Table E Operation Restrictions Imposed by the Existing Resource Consents. Consent Number. Condition Number /1

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1 The mean inflow to Lake Matahina is 71 cubic metres per second (ʻcumecsʼ). While being a sizeable water body, its useable storage is confined to 6.6 million cubic metres. At average inflows, this provides only one days storage. Consequently, Lake Matahina only provides daily or, at best, weekly rather than seasonal storage. That is not to say, however, that the Lake cannot be used to offset flood flows. With judicious management it can be used to attenuate minor floods and provide some peak reduction for large floods. The combination of reasonably high inflows and the limited storage capacity of Lake Matahina means that it is typically operated on a ʻrun-of-riverʼ basis. This sees a reasonably high flow (referred to as a ʻbase flowʼ) maintained in the Rangitaiki River throughout the day, with output above the base flow being increased and decreased to reflect periods of peak demand and/or price signals from the wholesale electricity market. The process of increasing and decreasing output from the Scheme (and thus water flow within the River downstream) is referred to as ʻpeakingʼ. The rate that output is increased or decreased is termed the ʻramping rateʼ. In 2001 TrustPower applied to change its resource consent so that two operating peaks were allowed per day as opposed to one peak. This application was ultimately granted. Consequently two operating peaks are now a typical feature of the Scheme. Of some note is that of TrustPowerʼs 18 hydroelectric power schemes, only MAT is constrained to a number of daily peaks. The constraint is significant as it limits the manner in which the Schemeʼs output can be offered into the electricity market. Were the Scheme unconstrained (from an environmental perspective), the inflow, lake level, capacity of the powerhouse and transmission lines and market would be the determinants of its operation. As signalled above, however, the restrictions imposed by the existing regime of resource consents place significant additional impediments on MATʼs operations. Table E sets out the most notable of the restrictions that are imposed. Table E Operation Restrictions Imposed by the Existing Resource Consents Consent Number Condition Number Nature of Constraint Description of Constraint /1 3 Lake Matahina Operating Regime Extreme Min. Reservoir Level = 71.6m Min Operational Reservoir Level = 73.15m Max Operational Reservoir Level = 76.2m Max Flood (less than 200 cumecs) Reservoir Level = 76.4m Design Flood Level = 76.8m Spillway Gate Crest Level = 76.4m 3.8 Maximum Reservoir Level Rate of Change The reservoir level rate of change shall not exceed 0.25m/hr except when operating under emergency conditions when the spillway is operating. 14

2 5.1 Rangitaiki River Minimum Flow The minimum flow shall not be less than 40 cumecs (22MW) except when the inflow is less than this. 5.1 / 5.2 Number of ʻPeaksʼ No more than two operating peaks may occur each day. No peaks are permitted when inflows are less than 40 cumecs. 5.3 Upward ʻRamping Ratesʼ Flows discharged from the Scheme shall not increase by more than 70 cumecs (37MW) per hour except in system low frequency conditions. 5.4 Downward ʻRamping Ratesʼ 6.1 / 6.2 Minor Flood (being floods up to 500 cumecs) Operation Flows discharged from the Scheme shall not decrease by more than 30 cumecs (16MW) in the first hour, 22 cumecs (12MW) in the second hour and 14 cumecs (8MW) for every hour thereafter. The maximum discharge shall not exceed 600 cumecs unless the reservoir is rising rapidly whereby EBoP may permit a discharge of up to 755 cumecs. The reservoir drawdown rate shall not exceed 0.3m per hour, unless in emergency situations when EBoP may permit a drawdown rate of up to 0.4m per hour. The total discharge from the Scheme shall not exceed 550 cumecs when the lake is being drawn down. Flows discharged from the Scheme shall not increase by more than 70 cumecs when the Reservoir is being drawn down. The maximum rate of river level drawn down shall not exceed 1.2m per 8 hours (as measured in the tailrace). 6.2 Major Flood (being floods exceeding 500 cumecs) Operation As for the ʻMinor Floodsʼ with the following additional requirements. EBoP may request that the Reservoir be drawn down to 71.6m to provide flood storage. Given the above, Lake Matahina has an operating range of 3.05 metres during normal operations. This may be increased to 3.25 metres when flows are less than 200 cumces and to 5.2 metres when flows exceed 500 cumecs. TrustPower has sought consent to discharge up to 160 cumecs from the MAT Powerhouse. When the base flow (approximately 45 cumecs at 22MW output) is subtracted, this means that two daily flow variations of up to 115 cumecs are permitted, subject to the ramping constraints being achieved. 15

