermal system in the area rhyolite lavas (approximately 5,000 to 9,000 years between Lake Rotoehu, Lake Rotoma, and the old), volcanic breccias and pyroclastics. East of Tarawera River. Thermal manifestations, occur the caldera boundary, the approximately 200,000 along the shores of both lakes, at Tikorangi, and year old Haparangi rhyolites make up the within the Te Haehaenga Basin further south. The Maungawhakamana massif and Rere hills bordering Puhipuhi Basin, south of the Tarawera River, was Lake Rotoma. To the south, the Puhipuhi Basin added to the area of interest because of evidence marks the site of a small depression or caldera of intense alteration on Puhipuhi Hills, and the now largely filled with lacustrine sediments and existence of the neighbouring Waiaute warm ignimbrites which were uplifted and altered by the springs. emplacement of the Puhipuhi dacite volcano (160,000 years old). The Puhipuhi dacite is A number of previous geophysical surveys, highly brecciated and has been intensely altered conducted in this area, were used to guide the by acidic fluids to an assemblage consisting of an recent work. These included: an assessment of advanced argillic cap of alunite-cristobalite Okataina Volcanic Centre using gravity, seismic, (opal) and pyrite, underlain by kaolinite and resistivity and aero-magnetics (Rogan, 1980); a pyrite. Silica flooding is also common. This brief resistivity survey of the Rotoma-Tikorangi advanced argillic cap is typical of the surface area by students from the Geothermal Institute expression of shallow boiling in epithermal (Doens, 1985, Kohpina, 1985); and a sequence of environments, and it may be underlain by a detailed aero-magnetic surveys flown over the paleo-boiling zone containing mineralisation. Haroharo and Tarawera complexes (Salt, 1986). Gold and silver traces were reported by These are discussed in more detail by Hochstein prospectors in the 1920's in opalised pyritised et al. (1987). Late in 1987, another two quartz veins. The lack of significant surface Institure students (Ayala, Estrada) conducted thermal features around Puhipuhi suggests that follow-up resistivity and gravity work. this prospect is probably a waning hydrothermal system. The geophysical studies described here include a gravity survey of 208 stations, a resistivity traversing survey of 278 stations (with AB/2 The major thermal features of interest (see Figure spacings of 500m and 1000m), 40 deep resistivity 2) are located at Tikorangi (solfataras), Lakes soundings, and some additional magnetic property Rotoma and Rotoehu (Waitangi and Otei Springs), in measurements on surface rock samples. the Te Haehaenga Basin (Mangakotukutuku Spring), 124 Bromley et al. and west of Puhipuhi Hills (Waiaute Spring). Other nearby thermal features are located on the south eastern shore of Lake Okataina, Humphreys Bay of Lake Tarawera, and the Centre Basin of Lake Rotoiti. Descriptions of the major thermal manifestations are given by Nairn (1981) and Yamada (1985). During the present geophysical survey another thermal feature was discovered in a swamp along Waterfall Road next to the Tarawera River (Grid: N77 993029). An extensive area of C0? degassing is associated with warm chloride fluids within the swamp. A maximum temperature of 30°C was recorded in mud at about lm depth. Measurements of flow rate and chloride concentration of the Tarawera River have identified a substantial increase in total chloride flux (about 150 gm/s) entering the river between the Tarawera Falls and the Waterfall Road bridge. RESISTIVITY SURVEYS Previous resistivity measurements in the area include an early DSIR traversing survey along State Highway 30 and six Schlumberger soundings, some dipole-dipole measurements and magneto-telluric soundings by Rogan (1980) along the Tarawera River. Rogan's models are reasonably consistent with subsequent resistivity sounding interpretations, although there is some doubt over the existence of a 1 ohm-m layer at 3 km depth near Lake Tarawera, which is based on one noisy dipole-dipole reading. A deeply penetrating magneto-telluric sounding located beside the outlet of Lake Tarawera revealed apparent resistivities of less than 10 ohm-m at a period of 10 seconds, increasing