The quality of coastal waters between Kaikoura and Pegasus Bay July 1993 – June 2006

Report U07/16

Lesley Bolton-Ritchie

March 2007

Report U07/16

58 Kilmore Street PO Box 345 Christchurch Phone (03) 365 3828 Fax (03) 365 3194

75 Church Street PO Box 550 Timaru Phone (03) 688 9069 Fax (03) 688 9067

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

The quality of coastal waters between Kaikoura and Pegasus Bay

Executive Summary

This report presents and interprets the water quality data collected by Environment Canterbury at sites located from Kaikoura to south Pegasus Bay between July 1993 and June 2006. The data were collected for varying periods of time, over different time periods and the sites sampled changed over time.

For the purpose of this report the coastline from Kaikoura to Pegasus Bay was divided into three geographic areas. These areas were Kaikoura (from just north of Kaikoura township to Haumuri Bluffs), Hurunui (from Haumuri Bluffs to just north of the Waipara River mouth) and Pegasus Bay (from just north of the Waipara River mouth to Scarborough Beach). Samples were collected from nine Kaikoura, six Hurunui and eight Pegasus Bay sites. Sites were typically sampled monthly over a year-long period but the year/s of sampling at the sites varied. Some sites were only sampled for a year while other sites were sampled for two or more year-long periods.

In the Kaikoura area nutrient and other determinand concentrations differed between sites and were also more variable at some sites than others. The results indicate that the rivers, creeks and streams that discharge to the coast in this area impact on coastal water quality, with: • Lyell Creek affecting coastal water quality at the site located just right of the creek mouth • The Kowhai River affecting coastal water quality in South Bay • The Ote Makura stream affecting coastal water quality in Goose Bay • The Oaro River affecting coastal water quality at Oaro

Oxidation pond seepage in particular, but also dairy factory wastewater and Middle Creek water, could account for the variability in TN and TP concentrations in the sea water 1 – 2.5 km south of these inputs. The coastal water in Ingles Bay is not impacted by any significant nutrient inputs.

In the Hurunui area the variability in nutrient concentrations at some sites indicated site specific, localised influences on coastal water quality. These localised influences are more than likely the surface water bodies that discharge to the coast in the vicinity of each sampling site.

In Pegasus Bay the near shore salinities were lower than those further from the shore which suggests that all of the nearshore water in Pegasus Bay is slightly diluted. The freshwater sources are the Waimakariri, Waipara and Kowai rivers, Ashley Estuary and Avon-Heathcote Estuary/Ihutai and stormwater outlets. The nutrient data indicate that water flowing out of the Avon-Heathcote Estuary/Ihutai affects the sea water nutrient concentrations to at least 6.2 km north and 1.8 km south of the estuary mouth. Avon-Heathcote Estuary/Ihutai water has a greater impact on nutrient concentrations at the waters edge in Pegasus Bay than the Waimakariri River does. This should change once sewage is no longer discharged into this estuary. The data suggests that Waimakariri River water affects the salinity but not the nutrient concentrations at Woodend Beach (5.5 km north) and Spencerville Beach (4.6 km south) of the river mouth. To determine the along-shore extent of the impact on the Waimakariri River on nearshore nutrient concentrations will require sampling at sites located close to and at increasing distances away from the river mouth. The stormwater discharged at Waimairi Beach likely affects enterococci and chlorophyll-a concentrations in the sea water at this beach.

The information in this report provides: • a baseline against which any large changes in water quality as a result of the discharge of treated sewage directly into Pegasus Bay (from the Waimakariri District Council outfall and the Christchurch City Council outfall) can be assessed. • a baseline against which any large changes in water quality as a result of lower nutrient concentrations in the Avon-Heathcote Estuary/Ihutai (once sewage is no longer discharged into the estuary) can be assessed. • information that will be useful to resource managers in assessing the suitability of water quality for the uses and values associated with this part of the coast • information that will be useful to future resource consent applicants for, for example, aquaculture or discharges to the coast.