3 When inflows drop below the base flow of 45 cumecs, TrustPower ceases operational peaks and attempts to match the flows into Lake Matahina with the discharges from the powerhouse. The rough running regime hinders this when flows are between approximately 29 and 41 cumecs. In these situations TrustPower seeks to match the inflows and outflows over a 24-hour period. Typically this sees higher flows discharged during the day with lower flows being discharged at night. The wording of the existing consent conditions effectively result in all floods less than 200 cumecs being captured within Lake Matahina. The conditions regulating the operation of the Scheme during floods, particularly those that exceed 500 cumecs, are aimed at employing MAT to (i) provide some attenuation of the downstream environment, and (ii) preserve the integrity of the Rangitaiki-Tarawera flood protection schemes. In practice, TrustPower works alongside EBoP and in tandem with Bay of Plenty Energy (which owns and operates the upstream Aniwhenua Hydroelectric Power Scheme) when floods occur within the Rangitaiki River catchment. Scheme Maintenance Activities TrustPower conducts a number of routine and non-routine maintenance events each year in order to keep the Scheme safe and operational. The vast majority of the maintenance activities occur within the Powerhouse and thus are not matters of direct relevance to TrustPowerʼs resource consent applications. Others occur in association with assets that operate under separate suites of resource consents, such as those associated with the various structures and boat ramps that TrustPower maintain. While it is useful to acknowledge that maintenance occurs around such facilities, it is also of no direct relevance to the applications lodged by TrustPower in this instance. As is apparent from Table A, TrustPower is seeking consent for two types of maintenance events, being: a. The repair of the civil structures and monitoring equipment associated with the Scheme. Key activities here are (i) the maintenance of the concrete structures associated with the spillway and the repair and maintenance of the spillway gates, (ii) the repair of the intake screens, screen cleaners and cranes and their ongoing maintenance (including painting). These activities typically involve water or sand blasting, painting, the removal of gravel and submerged logs / debris and general maintenance of the rip rap around the tailrace. b. The control of weeds on the land based components of the Scheme using herbicide. Of note is that the herbicide will be applied using hand held applicators, with application occurring in accordance with the applicable instructions and ʻGrow Safeʼ guidelines. Also of note is that aspects of the maintenance activities occur annually, with a reasonable portion occurring bi-annually. There are aspects that occur every five (or more) years, specifically, the dredging of the invert of the tailrace, sandblasting and painting of the penstocks (internally) and structural repair work. 16

4 2.4 General location and context Sections 4.0 and 5.0 of the Assessment of Natural Character, Landscape and Visual Effects (Boffa Miskell Limited, May 2009) provide a useful description of the environs within which the Scheme sits. The Scheme sits astride the Rangitaiki River, approximately 10km southeast of Kawerau, in the Whakatane District. It is located within a gorge that separates the Raungaehe Range and Ikawhenua Range to the east and the Matahina Forest to the west. Lake Matahina extends for approximately 6km upstream of the Scheme. Galatea, Murupara and the Aniwhenua Hydroelectric Power Scheme exist beyond Lake Matahina. The Te Mahoe Village sits immediately downstream of the Scheme. Its principal features are a small community hall, a primary school and a small number of dwellings. Below the Scheme the Rangitaiki River follows a meandering course across the Rangitaiki Plains past Te Teko, Edgecumbe and Thornton to the coast, some 37km downstream. Figure G highlights the extent of the area of interest. Figure G: Approximate Area of Interest Approximate Area of Interest 17