to more than 100 ohm-m at 200 seconds. Again reliable interpretation is FIGURE 1: hindered by noisy data and three-dimensional Apparent Resistivity Contours AB/2 = 1000M effects, but a simple layered model of the the soundings and selected section lines are shown magneto-telluric curve suggests that if a 1 ohm-m in figure 2. Interfaces between the layers are layer exists at 2 to 3 km depth, then it is connected to portray subsurface variations in the probably only about 500m thick and is underlain by factors that have caused the resistivity much higher resistivities (in excess of 500 contrasts. In general, these factors are ohm-m). Geothermal Institute students Kohpina variations in porosity, temperature, saturating (1985) and Doens (1985) conducted a total of 10 fluid mineralisation and intensity of clay soundings and 18 traversing measurements between alteration. Together, these factors can provide Rotoma and the Tarawera River. These have been powerful indicators of the shallow hydrological reinterpreted in conjunction with the recent processes occurring in a geothermal system, resistivity survey. although care is necessary to avoid misinterpretations caused by combinations of The resulting apparent resistivity traversing alteration, porosity and fluid mineralisation contour maps reveal a complex zone of moderately contrasts without a corresponding change in low resistivities elongated in a north-south temperature. direction along the eastern caldera boundary (see Figure 1). The anomaly is bounded in most The first interface that appears in all the directions by resistivities in excess of 400 sections is closest to the surface, and probably ohm-m. The low resistivity zones form two represents the ground water table. It is marked anomalies: the Tikorangi-Rotoma-Te Haehaenga by a contrast in resistivity of approximately one anomaly and the Puhipuhi anomaly. The only zone order of magnitude from several thousand ohm-m of very low apparant resistivity (less than 10 (unsaturated porous pyroclastics, rhyolites etc) ohm-m) is a 1.2 km fan-shaped area north of the to several hundred ohm-m (interpreted to be porous Tikorangi solfataras suggesting the existence of a volcanics saturated with fresh ground
Load more

Recommended publications
  • The Sedimentation and Drainage History of Haroharo Caldera and the Tarawera River System, Taupo Volcanic Zone, New Zealand
    The Sedimentation and Drainage History of Haroharo Caldera and The Tarawera River System, Taupo Volcanic Zone, New Zealand Prepared by K A Hodgson and I A Nairn Environment Bay of Plenty Operations Publication 2004/03 August 2004 5 Quay Street P O Box 364 Whakatane NEW ZEALAND ISSN 1176 - 5550 Working with our communities for a better environment Environment Bay of Plenty i Acknowledgements The Department of Conservation (Rotorua Lakes Office) permitted our studies in lake and river reserves. Fletcher Challenge Forests (and its successors) provided detailed contour maps and aerial photographs. Bryan Davy and Hugh Bibby (GNS) provided a pre- publication copy of their paper on seismic imaging in Lake Tarawera. PGSF Contract IANX0201 funded this study. Sedimentation and Drainage History, Tarawera River System Operations Publication 2004/03 Environment Bay of Plenty iii Executive Summary Haroharo caldera has been formed by the coalescence of multiple collapse structures over the last 350 kyr, the latest major collapse accompanying voluminous rhyolite pyroclastic eruptions at ~50 ka. The caldera has formed a sink for precipitation on surrounding catchments, with overflow via the Tarawera River through the Whakatane graben to the sea at ~30 km to NE. Lakes have probably always occupied at least part of the caldera floor, but the early lacustrine history is largely obscured by younger eruptives. Since 26 ka, the Haroharo, Okareka, Rotoma and Tarawera volcanic complexes have grown within the caldera during eleven eruption episodes, confining ten lakes on the caldera margins. Growth of the volcanic complexes has greatly altered drainage paths and ponding areas within and marginal to the caldera, so that the present ~700 km2 caldera catchment area is about half the ~1400 km2 area that drained into the caldera between 26 ka and 9.5 ka.