Environment Canterbury Technical Report 1 The quality of coastal waters between Kaikoura and Pegasus Bay

2 Environment Canterbury Technical Report The quality of coastal waters between Kaikoura and Pegasus Bay

Table of Contents

Executive Summary...... 1

1 Introduction ...... 7 1.1 The study area ...... 7 1.1.1 Kaikoura...... 7 1.1.2 Hurunui...... 8 1.1.3 Pegasus Bay...... 9 1.2 Kaikoura to Pegasus Bay water quality ...... 9 1.3 Objectives of this study...... 10

2 Methods ...... 10 2.1 Sites and depths ...... 10 2.2 Sampling regime...... 10 2.3 Sample collection...... 10 2.4 Sample analyses...... 11 2.5 Data analyses ...... 11

3 Kaikoura results and discussion ...... 12 3.1 Results ...... 12 3.1.1 Between sites...... 12 3.1.2 Over time ...... 16 3.2 Discussion...... 16 3.2.1 Influences of creeks, streams and rivers ...... 17 3.2.2 Other influences...... 21 3.2.3 Site K3 in Ingles Bay...... 21

4 Hurunui results and discussion...... 21 4.1 Results ...... 21 4.1.1 Between sites...... 21 4.1.2 Over time ...... 24 4.2 Discussion...... 24 4.2.1 Influences of creeks, streams and rivers ...... 24 4.2.1 Other influences...... 27

5 Pegasus Bay results and discussion ...... 28 5.1 Results ...... 28 5.1.1 Between sites...... 28 5.1.2 Over time ...... 33 5.2 Discussion...... 36

6 Future investigations and monitoring...... 38

7 Acknowledgements...... 39

Environment Canterbury Technical Report 3 The quality of coastal waters between Kaikoura and Pegasus Bay

8 References...... 39

Appendix I: Details of the sampling sites...... 41

Appendix II: Details of analyses included in the water quality monitoring programme...... 42

Appendix III: Comparison of surface water nutrient concentrations between sites in:...... 43

• the Kaikoura area ...... 43

• Pegasus Bay ...... 43 over each year-long sampling period...... 43

Appendix IV: Comparison of chlorophyll-a, enterococci, salinity and turbidity between Pegasus Bay sites over 2005-2006...... 46

Appendix V: DIN concentrations in Lyell Creek, Kowhai River and Middle Creek over 2005-2006...... 48

Appendix VI: Summary of nutrient concentrations at the Karaki Yacht Club, Waimakariri River mouth (2002 - 2006) (Site CRC300245) ...... 49

4 Environment Canterbury Technical Report The quality of coastal waters between Kaikoura and Pegasus Bay

List of Figures

Figure 1.1 Kaikoura to Pegasus Bay. Each area is marked 7 Figure 1.2 Kaikoura Peninsula details 8 Figure 1.3 Pegasus Bay details 9 Figure 2.1 Kaikoura area sampling sites 10 Figure 2.2 Hurunui area sampling sites 10 Figure 2.3 Pegasus Bay sampling sites 11 Figure 3.1 Nutrient concentrations (mg/L) at sites in the Kaikoura area 14 Figure 3.2 Concentrations of other determinands at sites in the Kaikoura area 17

Figure 3.3 Concentrations (mg/L) of NH3N, NNN, TN and TON over time at sites in the Kaikoura area 18 Figure 3.4 Concentrations (mg/L) of DRP and TP over time at sites in the Kaikoura area 19 Figure 4.1 Nutrient concentrations (mg/L) at sites in the Hurunui area 23 Figure 4.2 Turbidity at sites in the Hurunui area 24

Figure 4.3 Concentrations (mg/L) of NH3N, NNN, TN and TON over time at sites in the Hurunui area 25 Figure 4.4 Concentrations (mg/L) of DRP and TP over time at sites in the Hurunui area 26 Figure 5.1 Nutrient concentrations (mg/L) at sites in Pegasus Bay 30 Figure 5.2 Concentrations of other determinands at sites in Pegasus Bay 32 Figure 5.3 Chlorophyll-a concentrations over time at sites in Pegasus Bay 33 Figure 5.4 Concentrations (mg/L) of NH3N, NNN, TN and TON over time at sites in Pegasus Bay 34 Figure 5.5 Concentrations (mg/L) of DRP and TP over time at sites in Pegasus Bay 35

