Update of Flow Statistics for Tributaries of the Upper Waitaki River

Home , Hakataramea River, Maerewhenua River, Pukaki River, Tekapo River, Twizel River, Waitaki River

Update of flow statistics for tributaries of the Upper Waitaki River

Report No. R13/66 ISBN 978-1-927257-68-5 (print) ISBN 978-1-927257-69-2 (web)

S Gabites

June 2013

Report No. R13/66 ISBN 978-1-927257-68-5 (print) ISBN 978-1-927257-69-2 (web)

PO Box 345 Christchurch 8140 Phone (03) 365 3828 Fax (03) 365 3194

75 Church Street PO Box 550 Timaru 7940 Phone (03) 687 7800 Fax (03) 687 7808

Website: www.ecan.govt.nz Customer Services Phone 0800 324 636

Update of flow statistics for tributaries of the Upper Waitaki River

Community Summary

This summary is for non-technical members of the community and based on the information found in this report. The community summary should be regarded as summarised technical material.

The purpose The purpose of this investigation was to add to the information we had on river flow for the Upper Waitaki River tributaries. We used this to update our understanding of the river network/system and ensure we have good robust knowledge of how much water there is, where water is coming from and where it is going.

What we did Over the years 2003 and 2004 Environment Canterbury hydrology field staff measured the surface water flows at least eight times is around 140 rivers and streams in the Upper Waitaki. This information was used to create a basic understanding of river flows. It also showed where gaps in our knowledge were. To fill these gaps our hydrology field staff measured water flows at 54 locations in the Upper Waitaki over the years 2007 and 2008. Combining the information from the two investigations helps us to further complete the picture and fit the recent information into the existing knowledge.

How are we using the information? Where to from here? We now understand better how much water is where. We will be able to give more robust estimates of flow statistics to better represent river and stream flow and build a numerical model representing the interactions between river/stream flow, groundwater and water quality in the Upper Waitaki. In the future Environment Canterbury may then use this information to assist in making decisions on water allocation, minimum flows, and nutrient load limits in streams and rivers in this region.

Environment Canterbury Technical Report i Update of flow statistics for tributaries of the Upper Waitaki River

Executive Summary

Between 2003-2004, an extensive field investigation throughout the Waitaki catchment was carried out with the purpose of gaining knowledge of flows at around 140 sites (Gabites and Horrell, 2005). Some of these sites had been measured in the past while for many there was no flow information. The information gained by this survey was invaluable. Gabites and Horrell (2005) estimated seven-day mean annual low flow (MALF(7D)), and mean flow, and made recommendations for further field work to improve areas of uncertainty.

Another field survey was carried out in 2007-2008, involving 54 sites focusing on the central Mackenzie Basin rivers and streams, including Grays River, Irishman Creek, Mary Burn, Twizel River, Quail Burn, Wairepo Creek and some selected tributaries of these streams. This report gives details of updated flow statistics for these streams. However, with any work of this kind there are complications caused by some sites lacking measurements at higher or low flows, which has resulted in some streams’ estimates not being available until further gaugings are completed.

This report also makes recommendations for further field work at selected sites throughout the catchment, including all minimum flow sites, and water quality monitoring sites. A greater number of field measurements, together with a greater number of consented takes being metered, should give us greater confidence in our flow knowledge of the catchment’s tributaries.

The results from this report will assist in developing an integrated surface water, groundwater and water quality model of the catchment, which will then lead into limit setting by way of a sub- regional plan for the Waitaki Catchment. The outcomes of the model and any subsequent analysis and information are likely to feed into the sub-regional flow plan review.

ii Environment Canterbury Technical Report Update of flow statistics for tributaries of the Upper Waitaki River

Table of Contents

Community Summary ...... i

Executive Summary ...... ii

Glossary ...... v

1 Introduction ...... 1 1.1 Background ...... 1 1.2 The Waitaki Catchment Water Allocation Plan (2005) ...... 1 1.3 Canterbury Water Management Strategy (CWMS) ...... 2 1.4 Recent consent history in the catchment ...... 2

2 River flow measurements ...... 3 2.1 Recorder sites ...... 4 2.1.1 Twizel River at Lake Poaka ...... 4 2.1.2 Quail Burn at Quail Burn Road ...... 5 2.2 Flow gaugings ...... 6 2.3 Naturalising method ...... 6

3 Results ...... 7 3.1 Fork Stream, Mary Burn, Irishman Creek and tributaries ...... 7 3.2 Grays River, Stony River and tributaries ...... 10 3.3 Twizel River and tributaries, plus some small streams in the central area...... 12 3.4 Quail Burn, Hen Burn, and Wairepo Creek area ...... 15

4 Current minimum flow sites ...... 17

5 Recommendations for future work ...... 19

6 Acknowledgements ...... 22

7 References ...... 22

Appendix 1: Forks/Mary Burn/Irishman Regressions ...... 25

Appendix 2: Grays/Stony Regressions...... 26

Appendix 3: Twizel and small streams in the central area regressions ...... 29

Appendix 4: Quail Burn and Wairepo area regressions ...... 32

Environment Canterbury Technical Report iii Update of flow statistics for tributaries of the Upper Waitaki River

List of Figures

Figure 2-1: Investigation area, including all measurement sites...... 3 Figure 2-2: Twizel River at Lake Poaka gaugings vs Ahuriri River at South Diadem daily mean discharges ...... 5 Figure 2-3: Quail Burn at Quail Burn Road gaugings vs Omarama Stream at above Tara Hills daily mean discharges ...... 6 Figure 3-1: Irishman Creek flow changes above Tekapo River confluence ...... 7 Figure 3-2: Mary Burn flow changes above Tekapo River confluence ...... 8 Figure 3-3: Hydrographs for Grays at Days Bridge and Mary Burn at SH8 ...... 10 Figure 3-4: Twizel River flow changes above Ohau River Confluence ...... 13 Figure 3-5: Quail Burn flow changes above Ahuriri River Confluence ...... 15 Figure 5-1: Gauging run 2013-2014 ...... 21

List of Tables

Table 2-1: List of recorder sites used for the basis of this investigation ...... 4 Table 3-1: Flow statistics for Forks Stream, Mary Burn, Irishman Creek and tributaries ...... 9 Table 3-2: Flow statistics for Grays River, Stony River and tributaries ...... 11 Table 3-3: Flow statistics for the Twizel and tributaries and some others in the central area ...... 14 Table 3-4: Flow statistics for the Quail Burn and tributaries, and Wairepo area ...... 16 Table 4-1: Calculated Q5 flows for existing and Plan minimum flow sites ...... 18 Table 5-1: Gauging run for the Waitaki catchment for 2013-2014 ...... 20

iv Environment Canterbury Technical Report Update of flow statistics for tributaries of the Upper Waitaki River

Glossary

• Water Level recorder – As we are not able to continuously record the flow in a river, we measure the water level and establish the relationship between level and flow from periodic gaugings (stage – discharge relationship). In using this relationship we can convert the continuously recorded water level to an equivalent flow. The rating is generally checked and calibrated monthly, so is usually very reliable.

• Primary Site - A water level recorder site with 20-30 years of data or more. This record is representative of long-term flow variability and climatic conditions.

• Secondary Site - A water level recorder site with less than 20 years of data.

• Tertiary Site - (also known as a Spot Gauging Site) A site where flow measurements are carried out, but without a continuous flow record.

• Gauging - A measurement of stream flow. Various methods are used to measure the velocity of the water and the cross sectional area. Multiplying the velocity (metres per second) and cross sectional area (metres squared) gives you flow at that time. This may be in cumecs (m3/s), or litres per second (l/s). Flows in this report are given in litres per second unless stated otherwise.

• Daily mean discharges (flow) - The mean/average flow for each day (midnight to midnight). taken from a flow record.

