Canterbury Strategic Water Study (CSWS) Stage 3

Final Report Canterbury Strategic Water Study (CSWS) Stage 3 Multi-stakeholder evaluation of water storage options PREPARED BY: Ian Whitehouse (facilitator) Andy Pearce (Chair) Grant McFadden (facilitator) On behalf of the Canterbury Mayoral Forum

SUMMARY Introduction Stage 3 of the Canterbury Strategic Water Study (CSWS) was a preliminary stakeholder assessment of a range of water storage options for Canterbury (options identified previously in Stage 2 of the CSWS). CSWS Stage 3 is part of a broader consideration of water availability and management. The report and public response to it will contribute to the comprehensive public engagement programme on Canterbury water management planned for 2008/09. The key findings of CSWS Stage 3 are that - before strategic water storage and water management decisions can be made - rigorous scientific and public consideration is required of: the impacts of land use intensification and its effects on water quality mitigation and management systems for water quality, and methods for maintaining or improving flow variability and low flows in major rivers. This summary has been prepared by the authors of the Stage 3 Report of CSWS (Ian Whitehouse [facilitator], Andy Pearce [Chair] and Grant McFadden [facilitator]) to accompany the release of the report by the Canterbury Mayoral Forum, March 2008. Background - Canterbury Strategic Water Study (CSWS) The Canterbury Strategic Water Study (CSWS) was initiated by Ministry of Agriculture and Forestry (MAF), Ministry for the Environment (MfE) and Environment Canterbury (ECan) following the severe drought of 1998. The drought raised concerns about whether Canterbury would run out of water in the future. CSWS Stage 1, published in 2002, was a sub-regional water balance evaluation of current and likely future water supply and demand (undertaken by Lincoln Environmental). Stage 1 concluded that, on an annual basis, there is enough water in Canterbury to meet likely future demand - but some catchments are water short and peak demands could not be met on a weekly basis. It also concluded that water storage should be considered as part of meeting future demands for water - primarily for irrigation - to supplement supply in times of low natural flows. CSWS Stage 2, under the auspices of the Canterbury Mayoral Forum, began in 2004, and identifies potential water storages in Canterbury and their hydrological feasibility, including the area they could irrigate and their impacts on river flows. The Aqualinc report on Stage 2 will be published in 2008. CSWS Stage 3, also undertaken for the Canterbury Mayoral Forum, began in early 2006. It involved an initial evaluation by multi-stakeholder groups of the environmental, social, cultural and economic impacts of the water storage options identified in CSWS Stage 2. The findings of CSWS Stage 3 are summarised below. CSWS Stage 3 identified two over-arching critical issues - land use intensification and its effects on water quality; and maintaining or improving, flow variability in major rivers - that need to be rigorously explored (including improved mitigation and management systems) and subjected to comprehensive public debate before Canterbury is in a position to make sustainable, long-term decisions about water storage or water management more broadly. [This public discussion will be the focus of CSWS Stage 4 a comprehensive public consultation programme to be undertaken in 2008]. Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 2

CSWS Stage 3 Objective The objective of Stage 3 was to undertake a preliminary evaluation of the water storage options identified in CSWS Stage 2 against a range of environmental, community, cultural, social and economic concerns, and to assess the likely public acceptability of each option. CSWS Stage 3 Process Multi-stakeholder groups were used to first, develop a framework to evaluate water storage options for Canterbury, and secondly to use this framework to evaluate water storage options from CSWS Stage 2 (and additional options identified by the group). The multi-stakeholder evaluation groups included people with a wide range of interests in water in Canterbury irrigation, angling, farming, environmental concerns, community development, Ngai Tahu, recreation, and conservation. Participants were present in their personal capacity as knowledgeable individuals or experts not as representatives of any organisation. Irrigators and farmers made up more than half of each group. Environmentalists and conservationists made up about a fifth of each group. The CSWS Stage 3 Report reflects the full range of views of participants, not just those of the majority. CSWS Stage 3 included five workshops developing the evaluation framework, two full days of information presentations and 14 one-day evaluation workshops. The options were evaluated on a six-point scale against 22 topics covering social, economic, cultural and environmental impacts. The evaluation identified the key concerns likely to influence public acceptability of each of the water storage options. The evaluation findings were discussed, in a very limited manner, with some interest groups including local government, Fish and Game and Aoraki Conservation Board, and at a public meeting in Timaru. Extensive public consultation is planned following the release of the CSWS Stage 3 Report as part of developing a Canterbury Water Management Strategy. CWSW Stage 3 Options Evaluated The multi-stakeholder groups evaluated water storage options based on 12 major reservoirs from Hurunui to Pareora Rivers. The group s evaluations indicated that some options, including Lake Sumner, Lake Coleridge, Lake Opuha, and reservoirs in a mid Hurunui River tributary, Lees Valley, Stour River and Pareora River, were more likely to meet a range of expectations and requirements than other options considered. For the sub-region from Ashley River to Rangitata River, the group considered that an integrated system, combining several individual options, was desirable and should be investigated further. Evaluation of water storage options for the Hurunui area was completed at the end of 2006, for South Canterbury in early 2007, and for mid-central Canterbury in September 2007. The options evaluated are merely potential storage sites and related infrastructure. Significant studies and extensive public and stakeholder engagement are required to fully develop any proposal based on any of the options evaluated. The CSWS Stage 3 evaluation process identifies a range of environmental, social, economic and cultural concerns and issues that need to be addressed for each of the options. Further studies and engagement may identify other issues, all of which would have to be considered and managed for any of the options to be taken further. CSWS Stage 3 only considered options based on major reservoirs (more than 50,000,000m 3 ). Limited consideration was given to on-farm storage. The option of no more major storage was also evaluated. Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 3

CSWS Stage 3 Key Findings and Conclusions 1. Impacts of both land use intensification and larger areas of intensively-used land must be rigorously addressed with good science and understanding of mitigation and management options before any major water storage option proposal can be progressed. In the evaluations of all the water storage options (and discussion with interest groups) the risk to water quality from land intensification (particularly dairying) from increased irrigation was a major concern. 2. Current approaches to river management do not adequately protect flow variability and the water storage options proposed would lead to substantially reduced flow variability in some rivers at, or near, minimum low-flow for much of January through March. All water storage options will affect river flows through takes to storage (mainly outside the irrigation season), and by both releases from storage and run-of-river takes to meet irrigation demand during the irrigation season. 3. The CSWS Stage 3 evaluation indicates a desire for an integrated and reasonably equitable solution to Canterbury s future water that addresses water demand in mid-central Canterbury regions including south of Rangitata River, minimises the major storages required, puts water back into lowland streams, protects flow variability and low-flows in major alpine rivers, and fully and properly accounts for environmental and social impacts. 4. The South Canterbury evaluation confirmed how water short the area is unless it can access water from alpine rivers (Waitaki and Rangitata Rivers). The current Opuha scheme is unlikely to meet demand from its existing irrigators in all years. In very dry years, like 1988, the lake may not refill in autumn/winter leading to irrigation restrictions of three months or more. The evaluation has identified the key features of the major water-storage options in Canterbury and a range of environmental, social, economic, cultural, infrastructure and equity issues, tradeoffs and concerns that would have to be considered and managed for any of the options to be taken further. All options have positives and negatives. For some participants all options were acceptable, for others all options were unacceptable. CSWS Stage 3 Key Contributions Provides a preliminary assessment of the likely and important considerations that will determine the acceptability of major water-storage options in Canterbury. Highlights the need to address the impacts of both land use intensification and larger areas of intensively-used land, and concerns about flow variability and low flows in major rivers. Confirms how water-short South Canterbury is. Contributes to this year s public consultation programme on water management in Canterbury. Next Steps CSWS Stage 4 Water storage is only one of the things that need to be considered in a water strategy for Canterbury. Other issues that need to be considered include land use intensification, water quality, cultural values, tangata whenua objectives, and recreation uses. Extensive public engagement is planned on all water-related issues as part of developing a Canterbury Water Management Strategy (CSWS Stage 4). The CSWS Stage 3 Report and public response to it will contribute to this public engagement programme. Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 4

1 Introduction Canterbury Strategic Water Study (CSWS) The CSWS was initiated by Ministry of Agriculture and Forestry (MAF), Ministry for the Environment (MfE) and Environment Canterbury (ECan) following the severe drought of 1998 that raised concerns about whether Canterbury would run out of water in the future. The first stage of the study, published in 2002, was a sub-regional water balance evaluation by Lincoln Environmental of current and likely future water supply and demand. This indicated that regionally, on an annual basis, there was adequate water to meet all future requirements but that this did not apply to all catchments individually, and peak demands could not be met on a weekly basis. That is, there is plenty of water in total but it s not always in the right place at the right time. The study suggested this mismatch of supply and demand could be addressed by the seasonal storage of water, by intercatchment transfers and through new ways to manage underground and surface water systems together. Storage is required to supplement supply in times of natural low flows to meet future irrigation demand. A second stage of CSWS, under the auspices of the Canterbury Mayoral Forum, began in 2004 and identifies potential water storages in Canterbury and their hydrological feasibility, including the area they could irrigate and their impacts on river flows. The Aqualinc report on CSWS Stage 2 will be released in 2008. The third stage of the study, also under the auspices of Canterbury Mayoral Forum, began in early 2006. CSWS Stage 3, reported here, evaluates the environmental, social, cultural and economic impacts of the water storage options. Evaluation of water storage options for Hurunui area was completed at the end of 2006, for South Canterbury in early 2007 and for mid-central Canterbury in September 2007. The CSWS approach, endorsed by the Canterbury Mayoral Forum from the start of the project, seeks to address all of the interests and values associated with water across the region. The first two stages of the project focused on water supply and demand, the third stage attempts to incorporate many of the wide range of interests and values associated with water. The fourth stage will extend the involvement of interests in water in Canterbury. The evaluation process reported here starts with the premise, from the CSWS Stage 1 water balance study, that major storage reservoirs should be considered as part of future water supply in Canterbury. In the mid-central Canterbury evaluation the group did discuss the likely impacts if there was no new major water storage in the area. The options evaluated are not development proposals they merely identify potential storage sites and related infrastructure. The CSWS Stage 3 evaluation of storage options is only a preliminary evaluation. Significant studies and extensive consultation are required to fully develop the proposals. The CSWS Stage 3 evaluation process identifies a range of environmental, social, economic and cultural concerns and issues that need to be addressed for each of the options. Further studies and consultation may identify other issues, all of which would have to be considered and managed for any of the options to be taken further. Neither CSWS 3 nor the evaluation groups are advocates for any particular storage option. CSWS 3 and the evaluation groups do support further work to develop an integrated Canterbury-wide approach to address future water supply and demand and to address water quality concerns from land intensification. The CSWS is a research and evaluation programme. CSWS does not have a statutory basis and is not part of a RMA process. It will not produce a water allocation plan. The technical parts of CSWS deal only with water quantity. Water quality, in-stream impacts and other aspects are included in the CSWS Stage 3 evaluation of storage options but no technical appraisal of these has been carried out for the study beyond a brief evaluation of Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 5

in-stream impacts by Dr John Hayes, Cawthron Institute. A strategic evaluation of water quality and land use is likely to be part of CSWS Stage 4. Water in Canterbury The alpine rivers provide nearly 90% of Canterbury s surface water with Waitaki and Rakaia Rivers providing nearly half. These rivers are also major contributors to groundwater. River recharge is estimated to provide nearly 60% of total recharge to the groundwater system between Rakaia and Waimakariri Rivers, the remainder coming from land-surface (rainfall) recharge. Canterbury uses about 60% of all water allocated nationally for consumptive use. About 80% of Canterbury s water use is for irrigation. There is about 1,000,000ha of irrigable land in Canterbury with resource consents for irrigation on about 650,000ha. There is increasing demand for water for irrigation from groundwater and run-of-river takes. Allocation has reached a stage where Environment Canterbury considers some groundwater zones to be over allocated and where new run-of-river takes are less able to provide reliable supply for irrigation. Notwithstanding this there are filed applications seeking allocations for more water from most rivers and groundwater zones. Canterbury water is in a gold rush period where irrigators are trying to secure a right to an increasingly scarce resource. Water, through irrigation, is critical to Canterbury s land-based economy. Irrigation provides opportunities for high-value crops that require reliable water supply and allows farmers to meet market expectations to deliver products in tightly-specified time periods and to increasingly exact specifications. The primary sector contributes over 60% of New Zealand s exports. In Canterbury the proportion is likely to be higher. Exports provide the foreign exchange needed to buy imported fuel, equipment and a wide range of consumer products that underpin New Zealanders standard of living and lifestyle. About 70% of all irrigated land in New Zealand is in Canterbury. Public perception is that all of the irrigated land is in dairying production or being converted to dairying. In fact, the main irrigated land uses are arable 27%, dairy pasture 34% and other pasture 36%, with the remaining 3% in horticulture and viticulture. The resource consent process makes case-by-case decisions and seems ill suited when resources are scarce, not plentiful. All of the multi-stakeholder group that were involved in developing the framework for this CSWS 3 evaluation agreed that the current salamisliced decisions could well produce a sub-optimal outcome. Certainly the consent process limits a strategic approach. The CSWS seeks to facilitate a strategic approach to meet future water demands for sustaining Canterbury s land-base prosperity without compromising environmental values or resource limits. CSWS 3 Coverage Over 20 options based on 12 storage reservoirs were evaluated. The storages evaluated range from Hurunui River in the north to Opihi River in the south. No options were evaluated north of Hurunui River as the CSWS Stage 1 study had shown that potential demand in the Waiau area could be met from Waiau River without storage. South of Opihi River, the proposed Hunter Downs scheme (using water from Waitaki River) was not evaluated as the proposal was in the resource consenting process. The evaluation only looked at major storage options of at least 50,000,000m 3. On-farm storage was not evaluated. On-farm storages of up to a million cubic metres are being established in mid Canterbury to increase reliability of supply where water is supplied intermittently (such as from Rangitata Diversion Race). By themselves, on-farm storages are unlikely to meet future water demand but may be a useful complement to major storage dams. One of the mid-central Canterbury group, who has created on-farm storage, indicated that the capital cost, per unit of water, is about eight-times more for on-farm storage than for a major storage dam. Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 6