List of Tables

Table 2.1 Chemical, biological and physical determinands 11 Table 3.1 Summary of nutrient concentrations (mg/L) at Kaikoura sites, 1993-2006. 13 Table 3.2 Summary of concentrations of other determinands at Kaikoura and Hurunui sites 16 Table 4.1 Summary of nutrient concentrations (mg/L) at each Hurunui site, based on all the data collected between 1994 and 2001 22 Table 5.1 Summary of nutrient concentrations (mg/L) at each Pegasus Bay site, based on all the data collected between 2000 and 2006 29 Table 5.2 Summary of concentrations of other determinands at sites in Pegasus Bay 31

Environment Canterbury Technical Report 5 The quality of coastal waters between Kaikoura and Pegasus Bay

6 Environment Canterbury Technical Report The quality of coastal water between Kaikoura and Pegasus Bay

• Pegasus Bay – from north of the 1 Introduction Waipara River mouth to Scarborough in Christchurch. This is approximately 1.1 The study area 60 km of coastline.

The study area extends from just north of 1.1.1 Kaikoura Kaikoura township to Scarborough in

Christchurch (Figure 1.1). This is approximately 190 km of coastline. For the This area features rocky coastline and shingle purpose of this report the coastline has been beaches. The rivers and creeks discharging into divided into three geographic areas (Figure the sea in this area are (from north to south) Lyell 1.1). These areas are: Creek, Kowai River, Kahutara River, Ote Makura • Kaikoura - from just north of Kaikoura Stream and the Oaro River. These water bodies township to Haumuri Bluffs. This is flow from bush through farmed areas to the sea. approximately 40 km of coastline including Kaikoura Peninsula. • Hurunui - from Haumuri Bluffs to north of the Waipara River mouth. This is approximately 90 km of coastline.

Figure 1.1 Kaikoura to Pegasus Bay. Each area is marked

Environment Canterbury Technical Report 7 The quality of coastal water between Kaikoura and Pegasus Bay

The township of Kaikoura is adjacent to Kaikoura end up in the sea. It was estimated (in 1998) that Peninsula (Figure 1.2). There is a settlement in tourism was directly responsible for 25% of the South Bay but the commercial centre and largest peak demand of sewage treatment (Simmons and area of housing is on the northern side of the Fairweather, 1998 as cited in McNicol et al, peninsula. Kaikoura township has a permanent 2001). It is likely that this percentage has since population of approximately 2,200 (2006 Census) increased. with a considerable number of holiday homes and a large number of tourists (local and overseas). In 1998 the calculated number of tourists visiting Kaikoura in a year was 493,000, with 356,000 of these staying overnight (Simmons and Fairweather, 1998 as cited in McNicol et al, 2001). In addition the calculated growth rate in visitor numbers for the period 1999 to 2003 was 14% per annum, with the estimated annual tourist numbers for 2003 being 1.3 million. As a result of Kaikoura being such a popular tourist destination, there has been considerable growth in facilities such as accommodation, shops and restaurants, and an increase in job opportunities (approximately 30% of jobs in the Kaikoura district depend directly or indirectly on tourism, McNicol et al., 2001). This increase in job opportunities has lead to an increase in housing in the town.

With the number of people living and visiting the town and the developments that have occurred comes: • Considerable volumes of sewage

• Considerable volumes of traffic • An increase in the area of impervious Figure 1.2 Kaikoura Peninsula details surfaces (buildings and carparks).