• Flow statistics - Statistics that describe the streamflow regime. Ideally these are taken from a long-term flow record. In the case of this investigation, flow statistics were derived from available long-term records. A correlation between a long-term site and Tertiary Site is established and used to determine estimates for: o MALF (7D) = mean annual low flow (seven-day) –Determined by taking the lowest flow recorded, at a given site, over seven consecutive days in a single year. Annual values for the entire period of data are averaged to give the MALF(7D) for that site. 7- day values are used in preference to shorter durations because they are less affected by isolated short-duration errors that can occur in stream flow records. o Mean (or average) flow - Determined by taking the average flow over the length of flow record, and can be influenced by large flood events. o Median flow - The flow that is exceeded 50% of the time o Q5 = 5-year, 7-day low flow. Determined by taking the lowest flow recorded, at a given site, over seven consecutive days in a single year. All available annual flows are considered in a Frequency Analysis to determine that flow which is likely to occur once every 5 years.

• Normalising – Extending the length of flow record at a particular site by estimating historic flows. We have a few water level recorder sites which have a short term record. We can classify these as secondary sites, but generally they require normalising. This requires taking available flow data, correlating with the record of a long-term recorder nearby. Using this regression relationship, we can create a synthetic record, to basically ‘stretch’ the record to a 20-30 year period. Where this was necessary, the standard errors of the predicted flow statistics are calculated and are listed.

Environment Canterbury Technical Report v Update of flow statistics for tributaries of the Upper Waitaki River

vi Environment Canterbury Technical Report Update of flow statistics for tributaries of the Upper Waitaki River

1 Introduction

1.1 Background The Waitaki catchment is a catchment of extremes, with very high natural values in some areas to being the most modified catchment in the Canterbury region. It is the largest in the Canterbury Region, at close to 12,000 km2, and incorporates New Zealand’s highest peak, Aoraki/Mt Cook (3,754 m). There is a steep rainfall gradient with the highest parts of the catchment receiving around 8,000 mm, lowering to around 4,000 mm in the Mt Cook Village, to only 450 mm at Grays Hills Station, only 70 km from the main divide (Gabites and Horrell, 2005).

Gabites and Horrell (2005) estimated seven-day mean annual low flow (from here known as MALF(7D)) and Mean flow for 140 sites throughout the Waitaki catchment, using historical data and numerous measurements carried out in the 2003/2004 period. A significant number of further gaugings in some areas was also recommended to improve and verify these flow statistics.

In 2007/2008 a series of gaugings at approximately 60 sites, were carried out on the Upper Waitaki tributaries, including Grays River, Irishman Creek, Mary Burn, Twizel River, Quail Burn, Wairepo Creek and some selected tributaries of these streams. This series of gaugings also included many sites measured in 2003/2004.

The aim of this report is to update the flow statistics for the central Mackenzie Basin area found in Gabites and Horrell (2005) and includes several previously unmeasured locations. The methods used here are effectively the same as those found in Gabites and Horrell (2005), any variations from these are noted.

The results will assist in the development of an integrated surface water, groundwater and water quality model of the catchment, which will lead into limit setting by way of a sub-regional plan for the Waitaki catchment. The outcomes of the model and any subsequent analysis and information are likely to feed into the sub-regional flow plan review.

1.2 The Waitaki Catchment Water Allocation Plan (2005) The Waitaki Catchment Water Allocation Regional Plan (2005) (known as The Waitaki Plan) was prepared by the Waitaki Catchment Water Allocation Board under the Resource Management (Waitaki Catchment) Amendment Act 2004. The Waitaki Plan provides for allocation of water in the Waitaki Catchment and also provides guidance on environmental flow regimes, for many of the larger and more highly allocated sub-catchments. For the remaining sub-catchments, The Waitaki Plan, states that minimum flows will be the 5-year, 7-Day low flow (known from here on as the Q5), and if required, a flow-sharing threshold will be based on the mean flow.

The references for these regimes were found in Annex 1 of The Waitaki Plan (2005b) which reads:

Policy 111: In general, environmental flow and level regimes were set on the following basis:

• a minimum flow or level as specified in existing consents, or set as the 5-year 7- day low flow allocation limits are used where the removal of only a small proportion of water is considered appropriate; where further allocation is considered inappropriate (small spring-fed streams like Waikakahi Stream); in Fork Stream to maintain flows in the Tekapo River; and in areas where there are no flow recorders and it will be difficult to effectively manage minimum flows (the eastern part of the Mackenzie basin)

• flow sharing below the mean in those rivers that are important spawning tributaries of the Lower Waitaki River.

Environment Canterbury Technical Report 1 Update of flow statistics for tributaries of the Upper Waitaki River

Later in this report the derived flow statistics will be compared with the current minimum flows found on consents and those listed in the plan. This will give guidance for any future minimum flow changes.

1.3 Canterbury Water Management Strategy (CWMS) The Canterbury Water Management Strategy (CWMS) zone committee for the Upper Waitaki Zone has numerous recommendations for further work, analysis, and collaboration in the Upper Waitaki Zone Implementation Programme (ZIP) (2012). The recommendations that apply here include:

1.14 Rationalise and integrate the monitoring networks. To include: DOC, energy companies, University, District Councils and private consents data

Integrating the monitoring networks from various agencies and individuals will require cooperation and openness between all parties. It would be ideal to have all this information available in an easy-to-use public location. There is definitely room for improved facilitation between Environment Canterbury and consent holders (or at least consultants working for the consent holders), and careful management of data transfer and storage of this huge influx of water use and measurement data. Data of this kind will add extreme value to investigations such as this.

2.10 Establish, continue or extend ongoing programmes of research and monitoring to assess the effectiveness of environmental flows and nutrient limits. Progressively reassess the environmental flows that have been set on the basis of a hydrological formula in the WCWARP, with an option to use the IFIM methodology if appropriate

Section 4 and Table 4.1 show the results and how they match with the current minimum flows and flow statistics. They highlight sites that may benefit from an assessment of instream values to better determine an appropriate minimum flow.

1.4 Recent consent history in the catchment 33 consent ‘bunches’ were involved in the Upper Waitaki hearings held in early 2010. These 33 ‘bunches’ included a total of 104 consent applications, 60 of which were water permits; the remaining 44 were associated land use and discharge consents. Many of these are currently under appeal to the Environment Court and discussions around the final conditions are being mediated.

The surface water take consents granted through this process have an intensive monitoring regime attached. This includes surface water quantity and quality conditions. There are discussions around trying to collaborate as much as possible with regard to the water quality conditions, especially if they require lake monitoring. The quantity conditions are being worked through, and many of those requiring metering and measuring conditions have been implemented.

2 Environment Canterbury Technical Report Update of flow statistics for tributaries of the Upper Waitaki River

2 River flow measurements Surface water flows were measured at 54 sites throughout the Mackenzie Basin, primarily over the 2007/2008 period. Some subsequent gaugings have been carried out, for various reasons, and have been included wherever possible. The locations of all measurement sites, including recorder sites can be seen in Figure 2-1.

Figure 2-1: Investigation area, including all measurement sites

Environment Canterbury Technical Report 3 Update of flow statistics for tributaries of the Upper Waitaki River

2.1 Recorder sites Many of the recorder sites used in Gabites and Horrell (2005) have also been used here. However Omarama Stream at above Tara Hills has been upgraded from a secondary site (short-term recorder site which requires some analysis to produce 30 year synthetic flow series) to a primary site (with 30 years of record) with another eight years of data since the last investigation. All site information was updated to include data to at least the end of 2011. Flow statistics were also updated to include these data, with the exception of the Q5 values which were last calculated for the whole of the Canterbury region in 2008. These results have been used here. Details on these sites are described in Table 2-1. Two sites that are regarded as secondary sites, due to shorter flow records, the Quail Burn, and Twizel at Lake Poaka, are discussed in the following sections.