The evaluation primarily looked at storage options identified by Aqualinc, though participants did suggest some additional options and variations to those proposed by Aqualinc. The options brought to CSWS 3 were those Aqualinc considered to be the most promising of the options identified in previous studies. Aqualinc filtered out many of the storage sites previously identified for example in mid-central Canterbury Aqualinc identified 49 storage sites from previous studies (see map below) but only modelled and presented options to CSWS 3 based on three reservoir sites. Major water storage options identified by Aqualinc for mid-central Canterbury from previous studies. Only the four most promising of these (Lees Valley dam, Waianiwaniwa dam and Stour River dam) were modelled by Aqualinc and presented to CSWS 3. A Lake Coleridge option was presented to CSWS 3 by Trustpower. Options integrate run-of-river abstraction and storage All the options evaluated combine major storage with run-of-river abstraction to supply water for irrigation at a very high level of reliability. Run-of-river water is used to meet irrigation demand whenever possible (i.e. when the river is above regulated minimum low flow). Releases from storage are used to meet run-of-river shortfall (particularly in the latter half of the irrigation season and in dry seasons). Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 7

2 Evaluation Process Evaluation Framework The evaluation used a 26-topic framework covering a wide range of environmental, economic, social and cultural aspects. A copy of this framework is provided in Appendix 1. The framework was developed by a multi-stakeholder group (see Appendix 2 for a list of those involved). Many of those involved in the development of the evaluation framework were also part of the subsequent multi-stakeholder groups that carried out the evaluation of all or some of the storage options. The multi-stakeholder group involved in the development of the framework identified that it needed to be better informed about current knowledge on key issues relating to water and irrigation in Canterbury. Two day-long workshops were held in August and September 2006 with presentations from experts covering social and economic impacts of irrigation, water quality and irrigation, land-use intensification (including impacts of dairying), impacts on river birds, in-stream (fish) impacts, climate change impacts, Ngai Tahu and water, and electricity and irrigation. Multi-Stakeholder Groups The evaluation of water storage options for Canterbury was done by multi-stakeholder groups of about 15 30 people in three pieces options for Hurunui River in four one-day workshops in September to December 2006, for South Canterbury in four workshops in February to April 2007, and for mid-central Canterbury in five workshops from May to July 2007. In early September 2007 a one-day workshop of participants from all three groups and from the CSWS Mayoral Forum Steering Group explored an integrated option for midcentral Canterbury. The multi-stakeholder groups included people with a wide range of interests in water in Canterbury irrigation, angling, farming, environmental concerns, community development, Ngai Tahu, recreation, and conservation. Irrigators and farmers made up more than half of each group. Most of the participants were male. Environmentalists and conservationists made up about a fifth of each group. A core of 8 people was involved in all three groups with an additional four people involved in the evaluations for two areas. Lists of participants are provided at the end of the evaluation for each of the three areas. The multi-stakeholder groups provided a very robust evaluation of the water storage options, identifying the key features of each option and the beneficial and adverse impacts. There was generally a range of views with differences understood and respected by others in the group. The summaries presented here of the evaluations reflect the full range of views of participants, not just those of the majority. Hydrological Modelling For all options, daily irrigation demand and river flows were modelled by Aqualinc using 30 years of river and climate records (generally 1973 to 2003). Irrigated area for Hurunui District and mid Canterbury storage options was assessed using a very high reliability of water supply in the 30 years modelled there could not be more than 10 continuous days without water or a restriction on water supply. The modelling for South Canterbury used a lower reliability criteria that of the current Opuha Scheme. The modelling assumed that all new schemes would use highly-efficient spray irrigation. A description of the modelling approach and detailed results are provided in the CSWS Stage 2 report. Evaluation Process No site investigations or environmental impact assessments have been made of any of the potential water storage sites. Many of the sites have been identified in previous studies and limited technical information and cost estimates are available from these. Most of the Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 8

people in the evaluation groups did not have first-hand knowledge of the proposed storage sites though there were individuals who had good knowledge of the sites. The first workshop for each of the three areas included briefing on CSWS and progress to date, an overview from John Bright and/or Andrew Dark (Aqualinc) of the storage options for the area identified as part of their CSWS Stage 2 investigation, and an evaluation by John Hayes (river ecologist, Cawthron Institute) on in-stream impacts of the proposed options. Participants identified additional options or variations on options proposed and these were modelled by Aqualinc and presented and evaluated at subsequent workshops. The evaluation of each individual option started from a technical (primarily hydrological) description by Aqualinc of the water storage and river flow changes to identify, in nontechnical terms, the key elements and concerns of the proposed options. After initial questions of clarification from participants the evaluation of the option using the framework was done by smaller groups of five to eight who reported back to all participants. Key features, positives and concerns were discussed and recorded by the facilitator. The last workshop for each of the three areas included participants reviewing how they felt about each option, the reasons for this and the relative merits of the option. This evaluation summary draws on material from the small group evaluations of each option, notes taken of group feedback and discussion on options, records of how each participant felt about each option (and the reasons for this), and group discussion of the merits and concerns about all of the options for an area. Copies of the small group evaluations using the 26-topic framework and other material are lodged at ECan with the Project Manager (Ken Taylor). A list of this material is provided in Appendix 3. Drafts of the summaries of the evaluations for each of the three areas were provided to participants for comment and suggestions. The final summaries incorporate changes in response to these. A draft of this report was sent to all participants for comment and suggestion. Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 9

3 Mid-central Canterbury storage options Summary of options evaluated Irrigated area (ha) 1 Location of irrigated area 1 Lees Valley storage 141,100 2 North of Waimakariri & between Waimakariri and Rakaia Rivers 2 Waianiwaniwa storage 63,300 2 & between North of Waimakariri Waimakariri and 3 Lake Coleridge (with northern & southern storages) Not modelled 6 Rakaia Rivers North and south of Rakaia River? 4 Stour Storage 126,600 8 Rangitata Rivers & Between Rakaia and south of Rangitata R. Active storage Maximum new run-of-river take for irrigation (m 3 /s) (Mm 3 ) Waimakariri Rakaia Rangitata 656 66 3 20 4-194 35 5 20 4 - not modelled 57 7-200 - 37 9 30 1 net irrigated area, including existing irrigated areas 2 total net irrigable area north of Waimakariri River (including Loburn-Ashley) and between Waimakariri and Rakaia Rivers is 141,100ha. 3 does not include 15m 3 /s maximum take from Esk River to Lees Valley Lake. Only very rarely would substantial take to storage occur at the same time as substantial run-of-river take for irrigation. 4 if 50/50 flow sharing with Ashburton District (as per CPW/ACWT agreement) the maximum new run-of-river take from Rakaia River would be 40m 3 /s. 5 does not include 10m 3 /s maximum take to Waianiwaniwa storage. Only very rarely would substantial take to storage occur at the same time as substantial run-of-river take for irrigation. 6 irrigated area depends on what storages used and size of the run-of-river take from Waimakariri River. Likely to be able to irrigate at least 180,000ha 7 assumed that all new water is used in this option (i.e. CPW, ACWT and Barrhill-Chertsey allocations). 8 if Rangitata River take is capped at 27m 3 /s to allow 3m 3 /s of water to go south, irrigated area is 115,050ha. Total irrigable area between Rakaia and Rangitata Rivers is about 155,000ha excluding that irrigable cost-effectively from groundwater. 9 assumed that ACWT and Barrhill-Chertsey allocations are used in this option. Areas irrigated Net irrigated area (ha) North of Waimakariri Waimakariri-Rakaia Rakaia-Rangitata Total existing new existing new existing new 1 Lees Valley storage 141,100 18,000 39,100 84,000 1 - - 2 Waianiwaniwa storage 63,300-63,000 1 - - 3 Lake Coleridge (with northern & southern storages) Not - - modelled 2 4 Stour Storage 126,600 3 - - - 63,800 62,800 4 1 Split between new and existing not known most existing users are groundwater irrigators 2 irrigated area depends on what storages used and size of the run-of-river take from Waimakariri River. Likely to be able to irrigate at least 180,000ha 3 if Rangitata River take is capped at 27m 3 /s to allow 3m 3 /s of water to go south, irrigated area is 115,050ha. Total irrigable area between Rakaia and Rangitata Rivers is about 155,000ha excluding that irrigable cost-effectively from groundwater. 4 includes Barhill Chertsey area (35,600ha). Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 10

Overview map (adapted from Aqualinc) showing four options evaluated in mid-central Canterbury Ashley Gorge Lake Coleridge Head race schematic only Waianiwaniwa Valley Stour River Description and evaluation of storage options for mid-central Canterbury Lees Valley storage This is a very large storage that, with run-of-river takes, would reliably supply water to irrigate all of the irrigable area (141,100ha) north of Rakaia River including the north bank of Waimakariri River and Ashley-Loburn areas. Water would be taken from Esk River, a tributary of Waimakariri River, through a 14km tunnel to Lees Valley to provide 656,000,000m 3 active storage behind a high dam at the top end of Ashley Gorge. The floor of Lees Valley would be inundated. The height of the dam depends on decisions on operating range a 180m high dam is required if the operating range is kept small (7m), a 105m high dam would have an operating range of about 22m, or if a large operating range (72m) was acceptable the dam would be only 90m high. A small operating range provides more recreation opportunities and limits the area of seasonally-exposed lake bed. All of these options are significant dams Benmore, New Zealand s largest dam, is 110m high. The inflow from Esk River is small and initial filling of a storage lake (with a small operating range) would take about ten years. Once filled, the Esk River inflows are able to replenish active storage between irrigation seasons except in very dry years. The Group was concerned about the time required to fill the lake and options were scoped of taking water from Poulter River or pumping from the Waimakariri River at its junction with the Esk to speed initial filling. The relatively small reduction in filling time of only about 2 years was not considered sufficient, however, to offset the consenting challenges of taking water from Poulter River adjacent to or in Arthurs Pass National Park or the cost of pumping from Waimakariri River. Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 11

Water from the storage lake would be released through Ashley Gorge to a headrace at the downstream end of the Ashley Gorge. This headrace links to the Waimakariri River abstraction structure and to an infrastructure of canals (or tunnels) south between Waimakariri and Rakaia Rivers. Irrigation demand would be met, in the first instance, from run-of-river takes from Waimakariri River as available within the rules of the current Waimakariri River Regional Plan. When Waimakariri River takes can not meet irrigation demand water would be taken from Rakaia River (for irrigating Selwyn area) and/or from storage. The run-of-river take would reduce flow, in the section of Waimakariri River below the Gorge Bridge to the mouth, to the minimum low flow (50m 3 /s at Gorge Bridge) for much of the summer January through end of March. There would be significant impact on flows in Ashley River. In Ashley Gorge, winter flows are reduced as water is harvested to storage, while in the irrigation season flows are substantially increased as flows of up to about 80m 3 /s are released to meet irrigation demand. In the Ashley River below the irrigation headrace flow magnitude and variability would be reduced though there is opportunity to manage releases from the storage to provide flushing flows, flow variability and increase currently-low minimum flows in the lower Ashley River. Evaluation of Lees Valley option The Group was attracted to this option as a single solution to meet all future irrigation demand north of Rakaia River. With the Lees Valley storage, the Waianiwaniwa Valley storage (see below) would not be required. The scale of the project was seen a positive on the one hand but also as presenting challenges. One person summed up this feeling with the comment too large, too hard. Funding of a $1 billion project was seen as beyond the resources of a community-based scheme and would require Government and/or external investment. The option was seen as a regional option requiring very wide support. This was seen as a challenge, though not necessarily an insurmountable one. The time to initially fill the storage was seen as a negative, adding to the investment challenge, though it was felt there may be possibilities of staging irrigation development and/or using water from the lake during the filling period. Concern about the time to fill led some to question whether there was a risk of the storage failing to refill after very dry seasons, although this had not occurred in the 30 years modelled as part of the Aqualinc investigation. Storage performance may need further investigation. As noted above, shortening the fill time by taking water from Poulter River or pumping from the Waimakariri River at its junction with the Esk, was not favoured by the Group. For some of the Group, the impact of the diversion of water from the Esk, to fill the Lees Valley storage, was not considered to be an issue for river flows through Waimakariri Gorge. Others had concerns about abstraction anywhere above the Gorge. Some commented that it was important that the Waimakariri River above the Gorge Bridge not be messed up. The Waimakariri River Regional Plan, Rule 7.5, prohibits the erection of a weir on the Waimakariri River or any of its tributaries above Woodstock i.e. the structure required to divert water from the Esk River is prohibited in the Plan. The significant scale was a concern to some of the Group because of the increased risk of nitrate leaching and other water quality issues from the large increase in intensive land use (including dairying). It was acknowledged by many of the Group that these risks may be mitigated or avoided through adoption of best land management practices though some believe this would not be sufficient to solve the problems of nitrate leaching and other water quality impacts. The Group believed the proposed new irrigation would positively impact on flows in lowland streams and on the water available for groundwater irrigators on the lower plains. Annual rainfall recharge to the groundwater system is almost doubled on irrigated land compared to non-irrigated land. Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 12