The coastal water quality issues that arise from these are direct or indirect discharges of 1.1.2 Hurunui stormwater and sewage. This area features rocky reefs and shingle beaches backed by cliffs along much of the Stormwater transports any nutrients, soluble and coastline. The rivers discharging directly into the insoluble toxic substances (metals, pesticides, sea in this area are (from north to south) Conway petroleum hydrocarbons) litter, pathogens and River, Waiau River, Hurunui River, Blythe River sediment (Vincent and Pugh, 1997) that are and Motunau River (Figure 2.1). The northern present on impervious surfaces. There are two three of these flow from the mountains/foothills consented discharges of stormwater to the sea through farmed areas to the sea. The Blythe and (Figure 1.2) and a number of other stormwater Motunau rivers flow from the farmed coastal hills discharges to the foreshore of Ingles Bay (M. to the sea. There are also small creeks that flow Dazzler, Connell Wagner, Pers.comm.). from the farmed coastal hills to the sea. Stormwater is also discharged to soakage pits adjacent to the foreshore and into Lyell Creek, There are small coastal settlements in Gore Bay and there is diffuse runoff from the roads; it is and Motunau (Figure 2.1). These settlements likely that most contaminants from these sources consist of permanent residences and holiday would eventually end up in the sea. homes. The houses have septic tanks for their sewage and wastewater. Stormwater flows to The Kaikoura sewage treatment plant (north of adjacent waterways to eventually end up in the Kaikoura) discharges secondary treated sewage sea. from the oxidation ponds into soakage pits adjacent to the coast (Figure 1.2). It is likely that There is no public road access to long stretches of the nutrients from the treated sewage eventually the coast, in this area.

8 Environment Canterbury Technical Report The quality of coastal water between Kaikoura and Pegasus Bay

1.1.3 Pegasus Bay discharged to land. Treated Rangiora, Kaiapoi This area features both shingle and sand and Woodend sewage is now discharged directly beaches. The shingle beaches occur north of into Pegasus Bay some 1.5 km from shore (Figure about the Kowai River and the sand beaches 1.3). This outfall was commissioned in April 2006. occur about south of this river. The rivers Prior to this treated Rangiora and Kaiapoi sewage discharging directly into the sea are (from north to was discharged into tributaries of the Waimakariri south) the Waipara River, Kowai River, and River and treated Woodend sewage was Waimakariri River (Figure 1.3). These rivers flow discharged to land. At present the Christchurch from the mountains/foothills through farmed areas City tertiary treated sewage is discharged into the to then discharge into the sea. Other creeks and Avon-Heathcote Estuary/Ihutai. The discharge to rivers discharge into estuaries or a lagoon to then the estuary will continue until 2009. Then the interface with the sea. Saltwater Creek and treated sewage will be discharged directly into Ashley River discharge into the Saltwater Pegasus Bay some 3 km from shore. Creek/Ashley Estuary, the Styx River discharges into Brooklands Lagoon and the Avon and Stormwater from Christchurch City is mainly Heathcote rivers discharge into the Avon- discharged into The Avon and Heathcote rivers Heathcote Estuary/Ihutai. The Ashley River and the Avon-Heathcote Estuary/Ihutai but there arises in the foothills and flows through farmed are some stormwater outlets directly to Pegasus areas while Saltwater Creek the Styx, Avon and Bay. Stormwater from the inland towns flows to Heathcote rivers are spring fed. adjacent waterways.

1.2 Kaikoura to Pegasus Bay

water quality In October 1993 Environment Canterbury began water quality sampling at four sites in the Kaikoura area. At these sites, one in Goose Bay and three at Oaro, shellfish and water samples were collected. The water samples were used to investigate localised coastal water quality. In Goose Bay there is a popular camping ground and a stream that flows from the coastal hills through the camping ground and into the sea. At Oaro there is a small coastal community and a river that flows from the hills through farmland to the sea. The camping ground and houses in these areas use septic tanks for the treatment and disposal of wastewater. Sampling at these Kaikoura sites continued into 1994 when another Kaikoura site and three Motunau (Hurunui area) sites were added to the sampling regime. At Motunau, sites were selected to investigate the impacts of the Motunau River on coastal water Figure 1.3 Pegasus Bay details quality.