Table 2-1: List of recorder sites used for the basis of this investigation

Mean Median - Site Site Area flow flow MALF(7D) Q5 (Ls number Site name Agency classification Grid ref Start of record (km2) (Ls-1) (Ls-1) (Ls-1) 1)(2008) Ahuriri River at South 71116 Diadem NIWA Primary G39:497-320 18/09/1963 566 23,314 17,920 8,945 7,700 71129 Fork Stream at Balmoral NIWA Primary I37:014-892 30/07/1962 104 3,159 2,463 1,272 1,040 Hakataramea River at above 71103 Main Highway Bridge NIWA Primary I40:1130-0633 26/11/1963 896 5,668 3,261 1,124 780

71122 Mary Burn at Mt McDonald NIWA Primary I38:923-783 22/10/1969 49 547 398 273 228 Omarama Stream at above Environment 71189 Tara Hills Canterbury Primary H39:625-259 4/10/1988 174 1,680 1,134 612 383 16/10/1986 - Quail Burn at Quail Burn Environment 31/05/1988, 71118 Road (adj Cloud Hill) Canterbury Secondary H39:638-371 24/02/2011 - 82 722 542 305 216 03/17/1986 - Environment 30/06/1995 71117 Twizel River at Lake Poaka Canterbury Secondary H38:7860-6263 27/10/2007 - 121 2,766 1,679 444 209

2.1.1 Twizel River at Lake Poaka The Twizel River at Lake Poaka water level recorder site was re-installed in 2007 as part of a further gauging run recommended by Gabites and Horrell (2005). The Waitaki Catchment Commission had recorded water level at this site from mid-1986 to mid-1995, when it was removed. Previous analysis determined that this site was a very useful secondary site.

Attempts were made to correlate the available record with a nearby long-term flow regime for several sites including Forks, Mary Burn and Omarama. The ‘best’ fit was between the Ahuriri River at daily mean discharge (DMD) and Twizel River gauged flows (Figure 2-2). However this resulted in a fairly large amount of scatter with the large number of concurrent flows, and resulted in large standard errors.

I decided to use those 12 years of actual record rather than generate a synthetic data set from any long-term recorders. By introducing large standard errors at this phase, it will introduce much lower accuracy and greater uncertainty when used to estimate flow statistics for other sites. Obviously a longer time period would be preferable but in this case 12 years was considered the best option. Section 3.3 details the consented takes for this reach.

4 Environment Canterbury Technical Report Update of flow statistics for tributaries of the Upper Waitaki River

Figure 2-2: Twizel River at Lake Poaka gaugings vs Ahuriri River at South Diadem daily mean discharges

2.1.2 Quail Burn at Quail Burn Road The Quail Burn at Quail Burn Road water level recorder site was re-installed in 2011. This was recommended after the 2007/2008 gauging run was completed as it was clear the Serpentine, Wairepo, and Hen Burn catchments are hydrologically different from all the surrounding catchments.

Using available gaugings and DMD for the available record to 29 August 2012, the regression with the closest long-term recorder, Omarama Stream at above Tara Hills resulted in a positive relationship. For this reason it was decided to use the Quail Burn gaugings along with the DMD for Omarama Stream to better determine flow statistics for this site. The linear regression model is shown in Figure 2-2. This resulted in a coefficient of determination (r2) of 0.63. This regression equation was then used to estimate a mean flow, MALF(7D) and a Q5 value for the Quail Burn site, of 722, 305, 216 litres per second respectively. Errors for these estimated values are large (180, 179, 181 ls-1 respectively) as expected with a scatter as in Figure 2-3. These are considered the best estimates for flow statistics for this site at this time.

It should also be noted that a large snowfall occurred in the area on 15/8/2011. Two months following the snowfall, the data were removed from the regression due to raised flows in Omarama but not Quail Burn.

Environment Canterbury Technical Report 5 Update of flow statistics for tributaries of the Upper Waitaki River

Figure 2-3: Quail Burn at Quail Burn Road gaugings vs Omarama Stream at above Tara Hills daily mean discharges

2.2 Flow gaugings Concurrent flow gaugings at 54 sites, including flow recorder sites, were carried out in a series of runs over a three-day period, through 2007 and 2008. Generally it is recommended that concurrent gauging runs are done on the same day, but given the size of the investigation area, the long distances between sites, number of sites and available resources, I consider gaugings within three days is acceptable. Wherever possible, gaugings in each sub-catchment were done on the same day.

Some sites that had been measured previously, either historically or over the 2003/2004 survey, were not measured over the 2007/2008 period. In some cases it was considered that the available data were sufficient. Other sites were so remote it was decided a more effective use of the field resources pick up new sites to give us a better distribution through the basin, and to fill some gaps identified in Gabites and Horrell (2005).

2.3 Naturalising method The quantity of consented abstraction has changed very little since the Gabites and Horrell (2005) study, mainly due to the Government call-in of consents for the Waitaki Plan process and subsequent consent hearings, resulting in most consents being on hold for most of this time. The same methods for naturalising flows and estimating flow statistics were used as described in the Gabites and Horrell (2005) report. The methodology description is not repeated in this report.

6 Environment Canterbury Technical Report Update of flow statistics for tributaries of the Upper Waitaki River

3 Results

Flow statistics for mean flow, MALF(7D), and Q5 have been estimated using regression analysis for each of the measured sites. The results will be discussed in the following sections.

3.1 Fork Stream, Mary Burn, Irishman Creek and tributaries This section looks at flows and relationships in the Fork Stream, Mary Burn and Irishman Creek area. Most sites in this area correlate well with the long-term water level recorder at Mt McDonald in the upper reaches of the Mary Burn. Using these good correlations, flow statistics have been estimated (Table 3-1).

I have included gain/loss profiles for Irishman Creek (Figure 3-1) and Mary Burn (Figure 3-2) from the most upstream site down to the confluence with the Tekapo River. For reference, the estimated flow statistics for these sites are included on the plots. It is quite clear that between the few sites in the upper parts of the catchments there are only small changes in the flows, with the main differences occurring in the lower parts of the catchments. Irishman Creek spreads out across the wide plains, into numerous channels. As some flow is likely to be lost to shallow groundwater, the site that was measured represents only part of the flow in the ‘greater’ Irishman Creek. In contrast, the lower reaches of the Mary Burn have large increases in flow. It is likely that a good portion of the Irishman Creek water flows, both through surface flows and subsurface flows, into the Mary Burn above the Tekapo confluence site.

Figure 3-1: Irishman Creek flow changes above Tekapo River confluence

Environment Canterbury Technical Report 7 Update of flow statistics for tributaries of the Upper Waitaki River

Figure 3-2: Mary Burn flow changes above Tekapo River confluence

8 Environment Canterbury Technical Report Update of flow statistics for tributaries of the Upper Waitaki River

Table 3-1: Flow statistics for Forks Stream, Mary Burn, Irishman Creek and tributaries

Historical gaugings + 1814 Irishman Creek at Braemar Road 2003/2004 +2007/2008 903 391 331 378 237 385 20 y = 2.0888x - 239.39 0.69 Mary Burn at Mt McDonald Previously with Windy Ridge but now no longer secondary site. Data naturalised. Irishman trib (1) at Braemar Rd 1711380 (culvert 22) New site in 2007/2008 17 4 0 3 0 4 7 y = 0.0667x - 19.203 0.94 Mary Burn at Mt McDonald Visited 8 times but only 3 flowing gaugings. Mean outside range of gaugings. Irishman trib (2) at Braemar Rd 1711379 (culvert 38) New site in 2007/2008 0 0 0 Visited 8 times but only one flowing gauging . Mean outside range of gaugings. Irishman trib at Tekapo Canal (north 1711378 side) New site in 2007/2008 34 2 13 3 9 3 7 y = 0.077x - 8.3263 0.88 Mary Burn at Mt McDonald

Recorder site 62-72 + Irishman Creek at Windy Ridge (AKA Historical gaugings + 71128 SH8) 2003/2004 +2007/2008 1408 351 493 341 343 344 56 y = 3.3404x - 418.89 0.60 Mary Burn at Mt McDonald Not required as secondary site. Naturalised.