The dam will be a very significant structure. There was discussion of the relative merit of a very high dam with a small operating range versus a high dam with a large operating range. The very high dam, with its smaller operating range, was seen as offering recreational opportunities close to Christchurch. It was also seen as providing more hydro-generation. On the other hand, it would be more expensive and take longer to fill. The major canal (or tunnel) infrastructure required to distribute irrigation water, particularly across the top of the Plains, will impact many landowners. It was felt that compulsory land acquisition would not be popular given the experience with the proposed Central Plains scheme. Any option, however, for new irrigation south from Waimakariri River will require a major headrace across the top of the Plains between Waimakariri and Rakaia Rivers. The Group had concerns about the impacts on the Ashley River. High flows in the Ashley Gorge would enhance opportunities for expert kayaking but would likely displace trout, juvenile salmon and native fish, be dangerous for anglers, hunters and swimmers, and change the river character at the popular picnic area and campground at the downstream end of Ashley Gorge. Flows in the lower Ashley River would also be significantly changed, affecting wildlife, fisheries and recreation, though some adverse impacts may be mitigated by release of flushing flows and by increasing low flows with releases from storage. Some of the group expressed considerable concern in regard to the impact of reduced flows and loss of flow variability ( flat-lining for much of the summer) in the lower Waimakariri River on ecological, mahinga kai and recreation values. Concern was expressed on the likely reduction in the number of days suitable for salmon angling, reduced flows for jet boating and possible changes to river mouth. Salmon anglers prefer to fish the river as flows fall after flood freshes. In this option (and the Waianiwaniwa Valley storage described below) run-of-river takes would cause after-flood flows to fall quicker, reducing the number of days of best fishing conditions. There was also concern about possible reduction of supply from the Waimakariri River to the Christchurch City aquifer system from reduced flows in the river. One of the group had concerns about the possible impacts on gravel transport in Waimakariri River and on coastal dynamics. Some in the Group commented that the Waimakariri River Management Regime needed to be revised to improve flow variability and increase the protection of low flows. Waianiwaniwa Valley storage This option is similar to the proposed Central Plains scheme (CPW) except water supply is not restricted to Selwyn area and could also be used north of Waimakariri River. Water from Waimakariri River is diverted through a canal or tunnel to a 194,000,000m 3 storage in Waianiwaniwa valley, above Glentunnel, at the top of the Plains between Waimakariri and Rakaia Rivers. The lake is dammed by a 50m high, 2km long dam and inundates about 12km 2 of farmland. Irrigation demand would be met, in the first instance, from run-of-river takes from Waimakariri River as available within the rules of the current Waimakariri River Regional Plan. When this can not meet irrigation demand water would be taken from Rakaia River (for irrigating Selwyn area) and/or from storage. The run-of-river take would reduce flow in the Waimakariri River below the Gorge Bridge to the mouth to the minimum low flow (50m 3 /s at Gorge Bridge) for much of the summer January through end of March, though not quite as often as with the Lees Valley option (above). Evaluation of Waianiwaniwa Valley option The Central Plains irrigation scheme has been extensively discussed in the media and views strongly expressed in letters to newspapers. Views are somewhat polarised on the attractiveness, or otherwise, of the option. Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 13

Concerns expressed about the CPW option were echoed in the Group s discussion of the Waianiwaniwa Valley option. Some of these concerns are the same as those for the Lees Valley option (above) the increased risk of adverse water quality impacts from the increased area of intensive land use, and the impacts of the reduced flows in the lower Waimakariri River. In addition, concerns were raised on the impacts of damming Waianiwaniwa Valley including those on the significant population of Canterbury mudfish, a nationally endangered species. The Group thought the recreation gains from the storage lake would be small. The Group recognised that this option, like the other options evaluated, would increase land use options and lead to an increase in the area under higher-value crops (e.g. seed crops and vegetables) and other high-value land use (e.g. dairying). This would provide significant economic benefit at the farm, district and regional scale and, in turn, retain and probably enhance health, education and other social infrastructure though not necessarily in the irrigated area. There was comment, however, that this option (unlike Lees Valley storage) would not fully meet the irrigation demand north of Rakaia River. It was felt that this option was more immediately do-able than the Lees Valley option (because of scale) and should not be dismissed just because it would not be required if Lees Valley option was built. The conservation and landscape issues for the Waianiwaniwa options were thought to be less than those for the Stour River option (see below). Lake Coleridge option Trustpower provided limited information on an option they are currently scoping that would supply water from Lake Coleridge to a major storage to the north (e.g. Waianiwaniwa Valley storage) and south to RDR and Barrhill-Chertsey distribution systems. Information from Trustpower was provided on a confidential and privileged basis. Trustpower will release information on this option once scoping studies are completed. Trustpower consider that operating requirements and lake-level constraints mean that while Lake Coleridge can be used to improve short-term reliability of water supply for irrigation it can not provide the storage required to improve reliability in dry years. Additional major storage is required to provide a high level of reliability of water supply in all years. The option described by Trustpower increases hydro-generation capacity and the area able to be reliably irrigated in mid-central Canterbury. The option does not require changes to the current conditions for Trustpower s abstractions from Wilberforce and Harper Rivers, nor to rules restricting fluctuations in Lake Coleridge. In the irrigation season, flows in the Rakaia River through the Gorge would be reduced. Flows below the Gorge would comply with the Rakaia Water Conservation Order. Evaluation of Lake Coleridge option The Group had less information on this option than for other options, in particular no information on irrigable area and no detailed modelling of the impact on river flows. Acknowledging information limitations, many in the Group thought this option had merit, combining additional hydro-generation with improved reliability of water supply (and probably an increase in irrigated area) while retaining flows in Rakaia River below the Gorge. The reduction in summer flows through Rakaia Gorge appear to be relatively small but were a concern to the Group and it was acknowledged that Trustpower had focused scoping investigations on possible impacts in this reach. Some in the Group noted that the reduction in flow in the Gorge would mean less water for fishing and that this might possibly change the fishing experience to that associated with a smaller river. It was noted that the flow reduction would be unlikely to adversely impact jet boating in the Gorge. Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 14

The use of a siphon to take water south across Rakaia River was seen as attractive by the Group enabling a connection to the RDR without requiring pumping. This was seen as a significant positive for the Barhill Chertsey irrigation scheme. It was noted that reliability of supply would also be increased for the Barhill Chertsey scheme. New takes of water above Rakaia Gorge are not permitted under the Rakaia Water Conservation Order (WCO). The Group discussed the proposed diversion of water from Lake Coleridge in relation to the WCO. The Group felt there would be considerable opposition to Trustpower s proposed option because it does not comply with the WCO. Some commented that while the impacts to the WCO rules would appear to be minimal, the potential to set a precedent by reviewing (and changing) a WCO would be a very major hurdle for this option. It was noted that water from Coleridge could provide opportunities to improve flows in the lower Ashburton River (and possibly Selwyn River) and that this may be welcomed by some parties who do not appear to consider the possibility of reviewing the WCO. The Group believes it is important that the option must not compromise the values of the Rakaia WCO. The Group considered that any review of Rakaia WCO must not be an excuse for an all-out assault on the WCO. For some in the Group, a WCO had the same standing and importance as a National Park. Fish and Game is opposed to any changes to the WCO. One of the Group, who is employed by Fish and Game, took no further part in the evaluation when it became apparent that the Group was discussing a water storage option that requires a challenge to the Rakaia WCO. He stated he did not believe that a public process should be used to undermine a river plan which has been determined via a thorough legal process in the light of robust scientific evidence. The Group recognised the importance of the Rakaia River in providing water to midcentral Canterbury it is a big, alpine-fed river able to provide water north and south to irrigate a large area. The Trustpower option was seen as increasing irrigation from the Rakaia River while at the same time increasing electricity generation. That Lake Coleridge was already a managed natural storage was seen as a positive (in comparison to creating a new reservoir) as was the ability to supply water north (to Selwyn District) and south (to Ashburton District). It was recognised, however, that Lake Coleridge was not a stand-alone option but would require other storage (for dry-year reliability). The Group considered that the use of Lake Coleridge water was likely to be a critical part of an integrated option for mid-central Canterbury. Stour River storage This option takes about 6m 3 /s of water from upper South Ashburton River (about 3km above Buick s Bridge) to fill a 200 million cubic metre storage behind a 80m high dam in a natural gorge in the Stour River. About 6km 2 of land, much or all under Department of Conservation management, is flooded behind the dam. There may be hydro-generation potential although the lake would have an operating range of about 70m. In one very dry period modelled the storage lake took three years to fill. The canal from the take in the upper Ashburton River to the storage lake would be sited to avoid sensitive wetlands in the vicinity of Maori Lakes. This option utilises run-of-river takes from Rakaia and Rangitata River and the existing Rangitata Diversion Race (RDR) infrastructure. Irrigation demand would be met, in the first instance, from run-of-river takes from Rakaia and Rangitata River as available within the rules of the national water conservation orders on these rivers. When this can not meet irrigation demand water would be taken from the Stour storage. About 126,600ha of land between Rakaia and Rangitata Rivers can be reliably irrigated in this option including existing areas irrigated from RDR and the Ashburton Lyndhurst schemes. This is over 90% of the area (below RDR) irrigable by surface water in Ashburton District. If 3m 3 /s water from the Rangitata River is taken south (rather than to the Ashburton District), the area reliably irrigated in this option between Rakaia and Rangitata Rivers is reduced to 115,050ha. Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 15

There would be significant impacts on South Ashburton River. In the reach of about 16km from below the diversion to the Stour storage and above the Stour River, flows would be reduced to low levels for most of the time and the few remaining flood peaks significantly reduced as water is harvested to storage. Below the Stour River junction the flows in the river are also significantly altered through the combined effects of releases to meet irrigation demand and harvesting of water to storage. This leads to significant changes to the current pattern of flows. In the irrigation season high flows are common but of short duration, falling as fast as they rise (unlike natural floods), while at other times flows are often at or near the low-flow minimum. Below the irrigation take for the RDR, flows are also significantly altered with reduced variability, few freshes and long periods of low flows. As modelled the river would be at the low-flow minimum for about 30% of the time. The Group, however, believe there is opportunity, as noted below, to improve flows in the lower Ashburton River with this option. Flows in the Stour River below the dam are also significantly altered with releases from storage of up to 35m 3 /s, equivalent to the 100-year flood flow. Evaluation of Stour River storage This option utilises existing RDR infrastructure and this was seen as a positive. It was also noted that the Stour River option appears to be the best (only?) major storage option going for Ashburton District. The Group was concerned about the impacts on the Ashburton River and believed the adverse impacts would need to be minimised more than they had been in the modelled option presented. The Group believed a reservoir in the Stour Valley should provide opportunity to improve the flows in the lower Ashburton River including increasing low flows by 5m 3 /s to ensure the river mouth remains open through late summer. They believed some of the water for this could be contributed from the current stock-water system. Concern was expressed on the impact of the diversion canal and storage-reservoir on the wetlands, iconic lakes (such as Lake Emma) and landscape of the Stour River valley, though one person expressed the view that the ecological negatives were overstated in the Group s discussion of this option. The Stour River storage would be in an area that Forest and Bird is proposing for World Heritage Area status and the Natural Heritage Advisory Group, Department of Conservation, has recommended the area as a high priority for immediate World Heritage listing. A detailed assessment would be required of the ecological and landscape impacts in the vicinity of the proposed storage reservoir and for the Ashburton River. The proposed reservoir was not seen as adding significant recreation benefit because of its very large operating range. Concern was expressed on the impact on river birds. A section of the upper Ashburton River is important for some threatened and endangered bird species. The loss of most flood flows and a major reduction in variability would likely worsen habitat and major mitigation measures would need to be considered. It was recognised that there would be issues to be worked through between existing users (supplied from RDR) and new users. Existing RDR users may be reluctant to contribute as they already have a reliable water supply, as would the groundwater users who would benefit from increased land-surface recharge. As for other options there was concern about the risks to groundwater and surface water quality from the additional area of intensive land use, though some of the group believe these may be managed through best practice land management. Also, as for other options, the Group believed the proposed new irrigation would positively impact on flows in lowland streams and on the water available for groundwater irrigators on the lower plains. Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 16

The desirability of getting more water south of Ashburton River (currently constrained because of the gradient of the RDR) and ultimately south of Rangitata River was identified as a key goal that this option could help achieve. Some consider that the Stour River storage could be part of a bigger picture that included use of Lake Coleridge water and the use of some water to improve flows in the lower Ashburton River (analogous to the use of Lake Opuha releases to improve flows in Opihi River in South Canterbury). Others were strongly of the opinion that this was not an option given the impact on the Stour valley, the small iconic lakes and the upper Ashburton River. Evaluation of impact of no new water storage The Group discussed the likely impacts, adverse and beneficial, if there was no new (major) water storage in mid-central Canterbury. Water is seen as Canterbury s natural competitive advantage. The Group acknowledged that water for irrigation was an increasingly scarce resource. If major storage options did not progress it was predicted that competition for water would markedly increase and that water would become a traded commodity in mid-central Canterbury. Some commented that they believed the water resource was already over-committed and that the addition of water storage would only delay the realisation that there was no more water available for irrigation. One person noted that it was not water abstraction by conservationists that had got us to the current situation and implied that irrigators needed to be facing up to the reality that water was no longer there for the taking. It was acknowledged that there were some gains to be had through more efficient water use but that these gains were not considered to be as substantial as some may claim. There was opportunity in some areas for on-farm storage to improve reliability of supply (particularly from RDR) to enable more land to be irrigated, although the additional area would be relatively small. The Group noted that if there was no new (major) water storage in mid-central Canterbury: Irrigation development would likely stop, and probably contract; Farmers would increasingly struggle to meet market expectations to deliver products in tightly-specified time periods and to increasingly exact specifications; Opportunities for high-value crops that require reliable water supply would be fewer; Rural economy would decline with flow-on impacts on rural towns (e.g. Ashburton) and Christchurch, and on health, education and other social infrastructure; The opportunities for win-win gains for fisheries and irrigation from storage, such as those from Opuha Dam, would significantly diminish. The halt to the irrigation development would stop the increase in land intensification, reducing the concerns about the risk of water quality issues associated with this increase. It was noted, however, that there are environmental risks associated with dryland farming and particularly with irrigated farming with unreliable water supply. If there is insufficient water to grow a crop to harvest either because of unreliable irrigation or lack of rain not only is the crop wasted (with loss of farm income) but unused fertiliser remains in the soil and can be leached into groundwater or streams in autumn or winter rains. In addition, during fallow or long dry periods in non-irrigated situations, nitrogen in the soil is converted (nitrification) to a soluble form (nitrate) which can be leached from the soil in autumn or winter rains. The relative magnitude of these leaching risks was discussed but no agreement reached. Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 17