    [Show full text]
  • The Ecological Condition of the Rotorua Lakes Using Lakespi-2011
    The ecological condition of the Rotorua Lakes using LakeSPI-2011 Prepared for Bay of Plenty Regional Council August 2011 Authors/Contributors: Tracey Edwards John Clayton For any information regarding this report please contact: Tracey Edwards Biologist Aquatic Plants +64-7-856 7026 [email protected] National Institute of Water & Atmospheric Research Ltd Gate 10, Silverdale Road Hillcrest, Hamilton 3216 PO Box 11115, Hillcrest Hamilton 3251 New Zealand Phone +64-7-856 7026 Fax +64-7-856 0151 NIWA Client Report No: HAM2011-050 Report date: August 2011 NIWA Project: BOP11201 Contents Executive summary .............................................................................................................. 5 1 Introduction ................................................................................................................. 7 1.1 Study brief ............................................................................................................ 7 1.2 Study lakes .......................................................................................................... 8 1.3 History of the Rotorua Lakes ................................................................................ 9 2 Study methods .......................................................................................................... 11 2.1 LakeSPI ............................................................................................................. 11 2.2 Lake surveys .....................................................................................................
    [Show full text]
  • Walking and Hiking in Rotorua Bay of Plenty This Publication Is Produced by Department of Conservation and Destination Rotorua
    Walking and hiking in Rotorua Bay of Plenty This publication is produced by Department of Conservation and Destination Rotorua February 2017 Editing and design: DOC Publishing Team This publication is produced using paper sourced from well-managed, renewable and legally logged forests. All photos, unless otherwise credited, are copyright DOC. Cover photo: Walkers enjoying Redwoods walk. Photo: Adrian Hodge Contents Introduction 1 Visitor information 2 Keeping you and the environment safe 2 Fire and other emergencies 2 Geothermal hazards 2 Aquatic pests 3 Information for walkers and hikers 4 Track classifications 4 Essential gear 5 Plan and prepare 5 Camping 6 Hunting 6 Fishing 6 Restrictions 7 Dog exercise areas 7 Maps 7 For the whole family ... 8 Close to the city 8 New Zealand birds a plenty 8 Magnificent water 8 Geothermal action 9 Native Ōkataina 9 Tracks and reserves 12 Lake Tikitapu Scenic Reserve 12 Lake Ōkareka 14 Mount Ngongotaha Scenic Reserve 15 Hamurana Springs Recreation Reserve 16 Okere Falls Scenic Reserve 17 Rainbow Mountain Scenic Reserve 20 Lake Rotoiti Scenic Reserve 23 Lake Rotoma Scenic Reserve 25 Lake Okataina Scenic Reserve 26 Longer walks in Lake Okataina Scenic Reserve 29 Lake Tarawera Scenic Reserve 31 Camping around Lake Tarawera 34 Walks and tracks around Tarawera 34 Lake Rotomahana Wildlife Refuge 38 Kaharoa Conservation Area 39 Mangorewa Ecological Area 40 Mokaihaha Ecological Area 43 Te Waihou 44 Nau mai, haere mai ki te rohe o Te Waiāriki Welcome to the Rotorua Lakes area. White water rafting at Okere Falls. Photo: Kaitiaki Adventures Introduction Rotorua is a paradise for walkers and hikers.
    [Show full text]
  • Q:\MAS\RP\MIS\Lakes Strategy\La
    i Foreword For the past two years the Lakes Management Strategy Working Group has been preparing a Lakes Management Strategy. The initial public discussion document entitled Towards a Te Arawa Lakes Strategy identified a significant range of concerns and interests in the long-term welfare of the lakes. We remain committed to these views: • We need to co-ordinate our efforts towards a shining and enduring vision for the lakes of the Rotorua district. • We need a commonly held vision for the lakes and their catchments that provides leadership and acknowledges protection, use, enjoyment, and the interests of Te Arawa in the lakes. • The purpose of the vision is to focus community energy and resources into tasks that ensure that this vision is achieved. • We must ensure that we identify and prioritise the issues properly, that we identify the total costs and benefits of actions, that we are committed to carrying out our tasks, that we review our actions regularly for effectiveness and accountability, and that we report publicly. This strategy is not a statutory document under either the Resource Management Act or the Local Government Act or any other Act. Our aim is rather to identify and address the problems arising from a lack of co-ordination between many interests in management of the lakes and then to consider how the law and those concerned can work together to solve those problems as effectively and efficiently as possible. We see the Lakes Management Strategy as being an ongoing process with regular review and accountability for achieving key goals that will make a difference and protect the lakes.