Irishman Creek at above Tekapo 1893 Confluence 2003/2004 +2007/2008 NA NA NA ? Poor relationships with any primary site - no estimates possible. Naturalised. NIWA Primary site - UPDATED 71122 Mary Burn at Mt McDonald 2012 547 273 228 Historical gaugings + 71127 Mary Burn at Mary Hill 2003/2004 688 52 360 53 306 53 25 y = 1.1974x + 33.436 0.98 Mary Burn at Mt McDonald

71130 Mary Burn at SH8 Bridge ECan site - UPDATED 2012 715 221 444 221 400 221 108 y = 0.9896x + 173.97 0.92 Mary Burn at Mt McDonald Data naturalised 2003/2004 + 2005 -2011 Min Mary Burn at above Tekapo flow site being regularly 1872 Confluence gauged 3150 571 1834 571 1493 571 58 y = 4.2194x + 445.67 0.65 Mary Burn at Mt McDonald Data naturalised y = Tekapo River at below Mary Burn (1.182107*Forks)+(0.26428 Not natural flows. Residual flow due to Tekapo A power station. Multiple regression 171160 Confluence 2003/2004 +2007/2008 8750 875 6171 875 5807 875 15 4*Mary Burn)+4183.169 0.87 Forks and Mary Burn used here. No plot given in Appendix. Water level recorder installed October 2012

Environment Canterbury Technical Report 9 Update of flow statistics for tributaries of the Upper Waitaki River

3.2 Grays River, Stony River and tributaries Most of the tributary sites in this part of the Mackenzie Basin have good relationships with a primary site, the majority having flow characteristics similar to the Mary Burn and the Hakataramea River. The correlations and estimated flow statistics are found in Table 3-2.

The Grays River catchment consists of extensive plains with a number of tributaries which appear to flow into the mainstem but on closer examination are ephemeral streams and only actually flow during extremely high flow events. Since the Gabites and Horrell (2005) study, ECan field staff have installed a water level recorder at the Days Bridge site on the Grays River. This is the existing minimum flow site in this catchment, and the new recorder is providing useful information on the flow regime. The additional flow information confirms the good relationship with flows in the Mary Burn displayed in Figure 3-3.

The streams that flow from Burkes Pass and the western side of the Rollesby Range are generally small and some dry even under generally average conditions. Gabites and Horrell (2005) suggested that most of the flow measured at Days Bridge comes from instream gains, fed from groundwater and swampy storage. Figure 3-3 shows the hydrographs for the Grays River compared with the swampy, spring-fed flows in the Mary Burn. Both have similar flow patterns, with long slow recession periods. There are a few exceptions in the Mary Burn plot where irrigation takes are turned on and the flow drops.

Figure 3-3: Hydrographs for Grays at Days Bridge and Mary Burn at SH8

Environment Canterbury Technical Report 10 Update of flow statistics for tributaries of the Upper Waitaki River

Table 3-2: Flow statistics for Grays River, Stony River and tributaries

Std Error of Std Error Status - years of Std Error of MALF(7D) Predicted Q5 (from of Site measurements/length of Mean flow Predicted estimate MALF(7D) 2008 Freq Predicted number Site name record estimate (l/s) Mean (l/s) (l/s) (l/s) Analysis) Q5 (l/s) N Regression Equation r2 Primary site Result comment Balloon Stream at below Stony River Historical gaugings + 2299 Road 2003/2004 459 98 104 93 78 95 8 y = 0.0781x + 16.701 0.75 Hakataramea at MHB Used 2003/2004 gauging only - older ones of poor quality - few verticals Black Forest Stream at Cattle Historical gaugings + 2263 Yards/Lake Benmore 2003/2004 165 15 21 13 10 13 13 y = 0.0316x - 14.563 0.95 Hakataramea at MHB Dead Mans Creek at Fence (about Use caution due to scatter but did use Irishman Creek as check site and 7dMALF 1711382 500m from end track) New site in 2007/2008 74 17 26 17 19 18 8 y = 0.1739x - 20.958 0.90 Mary Burn at Mt McDonald appears to fit well.

1711381 Edward Stream at SH8 New site in 2007/2008 616 48 0 Assumed 0 0 Assumed 0 8 y = 2.4739x - 730.24 0.99 Mary Burn at Mt McDonald This site goes dry when Mary Burn is approx 300 l/s. Visited 8 times but only flowing 5 Edwards Stream at Camp One/Lower Historical gaugings + 1838 Gorge 2007/2008 573 198 184 203 121 204 22 y = 1.4179x - 202.71 0.84 Mary Burn at Mt McDonald 1837 Edwards Stream at Mt Hay Station Historical gaugings only 426 66 NA NA 11 y = 1.7272x - 519.18 0.94 Mary Burn at Mt McDonald Appears to be large loses to shingles at lower end Fett Stream at above Snow 1711386 Confluence New site in 2007/2008 NA 0 Assumed 0 0 Assumed 0 Mary Burn at Mt McDonald Visited 8 times but only flowing 2

1711388 Grays Hills Stream at Little Pass New site in 2007/2008 NA 2 1 0 Assumed 0 Hakataramea at MHB Visited 8 times but only flowing 3 Predicted - Grays River (Bullocky Creek) at Glen 24 but 1711383 Rock track New site in 2007/2008 NA assumed 0 Calc +/- 30 0 Assumed 0 Mary Burn at Mt McDonald Visited 8 times but only flowing 2 Grays River at above Tekapo Historical + 2003/2004 + 2005 - 1875 Confluence 2011 Gauged regularly with 3725 558 2223 561 1977 564 34 = 1.0597x + 239.32 0.74 Mary Burn at Mt McDonald Only used data 2003 onwards. 1 outlier removed due to rainfall Ecan recorder site - UPDATED Only used data 2003 onwards. 3 outliers removed due to rainfall, freezing and a very 1871/71162Grays River at Days Bridge 4/10/2012 3331 538 1772 543 1516 548 66 y = 5.5809x + 279.77 0.78 Mary Burn at Mt McDonald low flow in the Grays Grays River trib at above Hut 1711385 (approx 100m) New site in 2007/2008 NA 8 5 5 5 7 y = 0.0093x-2.5246 0.57 Hakataramea at MHB Use caution as regression poor and well outside mean range so no estimate provided Grays River trib at Grampians Site was visited 8 times and was dry 6 of them, so can ssume 7dMALF is 0 l/s. No 1711387 driveway (Ford + Bridge site) New site in 2007/2008 NA 0 Assumed 0 0 Assumed 0 confidence with mean estimate Historical gaugings + 1839 Mackenzie River at Memorial 2007/2008 - 339 36 54 31 33 31 27 y = 0.0626x - 16.261 0.87 Hakataramea at MHB Moffat Stream at Stony River Road Historical gaugings + Mean flow outside range of gaugings - use with caution, Q5 well outside range - not 2297 Ford 2003/2004 155 28 11 23 NA 12 y = 0.0316x - 24.554 0.71 Hakataramea at MHB supplied. Red Hut Creek at DS confluence (5 or Site was visited 8 times and was dry 6 of them, so can ssume 7dMALF is 0 l/s. No 1711384 6 willows from bottom) New site in 2007/2008 NA 0 0 Mary Burn at Mt McDonald confidence with mean estimate Historical gaugings + Not great relationship but checked regression using historic gaugings with Opuha and 1735 Sawdon Stream at Mt Burgess 2007/2008 677 53 232 61 194 61 48 y = 0.103x + 132.5 0.63 Opihi at Rockwood happy with estimates provided using Opihi. *Poor relationship but 7dMALF estimate losses from above site from channel 1711391 Sawdon Stream at SH8 New site in 2007/2008 NA 100* NA upstream. Historical gaugings + 2259 Snow River at above Fett Confluence 2007/2008 248 27 94 22 59 22 22 y = 95.34ln(x) - 575.8 0.82 Hakataramea at MHB Used Stony at Slip panel as Secondary site due to poor relationship with anything Stony River at Slip Panel else.Leading to large Std Errors. Q5 and mean flow outside range of gaugings - use with 2279 Stony River at Haldon Station Bridge Historical gaugings only 1427 379 194 240 101 246 10 y = 0.951x - 202.3 0.82 Corner caution. Flows dependent on discharge from Haldon Station Irrigation Used Stony at Slip panel as Secondary site due to poor relationship with anything Stony River at Slip Panel else.Leading to large Std Errors. Q5 and mean flow outside range of gaugings - use with 2280 Stony River at Hinch Bend Historical gaugings only 1790 387 296 248 183 254 10 y = 1.153x - 184.2 0.88 Corner caution. Flows dependent on discharge from Haldon Station Irrigation Historical gaugings + 1890 Stony River at Slip Panel Corner 2007/2008 1717 177 416 103 318 104 31 y = 0.285x + 96.02 0.72 Hakataramea at MHB Mean flow outside range of gaugings - use with caution.