How people felt about the options At the last meeting the participants individually recorded how they felt about each option on a seven point scale from very positive to very negative, and why. The distribution of scores provides some indication of the relative attractiveness of different options to the group (see below). The diagrams indicate that more of the group were positive about the Lees Valley and Lake Coleridge options and that all were negative towards the option of no storage. Lees Valley Lake Coleridge No storage Waianiwaniwa Valley Stour Valley Strongly positive Neutral Strongly negative Compilation of how individual participants felt about each option on a seven-point scale from strongly positive (green or left bars) to strongly negative (red or right bars). Overall evaluation The Group found positives in all the options particularly the economic development and related social and rural community benefits. They also found negatives in all the options. The evaluation identified that all of the options (Lees Valley, Waianiwaniwa Valley, Lake Coleridge and Stour River) had significant concerns and adverse impacts that would need to be addressed. For some of the Group concerns about the impacts of land intensification and/or river impacts meant all the options evaluated were unacceptable. For others, all options were acceptable. Notwithstanding the concerns, not progressing with water storage was not seen as an option by the Group. Some considered that the way forward was on-farm and/or mediumsize storages within farmland (i.e. outside river valleys). It was felt that these smaller (offchannel) storages would be more readily accepted by the wider public because there would be fewer non-farming objections. Some felt that smaller storage (off-farm but not mega-dam) were not discussed enough. Many on the Group, and the Aqualinc technical advisors, however, believe that only major storage reservoirs (50,000,000m 3 or more) are economically viable. Many on the Group believe that future water demand in mid-central Canterbury can only be met with the addition of major storage reservoirs and an accompanying increase in runof-river abstraction but acknowledge that this should not be at a cost to the environment particularly to in-stream values and water quality although the concerns were not restricted to these. Some of the Group were strongly of the view that water quality issues must be given the same level of scrutiny as those of water quantity and that these concerns need to be addressed before any options are progressed. At least one of the group commented that the evaluation outcome was influenced by the composition of the group mostly male farmers and irrigators. This summary does reflect the full range of views expressed not just those of the majority. It was also noted that the evaluation outcome was influenced by only a few of the group being familiar with the environmental, recreation, cultural, landscape, social and other values of the land and rivers that would be most affected by each option. One person felt that there may not have Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 18

been real depths of thought go into evaluation of environmental, social and cultural impacts. They believe that environment, ecology and other issues not directly related to farming were not given the time they deserve. Exploring an integrated option At the end of the mid-central Canterbury evaluation, the Group recognised that an integrated approach was required that combined some of the storage options in ways that delivered water for new irrigation, maintained flows in the alpine rivers and enhanced flows in other rivers. A description of an integrated option and its evaluation are provided at the end of this report. Group membership mid-central Canterbury evaluation Andy Pearce Chairman Graeme Sutton Irrigation New Zealand Gerry Clemens Waimakariri Irrigation Ross Millichamp Fish and Game Anna Heslop Rural communicator Murray Lane Water Rights Trust Ian Morton (or Michael Oliver) Rangitata South, Orari farmer Kelvin Coe Federated Farmers, Selwyn District Councillor Te Marino Lenihan Ngai Tuahuriri Claire Mulcock Resource Mgt Consultant Bruce Allan, Environmentalist, farmer Ken Hughey Lincoln University Mervyn Gray Retired farmer, fisherman Ian Mackenzie Ashburton Community Trust, Eiffelton Irrigation Scheme John van Polanen Ashburton Lyndhurst Community Development, Selwyn District Ann Jarman Ian Morton Will Nixon Ashburton Lyndhurst Frank Scarf Hydrologist Bruce Ashburton Trading Bob McPherson Society Engelbrecht, Matthew Hall Salmon Anglers Tony Howey Rangitata South, Orari farmer Farm advisor, Ashburton Opuha Irrigation Company Barrhill Irrigation John Wright, Scheme Edith Smith Forest & Bird Michael Morrow Groundwater irrigator Hugh Canard kayaker Don Church, Ashburton Water Trust Peter Howden Environmentalist, farmer David Keely Mayfield Hinds Irrigation Many of the Group were unable to attend all five meetings. Ross Millichamp withdrew from the evaluation process at the start of the fourth workshop, when it became apparent the Lake Coleridge option would require a change to the Rakaia Water Conservation Order. Ross did attend the meeting on an integrated option for mid-central Canterbury (see Section 7). John Donkers, Central Plains Water, was present for the presentation by Aqualinc of the Lees Valley option. Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 19

4 South Canterbury options Summary of options evaluated Irrigated area (ha) 1 Reliability 2 Active storage (Mm 3 ) Average (peak) seasonal volume from Tekapo (Mm 3 ) 1 Opuha dam (current) 16,000 28 (92%) 83-2 Raised Opuha dam (6m) 18,800 23 (93%) 133-3 Opuha (current) + Opihi dam 33,000 22 (93%) 240-4 Tekapo water (5m 3 /s) with current Opuha + Opihi dam (20m operating range) 5 Tekapo water (7.5m 3 /s) with current Opuha + Opihi dam (5m operating range) 6 Tekapo water (9m 3 /s) with current Opuha + Tengawai dam 7 Tekapo water (10m 3 /s) with current Opuha dam 8 Off-channel storage (Stoneleigh Rd, South Opuha) with current Opuha dam + Tekapo water 33,000 14 (96%) 179 48 (130) 33,000 14 (96%) 121 65 (172) 33,000 19 (95%) 98 82 (208) 33,000 15 (96%) 83 94 (227) 33,000 Not modelled 163 (80 + 83) Not modelled 9 Pareora dam 6,250 2 (99%) 54-1 2 potential irrigable area in the Opihi, Opuha and Tengawai Rivers is 41,000ha Number of periods of ten or more consecutive days on irrigation restrictions. Percentage figure in brackets is the proportion of time supply equals or exceeds irrigation demand) Context The area is water short. Climate change may exacerbate this. There is about 41,000ha (net) irrigable land that could be supplied from Opuha, Opihi and Tengawai Rivers. The Opuha dam, commissioned in 1999, currently provides water to irrigate about 14,500ha. Existing irrigators are happy with the reliability of supply to date. Modelling indicates that irrigation supply would be severely restricted in very dry years such as occurred in 1988 with limited winter inflows and high irrigation demand. At such times irrigation restrictions may be in place for more than 90 consecutive days. In the 30-year period from 1972, water supply would have been less than irrigation demand for about 8% of the time. The reliability of the existing Opuha scheme was used as the benchmark for new storage options in South Canterbury. This benchmark is significantly lower than the reliability criteria used when modelling mid-central Canterbury and Hurunui District storage options. The Opuha and Opihi are regionally important trout (particularly) and salmon fisheries. Algal proliferation has been an issue below the Opuha dam and is being controlled by flushing flows. The Opuha dam has benefited fisheries and the lake is a valued recreation resource. The study by Simon Harris, Geoff Butcher and Willie Smith in 2006 showed that the Opuha irrigation scheme has had significant economic impacts on farm and to the district, and positive social changes. Total revenue per hectare for farms supplied by the Opuha scheme was 2.4 times that of comparable dryland farms. Cash surplus as a proportion of total revenue was similar for irrigated and dryland farms but the dollar value of the surplus on the irrigated farms was substantially higher. For the whole scheme the increase in total farm revenues was $40,000,000 per year with a cash farm surplus increase of $12,000,000 per year over a comparable non-irrigated area. Irrigated farms generated Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 20

two-times as many jobs and three-times as much household income per hectare as did dryland farms. The study showed that irrigated farmers were younger, better educated and larger employers of local services. The study authors say that these changes are likely to result in more vibrant and sustainable rural communities. The authors acknowledge that environmental impacts (adverse and beneficial) of the scheme are less well understood or documented at present. Evaluation of water storage options Opihi and Pareora Rivers The evaluation only considered storage options in Opihi, Opuha, Tengawai and Pareora Rivers. The group did not consider the proposed Hunter Downs scheme (fed from Waitaki River) as this is in the resource consent process. Evaluation of a storage reservoir in Orari River was deferred for possible consideration with mid-central Canterbury options as the reservoir would be filled, in part, from Rangitata River. Overview map (adapted from Aqualinc) showing options evaluated in Opihi area. Based on infrastructure for Tekapo water with existing Opuha dam and a dam on Opihi River. Te Ngawai Reservoir Raised Opuha dam This option involves raising the dam by six metres. Irrigators in the group considered this is likely to be a very hard sell to current irrigators given the high cost of raising and replacing the dam for little additional irrigated area. The view is that those in the Opuha scheme are happy with current water supply and would see little gain in raising the dam either to improve reliability or increase irrigated area. The need to empty the existing lake while constructing a new higher dam, thereby not being able to provide water for at least one irrigation season, was seen as a major obstacle for this option. On the other hand, some of the group commented that this option appears highly consentable as it adds to an existing scheme that already has improved fishing and has good public acceptance. John Hayes, river ecologist, Cawthron Institute, noted in his consideration of in-stream impacts that the raised Opuha dam option would need to improve flushing flow regime to avoid algal proliferation and vegetation encroachment. He noted there was potential to augment minimum flows further thereby enhancing in-stream habitat to benefit trout fishery and angling. Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 21

Raised Opuha and Opihi dam This option combines a raised Opuha Dam with a 45m-high dam at the upstream end of the Opihi Gorge (about 10 km below Fairlie). The Opihi lake would extend to within a few kilometres of Fairlie. This option provides sufficient water to double the amount of irrigated land in the Opuha-Opihi area. Some of the group have significant concerns about damming the Opihi River with impacts on fish (disruption of salmon and trout passage leading to significant impacts on spawning and rearing upstream of Fairlie) and landscape/amenity value of Opihi Gorge. There was also concern about likely dust nuisance and visual impact from the 30m operating range of the Opihi lake. Affordability and value for money was an issue for many of the group. Construction of the water distribution system and Opihi dam are estimated to cost about $90 million ($33 million for dam alone). The high cost per hectare, with insignificant reliability gains, led people to consider this option as expensive. One person considered that there was no more water in the catchment so it wasn t worth while spending more money on expensive plumbing. It was recognised, however, that this option enabled irrigation of the greatest amount of land (33,000 ha) without requiring water from Tekapo. Concern was expressed that you shouldn t dam another South Canterbury river. One person expressed a fundamental objection to an Opihi dam. Introduction and comment on options using water from Lake Tekapo All options considered irrigate 33,000ha with improved reliability compared with current Opuha scheme. At least half the group consider that access to water from Tekapo is the only way to meet future water demands in South Canterbury. The water does not need to be pumped. Some considered that piping would be necessary to minimise landscape impacts. The group recognised that steps would need to be taken to avoid mixing-ofwaters impacts, along with the effects of a major flow increase (up to 10-fold in irrigation season) in the Opihi River from Burkes Pass to Ashwick Flat. The group acknowledge there are significant economic, planning and legal barriers to accessing Tekapo water. Mixing of water from Lake Tekapo ( glacial cold & turbid) with Opihi water ( warm and clear) will be an issue for Maori and the Opihi River ecosystem. In some of the options and at some times of the year half of the water in the upper Opihi could be Tekapo water and the impact of the fine suspended sediment on in-stream values would need to be considered. Use of Tekapo water for irrigation in the Opihi removes water from the Waitaki River system. This water is not available for electricity generation through the eight power stations, nor can it contribute to low flows in the lower Waitaki River. There is already considerable competition for Waitaki River water. Taking water for irrigation in the Opihi increases the competition. There are equity issues between the use of Tekapo water in the Waitaki system versus its use in the Opihi. Opposition to Tekapo proposals was largely around economic hurdles, equity issues and the cultural question of mixing of waters. In discussion most of the group would be supportive of Tekapo options if these hurdles could be overcome. There was a feeling that most of these issues could be overcome, i.e., if there is a will there is a way. Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 22

