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Submission on a Resource Consent Application to widen Kawarau Gorge above Smith's Falls

To: Otago Regional Council
Private Bag 1954
DUNEDIN

14 February 2001
Attention: Consents Administrator, Margaret Preston

New Zealand Recreational Canoeing Association (hereinafter NZRCA)
C/o Maree Baker
Conservation Officer
Wanganui

Applicant's name: Queenstown Lakes District Council
Consent No: 2000.632

Details of Applications: To remove part of rock buttress on TLF Kawarau River by extraction up to 12,000m3 of rock to widen Kawarau Gorge above Smith's Falls from 20 to 32 at normal flows

Location of Application: At entrance to Kawarau Gorge below Chard Farm

The NZRCA opposes the application No. 2000.632

Submission

  1. Introduction
    1. The New Zealand Recreational Canoeing Association (hereinafter NZRCA) is the national representative organisation of canoe clubs throughout New Zealand. The NZRCA is an incorporated society and is affiliated to the New Zealand Canoe Federation which in turn is affiliated to the International Canoe Federation.
    2. Currently there are approximately 20 member clubs with a membership of approximately 800. The total number of canoeists in New Zealand greatly exceeds the number of members of the NZRCA and the numbers are continuing to increase. Outdoor recreation programs at polytechnics along with many high schools and outdoor education centres now all include canoeing in the syllabus.
    3. The NZRCA is committed to long-term sustainable management of New Zealand's water resources. The association is a nationally recognised body that has continued to be actively and constructively involved in resource management processes.
    4. The NZRCA's member club in the Otago region, the Otago Canoe and Kayak Club, participated in the hearing for the National Water Conservation Order over the Kawarau river and its tributaries.
    5. All members of the executive of the NZRCA are volunteers.
  2. Submission - this application should be declined because:
    1. It will have an adverse effect, that cannot be adequately mitigated, on the outstanding scenic amenity of the Kawarau Gorge.
    2. It will have an adverse effect that cannot be adequately mitigated on the access to and enjoyment of the river, and its surroundings, for recreational river users , such as kayakers, rafters and river surfers during the operation of the consent.
    3. It will have an adverse effect that cannot be adequately mitigated on the wild and natural scenic amenity of the river in the long term.
    4. It will have an adverse effect that cannot be adequately mitigated on the natural white water features of the Kawarau River, namely in the Smiths Falls rapid and surrounds during the operation of the consent, and in the long term.
    5. It may make the area unsafe and unstable for recreation and commercial river users both during the operation of the consent and in the long-term.
    6. It is not likely that the proposal will have a significant effect on the potential for flooding in Queenstown.
    7. It will have an adverse effect on the scientific values of the Kawarau gorge.
  3. The reasons for my submission are:
    1. The Kawarau River is the subject of a National Water Conservation Order. It is recognised as outstanding, on a national scale, in terms of the following:
      1. Wild and scenic characteristics.
      2. Natural characteristics
      3. Scientific values
      4. Recreational purposes, in particular rafting, jetboating and kayaking.
      The application would have an unacceptable adverse effect on the above nationally outstanding characteristics.
    2. The Kawarau River, including the "Dogleg" section the subject of this application, is ranked as one of New Zealand's most nationally significant white water rivers for recreational kayakers. It is an extremely popular river, not only among local kayakers, but also nationally. Kayakers from all over New Zealand frequently kayak on this section of river.
    3. The Kawarau River is one of very few, high volume, grade 3 to 4 rivers in New Zealand. It provides an excellent white water, wild and scenic experience that is unmatched in New Zealand.
    4. In the River Use survey conducted by the NZRCA in 1991 this section of river ranked 6th nationally in importance. It ranked 5th in terms of the geographic diversity of users, which implies that people from all over New Zealand travel to kayak the Kawarau.
    5. The "Dogleg" section of the Kawarau one of New Zealand's premier white water river runs. The Smiths Falls rapid is the first significant rapid on this section, and is in close proximity to the proposed works. The proposal is likely to have an adverse effect on river users in terms of access, safety, quality of experience, detraction from wild and scenic characteristics and possible alteration to the white water features (see Appendix 1 for further details).
    6. The Kawarau River, in its present state, is an asset for the Otago Region, as it brings people to the region to enjoy the recreational opportunities it provides.
    7. It is not likely that the proposed work will solve Queenstown's flooding problem. It is only anticipated to have a minor effect of reducing the lake level by 0.1m during a 150 year flood. During lesser floods it is not anticipated to have a significant positive effect (see Appendix 2 for further details).
    8. The proposal does not promote the purpose of the Resource Management Act 1991.
    9. The proposal is contrary to section 6 (a) (b) and (d):
      "Matters of National Importance In achieving the purpose of this Act all persons exercising functions and powers under it, in relation to managing the use, development, and protection of natural and physical resources, shall recognise and provide for the following matters of national importance:
      (a) The preservation of the natural character of the coastal environment (including the coastal marine area), wetlands and lakes and rivers and their margins, and the protection of them from inappropriate subdivision, use, and development:
      (b) The protection of outstanding natural features and landscapes from inappropriate subdivision, use and development:
      (d)The maintenance and enhancement of public access to and along the coastal marine area, lakes and rivers."
    10. The proposal is contrary to section 7 (b) (c) (d) (f) and (g):
      "Other matters- In achieving the purpose of this Act, all persons exercising functions and powers under it, in relation to managing the use development and protection of natural and physical resources shall have particular regard to-
      (b) The efficient use and development of natural and physical resources;
      (c) The maintenance and enhancement of amenity values;
      (d) Intrinsic values of ecosystems:
      (f) Maintenance an enhancement of the quality of the environment:
      (g) Any finite characteristics of natural and physical resources."
    11. The proposal is contrary to section 104 (g), in that regard must be given to the National Water Conservation Order.
  4. My submission would be met by the ORC making the following decision:
    1. Decline the application in its entirety.
  5. I do wish to be heard in support of my submission
  6. If others present similar submission I would be prepared to present a joint submission, if I consider it appropriate.