Environment Canterbury Technical Report 11 Update of flow statistics for tributaries of the Upper Waitaki River

3.3 Twizel River and tributaries, plus some small streams in the central area As described in Section 2.1.1, the Twizel River at Lake Poaka water level recorder has been upgraded to a secondary site as part of this investigation. With 12 years of record, it has become a very important site in the central section of the basin. Most of the gauging sites in the catchment and a number outside the catchment, have a good relationship with the Twizel River at Lake Poaka flows. Details of the correlations, and estimated flow statistics are found in Table 3-3.

As explained in Gabites and Horrell (2005), the Twizel River loses surface flow in the reaches below the confluence with the Gladstone River and the recorder at Lake Poaka. Gabites and Horrell (2005) recommended detailed gauging runs down the length of the river to further ascertain the extent of these gains and losses. The results from the eight runs can be seen in Figure 3-4, along with the estimated MALF(7D) and mean flow for each site. These gauging runs have highlighted a significant loss of surface flow over a 4.5 km reach in the area downstream of the Fenceline/Airstrip, down to the Rhoboro Downs Bridge. There are two consented takes in this reach;

- CRC011698.1, Rhoborough Downs Station Ltd (transferred from Preston March 2012), takes a total of 140 l/s from three locations for stockwater and domestic purposes.

- CRC990007, which authorises the Department of Conservation (DOC) to divert up to 250 l/s, is noted on the consent as a non-consumptive diversion for a Wildlife Pond. It is understood all water ends up back in the Twizel River, either by water or via groundwater seepage in and around Lake Poaka.

Water for these two consents is taken throughout the year. When naturalising flows a conservative approach was taken, and 140 l/s was added to all flows downstream of the takes. Despite accounting for this loss, it makes very little difference to the consistent loss in this reach, which under mean flow conditions is almost 1300 l/s and under MALF(7D) conditions almost 900 l/s. Below Lake Poaka, and downstream of the Pukaki Canal, the river is joined by Dry Stream and Fraser Stream, which under mean flow conditions contribute around 1300 l/s and under low flow conditions only 400 l/s.

Below SH8, the only main contributor is Bendrose Stream (with two consented takes of 51 l/s and 18 l/s), and even though there is no relationship with the flows in the Twizel (as noted in Table 3-3) it has a fairly reliable flow, characteristic of spring fed streams, of between 200 and 500 l/s through the range of Twizel flows, from MALF (7D) through to mean flow. It appears likely that these flows are lost to groundwater as they not obvious in the measured flows and estimated flow statistics for these sites. In December 2012 a new recorder was installed in the lower reaches of the Twizel River; together with concurrent gaugings through this catchment this will improve understanding of the local hydrology.

Environment Canterbury Technical Report 12 Update of flow statistics for tributaries of the Upper Waitaki River

Figure 3-4: Twizel River flow changes above Ohau River Confluence

Environment Canterbury Technical Report 13 Update of flow statistics for tributaries of the Upper Waitaki River

Table 3-3: Flow statistics for the Twizel and tributaries and some others in the central area

Barclays Creek at Glenbrook Farm Omarama at above Tara 171149 Track 2003/2004 only 54 4 21 5 NA 8 y = 0.032x + 0.622 0.95 Hills Q5 not estimated as well outside gauging range. 7dMALF use with care

Bendrose Stream at above Bendrose 1711006 Station Intake 2003/2004 + 2007/2008 NA NA NA No regression with any primary site

171119 Coal Creek at below Falconer Take 2003/2004 only NA 0 0 No change from 2005 report

1711373 Darts Bush US Fraser Conf New site in 2007/2008 513 250 NA NA 7 y = 120.63e0.000523x 0.64 Twizel at Lake Poaka 7dMALF and Q5 well outside range of gaugings- not supplied 1711376 Dry Stream at Ford New site in 2007/2008 218 40 NA NA 7 y = 57.385e0.000482x 0.92 Twizel at Lake Poaka 7dMALF and Q5 well outside range of gaugings- not supplied Dry Stream trib at about 300m 1711375 below gate New site in 2007/2008 NA NA NA Flows too small to obtain statistics, only 3 measurable gaugings, 8-81 l/s Exhibition Gully at Glenbrook Farm Omarama at above Tara 171150 Track 2003/2004 only 54 10 19 12 NA 8 y = 0.033x - 2.037 0.78 Hills Q5 not estimated as well outside gauging range. 7dMALF use with care Falstone Creek at Falstone Road Historical gaugings + 1844 Bridge 2003/2004 203 18 115 18 100 19 y = 0.324x + 26.10 0.81 Mary Burn at Mt McDonald No change from 2005 report Siginificant changes in this site between 03/04 (gauging range 10 - 23 l/s) and 2010/11 gaugings ( 125-136 l/s).Location slightly changed and new irrigation scheme has 171120 Farm Drain at below 'The Glens' 2003/2004 + 2010/2011 NA NA NA increased flows markedly. No regression available.

Recorder site 71-74 + Historical gaugings + Some scatter around mean flow, and Q5 outside range of gaugings - use with caution. 71114 Fraser Stream at Ben Ohau 2007/2008 1411 376 378 363 273 369 18 y = 0.4456x + 180.2 0.60 Twizel at Lake Poaka Naturalised.

1711374 Fraser Stream US Darts Bush Conf New site in 2007/2008 511 171 NA NA 7 y = 0.1064e0.000567x 0.80 Twizel at Lake Poaka 7dMALF and Q5 well outside gauging range- not supplied Shepherds Creek at above Falconer 171123 Take 2003/2004 only NA NA NA No regression with any primary site. Gauging range 35-65 l/s. Naturalised. Omarama at above Tara 171124 Silver Creek at Gorge (above intake) 2003/2004 only 87 13 40 15 NA 8 y = 0.043x + 13.03 0.78 Hills Q5 not estimated as well outside gauging range. 7dMALF use with care Sutherlands Creek at Buscot Station 171151 Track 2003/2004 only 79 11 14 10 NA 8 y = 40.11ln(x) - 267.9 0.82 Hakataramea at MHB Q5 not estimated as well outside gauging range. 7dMALF use with care

1711389 Tay Stream at Pukaki Downs track New site in 2007/2008 55 6 NA NA 6 y = 0.0717x + 8.021 0.94 Twizel at Lake Poaka 7dMALF and Q5 well outside gauging range- not supplied Tay Stream trib at Pukaki Downs Flows too small to get anything useful (dry on 4 occasions and only 2 measurable 1711390 track New site in 2007/2008 NA NA NA flows, 8 and 22 l/s) Temple Creek at above Sutherlands Omarama at above Tara 171152 Take 2003/2004 only 66 8 17 10 NA 8 y = 0.0456x - 10.786 0.90 Hills Q5 not estimated as well outside gauging range. 7dMALF use with care 7dMALF and Q5 outside range of gaugings - some confidence due to good linear 1711377 Twizel at Fenceline (Airstrip) New site in 2007/2008 3818 391 799 405 493 422 7 y = 1.3x + 222.19 0.94 Twizel at Lake Poaka regression but use with caution Twizel River at DS Gladstone 7dMALF and Q5 outside range of gaugings - some confidence due to good linear 2376 Confluence 2003/2004 +2007/2008 3655 463 1303 493 1065 504 14 y = 1.0135x + 691.12 0.87 Twizel at Lake Poaka regression but use with caution Ecan recorder site -Updated - 71117 Twizel River at Lake Poaka SECONDARY site 2766 444 209 Secondary site. Possible these statistics are a slight under estimate. Naturalised.