Specific options evaluated using Tekapo water Tekapo water with Opuha and Opihi dams Two options were modelled with different takes from Lake Tekapo and different operating ranges for the lake behind a 40 metre dam at the upstream end of the Opihi Gorge. These options use less Tekapo water than the other options. Some considered this important as it shows that South Canterbury is doing as much as possible to harvest water before taking Tekapo water. Some believe this may be more palatable for Meridian. It was acknowledged, however, that the options result in dams on both main stems of the Opihi River. Some felt there would be national concern about proposals that included two significant dams and the take of Tekapo water. The Opihi dam would have adverse impact on trout and salmon fisheries. Tekapo water with Opuha and Tengawai dams This option takes more water from Tekapo and uses the current Opuha Dam and a storage behind a 25 metre high dam in the upper Tengawai River. The salmon and trout fisheries in the Tengawai are considered less significant than those in the Opihi River. This option retains the Opihi River fisheries. A dam in the Tengawai would have significant impacts on flows in the Tengawai River. This may impact spawning, native fisheries and river-nesting birds. On the other hand the development is likely to increase low flows in the Tengawai River. Reliability would improve for irrigators in the Tengawai area but would be mixed elsewhere. Tekapo water with Opuha Dam only This option takes more water from Tekapo to augment the current Opuha storage. This option avoids damming other tributaries of the Opihi River. Therefore impacts on fish and other in-stream values should be less. It was noted that this option results in most of the water ending up in the northern part of the catchment with more infrastructure required to deliver water to Tengawai and other areas. The option utilises existing infrastructure and does not require a second dam (with consequent adverse impacts). Tekapo water with off-channel storage (Stoneleigh Rd) and Opuha dam An off-channel storage site has been identified by one of the group. This site, at about 520m altitude near Stoneleigh Rd, south of South Opuha River, may be able to store up to 80,000,000m 3 in two adjacent basins. Two dams would be required, one about 620m in length, the other about 440m in length, with a maximum height of 85m. Such a dam would be expensive, probably three times the cost of the proposed Opihi dam (i.e. about $100 million). The lake would be filled via a race from South Opuha River. This would take water that is currently stored behind the Opuha dam and this would have to be replaced with water from Tekapo. This option was not modelled and no detailed investigations have been carried out. It is likely that 33,000ha could be irrigated with moderate inflows from Tekapo. The group noted that while such a dam would be much more expensive than the Opihi or Tengawai options it offers co-generation opportunities and the ability to supply water (under gravity) to Opihi and Tengawai irrigable areas. Pareora dam This is a stand-alone option (not requiring transfer of water from outside the catchment) based on a dam at the upstream end of the Pareora gorge (at Motukaika). The proposal is for a 35 metre high dam, with an operating range of 13m, providing water to reliably irrigate 6,250 ha (64% of the potentially irrigable land in the catchment). The irrigated area includes existing irrigators supplied from Pareora River they would become part of the new scheme. The option was modelled with the high reliability of supply criteria used in CSWS 2 (i.e. no periods of water restrictions of ten days of longer for the record period from 1982 to 2001). Several people with local knowledge, including one of the group who Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 23

lives in the Pareora area, believe the model may over-estimate reliability. Additional hydrological data is required. The Pareora River is currently degraded water quality is poor at times, algal blooms common and riverbed vegetation an issue. The lower reaches of the river dry up in the summer and, while exacerbated by irrigation takes, this is likely to be a natural phenomenon. The river mouth closes in summer when flows are low. The river, except for the coastal lagoon, is not highly valued for fishing. The group considers the storage option could improve the river environment through provision of higher low flows in summer. Flushing flows would probably be required to manage algae build ups. The soils in the irrigable area are relatively heavy and increased nutrient loading should be manageable although one of the group was concerned about the risk of increased nutrient runoff to streams from land intensification. One of the group raised the possibility that nutrient runoff from farmland into the lake could cause water quality issues in the lake and downstream. Timaru District Council currently takes water from the upper Pareora River. The proposed storage option would not impact this. The proposed storage option is estimated to cost about $20 million. The group identified the need to realign about 10 km of roading as a significant additional cost (perhaps adding another $10 million). It was noted that the dam would provide water to a very dry corner of South Canterbury. Overall evaluation The group agreed that access to water from Tekapo (Waitaki River water) is very important as the area is very dry and local runoff can not meet irrigation demand or reliably supply water to the potentially irrigable land in the Opuha-Opihi-Tengawai area, even with additional storage. Irrigators in the existing Opuha scheme will face extended water restrictions (probably including zero supply) for long periods during very dry seasons (as occurred in 1980s). The reliability criteria used in the modelling and evaluation of South Canterbury storage options are considerably lower than the criteria used for the options in Hurunui River (no periods of water restrictions of ten days of longer for the 30- year record period). The group believes that a small amount of water from Tekapo (average about 90,000,000m 3 per irrigation season about 1% of Waitaki River discharge) would do a lot for community and regional development. The group acknowledges the challenges to accessing this water given the current Meridian consents for the Waitaki River and the demand by other users for water from the Waitaki River. The group also acknowledges the environmental and cultural challenges to bringing water from Tekapo into the Opihi-Opuha system particularly including mixing of waters (a concern for Ngai Tahu), and ecosystem impacts of cold turbid water. In evaluating options for use of Tekapo water the group favours the option presented that does not require new water storage (i.e. use of existing Opuha storage only). Two-dam options are generally considered by the group to be less attractive, particularly an Opihi River dam. The option of Tekapo water with the existing Opuha dam and a dam in upper Tengawai was viewed positively by many of the group though there were concerns about the impact on Tengawai River. The off-channel option was only introduced at the last meeting of the group and irrigated area, requirements for Tekapo water or river flow impacts were not modelled. The option was viewed positively by many in the group, notwithstanding the lack of information, though the cost of the storage (probably three times that of a Tengawai dam) was a major concern. The group considered the proposed Pareora dam was a stand alone option that could be considered further. Members of the group from outside South Canterbury appeared to find the Pareora option more attractive than locals. The latter were concerned about affordability (particularly unknown cost of road realignment), possible sedimentation of Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 24

lake, reliability of supply and likely uptake by local farmers. Some of these concerns may be allayed with more information. It appears that relative contributions of different parts of the Pareora River are different in flood and low flows. The catchment above the proposed dam appears to contribute a relatively higher proportion of flood flows than for low flows. Installation of flow recorders, or regular concurrent gaugings, on the main Pareora River above proposed dam site and on the South Pareora River should be considered to improve the hydrological data for this option. How the group felt about the options At the last meeting the participants individually recorded how they felt about each option on a seven point scale from very positive to very negative, and why. The distribution of scores provides some indication of the relative attractiveness of different options to the group (see below). The diagrams indicate that more of the group were more positive about options with water from Tekapo, and most positive about the option of using Tekapo water with the existing Opuha dam, though some were negative about these options. Using local water Raised Opuha With water from Tekapo Opuha + Opihi 20m range 5m Opuha + Opihi Opuha + Tengawai Pareora Opuha + off-channel storage (Stoneleigh Rd) Strongly positive Neutral Strongly negative Opuha only Compilation of how individual participants felt about each option on a seven-point scale from strongly positive (green or left bars) to strongly negative (red or right bars). Feedback from discussions with interest groups and public presentations The results of the evaluation of South Canterbury storage options were discussed with South Canterbury Mayors (Timaru and Mackenzie Districts) and Timaru District councillors, and the South Canterbury Irrigation Trust (SCIT comprising irrigators, farmers, Meridian Energy and District Councils) and presented to a public meeting in Timaru organised by South Canterbury Water Enhancement Group (SCWEP). The South Canterbury mayors and councillors questioned the coverage of the evaluation and accepted that the Hunter Downs scheme had been excluded because it was currently in the resource consenting process. The meeting noted the possibility of a storage in Pareora River and agreed that additional hydrological data were required to evaluate this option. The reliability of the current Opuha Scheme was also discussed. The meeting was most interested in the wider picture of water supply for the region. Participants particularly noted that the CSWS work provided independent data to quantify concerns they had long held about the area being water short relative to the areas immediately north and south. Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 25

At the South Canterbury Irrigation Trust meeting there was a lot of discussion about the essentiality of Tekapo water becoming available at some time (even though a Meridian representative was present). Some participants believed that Tekapo water would never be made available until all local resources were seen to been used, and that would probably mean a storage on the Opihi, as well as on the Opuha. There was also a lot of discussion about the reliability of the current Opuha scheme, with some defensiveness from those associated with the Opuha scheme. Participants at the public meeting in Timaru were pleased that another study had acknowledged that the area was water short and this could only be addressed by accessing water from outside the area. Some participants expressed frustration at not being able to access water from Lake Tekapo. There was a range of views on the water quality risks with land intensification from new irrigation. Some believed any risk could be avoided or reduced through best farm management practices, others believed the risk was significant and were more sceptical about the adoption and effectiveness of best practice. Many of the South Canterbury-based members of the evaluation group attended the public meeting in Timaru. One of them commented that this was the most strongly unified meeting on water options that he could remember in the region with individuals and interest groups, who usually found something to disagree on, all positive and supportive of the thrust of the evaluations. Group membership South Canterbury evaluation Andy Pearce Chairman Graeme Sutton Irrigation New Zealand Peter Scott Opuha Irrigation Company, Sustainable Water Programme of Action Jay Graybill Fish and Game Lyn Stratford Farmer, Opuha Scheme Murray Lane Water Rights Trust Hugh Canard kayaker Dermit Farmer, Fairlie Basin Herstall Ulrich Farmer, Pleasant Point O Sullivan Claire Mulcock Resource Mgt David Henshaw Farmer, Pareora Consultant Ken Hughey Lincoln University Frank Scarf Hydrologist Ian Mackenzie Ashburton Community Fraser Ross Forest & Bird Trust, Eiffelton Irrigation Scheme Ann Jarman Community Development, Selwyn Tony Howey Opuha Irrigation Company District Tom Lambie Opuha Water Company Many of the group were unable to attend all four meetings. Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 26

5 Hurunui District water storage options Context The Hurunui and Waiau Rivers are the major alpine rivers supplying water to North Canterbury. This evaluation only considered options using water from Hurunui River. The CSWS Stage 1 study had shown that potential demand in Waiau area could be met from Waiau River without storage. The Hurunui and Waipara Basins are very dry in summer with extensive dryland farming and viticulture (in Waipara area). Current irrigation schemes provide water to less than 10% of the irrigable area of 74,800ha. The Hurunui River is a nationally important wild and scenic river. In mid 2007 Fish and Game, Forest and Bird and the New Zealand Recreational Canoeing Association lodged a Water Conservation Order application for the upper reaches of the river and Lakes Sumner and Taylor and Loch Katrine. The river is rated the fifth best salmon fishery in New Zealand and a regionally important trout fishery. It is an important habitat for endangered black-fronted tern. Only 5 10,000 of these terns remain in Canterbury and the black-fronted tern population is in serious decline. The Hurunui River is a nationally important kayaking river. It is valued by beginners to experts with the Maori Gully reach the top attraction. Changes to Hurunui River Management Plan The evaluation was done in September December 2006. The modeling by Aqualinc of water supply for storage and run-of-river takes was based on the current flow regimes on the Hurunui River (the 1980 River Plan and the Balmoral Irrigation Scheme regime). In mid 2007 ECan released a Draft Hurunui River Management Regime which has been publicly notified as Variation 8 to the Provisional Natural Resources Regional Plan (PNRRP). The proposed river regime is significantly different to the current river plan and includes changes to minimum flows, definition of allocation block sizes and seasonal caps on abstraction. The proposed river regime significantly reduces the water available for new irrigation takes from the Hurunui River, restricts when water can be taken to storage and caps takes in winter to 90,000,000m 3. The proposed changes to the river regime have a marked impact on the options modeled and evaluated. For example, the current river regime allows the option of managing Lake Sumner within its historical lake level range (option 3 in Table below) to irrigate an area of 37,000ha but this is reduced by about 60% (to 16,000ha) under the proposed river regime. The evaluation of storage options is based on information using the current river regime as the proposed regime was not available at the time of the evaluation in 2006. It is likely that the group s evaluation would have been significantly different if the options had been modeled using the proposed river regime, as the irrigated area for each option is much reduced. The irrigators and farmers in the group probably would not have considered any of the options attractive given the small additional irrigated area for considerable consenting, construction and delivery costs. Evaluation process The evaluation was the first one to be done in CSWS Stage 3. The evaluation was done by a multi-stakeholder group including people with interests in irrigation, fishing, community development, kayaking, farming, environmental issues and Ngai Tahu. Most of the group was male and irrigators/farmers were in the majority. Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 27

Summary of options evaluated Storage option Area irrigated (ha) Proportion of irrigable land* Peak irrigation demand (m 3 /s) 46,000 61% 23 35,000 47% 18 37,000 49% 19 21,276 28% 12.5 68,000 91% 31.6 63,650 85% 30 44,800 60% 22.5 With current Hurunui River Regime Plan 1 South Branch operated to meet current low flow requirements 2 South Branch operated to meet Mosley flow (with flow sharing) 3 Lake Sumner operated within historical range but without natural lake variation 4 Lake Sumner operated within historical range with natural lake variation 5 South Branch storage with Lake Sumner as storage of last resort 6 Lake Sumner storage with South Branch storage as last resort 7 Lake Sumner storage (including natural lake variability) with Mandamus dam 8 Lake Sumner storage (without natural lakelevel variability) with Mandamus dam 60,000 approx. approx. 80% approx. 28 9 Lake Sumner raised about 9 m 74,000 100% approx. 35 With proposed Hurunui River Regime (2007) Lake Sumner (option 3 above) ** 16,000 22% 10 * total irrigable area is 74,000 in Hurunui, Omihi and Waipara basins ** this option was not evaluated the proposed Hurunui River regime was notified by ECan in mid 2007. The evaluation of storage options was done in 2006. Mandamus dam Description and evaluation of storage options for Hurunui District Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 28