Appendix 1: Comments on Appendix 2 of the Resource Consent Application, 'Landscape Assessment'

Synopsis

An assessment has been made of this document to consider the analysis presented on the impact of the proposed gorge widening. In this assessment we have found that there are a number of claims made in the assessment with which we would take issue. We present reasons for our concerns in these areas.

Summary of Document

The proposal is discussed and outlined. The landscape context is then discussed in terms of the features present, and the effects options of rock removal will have on these features. Sections of text of relevance to our concerns about this proposal have been excised from this report and are repeated below (in quotation marks and italics).

In the assessment Smith Falls are described as "relatively minor rapids but are the first encountered in the gorge when moving downstream from Lake Wakatipu". "Based on both biological and landscape aspects of natural character, the potential adverse effects of the proposed gorge widening are significant." "No analysis has been made of the physical aspects of the river's flow regime and characteristics, which will also be affected by the works."

"In terms of this outstanding landscape feature, the loss of the rock buttress with its prominent peak and the possible loss of the adjacent rock knob will be considerable. The drama of this impressive gorge will be diminished from on the water. The replacement of the existing weathered buttress with a 'clean' series of rock faces will introduce artificiality that will have a locally significant adverse effect on landscape quality for many years.

The amenity value of this feature will be adversely affected.

The rock buttress creates a great sense of anticipation as it blocks the view of the river downstream and signals white water ahead.

These investigations have not assessed the effects that a new ledge at water level may have on in-river activities. This will require careful analysis to ensure that it will not create safety issues or damage the experience of the Smith Falls."

The report suggests appropriate mitigation should be done to restore the rock gorge faces to a form that appears largely natural. "This may involve introducing variation to the rock platform close to water level through uneven excavation. This would help to mitigate its unnatural appearance at low flows. This will need to be assessed from a boating safety perspective."

The report concludes "in both (excavation) cases the potential adverse effects on the natural character of the Kawarau River and its amenity values are considered to be locally significant. To a lesser extent this is also true of the effects on the outstanding natural features and landscape of the gorge."

Comments on this Document

There are a number of points raised in the Landscape Assessment which we would take issue with.

1. The description of Smith Falls as a "relatively minor rapid" is totally misleading. By many river standards it is a major rapid because of the size of the whitewater it contains.

Also there are a number of other 'noticeable' rapids and whitewater and river features, albeit limited, on the Kawarau other than Chinese Dogleg and Nevis Bluff, which are claimed to be 'the most noticeable' in the document. Citroen, Retrospect, Do Little Do Nothing, the Natural Bridge and Maneater and others in the Roaring Meg section are all well known, but there are not many of them in total.

Many of the rapids on the Kawarau are only the preserve of experts, and only those that are prepared to run them, because of their power and difficulty. Nevis Bluff is only run by a very small number of the world canoeing fraternity, because of the technical difficulty and hazard posed by the size and power of the whitewater it contains. The rapid is huge even by world standards. Citroen and Retrospect are slightly less difficult but are still only essentially the preserve of expert boaters. Other rapids, such as the magnificent Sargoods Weir (previously the next most difficult rapid on the river after Nevis Bluff) and the Bannockburn Rapid are now gone, drowned under Lake Dunstan.