In 2000-2001 Environment Canterbury initiated a new coastal water quality monitoring programme The ever-growing city of Christchurch is located at to support the then proposed Regional Coastal the southern end of Pegasus Bay with coastal Environment Plan for the Canterbury region communites and developing towns (Kaiapoi, (RCEP). For the purposes of this monitoring Woodend, Rangiora, Amberley) inland from the programme the Canterbury coast was divided into coast, north of Christchurch (Figure 1.3). five areas. Sampling then consisted of monthly sampling over a year-long period at sites in a particular area, with each area being sampled for With centres of human population comes sewage a year every five years. One of these areas was and stormwater. Treated Amberley sewage is

Environment Canterbury Technical Report 9 The quality of coastal water between Kaikoura and Pegasus Bay

Kaikoura to Pegasus Bay. Over 2000-2001, sampling was undertaken at two sites in the Kaikoura area, three sites in the Hurunui area and three sites in Pegasus Bay. Over 2005-2006, sampling was undertaken at four sites in the Kaikoura area and eight sites in Pegasus Bay.

The water quality data collected since 1993 at sites from Kaikoura to Pegasus Bay are the focus of this report.

1.3 Objectives of this study • Document the water quality at sites from Kaikoura to Pegasus Bay.

• Determine if there is a significant difference in water quality between sites in an area. • Determine if there is a significant difference in water quality over time at sites sampled over different time periods.

• Investigate impacts of rivers and discharges on coastal water quality Figure 2.1 Kaikoura area sampling sites

2 Methods

2.1 Sites and depths Samples were collected from nine Kaikoura, six Hurunui and eight Pegasus Bay sites (Figures 2.1 – 2.3). Details of the sites are given in Appendix I. At each site the surface water (0 – 0.5 m depth) was sampled.

2.2 Sampling regime These sites were sampled over various time periods between July 1993 and June 2006. The details of the sampling regime at each site are given in Appendix I. Over the periods of sampling, samples were typically collected monthly.

2.3 Sample collection

The samples were collected by staff from the Surface Water Resources and Ecosystem Health Figure 2.2 Hurunui area sampling sites section of Environment Canterbury.

10 Environment Canterbury Technical Report The quality of coastal water between Kaikoura and Pegasus Bay

temperature was measured using a field meter and over 2005-2006 water temperature, dissolved oxygen and salinity were measured using field meters.

2.4 Sample analyses

The water samples collected over 1994-1996 were analysed for nitrogen and phosphorus-based chemical determinands (nutrients) (Table 2.1). Those collected over 2000-2001 were analysed for nutrients and turbidity. Samples collected over 2005-2006 were analysed for each of the determinands, except turbidity, listed in Table 2.1.

All analyses were carried out in the Environment Canterbury laboratory. The details of the analytical methods are given in Appendix II.

2.5 Data analyses Figure 2.3 Pegasus Bay sampling sites Microsoft Excel 2000 and Systat (version 9) (SPSS, 1999) were used for the production of summary statistics, charts, box plots and all statistical analyses.

At all sites except New Brighton, samples were The data presentation and analyses are by area, collected from the water's edge. At New Brighton i.e. Kaikoura, Hurunui and Pegasus Bay (Figures samples were collected some 300 m from shore 2.1-2.3). off the pier.

All water collected was stored in specially prepared bottles provided by the laboratory undertaking the analyses, and kept cooled in chilly bins until delivery to the laboratory.