South Branch storage This dams the South Branch, Hurunui River, upstream of the North Esk River confluence. The dam would be 65m high with an operating range of 30m and when full the lake would inundate about 484ha. Active storage behind the dam is 96,000,000m 3. The cost of the dam would be about $23-$42,000,000. Hydro-generation could be included as part of the scheme. Run-of-river takes from Hurunui River are used to meet irrigation demand whenever possible within the current river plan. The irrigation intakes would be just below the Mandamus confluence and link to the existing Balmoral Irrigation Scheme on the north bank and to a new headrace on the south bank. There would be higher flows during the irrigation season in the Hurunui River above the intake as water is released from the dam to meet irrigation demand. This would double the flows in a period when the river is generally at low flow and would also reduce flow variability. Below the irrigation intakes flows in the Hurunui would be reduced particularly in the irrigation season with some flat-lining in the January to March period. The South Branch option was modeled using the current flow regime and the more conservative Mosley low flow regime (with flow sharing). The current river plan allows irrigation of 46,000ha, the Mosley flow regime only 35,000ha. The South Branch is believed to be a major contributor of sediment to the Hurunui River (as Lake Sumner significantly reduces sediment supply from the north branch). The dam will reduce sediment supply to the Hurunui River but the impact of this is not known. Evaluation of South Branch option The group was concerned that the dam would flood the main salmon spawning area in the Hurunui River leading to a loss of the salmon fishery. Fish passage would not be possible over the 65m high dam. There was also concern about the impact on the trout fishery. Some of the group were concerned about the likely inundation of valuable river-bird nesting habitat though it was acknowledged that more information was required. The kayaker in the group considered that this option would have a mixed impact for kayaking with higher flows good for some reaches but the loss of the pool and drop character in Maori Gully (drowned-out in higher flows) would be a significant adverse impact. Lake Sumner managed storage This option manages Lake Sumner within its historical range of about 3.5m through the use of control gates at a low weir at the lake outlet. The cost of this structure is about $2- $4,000,000. Two options were modeled, one that managed storage so that lake levels varied in a manner similar to the current natural pattern, the other with the lake operated with no attempt to retain natural lake level variations. In both options the average lake level is about 0.75m higher than the current average level. Irrigated area is 21,275ha when the lake is operated in a manner that retains natural lake level variation and 37,000ha when it is operated without a natural pattern of lake level variation. The use of run-of-river takes to meet irrigation demand wherever possible and the intake and distribution infrastructure are the same as for the South Branch option. Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 29

Evaluation of Lake Sumner managed storage Many of the group thought this option was cost-effective and worth considering further although some thought that by itself it did not irrigate a big enough area. There was concern that the area was conservation land and that there was an expectation that it remain in a natural state. This concern prompted the request to model the option that operated the lake storage in a manner that mimicked the natural pattern of lake level variation. In evaluating this option, however, most of the group believed its benefits were small (if any), as the beaches on the lakeshore are steep gravel, and did not balance the significant reduction in irrigated area. There was acknowledgement that operating the storage in a manner that mimics natural lake-level variations could be perceived as less change to an area of high natural value. The group thought that there may be opposition to the option because of concerns about the impact on Lake Sumner s wilderness and iconic values. The lake control structure was not seen as likely to restrict fish passage and the option was viewed much more favorably from a fishery perspective than the South Branch dam. South Branch and Lake Sumner used together Two options were considered. The first used the South Branch reservoir as the primary storage with water only being released from Lake Sumner when no water was available in the South Branch reservoir. The second had Lake Sumner as the primary storage reservoir and South Branch as the backup. In both options, water is only required from the backup reservoir in a handful of years in the 30-years modeled. Under the current river plan, these combined options provide sufficient water to reliably irrigate 68,000ha and 63,650ha respectively. They would provide water to irrigate land in Omihi and Waipara basins. The peak irrigation demands are greater than for the options that only involve one storage reservoir. As a consequence, the impacts on river flows are greater above the irrigation intakes flows are higher due to larger releases from storage, below the intakes flows are flat-lined for much of the irrigation season due to increased abstraction for irrigation. Evaluation of South Branch and Lake Sumner combinations The group saw these options as being able to provide water to most of the irrigable area and this was considered a positive by farmers and irrigators. The larger area was seen as a positive in that the scale of economic and social benefits would be greater, but also as a negative by some of the group because of the environmental risks from land intensification would also be greater. The group noted that transfer of water to Waipara area may be of a concern to Ngai Tahu because of mixing of waters but the group felt this concern could probably be addressed. The group noted that both options provided good opportunity for electricity co-generation at South Branch dam and also the opportunity to release water to augment low flows and to meet recreation demands (particularly kayaking). Lake Sumner with Mandamus storage This option was modeled in response to a request from the group to look at an option combining Lake Sumner with a storage reservoir other than South Branch. Previous studies had identified potential storage sites in Mandamus, Waitohi and Pahau valleys. Aqualinc modeled an option that combines Lake Sumner with a backup reservoir formed behind a 50m high dam in Mandamus valley about 1km above the confluence with Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 30

Hurunui River. This reservoir would have an operating range of about 30m and active storage of 50,000,000m 3. The lake would inundate about 300ha including developed farmland and historic farm buildings. The combination of these two storages enables about 60,000ha to be irrigated under the current river plan. The impact on Hurunui River flows is similar to that of the South Branch Lake Sumner combined options but this option retains the supply of sediment and floods from South Branch. There are no measured flow records for Mandamus River and the modeling of this option is indicative only. If the option is to be progressed further a flow recorder should be installed on Mandamus River for two years. Evaluation of Lake Sumner combined with Mandamus reservoir The group saw this option as providing the benefits of a two-reservoir option without the detrimental impact of the South Branch reservoir on the salmon fishery. It was acknowledged, however, that the option would have adverse local impacts in the Mandamus. The group also noted that the concerns about the Lake Sumner option and about the risks from land intensification also apply to this option. It was noted that this option offered less opportunity for co-generation. Raised Lake Sumner This option was modeled in response to one of the participants asking for an option with sufficient storage to irrigate all the irrigable area (74,000ha). The option raised Lake Sumner by about 9.0m to create a storage of 120,000,000m3. The nature and location of the dam was not scoped but it is likely the dam would have to be below the current outlet and would be of significant size (much more than 9.0m high). Raising the lake would join Loch Katrine to Lake Sumner. The option was not modeled in detail. Flows in Hurunui River would be the most modified of the options modeled as peak irrigation is greatest. In the irrigation season flows down the North Branch of Hurunui River would be over 40m3/s for much of the time (particularly in January to March). Below the irrigation intakes (from just below Mandamus confluence to river mouth) flows would be flat lined for much of the irrigation season at the current minimum low flow. Evaluation of raised Lake Sumner The group acknowledged that this option maximized economic benefit, avoided impacts on South Branch and did confine development to one location. There was concern about the major impact in the Lake Sumner Conservation Park with loss of lake-shore forest for 3 to 5m above present beach level. Most in the group believed there would be strong public resistance (locally and nationally) to damming the lake. While it was acknowledged that fish passage may be possible passed the dam, many in the group had concerns about the impacts on flows in Hurunui River including the adverse impact on fishability of the river below the lake and the drowning out of the Maori Gully kayaking reach. Overall evaluation The Group s thinking changed through the process with the option of managing Lake Sumner within historical range becoming more attractive as concerns increased about a high dam on South Branch with loss of salmon fishery and other adverse impacts. Most in the Group believe a water storage option should provide enough water to irrigate at least 60% of irrigable area, and probably 80%. The Group generally supported a combination of managing Lake Sumner as a storage with some other backup storage (but not South Branch dam). It was considered that such a combination would allow much of the land to Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 31

be irrigated with more social and economic benefits, and avoid the impacts of a South Branch storage though there would still be impact on river flows (and related in-stream uses) and concern about risk of nutrient leaching from a large intensively-used area. How the group felt about the options At the last meeting the participants individually recorded how they felt about each option on a seven point scale from very positive to very negative, and why. The distribution of scores provides some indication of relative attractiveness of different options to the group (see below). The diagrams indicate that more of the group were negative about options involving a South Branch storage. More felt positive about options managing Lake Sumner as a storage within its historical range (though not with operating rules that mimicked natural lake level variation), particularly the option of Lake Sumner with another storage (Mandamus modelled). South Branch (current rules) L. Sumner (with natural lake variation) South Branch (Mosley rules) L. Sumner (without var.) Raised Sumner Strongly positive Neutral Strongly negative South Branch & L. Sumner L. Sumner & Mandamus (with natural var) L. Sumner & South Branch L. Sumner & Mandamus (without var) Strongly positive Neutral Strongly negative Compilation of how individual participants felt about each option on a seven-point scale from strongly positive (green or left bars) to strongly negative (red or right bars). Group membership Hurunui District evaluation Andy Pearce Chairman Graeme Sutton Irrigation New Zealand Mike Hogden Hurunui Community Water Development Working Group Ross Millichamp Fish and Game Norm Amuri Irrigation Scheme Williamson Murray Lane Water Rights Trust Hugh Canard Kayaker Kelvin Coe Federated Farmers, Paul Horgan Ngai Tahu Selwyn District Councillor Claire Mulcock Resource Mgt Consultant David Viles Hurunui Community Water Development Working Group Ken Hughey Lincoln University Peter Brailsford Angler Ian Mackenzie Ashburton Community Trust, Eiffelton Irrigation Scheme Ann Jarman Community Development, Selwyn District Peter Mossman Farmer, Culverden Tony Howey Opuha Water Company Not all participants were able to attend all four meetings. Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 32

Engagement with interest groups The results of the Hurunui District were presented and discussed with Hurunui District Council, Hurunui Water Development Group, North Canterbury Fish and Game Council, Ngai Tahu and Aoraki Conservation Board. Lesley Shand attended the Aoraki Conservation Board meeting and, with Sam Mahon and Alison Erickson, the Fish and Game meeting. A public meeting in Waikari was planned for mid 2007 but cancelled following release of the proposed Hurunui River Regime Plan. The Fish and Game Council expressed a range of concerns about the study with the notes taken by their Regional Manager at the meeting recording these as: There are so many applications in process now for major development of the braided rivers that the water may all have been allocated by the time the CSWS process is complete. Suggest that the Mayoral Forum be asked to put other applications of hold while the CSWS deliberations are being conducted. Councillors had real concerns that water quality was not being considered as part of the strategy and storage options. The community may not want development at the expense of the environment. Suggest that the CSWS survey the views of the public on this issue and not make presumptions. There is a need to consult the Hurunui community more widely, not just the farmers. The reference group should consider doing nothing as one of the options. More study is required to understand whether the land in the target area is suitable for intensive farming, and what the downstream consequences will be in terms of water quality. The reference group needs to report that it is presenting views of a specific interest groups rather than the local/regional community. The estimates of the economic benefits of storage contained in the report should be costed against environmental/lifestyle/amenity losses. The Aoraki Conservation Board also had strong concerns about water storage and irrigation. They did not support big dams, offering on-farm storage as a better alternative. Irrigation was seen as intensive dairying and leading to pollution. They did not believe that best practice would solve the adverse impacts of irrigation. One Board member, from South Canterbury, did not believe that the Opuha irrigation scheme had delivered any economic or community benefits. Discussion at the meeting with Hurunui District Council included explanation of why storage options for the Waiau River had been excluded (with a copy of the CSWS Stage 1 evaluation of Waiau River subsequently being sent to the participants) and explanation of data sources for estimation of the storage available in Lake Sumner. At the meeting the Mayor made a strong comment on the need for Hurunui District Council to incorporate the CSWS work into the District s strategic plan that articulated future needs, priorities, directions, and balances between different demands. Councilors present were generally supportive of this view and overall this was a positive meeting. At the meeting with the Hurunui Water Development Group some of the Water Development Group expressed concern about the evaluation of the South Branch storage, the basis for their development proposal and sought explanation for why the evaluation had come to a negative opinion of options that included South Branch dam. The meeting included discussion of the Lake Sumner option, particularly the basis for the estimate of Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 33

irrigated area as an earlier study had indicated a smaller area. Following the meeting technical data on the options was provided by Aqualinc to the Water Development Group. The meeting at Ngai Tahu was with staff of Ngai Tahu Property and Te Runanga o Ngai Tahu. Ngai Tahu were interested in the Lake Sumner option as this potentially provided sufficient water to irrigate their area of interest (Balmoral forest). They raised the likelihood of a Water Conservation Order (WCO) application for Hurunui River and indicated that while they were likely to support a WCO application they did not want the WCO to prevent storage (and associated run-of-river takes). They indicated support for a WCO focused on sustainable development not just on preservation. Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 34