    [Show full text]
  • Groundwater in the Okataina Caldera: Model of Future Nitrogen Loads to Lake Tarawera
    Groundwater in the Okataina caldera: Model of future nitrogen loads to Lake Tarawera CBER Report 94 Prepared for Environment Bay of Plenty and Lake Tarawera Ratepayers’ Association By Nicolas Gillon1, Paul White2, David Hamilton1 and Warwick Silvester1 1. Centre for Biodiversity and Ecology Research, School of Science and Engineering, The University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand 2. Institute of Geological and Nuclear Sciences, Private Bag 2000, Taupo, 3352, New Zealand September 2009 1 Table of contents List of figures……………………………………………………………………………. 4 List of tables………………………………………………………………………………6 1. Introduction ................................................................................................... 6 2. Geomorphology and Land Use .................................................................... 7 2.1 Okataina Volcanic Centre ................................................................................................ 7 2.2 Lake Tarawera surface catchment ................................................................................... 9 3. Geology ......................................................................................................... 12 3.1 Geological history and lithological description of the Okataina Caldera complex ....... 12 3.1.1 Whakamaru Ignimbrite ......................................................................................................... 12 3.1.2 Matahina Ignimbrite ............................................................................................................
    [Show full text]
  • Estimates of Nitrogen and Phosphorus Loads to Twelve Bay of Plenty Lakes. Part 1: Land Use and Atmospheric Deposition
    Estimates of nitrogen and phosphorus loads to twelve Bay of Plenty Lakes. Part 1: Land use and atmospheric deposition April 2015 ERI report: XXX Prepared for Bay of Plenty Regional Council By Chris G. McBride, Piet Verburg, Marcus Bloor, David P. Hamilton…???? 1. Environmental Research Institute The University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand Bay of Plenty Lakes Catchment Loads Reviewed by: Approved for release by: John Tyrell University of Waikato University of Waikato Affiliation Affiliation ii Bay of Plenty Lakes Catchment Loads Executive Summary iii Bay of Plenty Lakes Catchment Loads Acknowledgements John McIntosh BoPRC LCDB OVERSEER etc iv Bay of Plenty Lakes Catchment Loads Contents Executive Summary ................................................................................ iii Acknowledgements ................................................................................ iv List of Figures ........................................................................................ vii List of Tables ........................................................................................ viii 1. Introduction ....................................................................................... 9 2. Methods ........................................................................................... 11 2.1 Study site –Rotorua Lakes ............................................................................................. 11 2.2 Land use classes and areas ...........................................................................................
    [Show full text]
  • NIWA Client Report No: HAM2014-067 Report Date: June 2014 NIWA Project: BOP14203
    Assessment of the Rotorua Te Arawa lakes using LakeSPI - 2014 Prepared for Bay of Plenty Regional Council June 2014 Authors/Contributors: Tracey Burton John Clayton For any information regarding this report please contact: Tracey Burton Freshwater Ecologist +64-7-8569 1852 [email protected] National Institute of Water & Atmospheric Research Ltd Gate 10, Silverdale Road Hillcrest, Hamilton 3216 PO Box 11115, Hillcrest Hamilton 3251 New Zealand Phone +64-7-856 7026 Fax +64-7-856 0151 NIWA Client Report No: HAM2014-067 Report date: June 2014 NIWA Project: BOP14203 Contents Executive summary .............................................................................................................. 7 1 Introduction ................................................................................................................. 7 1.1 Background .......................................................................................................... 9 1.2 Study lakes .......................................................................................................... 9 1.3 History of the Rotorua Lakes .............................................................................. 11 2 Study methods .......................................................................................................... 14 2.1 LakeSPI ............................................................................................................. 14 2.2 Field surveys .....................................................................................................