What is important is that Smith Falls is one of the significant rapids on the river for whitewater runners. Smith Falls is not too technically difficult and so is one of the few (three or four) rapids on the river suitable for beginner/intermediate paddlers and for introducing paddlers to 'big' water. The Dogleg section of the Kawarau, which includes Smith Falls, is the most popular river run on the Kawarau for kayakers and rafters. It only contains three rapids and Smith Falls is the only rapid in the upper section. Consequently Smith Falls is really important to the character of the whole run. Thus, it is an important rapid for white water river users throughout the country and not a "relatively minor" rapid as suggested in the landscape assessment.

2. Given the references early in the report to the characteristics the bluff provides to the river and the significance of its loss it is a little difficult to see how the conclusions are reached about the lack of importance of the bluff above Smith Falls.

In making a landscape assessment it is important to experience this and judge this from river level. The bluff not only guards the entrance to the gorge and obscures the rapid and view down the gorge but is immediately after the put in for running this section of river. When entering a gorge the narrower the entrance the greater the anticipation and visual impact of entry. When the bluff is rounded the vista of the first rapid and gorge opens up, a horizon line appears and the noise (of the rapid) announces Smith Falls. This is all really important to the overall impact of the river experience. Hence this bluff above Smith Falls is vital for the on-river whitewater experience and visual impact. It is an integral part of the natural features of the river. The river has a Conservation Order on it to protect important natural and recreational features. The bluff and Smith Falls are two important natural features and Smith Falls is one important recreational rapid.

3. In the assessment reference is made to the lack of analysis of the river flow characteristics that could be affected by the proposed works. We are concerned that removal of the bluff could affect the stability of Smith Falls.

Debris on the true left bank (TLB) just downstream, which is probably remnants of the material that created Smith Falls along with material on the opposite true right bank (TRB), could be more exposed and scoured away in floods. This could result in a more rapid widening of the river and degradation of Smith Falls than is happening naturally.

If the banks are pruned away the flow in the rapid will not be as concentrated and so the rapid will be diminished. At present the cliff probably forms a large eddy at high flows protecting the debris on the TLB from erosion, which could otherwise occur by water flowing past it if this area was effectively realigned into a straighter channel. Although modelling discussed in the hydraulic assessment shows that there would be a decrease in water velocities through the area in times of floods, we still have real concerns that erosion of the bank could occur, because although velocities would be reduced the flow pattern of water in the area and its effect on the banks could be drastically changed during floods. This could mean more scouring of the banks and accelerated natural degradation of Smith Falls.

Appendix 2: Comments on Part Three of the Resource Consent Application, 'Hydraulic Assessment of Effects of Widening Gorge Upstream of Smith Falls'

Summary

An assessment has been made of this document to gauge the benefits that accrue from the proposed gorge widening. This assessment has found that the proposal offers no real benefit in significantly reducing the level of Lake Wakatipu during floods. Alternative courses of action to investigate and alleviate the flooding are suggested.

Introduction

A consent of 2 years duration is sought to disturb the bed of the Kawarau River so that a rock buttress on the true left bank can be removed in order to widen the gorge above Smith's Falls from 20 metres to 32 metres at normal flows.

The background to this are calls to lower the levels of Lake Wakatipu during extreme flood events to reduce flood damage in Queenstown and adjacent areas. Various measures have been suggested including:

  • lowering the outlet sill at Kawarau Falls (at the lake outlet)
  • sluicing Shotover sourced gravels down the Kawarau River
  • modifications to Smith Falls
  • modifications to the area of the Kawarau gorge upstream of Smith Falls

A report prepared by Riley Consultants "Hydraulic Assessment of Effects of Widening Gorge Upstream of Smith Falls" on behalf of the Queenstown Lakes District Council (QLDC) suggests that widening the gorge entrance above Smith Falls would reduce upstream river levels at high flows, give a small reduction in the level of Lake Wakatipu during extreme flood events, and a reduction in the duration of floods in Queenstown. On the basis of potential hydrological benefits identified by Riley Consultants, QLDC have decided to proceed with applications for resource consents to modify the area of the Kawarau gorge upstream of Smith Falls.

Summary of Document

Queenstown Lakes District Council have commissioned a study to expand a hydraulic model to measure the effects of widening the Kawarau River by about 12 metres by removing a bluff just above Smith Falls.

According to the report the effects will be to:

  • Reduce water level (head) losses in this section of the river at higher flows (ie, gives a clearer water way so that more water can flow down the gorge). It will reduce flood rise in the gorge with decreasing effects upstream.
  • Increases water velocities through the upper river section at higher flows (but not immediately at Smith Falls) with the potential to take more gravel downriver.

Modelling shows that for flows less than 800 cumecs the effects of the widening will not extend up to the Shotover delta and therefore doesn't increase flows down the Kawarau nor affect lake levels in Queenstown. Such flows are typically produced in floods with return periods of about 20-25 years (eg, 1994 and 1995 floods respectively).