6 An integrated storage option for mid-central Canterbury Context At the last meeting of the mid-central Canterbury evaluation an integrated option was proposed to: provide new irrigation north and south of Rakaia River improve low flows and flow variability in most rivers (in particular, Waimakariri, and lower reaches of Ashley, Selwyn and Ashburton Rivers) only require one new storage reservoir (Lees Valley) to limit storage-related impacts to one location supply water south of Rangitata, if possible, to address water-short South Canterbury. The option combines Lees Valley storage, water from Lake Coleridge and run-of-river takes from Ashburton and Rangitata Rivers (as per existing RDR), Rakaia and Waimakariri Rivers. Aqualinc were asked to model the combination of the following: North of Rakaia the Lees Valley option with a minimum run-of-river take north from Rakaia (10m 3 /sec), a higher and more variable low-flow regime for Waimakariri River, improved flow variability and low flows for lower Ashley River, and enhancement to Selwyn River low flows. If these flow increases result in changes to irrigated area or to reservoir storage volume both should be modelled. South of Rakaia include run-of-river takes from Rakaia River (as per flow rules) and steady supply from Lake Coleridge into RDR (by siphon) and improved low flows for Ashburton (at least 5m 3 /s). In non-irrigation season fill as many small storages as possible on the uphill side of the RDR and use these storages only for dry year release so once filled are largely kept full and just topped off for evaporation and leakage. Investigate how much water could then be taken south from Rangitata, and how much is needed for the area south of there, including the Kakahu areas that could be supplied from here. If Kakahu can be supplied from Rangitata River, investigate what does that do to reduce takes from Lake Opuha, and what does that do for either increased reliability of Opuha scheme and/or reduced demand for water from Tekapo to supply irrigable area in Opuha, Opihi and Tengawai areas. Descriptions and evaluations of the Lees Valley option and use of Lake Coleridge are provided on pages 3 and 6 of the mid-central Canterbury evaluation summary. Not all of what was requested from Aqualinc was able to be modeled in the time available. Integrated option modeling results To maintain the irrigated area at 141,000ha (i.e. all irrigable area) north of Rakaia River the active storage in Lees Valley needs to increase by 22% to 800,000,000m3. This increases the operating range for the storage reservoir by abut 2.0m, to about 9.0m for the high dam option. To illustrate the result of changes to flow regime for Waimakariri River a 2m3/s increase in minimum flow and a 5m3/s gap between A and B allocation blocks was modeled. This increases minimum flows but flow variability is still significantly reduced compared with what currently occurs and there are long periods (of a month or more) in summer when flows are flat-lined at minimum flow levels. These impacts are similar to those for the Waianiwaniwa Valley option that also takes water from Waimakariri River. Rainfall recharge to groundwater on irrigated land is about twice recharge on unirrigated land. On irrigated land soil moisture levels prevent any rain that falls from being stored in Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 35

the soil. This adds about 300mm of recharge to groundwater. Flows in Selwyn River (and other spring-fed streams) would increase through a combination of additional irrigation recharge to the groundwater-lowland stream system and the shift of irrigation takes from Selwyn River to bulk water supply from the integrated scheme. South of Rakaia River, there would be a similar increase in flows in the lower Ashburton River and other springfed streams. The magnitude of these increases to lowland stream flows was not modeled. In the integrated option, flows in the lower Ashley River (below Ashley Gorge) are highly modified, through the combined effects of water harvesting to fill the lake and releases for irrigation, with substantial loss of flood flows and long low-flow periods. Low flows may increase from additional irrigation recharge to the groundwater system. The Lees Valley storage provides the opportunity to manage flows in the lower Ashley through releases of floods and freshes but this was not included in this initial modeling of the integrated option. South of Rakaia River, Aqualinc took a broad-brush water balance approach to model this part of the integrated option. Based on 1982-2005 climate and river-flow data the model shows irrigation-season water supply (from Rangitata, Rakaia and Ashburton Rivers) exceeds total irrigation demand in all years. Peak irrigation demand, however, can only be met for about 50% of the time if the total irrigable area in Ashburton District (155,000ha) is supplied with 0.6l/s/ha (5mm/day) without an additional storage (such as Stour Valley reservoir). Options for addressing the peak flow deficit in Ashburton District include a reduction in unit application rate, an increase in the area supplied from groundwater, allocation of more Rakaia River water south (with flow on consequences north of Rakaia River), or additional storage. A combination of some or all of these would be required to meet water demand in Ashburton District and to free up water for irrigation south of Rangitata River. Evaluation of integrated option This option was evaluated by a group of about 35 comprising people from all reference groups (mid-central, north and south Canterbury) and the CSWS Project Steering Group. Working in four groups they identified positive and negative impacts of the option environmental, social/cultural, economic and other. In addition, all participants wrote what they thought of the integrated option on a page and these were collected by the facilitator. Quotes from the one-page summaries are provided in the following section. The scale of the proposal was seen as a positive and a negative huge opportunity, huge risk, huge cost, huge task. Integration was described as a no brainer by many group members, with the caveat that it would need to change from that modeled, in particular to fully meet irrigation needs (particularly south of Rakaia River), protect flow variability in Waimakariri and Ashley Rivers, and address other key concerns (see below). The billion plus dollar cost and the need for partnership between central and local government, private sector and farmers were daunting for many of the group. It was recognized that an innovative funding approach was required that reflected the long-term nature of the infrastructure and the mix of public and private benefits. The additional recharge to groundwater from irrigation, leading to more water for lowland streams (including lower reaches of Selwyn, Ashburton and Ashley Rivers) and for groundwater irrigators, was considered a positive by many of the participants. There was questioning, however, whether these benefits were adequate compensation for the loss of flow variability in the Waimakariri River and the significant alteration to the Ashley River (including total change of character of the Ashley Gorge). Positives, negatives, risks and opportunities raised in evaluation of Lees Valley storage and Lake Coleridge options were traversed again in the evaluation of the integrated option. These included likely opposition to major irrigation infrastructure (canals or tunnels) across the top of the Waimakariri-Rakaia section of the Canterbury Plains, the benefits of additional hydro-power generation (from Lake Coleridge and Lees Valley reservoir), concerns of dam failure and consequences for Rangiora, the need to modify the Rakaia Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 36

Water Conservation Order and the take in Esk River (to fill the Lees Valley reservoir) being a prohibited activity in the Waimakariri River Management Plan. For some of the participants, the latter two are very significant hurdles and make this integrated option unacceptable. The scale of the integrated option heightened concerns identified in the evaluation of individual options. In particular, some participants believe the amount of new irrigation makes it imperative that public concerns about the impacts of land intensification, primarily about dairying, are addressed before the option is progressed further. The length of time to initially fill the Lees Valley storage was an issue for some participants though others believed it would be possible to stage development. The failure of the integrated option to supply sufficient water to irrigate all the irrigable land north of Rangitata River was a major negative for some in the group. There was a range of views on how this could be addressed by reduced delivery rates (0.4-0.5l/s/ha), by the use of on-farm and other small storages, by an additional major storage south of Rakaia River, or by a combination of some or all of these. Some of the participants were strongly of the view that an integrated option had to include a major storage reservoir in Ashburton District. The inability of the proposed integrated option to address water-short areas south of Rangitata River was also seen by some of the group as a significant negative. They believe that an integrated option needs to address future water supply and demand for most of Canterbury from Opihi to Hurunui River. Comments from participants on the Integrated Option Overall attractiveness of integrated option Provides the opportunity to address all the issues of future economic and environmental and social outcomes that Canterbury aspires to in a changing climate as an integrated package. Once it is established and operating, will avoid need to continually revisit water allocation issues on a case-by-case basis. Exciting but sobering in sheer scale and potential. The scale of the project (and especially the lead up, the buy-in, the articulation of the vision to the people of Canterbury and to wider New Zealand) is more huge than anything contemplated for some time in New Zealand. Our culture and current institutions are not geared up for such an undertaking (including at central government level). An exciting option and THE only option to serve the whole Canterbury region for the next 100 years. Huge yes! Is huge a negative, not necessarily. In the context that this integrated approach can solve most issues, size shouldn t be daunting. In fact the sheer scale may well be the factor that once and for all involves central Government. One plan of this scale could simplify the bureaucracy i.e. one act of Parliament to give effect. Offers more for farming sector than wider community so is unlikely to attract central government funding. I am ambivalent about the scheme at the moment. We need to know more about the costs and impacts environmentally and socially... There are too many environmental unknowns, the potential and very real threat to water quality, the potential for a negative impact on the marine environment, reduced amenity values, landscape values, the Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 37

absence of a down-side risk evaluation, and the lack of an exit strategy. On balance I believe we need to move with caution. If it did become a reality, it just has to be good. Will they say in 50 years they got it right The integrated approach (in general) is like starting over, designing the perfect solution and putting it in place but as the Irishman said, if that s where you are going I wouldn t start from here! However it would resolve all the angst over the water debate. I am nervous about committing too wholeheartedly to this option it could get bogged down in detail and court cases and nothing could happen, or it could be a winner. The cost is awesome and will be a challenge even for central government to approve but it is the one chance to provide a comprehensive solution. Far better than the current creeping incremental death by one thousand cuts/consents. We can not afford to have episodic irrigation development." It has sufficient scale to effect a transformation in the way we use our land, water and agricultural knowledge. We could afford to do the science to a higher level. Unclear in detail at present. This is the one opportunity that Canterbury has to use its natural resources wisely to generate economic, environmental and social benefits to the whole population rural and urban. When weighed up against a collection of smaller stand-alone schemes its size must be a positive one huge dam, one huge campaign and the only one required. It can be sold as the be-all and end-all of irrigation schemes with regional (and national) benefits. Environmental concerns The one chance to get it right, but only with the right process and involvement of environmental and other interests this must not be tokenistic. I think this proposal has the potential to meet long-term needs for water in the region while meeting community aspirations for sustainable environmental and social outcomes. However, to achieve this there a number of pre-conditions including: the need to obtain lots of new information on down-stream effects. the need to ensure that external impacts are accounted for in the early stages of development of the proposal. the need to engage the whole community in well-informed debate before irrevocable decisions are made. the need to determine, identify and quantify the economic costs and benefits from the development of the resource for all sectors of the community. A think big project. Big costs, big planning requirements and big environmental impacts. Will the benefits justify the costs and environmental impacts? Loss of landscape values, impacts of intensification water quality issues, impacts on social and cultural structures. Who will pay for it? Will there be significant environmental benefits, i.e. habitats for native wildlife, rather than focus solely on water for production from the land also look at what productive uses the land can provide without more and more water use. Need to consider efficiency of use of the available water. Climate change will lead to greater demand for more and more water. Need to keep some areas in a natural state high country lakes, rivers, streams and wetlands. Need to retain or enhance coastal wetlands. Need to retain Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 38

the few remaining natural areas, especially down country. Must be good for the environment as well as for the economy. Acknowledge efforts to retain the naturalness of river and wetland systems is important while accessing water for irrigation. Accessing water via prohibited activities and changes to Water Conservation Order should be avoided. This option has the capability of globally answering the water demand in irrigating Canterbury. This gives the opportunity of managing efficient application, sustainable land management, minimising and mitigating impacts on the environment and in some cases low flows in rivers. The opportunity to network the system to meet demand and manage compliance is an added benefit. Perhaps the greatest negative is simply a failure to recognise environmental impacts and to dismiss them because the cost to some will be argued as outweighing the benefit. Another negative is that often too much attention is paid to environmental low flow provisions rather than looking at the natural hydrograph for a river and what this means to a river. I m assuming irrigation negatives, i.e. nutrient overload are manageable and constant no matter what the proposal. Integrated scheme will allow better monitoring and best practice development than smaller integrated schemes. This is such a big scheme that the current practice of ignoring intensification effects during consenting, and assuming they can be dealt with later, may not apply. The bigger the scheme the more obligation there is on developers to prove there will be no effects. Effects of intensification needs a cross-sector group to set some baselines and establish what we know versus where we need to maintain the precautionary approach because we don t know. The wins being offered to instream users (higher flows in Selwyn and Ashley Rivers, increased minimum flow in Waimakariri River) are things that they can expect anyway, without further development. The alternatives are a piecemeal hotch potch that will not be a good outcome environmentally. Timescale Taking a long-term view, the time scale to develop the scheme is not a negative, and definitely not a reason not to start. This is a long term project and it s probably the right way to view this issue. Opportunity to address equity, environment and social concerns in one hit, i.e. make tradeoffs. Unlikely to get funding. Seven to 14 years before getting benefits is too long for any funder, even central government. Too large for consenting and takes too long to provide results 7-14 years with no change in present problems. Several smaller schemes may give good results a lot sooner. Difficult to stop individuals or corporates doing their own thing in the meantime. Only a partial solution for water demand It seems the most comprehensive option but doesn t achieve all things. Still leaves a storage requirement and possibly an unattained full irrigable-area potential for Ashburton District. Provides no solution in itself for South Canterbury area. Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 39

Also highlights other areas which are still water short such as south of Rangitata and Hurunui, thus identifying more work to be done to try and achieve a satisfactory outcome for greater Canterbury. This needs to be done to get total buy in of territorial local authorities so we go to Government with one united voice. Integrated option is the only way to go as it can address many issues at the same time. However the option as presented is not complete without further storage in the Ashburton area as the extra area irrigated is not enough unless extra water can go south past the Rangitata. Other methods of extracting more water from existing users, reduced area or reduced application rates are only tinkering around the edges. Potential area and demand overstated need some priority on responsiveness of soil types. Also scarcity will promote a variety of land uses and efficiencies. There is opportunity to cover the whole irrigable area if the area is supplied with 0.4 l/s/ha and not 0.6 l/s/ha. Note that 0.4 l/s/ha is the same for Opuha scheme and RDR schemes. For a scheme as huge as this all the irrigable area must be covered to remove potential detractors and achieve a status of national importance. Climate change would suggest a number of storage sites for Canterbury s future water needs. Implementation challenges Existing water users will perceive the approach as a major threat! I m not sure there is an equitable or easy solution to that. Farmers unwillingness to share water resources, relinquish consents, etc, will slow progress. Cannot proceed unless CPW, ACWT, BHC, Ngai Tahu Properties, Mainpower etc are parked. Not sure that local or central government has the nerve to do so. The Central Plains scheme could be confined to run of river until the dam in Lees Valley is operational. Can the community work together to meet the challenge. Parochialism may interfere with process. The key thing is to ensure urban Cantabrians are getting something tangible. Public opposition to CPW are an indication of what lies ahead for this scheme. Has major opposition to overcome from the general public and instream users which could make it un-consentable. Other issues People living in the area below the dam may take some convincing this large scale is a good idea. Should be tied into a Canterbury-wide irrigation plan. [the integrated option would] strengthen rural local social networks.... Prevent migration to the cities with a greater vibrancy in rural communities staving off big city problems (sprawl, transport, etc).... In a cold lonely valley called Lees The icy wind blows through the trees If they filled it with water (Let s face it they oughta) We could water for decades with ease. Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 40