    [Show full text]
  • Lake Rotorua
    Lake Level and Volume Summary of the Rotorua Lakes Prepared by Glenn Ellery, Manager Environmental Data Services Environment Bay of Plenty Internal Report 2004/08 November 2004 5 Quay Street P O Box 364 Whakatane NEW ZEALAND Working with our communities for a better environment Environment Bay of Plenty Contents Chapter 1: Introduction.................................................................................................1 1.1 Overview............................................................................................................1 1.2 Lake Monitoring Sites......................................................................................2 1.3 Lake Volumes...................................................................................................2 1.4 Lake Volume and Rainfall...............................................................................3 Chapter 2: Lake Rotorua..............................................................................................5 2.1 Introduction.......................................................................................................5 2.2 Lake Control Structures ..................................................................................5 2.3 Lake Level Hydrograph...................................................................................6 2.4 Lake Level Distribution....................................................................................7 2.5 Lake Level/Lake Volume Relationship .........................................................8
    [Show full text]
  • The Condition of Twelve Lakes in the Rotorua Lakes Region Using Lakespi
    The condition of twelve lakes in the Rotorua Lakes Region using LakeSPI NIWA Client Report: HAM2005-122 October 2005 NIWA Project: BOP05232 The condition of twelve lakes in the Rotorua Lakes Region using LakeSPI John Clayton Tracey Edwards Mary de Winton Prepared for Environment Bay of Plenty NIWA Client Report: HAM2005-122 October 2005 NIWA Project: BOP05232 National Institute of Water & Atmospheric Research Ltd Gate 10, Silverdale Road, Hamilton P O Box 11115, Hamilton, New Zealand Phone +64-7-856 7026, Fax +64-7-856 0151 www.niwa.co.nz All rights reserved. This publication may not be reproduced or copied in any form without the permission of the client. Such permission is to be given only in accordance with the terms of the client's contract with NIWA. This copyright extends to all forms of copying and any storage of material in any kind of information retrieval system. Contents Executive Summary iv 1. Introduction 1 1.1 Study brief 1 1.2 History of the Rotorua Lakes 1 1.3 Lake Vegetation changes 1 1.4 Plants as indicators of lakes condition 3 2. Methods 5 3. Results 6 3.1 Lake Rotomahana 7 3.2 Lake Rotoma 8 3.3 Lake Tikitapu 10 3.4 Lake Okataina 12 3.5 Lake Rerewhakaaitu 13 3.6 Lake Rotokakahi 15 3.7 Lake Okareka 17 3.8 Lake Rotoehu 19 3.9 Lake Tarawera 20 3.10 Lake Rotorua 22 3.11 Lake Okaro 24 3.12 Lake Rotoiti 26 4. Discussion 28 5. Conclusions 31 6. Recommendations 34 7.
    [Show full text]
  • Lake Okataina Scenic Reserve Super Site Resource (Part 4): Cultural History
    5. LAKE OKATAINA SCENIC RESERVE CULTURAL/HISTORY The name Okataina means the lake of laughter, a shortened form of the original name Te Moana-i-Kataina-a-Te Rangitakaroro, which means The Ocean Where Te Rangitakaroro Laughed. The name and its meaning relate to an incident, approximately 300 years ago, where the famous Chief Te Rangitakaroro and his warriors were resting on what is now a submerged rock. It is said that one member of his group referred to the lake as an ocean and this was seen as a great joke by the rest of the group. Their laughter echoed around the lake and now remains enshrined in its name, which for ease of pronunciation was shortened to Okataina. In previous times this area was settled by different iwi (tribes) who either pre-dated or derived from Te Arawa waka. According to Ngati Tarawhai history, the first people to settle in the area was the iwi called Te Tini o Maruiwi (the myriads of Maruiwi). They were followed by Te Tini o Ruatomore (the myriads of Ruatomore) who were to later adopt the name Ngati Kahupungapunga. They were followed by Rakeiao, whose chiefs were Ngataketake and his son Kahuupoko. Later the iwi was to adopt the name Kahuupoko. Soon after came Ngati Hinehuia and their chiefs Ngatata and Te Niho who lived in two Pa, Te Tawa and Ouruaroa. Then came Ngati Tarawhai, the iwi who now regard themselves as having tangata whenua (authority) status to this area, their main Pa being Te Koutu. It was at the time of Te Rangitakaroro, a son of Tarawhai (the eponymous ancestor of Ngati Tarawhai), that the contemporary name of the area came about (initial paragraph).