Historical gaugings + 7dMALF outside range of gaugings - some confidence due to good linear regression but 1711028 Twizel River at Rhoboro Downs Road 2007/2008 2525 288 152 292 NA 8 y = 1.0218x - 301.54 0.96 Twizel at Lake Poaka use with caution. Regression estimate Q5 would be 0 l/s - very low confidence Recorder site 62-70 + Historical gaugings + 7dMALF and Q5 outside range of gaugings - some confidence due to good linear 71121 Twizel River at SH8 2007/2008 4323 830 578 841 199 866 12 y = 1.613x - 138.4 0.79 Twizel at Lake Poaka regression but use with caution. Naturalised. 7dMALF outside range of gaugings - some confidence due to good linear regression but Twizel River at Upstream Ohau River Historical gaugings + use with caution. Using regression, estimate for Q5 would be 25 l/s - very low 2320 Confluence 2007/2008 4231 1028 412 1012 NA 14 y = 1.645x - 318.58 0.72 Twizel at Lake Poaka confidence. Naturalised. Water Level Recorder installed Decembver 2012.

Environment Canterbury Technical Report 14 Update of flow statistics for tributaries of the Upper Waitaki River

3.4 Quail Burn, Hen Burn, and Wairepo Creek area Gabites and Horrell (2005) recommended gauging runs be carried out on a number of sites in the Quail Burn, Hen Burn, and Wairepo Creek to increase the understanding. This field work was carried out over the period September 2007 through to June 2008. As mentioned in Section 2.1.2 the Quail Burn at the Quail Burn Road site was reinstated as a water level recorder in early 2011. It has been used as a secondary site (Section 2.1.2) for the purposes of this investigation as the flow characteristics in this area are different to other primary sites. Table 3-4 provides the site details and the calculated flow statistics. The large standard errors encountered during the normalising process are due to the use of the Quail Burn as a secondary site. In general the relationships between the Quail Burn and other sites in the area are very good.

Figure 3-5 shows the Quail Burn concurrently gauged flows. Unfortunately, all four sites were never gauged on the same day, but show similar trends. These sites are included in the 2012/2013 gauging survey, mainly targeting the higher range of flows, as nothing above mean flows had been measured at the upper two sites. Generally, the Quail Burn is a gaining stream, with contributions coming from Serpentine Creek above the recorder location. The noticeable losses are in the lower reaches after the stream flows out of the gorge and onto the Ahuriri plain down to Hen Burn Road. There are two consented takes in this area. For the purposes of this investigation, the two consented takes were measured at each visit and have been added back to the flows measured at Hen Burn Road, to represent ‘natural’ flows (Figure 3-5) and for the calculation of flow statistics (Table 3-4). Until recently these consents did not have minimum flows, but this has changed with new consents being granted in 2012. Further gaugings have been recommended to improve the understanding of this subcatchment.

Figure 3-5: Quail Burn flow changes above Ahuriri River Confluence

Environment Canterbury Technical Report 15 Update of flow statistics for tributaries of the Upper Waitaki River

Table 3-4: Flow statistics for the Quail Burn and tributaries, and Wairepo area

Historical gaugings + Ahuriri River at South 1889 Ahuriri River at SH8 Bridge 2003/2004 27912 2421 11283 1936 9842 1992 16 y = 1.1573x + 930.92 0.82 Diadem Naturalised. Water Level recorder installed December 2012 Hen Burn at Horse Gully above Quail Burn at Quail Burn GETTING MORE GAUGINGS at higher end - currently mean flow well outside range of 171121 Sutherlands Take 2003/2004 +2007/2008 NA 59 183 52 185 7 y = 0.0761x + 35.742 0.72 Road gaugings. Use with caution.

Hen Burn at above Quail Burn Historical gaugings + Quail Burn at Quail Burn GETTING MORE GAUGINGS. Some scatter at 7dMALF and below, use this estimates with 2146 Downs Intake 2007/2008 619 320 227 319 143 321 21 y = 0.9391x-59.461 0.83 Road caution. Naturalised. Historical gaugings + Quail Burn at Quail Burn GETTING MORE GAUGINGS at higher end - currently mean flow well outside range of 71115 Quail Burn at Upper Quail Burn 2007/2008 134 191 71 185 58 187 8 y = 0.1499x + 25.4 0.91 Road gaugings. Use with caution. Historical gaugings + Quail Burn at Quail Burn GETTING MORE GAUGINGS at higher end - currently mean flow well outside range of 2325 Quail Burn at Ribbonwood 2007/2008 177 192 73 186 50 188 8 y = 0.25x - 3.6348 0.96 Road gaugings. Use with caution.

Historical gaugings + Quail Burn at Quail Burn Road (adj 2007/2008/2010/2011 - Omarama Stream at above SECONDARY SITE using all Quail Burn gaugings + gaugings supplied by Dave Boraman, 71118 Cloud Hill) Updated as SECONDARY site 722 180 305 179 216 181 36 y = 0.3902x - 66.194 0.63 Tara Hills see Section 2.1.2 for details GETTING MORE GAUGINGS to confirm relationship - naturalised including 2 measured Quail Burn at Quail Burn takes. Use data with care until further gaugings and analysis completed. Includes 1711396 Quail Burn at Hen Burn Road New site in 2009/2010/2011 629 223 271 222 196 224 29 y = 0.8556x+11.005 0.97 Road Boraman gaugings 2005-2008 Quail Burn at Quail Burn GETTING MORE GAUGINGS at higher end - currently mean flow well outside range of 1711372 Serpentine Creek at Ford New site in 2007/2008 93 195 48 188 38 189 8 y = 0.1078x+14.983 0.75 Road gaugings. Use with caution. Serpentine Creek at Quail Burn Road Historical gaugings + Quail Burn at Quail Burn GETTING MORE GAUGINGS at higher end - currently mean flow well outside range of 1936 Culvert 2007/2008 136 195 58 194 41 196 14 y = 0.1874x+0.5969 0.95 Road gaugings. Use with caution. Omarama Stream at Tara GETTING MORE GAUGINGS at higher end - currently mean flow well outside range of 1711017 Spring Creek (Twizel) at SH 8 New site in 2005 + 2007/2008 148 17 83 14 69 14 9 y = 0.0607x+45.754 0.75 Hills gaugings. Use with caution. Wairepo Creek at Upper Ford - Quail Burn at Quail Burn 1711371 access from Quail New site in 2007/2008 269 221 130 202 100 204 8 y = 0.3332x + 28.116 0.80 Road

Quail Burn at Quail Burn 2286 Wairepo Creek at Ohau Downs Historical only 221.0 231 89 236 60 242 5 y = 0.3172x - 8.1903 0.86 Road Wairepo Creek at Ohau Downs Poor regression - no estimates available. Only 2 measurable flows, 9 and 21 l/s, other 1711368 driveway 1st culvert New site in 2007/2008 NA NA NA occasions 3 l/s or less) Wairepo Creek at Ohau Downs 1711369 driveway 2nd culvert New site in 2007/2008 0 0 0 Dry on every visit Wairepo Creek at Lower Ford - Ohau Quail Burn at Quail Burn 1711370 Downs New site in 2007/2008 91 199 55 189 47 191 8 y = 0.0879x + 27.93 0.57 Road Average regression - use care This site has not been measured flowing since 1981. CRC940233B can take 90 l/s from Wairepo Creek at Lake Ohau Road Historical gaugings + Quail Burn at Quail Burn intake just above this site. Min flow site on this consent is Wairepo Water Race 3.5 km 2359 Bridge 2007/2008 - 94 238 0 242 0 246 11 y = 0.2162x - 62.242 0.77 Road downstream.

Environment Canterbury Technical Report 16 Update of flow statistics for tributaries of the Upper Waitaki River

4 Current minimum flow sites

The Waitaki Catchment Allocation Regional Plan (2005a) specifies tributary minimum flows for a number of rivers and streams. Some were set at consent minimum flows (as at 2005) and some set at the estimated Q5 flow for that stream at the time of the hearing in 2005.

Some rivers and streams have also been set with an allocation limit and a flow-sharing threshold. Allocation limits were set where only a small amount of water abstraction was considered appropriate; as the Waitaki Catchment Water Allocation Board considered that some streams were already fully allocated (for example, in Forks Stream, to maintain flows in the Tekapo River). The board also refrained from setting limits in areas where they felt it would be difficult to effectively manage minimum flows due to lack of flow recorders. Flow-sharing was set to become active below mean flows in those rivers that were considered to be important spawning tributaries of the Lower Waitaki (Annex 1 to the Plan).