7 Where to next The integrated option generated considerable discussion, enthusiasm and concern, but is still far from being a satisfactory solution for future water supply in Canterbury. More work and wider discussion are required to develop the best possible integrated option, although even this will probably still not be acceptable to everyone nor meet the expectations of all interest groups. In the words of one of the participants, As a mechanism to engage community in a participatory approach to decision-making this [the integrated option] has much to offer. It is unlikely that this will be implemented but in so doing many of the silent problems in current water issues will be exposed and considered. Likely outcome is a much deeper appreciation of resource use (not just by farmers or recreationists but very generally). An end result of a much more modest resource-constrained integrated approach would be excellent. One of the features of the Stage 3 process has been the solution-seeking approach taken by the evaluation groups. Participants have suggested ways of overcoming or mitigating concerns. In some cases these suggestions led to new options that were then modelled by Aqualinc. Further development of an integrated option should be done by groups working in this solution-seeking manner. The Chair and facilitators believe that further development of an integrated approach be done with a multi-stakeholder/public group of about 150 and build on the CSWS Stage 3 process and its participants. This process needs to include expert presentations to ensure all participants are well informed on the water supply and demand in Canterbury, the results of monitoring and scientific studies and the range of ways of managing water and land resources to avoid or minimise adverse impacts. Wider public and interest group engagement is part of the work outlined for CSWS Stage 4 see Appendix 4 though not necessarily as described above as 150 people working together, face-to-face, to develop an integrated approach to water supply and demand in Canterbury. The CSWS Stage 3 process has identified that concerns about the impacts of land use intensification (particularly risks to water quality from irrigated dairying) must be confronted as part of development and evaluation of storage options. CSWS Stage 4 includes modelling of water quality impacts of large-scale land use intensification. The Chair and facilitators believe there is also need to define the key questions for which new topquality science is required to provide the answers, and environmental and other objectives and bottom lines that must be achieved through some combination of precaution, management practices, regulations and real time monitoring. This should be accompanied by multi-stakeholder group processes that seek to establish what is known (and agreed) and what precautionary approach is needed in recognition of knowledge gaps, uncertainties and likely long-term nature of the risks. Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 41

Appendix 1 CSWS Stage III Evaluation framework criteria developed by Reference Group, March-June 2006 Purpose Scoring to identify topics of concern that need to be discussed further by the Reference Group more than one score can be marked if there are significant differences amongst participants (to enable further discussion by the Reference Group). If statements are not applicable to the option, note this and do not score these. Assumptions the evaluation makes assumptions about the design, planning, development and operation of proposed schemes. These assumptions (see page 6) should be tested for each proposal. Evaluation of topics of concern 1 In-stream impacts The overall impact on in-stream values (including consideration of the requirements of instream birds, invertebrates and fish) from dam construction and operation of the scheme is likely to be: Significantly Adverse Slightly Slightly Beneficial Significantly adverse adverse beneficial beneficial Note the key impacts: 2 River ecosystems impacts The impacts on the environmental needs of the river (the whole ecosystem and from intake to river mouth) are likely to be: Significantly Adverse Slightly Slightly Beneficial Significantly adverse adverse beneficial beneficial Note the key impacts: 3 Surface water quality The scheme s impacts on surface water quality are likely to be: Significantly Adverse Slightly Slightly Beneficial Significantly adverse adverse beneficial beneficial Note the key impacts: Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 42

4 Groundwater quality The scheme s impacts on groundwater quality are likely to be: Significantly Adverse Slightly Slightly Beneficial Significantly adverse adverse beneficial beneficial Note the key impacts: 5 Land use The environmental impacts from the increase in agricultural production from the scheme are likely to be: Significantly Adverse Slightly Slightly Beneficial Significantly adverse adverse beneficial beneficial Note the key impacts: 6 Legal and planning conditions The impact of existing legal and planning conditions (such as a River Water Conservation Order) on the proposed scheme are likely to be a: Significant Constraint Slight Slight Enabler Significant constraint constraint enabler enabler Note key legal & planning conditions and their effect: 7 Local community support The support for the project from the local community (i.e. those directly affected by the storage or use of water) is likely to be: Why? Strongly Negative Slightly Slightly Positive Strongly negative negative positive positive 8 Regional community support The support for the project from the surrounding region is likely to be: Why? Strongly Negative Slightly Slightly Positive Strongly negative negative positive positive Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 43

9 National community support The support for the project nationally is likely to be: Why? Strongly Negative Slightly Slightly Positive Strongly negative negative positive positive 10 Equity Equity issues, such as those between new and existing users, or for users who may be required to switch from surface water to groundwater are likely to be a: Significant Constraint Slight Slight Enabler Significant constraint constraint enabler enabler Note key equity issues and their effect: 11 Storage area acquisition Issues relating to acquisition of land and flooding of land are likely to be a: Significant Constraint Slight Slight Enabler Significant constraint constraint enabler enabler Note issues and their effect: 12 Affordability The costs of meeting environment and social expectations relating to the scheme being affordable now and in the future are likely to be a: Significant Constraint Slight Slight Enabler Significant constraint constraint enabler enabler Note issues and their effect: 13 Recreation The impacts of the scheme on recreation are likely to be: Significantly Adverse Slightly Slightly Beneficial Significantly adverse adverse beneficial beneficial Note the key impacts: Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 44

14 Town impacts The scheme s impact on urban areas, such as to domestic water supply for local communities and on the flows in streams and rivers that run through urban areas, are likely to be: Significantly Adverse Slightly Slightly Beneficial Significantly adverse adverse beneficial beneficial Note the key impacts: 15 Economic benefits The scheme s financial impacts for individual farmers, the local community, the District, the region and New Zealand are likely to be: Significantly Adverse Slightly Slightly Beneficial Significantly adverse adverse beneficial beneficial Note the key impacts: 16 Co-generation and electricity use The overall impact of the scheme on electricity (including generation and electricity use) is likely to be: Strongly Negative Slightly Slightly Positive Strongly negative negative positive positive Why? 17 Tourism impact The scheme s impacts on tourism are likely to be: Strongly Negative Slightly Slightly Positive Strongly negative negative positive positive Why? 18 Societal benefits The scheme s impacts on local community physical and social infrastructure roads, hospitals & schools and on local demographics are likely to be: Significantly Adverse Slightly Slightly Beneficial Significantly adverse adverse beneficial beneficial Note the key impacts: Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 45

19 Kaitiakitanga The scheme impacts on kaitiakitangi are likely to be: Significantly Adverse Slightly Slightly Beneficial Significantly adverse adverse beneficial beneficial Note the key impacts: 20 Impacts on wetlands and springs The impacts on flows in waterways and aquifers including springs and wetlands are likely to be: Significantly Adverse Slightly Slightly Beneficial Significantly adverse adverse beneficial beneficial Note the key impacts: 21 Flood and flow impacts The impacts on river flood flows and on flow fluctuations are likely to be: Significantly Adverse Slightly Slightly Beneficial Significantly adverse adverse beneficial beneficial Note the key impacts: 22 Wider hydrological impacts The scheme s impact on the freshwater saltwater boundary of the river(s) and groundwater aquifers, and on the river mouth and adjacent coast are likely to be: Significantly Adverse Slightly Slightly Beneficial Significantly adverse adverse beneficial beneficial Note the key impacts: 23 Cultural values The scheme s impacts on cultural values, including historical and heritage sites are likely to be: Significantly Adverse Slightly Slightly Beneficial Significantly adverse adverse beneficial beneficial Note the key impacts: Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 46

24 Reliability of water supply The scheme s impact on supply-risk to existing water users, including for continued supply of water from related groundwater resources, is likely to be: Why? Strongly Negative Slightly Slightly Positive Strongly negative negative positive positive 25 Water availability & use big questions The proposal is the best use of [name river e.g. Rakaia ] water given other regional development options. Strongly Agree Slightly Slightly Disagree Strongly agree agree disagree disagree Why? 26 Impact on other options Proceeding with this scheme does not foreclose any foreseeable resource development options that could be beneficial to the community at large. Strongly Agree Slightly Slightly Disagree Strongly agree agree disagree disagree Why? Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 47

Testing assumptions Please check that these assumptions are reasonable for the storage option being considered. If not, identify the invalid assumption for further discussion with the Reference Group. Leadership The leadership for this proposed storage project is, or is likely to be, sufficient to ensure its success. The proposed storage has, or will have, tangible support from potential investors and members. Funding for capital works is, or is likely to be available. Cost and benefits The costs and benefits to all interest groups will be well identified. Construction and design The dam and scheme construction will use best engineering practice. The overall proposal will incorporate best environmental practice. Efficiency The proposal will incorporate consideration of the potential for increased efficiency in water conveyance, application or management in (related) existing schemes releasing water for irrigation of additional areas. Reliability of supply The proposal has assessed improving reliability of supply by other water-resource development options and is considered the best way of improving reliability. Land use The scheme will allow greater versatility of land use. Tangata whenua The proposal will contain an assessment of the likely position of iwi to any flow mixing. The proposal will consider Ngai Tahu Treaty rights to water. Resilience The proposed scheme is flexible and can respond to changing circumstances (including resilience to climate change and biosecurity incursion like didymo). Risks All significant risks will be identified and eliminated or reduced to acceptable levels. Innovative funding The proposal will consider diverse funding contributions and approaches (farmers, electricity generators, local government, central government, equity investors and others). The proposal will fully investigate the potential for public investment in return for environmental and social enhancement. Reliability of water supply The scheme will improve reliability of supply. Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 48

OVERALL APPRAISAL Purpose to convey the Reference Group s overall evaluation of the option. Where there is disagreement about the overall acceptability, the Reference Group will discuss this and clearly identify the reasons for such disagreement. Four-point overall evaluation scale (A D) A Appears an acceptable option (acknowledging uncertainties) B May be an acceptable option but critical information needed on specific issues to confirm this. C Probably is not an acceptable option but critical information needed on specific issues to confirm this. D Appears to be an option NOT worth further consideration CIRCLE ONE LETTER (if all group agree) INDICATE SPREAD OF SCORES (if range of scores in group) Compiled by Whit 20 September 2006 Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 49

Appendix 2 Multi-stakeholder group that developed the evaluation framework Andy Pearce Chairman Graeme Sutton Irrigation New Zealand Mike Hogden Hurunui Community Water Development Working Group Ross Millichamp Fish and Game Norm Amuri Irrigation Scheme Williamson Murray Lane Water Rights Trust Eddie Glass Ashburton Community Trust Kelvin Coe Federated Farmers, David O Connell Ngai Tahu Selwyn District Councillor Bill Hood Forest and Bird Bob Frame Landcare Research Ken Hughey Lincoln University Bob McDowall NIWA Ian Mackenzie Ashburton Community Trust, Eiffelton Irrigation Ann Jarman Community Development, Selwyn District Scheme Roger Sutton Orion Group Tony Howey Opuha Water Company Nick Brown Economist Don McFarlane South Canterbury Water Trust Appendix 3 CSWS Stage 3 evaluations and other material held at ECan Printed copies of the following are held at Environment Canterbury with the CSWS Project Manager (Ken Taylor): Descriptions of options and modelling results (from Aqualinc PowerPoint presentation); Commentary on in-stream impacts of options (from John Hayes, Cawthron Institute, PowerPoint presentation); Evaluations of options by small groups using 26-topic framework; How each participant felt about the options; What each participant thought of the integrated option; Memo on impact of proposed Hurunui River Regime Plan (from Andrew Dark, Aqualinc). Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 50

Appendix 4 Outline of CSWS Stage 4 The Mayoral Forum has agreed an outline of work for Stage 4. At the time of writing, a detail proposal has only been received (and accepted) for part 1. This work will be done by Aqualinc. Part 1 Meeting Canterbury s long-term water needs through integrated water management Task 1 optimise (hydrologically) the integrated management of ground water and surface water allocation and use (Phase 1). Task 2 integrate the management of storage-based surface water supply systems across Canterbury Plains catchments from the Ashley to the Orari. Task 3 optimise (hydrologically) the integrated management of ground water and surface water allocation and use (Phase 2). Task 4 assess the effect of irrigation efficiency gains on the size of key components of the water strategy. Task 5 compare the economic output resulting from strategy implementation with status quo output. Task 6 communications. Part 2 Institutional arrangements for integrated water management Scope identify the appropriate institutional arrangements for integrated water management in Canterbury. Integrated water management is likely to include development of water storage, redesign of existing irrigation infrastructure to improve water delivery efficiency and development of water delivery systems for distribution of water from water-rich to water-poor catchments. Part 3 Community consultation on findings of strategic water study Develop a community consultation strategy to include broad stakeholder engagement in discussion of the findings, identification of community values and priorities to be considered in formulating an overall strategy for water in Canterbury, and developing a framework for assessing community outcomes for different strategic options for water management. Part 4 Strategic management of water quality For the major storage options and associated irrigated land provide a strategic assessment of water quality addressing water quality implications, including cumulative impacts, of water storage, changes in river flow regimes, and transfer of water between catchments, standards and monitoring requirements for water quality management, and options for achieving water quality requirements through storage and flow management, land use controls and land use practices. Part 5 Integration of land use and water management Identify land use controls on irrigation and intensification practices to improve productivity and sustainability of land use, land use controls in sensitive catchments (e.g. to protect drinking water supplies), and information needed to assess likely effects of drainage and seepage from irrigation on surface water and groundwater systems. Part 6 More detailed investigations of specific sites These are likely to include Lake Sumner, Lake Coleridge and Lees Valley. Part 7 Land use designations Potential sites for storage and related infrastructure are to be identified in some way in relevant District Council and Regional Council planning instruments. Part 8 Biodiversity strategy Ensure that further consideration of water storage in Hurunui and Ashburton Rivers is done in parallel with development of a biodiversity strategy for these river systems. Final Report CSWS 3 evaluation of water storage options Hurunui River to Opihi River 51