Fishing News index> May 2007

The following summarises some of the key parts of the scheme and their potential effects on Fish & Game’s interests and values. We hope this helps you to understand more about the ramifications of this proposal.

Massive water abstraction from the Waimakariri River

· The total water take from the Waimakariri will be up to 40 cubic metres of water per second (40,000 litres per second).

· Takes will occur from two intakes on the south bank of the river –

(1) The upper intake is located approximately 3km upstream from the Kowai confluence. A bulldozer will be required in the riverbed repeatedly to push the river towards and into this intake.

(2) The lower intake will be tunnelled through the rock abutment supporting the Waimakariri Gorge bridge. Again some bulldozer work in the river will be required at this point.

· Irrigators are already allocated about 20 cubic metres of water per second from the Waimakariri - CPW would approximately triple the amount of water currently taken.

· Investigations by Fish & Game suggest that this water take will have a massive adverse effect on salmon angling. CPW will draw the river down to its minimum flow for extended periods during the peak salmon fishing period. This will reduce the frequency of flows in the estimated salmon fishable range by at least 70% - potentially even more during key months such as February and March.

· Salmon passage is also likely to be affected in braided sections, and also downstream of intakes.

· Fish & Game also believe that the flatlining of the Waimakariri River will also significantly restrict the abundance of adult trout in the river, through reducing the amount of available instream habitat.

· Flatlining may also render the Waimakariri more vulnerable to didymo infestation (further discussion on didymo risk is provided later).

· Reducing the flow variability of the river particularly during summer months will also increase contaminant concentrations in the lower parts of the river, increase water temperature, reduce dissolved oxygen levels, and increase the likelihood of algal blooms.

· Ecological productivity based on periphyton and water insects (which provide food for fish) will also be affected.

· The taking of such a large volume of water will inevitably draw huge numbers of adult fish and fish fry out of the rivers and into the intake system.

Massive water abstraction from the Rakaia River:

· The total water take covered by this application from the Rakaia will be up to 40 cubic metres of water per second.

· Takes will occur from two intakes on the Rakaia:

(1) CPW will take from one point on the north bank of the river, located approximately 7 km downstream from the Rakaia Gorge bridge. This will involve considerable bulldozer work in the river to create a diversion bank across part of the riverbed and a gravel weir to turn water into the intake channel; and to excavate a large channel off a major braid.

(2) Confusingly, a different group (the Ashburton Community Water Trust, or ACWT) are also covered by this consent application. ACWT intend to take their water take from an intake on the south bank about 5km upstream from the Highbank power station. Little is known about the ACWT intake

· ACWT and CPW will ‘share’ this water so CPW may take all 40 cumecs, while at other times ACWT may take some or all of this water.

· Irrigators are already allocated about 30 cubic metres of water per second from the Rakaia – CPW/ACWT will more than double this amount.

· NIWA investigated the effects of this water take on salmon fishing in 2002 and found that “unfortunately, fishing for salmon on the Rakaia River is not adequately protected by the minimum flows of the National Water Conservation Order.” They concluded that the proposed water take (which has not changed since 2002) would result in a significant decrease in the frequency of salmon fishable flows in the Rakaia.

· Many of the ecological effects noted above in relation to the Waimakariri water take will also apply to the Rakaia water take.

Open canals to take water from the rivers and move it around the plains:

· These canals will repeatedly cross a number of rivers and streams, requiring major disturbances to riverbeds at each crossing point.

· According to CPW, the rivers crossed, and the total number of crossings for each river, include:

- Kowai River (1)

- Hawkins River (4)

- ‘Unnamed’ rivers and streams (40)

- Hororata River (1)

- Selwyn River (1)

- Cordys Stream (1)

- Blacks Stream (1)

- Irwell River (5)

· We know this list is not complete. For example, Hacketts Creek (a significant salmon spawning stream just upstream from the Kowai River) will be hugely affected by the headrace canal – but this not mentioned in CPW’s description of the scheme.

· Major disturbances to riverbeds poses several threats to ecosystem health, including localised destruction of all instream habitat and aquatic life, sedimentation of rivers, and disruption of fish passage.