Table 4-1 compares recently calculated Q5 flows, the current minimum flows and those sites listed in the plan. Table 4-1 also includes the minimum flow sites found in the Lake Benmore/Aviemore sub catchments and those in the Lower Waitaki tributaries. This completes the list of minimum flow sites in the catchment, with the exception of the main stem of the Waitaki River and those sites classified as ‘residual’ flow sites. Unfortunately for most of the sites in the Twizel area Q5 estimates could not be supplied. This can be attributed to lack of the regression relationship being established with a primary site or due to the data range not extending down to Q5 low levels. It is anticipated that the sites that are missing the low end flows be picked up during the 2013/2014 field survey (see Section 5).

It is important to note that all the minimum flow information is based purely on flow statistics and not on individual instream values, ecosystem needs, or water quality. Instream assessments may be required during a sub-regional plan process.

Environment Canterbury Technical Report 17 Update of flow statistics for tributaries of the Upper Waitaki River

Table 4-1: Calculated Q5 flows for existing and Plan minimum flow sites

Estimated Comment if Q5 not Site number Site name Q5 (L/s) available Existing Minimum flow (L/s) Plan Minimum flow (L/s) Band 1 = complete cessation when flows below 12,000 l/s May-Jan, 71116 Ahuriri River at South Diadem 7700 10,000 l/s Feb - Apr WCO (Ahuriri) 1990

Band 2 = 50% reduction below 450 l/s, and complete cessation when flows below 170 l/s (no consents 71105 Awakino River at SH83 587 2005 estimate concurrently under Band 1) Q5 as determined by Ecan

171149 Barclays Creek at Glenbrook Farm Track NA outside data range 30 Q5 as determined by Ecan

2007 Duntroon Springs at Duntroon NA not yet calculated 100 Q5 as determined by Ecan 71129 Fork Stream at Balmoral (NIWA) 1040 1100 1711402 Forks Stream at U/S Tekapo insufficient data 1000 71162 Grays River at Days Bridge 1516 1800 1800 Band 1 = 50% reduction below 1500 l/s, and complete cessation 500 (Sept-Mar) 750 (Apr- 71103 Hakataramea River at Main Highway Bridge 780 when flows below 500 l/s Aug) use caution until more gaugings 2146 Hen Burn at above Quail Burn Downs Intake 143 available 20 71128 Irishman Creek at Windy Ridge (AKA SH8) 343 300

71156 Kirkliston Stream at US Water Supply NA no relationship Q5 as determined by Ecan Band 1 = 50% reduction below 600 l/s, and complete cessation when 71106 Maerewhenua River at Kelly's Gully 440 2005 estimate flows below 400 l/s 2005 Maerewhenua River at SH83 193 2005 estimate 400 1872 Mary Burn at above Tekapo Confluence 1493 1549 1500 71130 Mary Burn at SH8 Bridge 400 335 300

171127 McKays Stream at Haka Valley Bridge NA outside range 30 Q5 as determined by Ecan Band 1 = Complete cessation at 71189 Omarama Stream at above Tara Hills 383 250 l/s Nov-Apr, 750 l/s May-Oct WCO (Ahuriri) 1990 Band 1 = 50% reduction below 800 l/s and complete cessation when flows below 500 l/s Nov-Apr, 1200 71136 Omarama Stream at Wardells NA not yet calculated l/s May-Oct WCO (Ahuriri) 1990

1840 Otamatapaio River at above Footbridge 198 2005 estimate 200 Q5 as determined by Ecan

71178 Otekaieke River at Weir 200 2005 estimate 200 Q5 as determined by Ecan 71109 Otematata River at Pump house 1895 2005 estimate 1900 1711396 Quail Burn at Hen Burn Road 196 use caution 100 100

171129 Scour Stream at Haka Valley Bridge NA outside range 55 Q5 as determined by Ecan

171123 Shepherds Creek at above Falconer Take NA no relationship 14 Q5 as determined by Ecan

2280 Stony River at Hinch Bend 183 200 Q5 as determined by Ecan Sutton Stream at Gorge Outlet - above 2371 Waitangi NA outside data range 80 Q5 as determined by Ecan

171160 Tekapo River at below Mary Burn Confluence 5807 3400 outside data range 71121 Twizel River at SH8 199 but some confidence 1000 Twizel River at Upstream Ohau River 2320 Confluence NA outside data range 800 1711023 Waikakahi at Glenavy Tawai Road NA not calculated 210 210 Waikakahi at Te Maiharoa Road Bridge 71195 (Recorder) NA not calculated 210 210 1711002 Wainui Stream (Waitaki) at Camerons Culvert NA not calculated 2359 Wairepo Creek at Lake Ohau Road Bridge 0 dry 30

1711020 Wairepo Creek at Upstream Wairepo Lagoon NA insufficient data 30 1711029 Wharekuri Creek at SH83 NA not calculated

18 Environment Canterbury Technical Report Update of flow statistics for tributaries of the Upper Waitaki River

5 Recommendations for future work

Throughout this investigation, a list of recommended recorder sites and gauging sites was compiled. Environment Canterbury water quality staff were included in discussions to ensure sites of interest were being regularly monitored, and that important sites had recorders. The recommended recorder sites have now all been installed, and water levels are being recorded, flows rated and data telemetered. These sites are: - Tekapo River at Downstream Mary Burn confluence, installed October 2012, - Twizel River at upstream Ohau River confluence, installed December 2012, - Ahuriri River at State Highway 8, installed December 2012.

Table 5-1 outlines the recommended gauging run for 2013-2014, while Figure 5-1 shows these sites spatially. The first run was completed in December 2012. The 2013-2014 survey will include measuring 62 sites (but could change) including the water level recorder sites and selected spot gauging sites spread over a large part of the catchment. As a result, all of the minimum flow sites and some residual flow and Environment Canterbury’s monitored water quality sites in the catchment are measured. The aim is to cover a range of flows, from low flows to well above mean flows, but not flood conditions. Ideally this survey would be carried out monthly but given the spread of the catchment and the changing flow regimes and weather patterns, flexibility is required to complete each run when flows are suitable and staff are available. The survey requires 4 vehicles and 4-5 staff members (dependent on flow and weather conditions) over three consecutive days. It is recommended that the monthly groundwater and water quality monitoring runs are carried out during the same week. However, usually these monthly runs are fixed due to other commitments, making coordination difficult.

The intention is that results of this survey will enable more robust flow statistics which will likely feed the development, calibration and verification of an integrated surface water, groundwater and water quality model of the catchment, which will then inform limit setting by way of a sub- regional plan for the Waitaki Catchment.

Environment Canterbury Technical Report 19 Update of flow statistics for tributaries of the Upper Waitaki River