The direct effect of widening on reducing levels in the 1999 flood (which had a return period of 150 years) would be to reduce the lake levels by 0.1 metres (10cm).

Increased velocities down the river above and to Smith Falls will be possible, which could gradually result in regrading of the river and permit higher carrying capacity, as well as more effective gravel transport through the system.

The report discusses the effects of lowering the bed at Smith Falls by removal of the large rocks deposited in a rockslide in the 1960's, stating that degradation would be able to continue throughout the flow cycle but that it would have little effect at high flows in comparison to the effects of widening the narrow section of the gorge upstream. (Note that lowering of Smith Falls is not requested in the Resource Consent Application).

The report concludes that the depth and duration of flooding in Queenstown is influenced by flow constraints down the Kawarau River and that a major Kawarau downstream control is the gorge at Smith Falls. It concludes widening Smith Falls is a major initial step in improving flow conditions in the Kawarau River with major benefits in reducing flood rises in extreme flood events greater than the 1999 flood.

The report also concludes removal of boulders at Smith Falls will assist downstream flushing of gravels at low flows but has little effect on increasing flow at high flood levels. Also removal of boulders will reduce or remove the rapid at Smith Falls.

Comments on this Document

Overall the data in the report show that the benefits of widening the river are really small and not sufficient to justify undertaking the project. The report also neglects to address issues of concern to canoeists about the potential accelerated degradation of Smith Falls nor considers how the proposed work above Smith Falls would fit into a larger scheme for alleviation of flood damage.

  1. As the report concludes, major benefits are claimed when flood events larger than the 1999 flood occurs. The latter flood, however, was a 150-year return flood! In all probability we will not see one of this magnitude again in our lifetime! The reduction in the lake level for the 1999 flood is only predicted to be 0.1 metre, which is minor and not major as claimed, as the lake would already have risen to a very high level and caused a significant level of flooding and damage.
  2. No benefit accrues with floods of lower levels.
  3. The hydraulic assessment does not deal with aspects of relevance to whitewater users of this river and particularly users of Smith Falls. No discussion is presented on the likely effects of the bluff removal on the increased degradation of the rapid, which could be likely. The whitewater features in this river were one of the main reasons a Conservation Order was granted.
  4. The hydraulic assessment does not model any of the other scenarios suggested as possibilities to help alleviate high lake levels during large flood events. If this proposed work is part of a greater scheme then its place in this needs to be put in context so that the real impact of all components in the overall scheme are clear. As it is by it self this work seems to have little benefit and even with other proposals being initiated this could still be the case. The hydraulic models investigated should include analysis of the effects of all the proposed works because it may be that the work at Smith Falls is unnecessary and still of no benefit at all when any other works are completed.

Alternative Methods to Alleviate the Flooding from Lake Wakatipu

Perhaps the best solution to the problem that QLDC seeks to address would be to prevent any future building below the current 150 year return flood lake level and ensure floods therefore don't have the same impact in the future. Also progressively moving buildings and redeveloping areas, which were flooded in the 1999 flood, to higher levels and not permitting rebuilding at lower levels, would also be wise. Lets learn from what we see happening around us! The problem has been happening for centuries throughout the world where man has built near waterways!

More in depth hydrology studies may be useful to investigate other options for reducing the actual or impact of high lake levels as the result of severe rainstorm events and consequent flooding. These could include:

  • A much more comprehensive hydrological study of the issue, which really does canvass all the options for lessening the impact of floods in the region, and in which new cross section data and level data is gathered from adjacent to the Shotover River down to Smith Falls, is required to understand whether gravel is accreting or ablating where the Shotover joins the Kawarau. This would allow a greater understanding of the situation and help decide whether the bed sediment problem is getting better or worse. This may include some of the following options;
  • Methods to stabilize the Shotover Catchment and prevent or lessen the huge sediment transport out of that catchment. This could have the added benefit of slowing the runoff of water from that catchment and reducing the severity of floods;
  • Examination of the option to lower the level of Lake Wakatipu or control the lake level, so that the lake has a bigger buffer capacity to lessen the impact of major floods and not reach such high levels. This could incorporate controlled release of water from the lake before large rainstorm events, in the same process used by electricity generators to ensure hydro lake levels do not get too high (no information is supplied in this report as to whether or not this is feasible, but if it is it should be thoroughly investigated);
  • Acceptance that if, as the result of hydrological studies, the only option is to permit building above some defined level because in the final analysis there is no other cost effective way to sensibly control flooding in severe events, that this option be adopted. We need to learn to live with nature, engineering control structures cannot always provide the solutions we need, especially in the case of extreme rainfall events.

Maree Baker
Conservation Officer
New Zealand Recreational Canoeing Association

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