    [Show full text]
  • 2009 Rotorua Lakespi Report
    The ecological condition of the Rotorua Lakes using LakeSPI - 2009 NIWA Client Report: HAM2009-162 September 2009 NIWA Project: BOP09201 The ecological condition of the Rotorua Lakes using LakeSPI-2009 Tracey Edwards John Clayton Prepared for Environment Bay of Plenty NIWA Client Report: HAM2009-162 September 2009 NIWA Project: BOP09201 National Institute of Water & Atmospheric Research Ltd Gate 10, Silverdale Road, Hamilton P O Box 11115, Hamilton, New Zealand Phone +64-7-856 7026, Fax +64-7-856 0151 www.niwa.co.nz All rights reserved. This publication may not be reproduced or copied in any form without the permission of the client. Such permission is to be given only in accordance with the terms of the client's contract with NIWA. This copyright extends to all forms of copying and any storage of material in any kind of information retrieval system. Contents Executive Summary iv 1. Introduction 1 1.1 Study brief 1 1.2 Study lakes 2 1.3 History of the Rotorua Lakes 3 1.3.1 Geophysical changes 3 1.3.2 Lake vegetation changes 4 2. Study methods 6 2.1 Plants as indicators of lake condition 6 2.2 LakeSPI 6 2.3 Baselines 7 2.4 Lake classification 8 2.5 Lake stability 9 3. Results 10 3.1 Lake Rotomahana 11 3.2 Lake Rotoma 12 3.3 Lake Okataina 14 3.4 Lake Rerewhakaaitu 16 3.5 Lake Okareka 18 3.6 Lake Tikitapu 20 3.7 Lake Rotokakahi 22 3.8 Lake Rotorua 24 3.9 Lake Tarawera 26 3.10 Lake Rotoiti 27 3.11 Lake Okaro 29 3.12 Lake Rotoehu 31 4.
    [Show full text]
  • Lake Okataina
    2. LAKE OKATAINA Lake Okataina is a beautiful clean lake surrounded by bush. Its full name is Te Moana-i-Kataina-e-Te Rangitakaroro - the sea where Rangitakaroro laughed. Rangitakaroro and his warriors were sitting by the lake when one of his men called it the sea. This was seen as a great joke and Greg Tuuta laughter echoed around the lake. In pre-European times, Lake Okataina was part of a route from Lake Tarawera to Lake Rotoiti. Canoes were used on the lakes then carried across the land between each lake. Okataina is an ‘oligotrophic’ lake - very clean and clear with little nutrient and little sediment in it. Surrounding bush intercepts and takes up runoff from various farming blocks in the catchment, reducing the movement of nutrients and silt into the lake. The bush also provides shade along the shoreline and tributaries which helps keep water temperatures down. The lakes maximum depth is 78.5 metres and it covers an area of 10.83km 2. 2.1 HOW TO GET THERE The lake is situated about 30 kilometres from Rotorua, off State Highway 30. The turn off is at Ruato Bay of Lake Rotoiti and there is 7 kilometres of winding road to reach the lake. The lake is about 2 kilometres beyond the Okataina Outdoor Education Centre. The bush is teeming with birds and there are many grades of walk available. At the end of the road, on the lake edge there is a grassed picnic area with some shade trees and a shelter. Public toilets can be found near the picnic area.
    [Show full text]