Table 5-1: Gauging run for the Waitaki catchment for 2013-2014 Site Operative number Grid ref Site name minimum flow Comments Tekapo River Catchment 71129 I37:01399-89199 Forks Stream at Balmoral (NIWA) Yes NIWA recorder and Monthly WQ monitoring site at SH8 1711402 I37:05159-82439 Forks Stream at U/S Tekapo Yes 1875 I38:9796-5876 Grays River at above Tekapo River Monthly with recorder at footbridge 71162 I38:03697-60121 Grays River at Days Bridge Yes Ecan recorder 71128 I38:97799-76599 Irishman at SH8 Yes Monthly WQ monitoring site 71130 I38:95999-66699 Mary Burn at SH8 Yes Ecan Recorder and Monthly WQ monitoring site 1872 I38:95979-57989 Mary Burn at U/S Tekapo Yes 71194 H38:66699-53559 Ohau River at Below Syphon Yes Ecan Recorder 1890 I39:98399-44599 Stony River at Slip Panel Corner 2280 I39:910-454 Stony River at Hinch Bend Yes Richard De Joux recorder (to be installed?) 1071103 I38:95870-56620 Tekapo River at D/S Mary Burn New ECan recorder - LUWQ NODE - Input to Lake Benmore 1711428 H39:87600-48670 Tekapo River at DS Pukaki River 1892 H38:89399-51899 Tekapo River at Steel Bridge (US Pukaki River) Monthly WQ monitoring site Ohau / Twizel Catchment 1711006 H38:80339-56779 Bendrose Stream at US Bendrose Station Intake Residual Part of Twizel water balance 71114 H38:750-606 Fraser River at Ben Ohau new H38:76258-52228 Kellands Pond - Wairepo Lagoon flowing back 1711377 H38:75564-67895 Twizel River at Airstrip - Fenceline 2376 H38:7476-6960 Twizel River at DS Gladstone Confluence 71117 H38:7860-6263 Twizel River at Lake Poaka Ecan recorder 71121 H38:793-573 Twizel River at SH8 1071104 H39:85680-49810 Twizel River at Upstream Ohau River Confluence Ecan recorder and Monthly WQ monitoring site 2359 H39:70999-46299 Wairepo at Lake Ohau Road Yes 1711370 H39:68425-46524 Wairepo at Lower Ford - Ohau Downs 1711020 H38:76159-51819 Wairepo at US Wairepo Lagoon Yes Dave Boraman recorder (to be installed?) Ahuriri catchment 1071105 H39:76107-31402 Ahuriri River at end Ben Omar Road Monthly WQ monitoring site 1071105 H39:70450-33060 Ahuriri River at SH8 New ECan recorder - LUWQ NODE - Input to lake Benmore 71116 G39:49699-31999 Ahuriri River at South Diadem Yes NIWA recorder 171120 H39:69999-37699 Farm Drain at DS the Glens Residual 171134 H39:55199-24899 Frosty Creek (Omarama trib) at Fence Crossing New gauging site 171121 H39:5617-3419 Hen Burn at Horse Gully US Sutherland take only need to gauge when flows > 400 at Quail recorder 2146 H39:631-337 Hen Burn at US Quail Burn Downs Take only need to gauge when flows > 400 at Quail recorder 1711427 H39:54100-22500 Manuka Creek (Omarama trib) at Twin Peaks gauging site 171122 H39:6792-2964 Old Man Gully at US of Omarama Station Take 71189 H39:62424-25960 Omarama Stream at Above Tara Hills Yes ECan Recorder 71163 H40:611-154 Omarama Stream at Dunstan Peaks 71150 H39:612-251 Omarama Stream at Twin Peaks 71136 H39:67699-30499 Omarama Stream at Wardells Yes Ecan Recorder and Monthly WQ mon site 1711396 H39:65505-35420 Quail Burn at Hen Burn Road Yes 2 irrigation intakes 71118 H39:638-371 Quail Burn at Quail Burn Road Ecan Recorder 2325 H39:57999-44299 Quail Burn at Ribbonwood only need to gauge when flows > 400 at Quail recorder 71115 H39:55799-44499 Quail Burn at Upper Quail Burn only need to gauge when flows > 400 at Quail recorder 1711372 H39:58399-44699 Serpentine Creek at Ford only need to gauge when flows > 400 at Quail recorder 1936 H39:631-391 Serpentine Creek at Quail Burn Culvert only need to gauge when flows > 400 at Quail recorder 1711017 H39:72579-47829 Spring Creek (Twizel) at SH 8 only need to gauge when flows > 400 at Quail recorder 171424 H39:74320-5633840 Swampy (Sutherlands) Creek at Ben Omar Road Monthly WQ monitoring site 1711425 H39:69110-34380 Willowburn at Quail Burn Road Monthly WQ monitoring site Lake Benmore /Aviemore Tribs 1840 H40:759-167 Otamatapaio River at above Footbridge Yes Dave Boraman Recorder 1855 H39:789-238 Otamatapaio River at SH8 Confirm inputs to Lake Benmore 71109 H40:87859-16789 Otematata River at Pump house Yes Ecan Recorder 2371 I39:967-216 Sutton Stream at Gorge Outlet - above Waitangi Yes Dave Boraman Recorder (closed) but to reopen??? Lower Waitaki tribs 71105 I40:0715-0872 Awakino River at SH83 Yes Dave Boraman Recorder 2007 I40:26999-92499 Duntroon Springs at Duntroon Yes 71103 I40:11199-06199 Hakataramea River at Main Highway Bridge Yes NIWA Recorder 71156 I40:1291-1981 Kirkliston Stream at US Water Supply Ecan recorder 71106 I41:1974-8198 Maerewhenua River at Kelly's Gully Yes NIWA Recorder 2005 I40:272-920 Maerewhenua River at SH83 171127 I39:238-239 McKays Stream at Haka Valley Bridge Yes 71178 I41:14299-87999 Otekaieke River at Weir Yes 171129 I39:2314-3984 Scour Stream at Haka Valley Bridge Yes 1711023 J41:57999-86819 Waikakahi at Glenavy Tawai Road Yes 71195 J41:59533-86188 Waikakahi at Te Maiharoa Road Bridge (Recorder) Yes Ecan Recorder 1711002 I40:22999-96599 Wainui Stream (Waitaki) at Camerons Culvert Yes 1711029 I40:00899-11799 Wharekuri Creek at SH83 Yes

20 Environment Canterbury Technical Report Update of flow statistics for tributaries of the Upper Waitaki River

Figure 5-1: Gauging run 2013-2014

Environment Canterbury Technical Report 21 Update of flow statistics for tributaries of the Upper Waitaki River

6 Acknowledgements

The author would like to acknowledge the huge effort by Environment Canterbury’s Timaru based field team, in particular Anthony de Joux, Dion Ayers, Jim Morrison, Owen Payne and Monica Wilson, who ensured all measurements were carried out according to Environment Canterbury and ensured that any problems or issues were reported and dealt with accordingly.

I also would like to thank the landowners of the Mackenzie Basin. It hasn’t been an easy road, with long-running consent issues for many of them, but without their cooperation, an investigation like this would be much less effective, and not nearly as interesting. A number of these landowners continue to support the long-term environmental monitoring of the rivers in the catchment by agreeing to allow monthly access to our field teams to maintain the water levels recorders. We are very grateful for this on-going support.

Thanks also to Jeanine Topélen and Graeme Horrell (NIWA) for the internal and external review of this report.

7 References

Gabites, S.C and Horrell, G.A (2005) Seven day mean annual low flow mapping of the tributaries of the Waitaki River, Environment Canterbury Technical Report No, R05/16.

Upper Waitaki Zone Committee (2012) Upper Waitaki Zone Implementation Programme, Report No. R12/26.

Waitaki Catchment Water Allocation Board (2005a) Waitaki Catchment Water Allocation Regional Plan

Waitaki Catchment Water Allocation Board (2005b) Waitaki Catchment Water Allocation Regional Plan. Annex 1. Decision and principal reasons for adopting the Plan provisions.

Environment Canterbury Technical Report 22 Update of flow statistics for tributaries of the Upper Waitaki River

23 Environment Canterbury Technical Report Update of flow statistics for tributaries of the Upper Waitaki River

Appendices

Notes:

All flow plots shown in Litres per second

Flows where further gaugings would be beneficial in determining more reliable relationships and flow statistics

Environment Canterbury Technical Report 24 Update of flow statistics for tributaries of the Upper Waitaki River

Appendix 1: Forks/Mary Burn/Irishman Regressions

25 Environment Canterbury Technical Report Update of flow statistics for tributaries of the Upper Waitaki River

Appendix 2: Grays/Stony Regressions

Environment Canterbury Technical Report 26 Update of flow statistics for tributaries of the Upper Waitaki River

27 Environment Canterbury Technical Report Update of flow statistics for tributaries of the Upper Waitaki River

Environment Canterbury Technical Report 28 Update of flow statistics for tributaries of the Upper Waitaki River

Appendix 3: Twizel and small streams in the central area regressions

29 Environment Canterbury Technical Report Update of flow statistics for tributaries of the Upper Waitaki River

Environment Canterbury Technical Report 30 Update of flow statistics for tributaries of the Upper Waitaki River

31 Environment Canterbury Technical Report Update of flow statistics for tributaries of the Upper Waitaki River

Appendix 4: Quail Burn and Wairepo area regressions

Environment Canterbury Technical Report 32 Update of flow statistics for tributaries of the Upper Waitaki River

33 Environment Canterbury Technical Report