· It is also likely that recreational access to and along these rivers, and the Waimakariri and Rakaia Rivers, will be adversely affected.

Discharges of surplus water and contaminants

· The scheme will discharge surplus water and associated contaminants to a number of rivers. Single or multiple discharges are likely to occur in the following rivers:

- Rakaia River

- Hororata River

- Selwyn River

- Waimakariri River

- Hawkins River

- Waianiwaniwa River

· Discharges include ‘bywash’ discharges (this is excess water which travels through the scheme and is not used by farmers), ‘sluicing’ discharges, and ‘emergency’ discharges (CPW state these would occur following heavy rain or an electricity outage).

· Emergency discharges will be required following power outages or heavy rainfall. The size of these discharges is quite staggering – for example, an emergency discharge could see a brief pulse of 21.5 cubic metres of water per second suddenly released into the Selwyn River.

· Sluicing discharges flush sediment out of settling basins (these basins are enlarged canal sections near to the intake that are designed to slow flow and encourage ‘settling’ of suspended solids). CPW expect that each basin will trap about 20,000 cubic metres per year of sediment. To flush this out large flows will be sent about once a week through the basin – these discharges will have a high sediment load and will send a “noticeable floodwave” into the Waimakariri and Rakaia Rivers.

· Discharges will include water taken from both the Rakaia and Waimakariri Rivers. When the mixing of waters from CPW scheme is seen in a regional context, it becomes apparent that the scheme creates a linked body of water from the Rangitata River all the way north to the Ashley River. This creates a huge biosecurity risk. For example, if didymo infested any of these waters it would become very difficult to prevent it spreading quickly throughout Canterbury.

Using water to irrigate farmland:

• While CPW claim that 60,000ha will be supplied with water, we know that about 30,000ha of that land has access to groundwater, so the actual amount of land that will be irrigated from scheme water is difficult to say.

• The intensification of land use in the upper catchment will increase nitrates and phosphate contamination of groundwater. This, in turn, will increase nitrate and phosphate levels in lowland streams and Lake Ellesmere, with consequential effects on their instream environments.

• CPW will not put any restrictions on the type of farming supported by the scheme - use will be “farmer’s choice”. They believe that 60% of land will be used for pasture (most of which will be dairying) and the remaining 40% for crops. Many believe these figures are wrong, and that the scheme will exclusively support dairying.

• Farmers will have to order water at least 3 days in advance of needing it. Once they have ordered water, CPW will require farmers to use it - even if it rains and soils are already wet. This is both inefficient and will increase nitrate and phosphate contamination.

• CPW mention the development of a best practice irrigation ‘code of practice’ – but they will not publicly release this, and Fish & Game understand it will not be tabled until the hearing – so any claims made about a ‘code’ or ‘agreement’ should be treated with caution.

• CPW also state that the scheme will enhance lowland rivers. Fish & Game view this claim with great scepticism. For this to occur, the scheme would need to provide:

- A massive, year-round increase in the regional groundwater table.

- Protection of that added water from being ‘poached’ by other groundwater takers in and below the scheme area.

- Water leaching down to the bottom of the catchment that not contaminated by nitrates, phosphates and other contaminants.

• Technical reports must be tabled by CPW and peer reviewed by independent experts before we can reliably ascertain what effects (either positive or negative) the scheme will have on lowland streams.

Other Fish & Game concerns include:

· Potential effects on gamebird habitat and hunter amenity values.

· Poor standard of information provided by CPW about the effects of the scheme and how those effects will be avoided, remedied or mitigated.

· Loss of Fish & Game values in the Waianiwaniwa Valley (site of proposed dam).

· Water wastage through leakage and evapotranspiration of transporting water via an open canal network.

· The effects of construction (noise, dust, loss of access to and along rivers) on angler and hunter amenity values.

We welcome your feedback, suggestions and questions on the CPW scheme and how it may affect Fish & Game’s interests and values.

Please contact Environment Officer Jason Holland at:

Email: jholland@fishandgame.org.nz

This document updated 30 July 2006.