5 2.5 Summary - Existing Environment Commentary from the Technical Investigations All of the Technical Assessments commissioned by TrustPower describe the existing environmental context. The remainder of Section 2.0 summarises the descriptions provided. 2.6 Archaeology & History Clough and Associates Limited (ʻCALʼ) completed an investigation on the archaeological, historical and cultural resources supported by the catchment of the Rangitaiki River. A full copy of CALʼs Assessment is attached as Appendix 1 of Volume 2. General Context Maori settlement within the Catchment is thought to have occurred on the flood plains associated with the River due, principally, to the fertile soils and proximity of both the coastline and river. When compared with the surrounding areas, however, the flood plains accommodate a limited number of recorded archaeological sites. This may be due to an ʻunder recordingʼ of sites and/or natural events (such as the Tarawera eruption in 1886 and/or severe flooding events). Eastern Bay of Plenty lands were confiscated from Tangata Whenua in The confiscation occurred under the New Zealand Settlements Act 1863 and was in response to resistance encountered by Government Troops entering the area to apprehend those involved in the murders of Reverend Carl Volker and James Fulloon. Eventually some of the confiscated land was returned. In 1890, 80,000 acres of the Rangitaiki Plains (which extends over approximately 100,000 acres in total) was swampland. Of note is that the Rangitaiki River had no direct outlet to the sea, rather it was a tributary of both the Whakatane and Tarawera rivers. In order to convert the wetland to productive farmland a program of land drainage was developed. Drainage activities began in 1911 with the construction of a canal to ʻstraightenʼ / direct the Rangitaiki River out to sea. The canal was completed in 1914 and was instrumental in fostering agricultural activities on the flood plains. Central Government authorised the construction of the Scheme in The first real construction began in 1962 and was completed in January Some archaeological sites were affected by the construction of the Dam, as was a traditional eeling site in the Catchment. Recorded Archaeological Sites Below the Matahina Dam Twenty-five recorded archaeological sites exist within close proximity to the Rangitaiki River below the Scheme. Of the sites, 17 are pa with the remaining sites consisting of a mill, two Maori terrace sites, an agricultural area and two possible areas of cultivated soils. CAL undertook a field survey in preparation of its Technical Assessment. The field survey focused on (i) assessing sites that were situated immediately adjacent to the River and which had the potential to be adversely affected by the Scheme, and (ii) identifying previously unrecorded sites. Ten previously recorded sites, and three unrecorded sites were visited during the survey. Figure H identifies which sites were visited. 18

6 Figure H Sites Visited During Field Survey Site no. Site type Description V16/31 Pa V15/1194 Agricultural area Western bank of river close to river. Dense vegetation. Headland pa. Recorded Western bank of river. Waimangeo Spring Flats. Complex of ditches and banks. Some say a European fortification. Jones and Spring Rice say it is an agricultural area. Recorded V15/1195 Maori pits/ Armed C camp associated with Fort Alfred Western bank of river. Spring Rice has undertaken test trenching. Recorded V15/416 Fort Alfred, Armed C post V15/139 Pa- Puketapu Western bank of river. Confluence of Waimangeo Creek and Rangitaiki River. Recorded Western bank of river, on prominent knoll. 2km south of Te Teko. Has been used as a cemetery. Named on 1921 plan. Recorded V15/158 Gunfighter Pa/SAPS 1965 Situated on western bank of river, south of Te Teko, near Tahuna Rd. Firing and sapping trenches dug by during Major W. Mair and his Arawa column still visible in Location of site shown on 1891 plan. Recorded V15/211 Terrace/kainga/pa - Kokohinau Situated on western bank of river, Te Teko. SRF states that ʻIt is now the site of an urupaʼ ML 9048 (1915) indicates ʻcultivationʼ on the riverʼs edge near where the marae standsʼ. It also shows the pa (faintly) and the church. Recorded V15/1190 Cultivated soil V15/1191 Cultivated soil V15/159 Pa - Harakeke Situated on western side of river. Recorded An 1891 plan (SO5444A) shows ʻflax, wiwi and raupoʼ throughout this area. Situated on western side of river. Recorded An 1891 plan (SO5444A) shows ʻflax, wiwi and raupoʼ throughout this area. Situated on east bank of river, opposite the Gunfighter Pa and saps (V15/158). Site recorded 1964 Location of site shown on 1891 plan. 19