At the time of sampling the weather conditions (cloud cover, wind direction, wind strength) were recorded. In addition, over 2000-2001 water

Table 2.1 Chemical, biological and physical determinands

Nitrate and nitrite nitrogen (NNN)

Total ammonia nitrogen (NH3N) Dissolved inorganic nitrogen (DIN) (=NNN+NH3N) Total nitrogen (TN) Dissolved reactive phosphorus (DRP) Total phosphorus (TP) Dissolved oxygen Chlorophyll-a Enterococci Turbidity Salinity Water temperature

Environment Canterbury Technical Report 11 The quality of coastal water between Kaikoura and Pegasus Bay

To determine if there was a significant difference, the Kaikoura area over the period July 1993 to in the surface water concentration of each nutrient June 2006, are summarised in Table 3.1. (NNN, NH3N, TN, DRP and TP) and other The data for each nutrient at each site are determinands, between sites in an area, the presented in box and whisker plots (Figure 3.1). Wilcoxon signed rank test (Systat V9) was used. For sites K2 and K4, where twelve samples were These analyses were carried out on the data from collected over each of two year-long periods, the each year-long sampling period. In Kaikoura, data from each period are separated (K2a and Hurunui and Pegasus Bay the sites sampled and K4a (2000-2001) and K2b and K4b (2005-2006)). periods of sampling varied over time. Hence the For sites K5, K6, K7 and K9 where up to eight analyses were for the following time periods and samples were collected over a year-long period sites in each area. (and for two or three years), the data have not been separated by year. Kaikoura: • 1993-1994 (sites K7, K8 and K9) The between-site comparison of nutrient • 1994-1995 (sites K5, K6, K7 and K9) concentrations between sites is complicated by • 1995-1996 (sites K5, K6 and K7) the fact that: • 2000-2001 (sites K2 and K4) • the sites sampled differed over time. • 2005-2006 (sites K1, K2, K3 and K4) • the time periods (years) of sampling sites differed. Hurunui: • 1994-1995 (sites H3 and H6) For these reasons no statistical analysis was • 1995-1996 (sites H3 and H6) undertaken to investigate differences in nutrient • 2000-2001 (sites H1, H2 and H5) concentrations between all Kaikoura sites. However, the Wilcoxon two-tailed signed rank test Pegasus Bay: was applied to the data from sites sampled over • 2000-2001 (sites P1, P3 and P5) each specific year-long period to investigate • 2005-2006 (sites P1-P8) differences in nutrient concentrations between these sites. The periods were 1993-1994 (sites To determine if there was a significant difference K7, K8 and K9), 1994-1995 (sites K5, K6, K7 and in the concentration of each nutrient between K9), 1995-1996 (sites K5, K6 and K7), 2000-2001 2000-2001 and 2005-2006 (sites K2, K4, H1, H3 (sites K2 and K4) and 2005-2006 (sites K1, K2, and H5) the Kruskal-Wallis ANOVA (Analysis of K3 and K4). Variance) (Systat V9) was used. There was no significant difference in nutrient Where concentrations of nutrients were less than concentrations between sites sampled over 1993- the analytical limits of detection, the results were 1994. Over each of the other year-long periods reported as ‘less than’ the detection limit. These there were significant differences in the non-detect data were converted to a value equal concentration of two or more nutrients between to half the detection limit for the purposes of sites (Appendix III). analysis. Ammonia nitrogen (NH3N) NH3N concentrations ranged from <0.005 to 1.2 mg/L.

3 Kaikoura results and The NH3N concentrations were significantly higher just south of Lyell Creek (K2) than in South Bay discussion (K4) over 2000-2001.

3.1 Results There were no significant differences in NH3N concentrations between sites sampled over any of the other time periods. 3.1.1 Between sites

3.1.1.1 Nutrients The data for the nitrogen- and phosphorus-based determinands (nutrients), collected at each site in

12 Environment Canterbury Technical Report The quality of coastal water between Kaikoura and Pegasus Bay

Table 3.1 Summary of nutrient concentrations (mg/L) at Kaikoura sites, 1993-2006.

n = number of samples

Sites: K1 - behind the supermarket, K2 - just south of Lyell Creek, K3 - Ingles Bay, K4 - South Bay K5 - South Bay, K6 - Goose Bay, K7 - Oaro first reef, K8 - Oaro second reef, K9 - Oaro south of second reef

2005-2006 2000-2001 2005-2006 1993-1996

2005-2006 2005-2006 2000-2001 1994-1996 1994-1996 1993-1996 1993-1995 K1 K1 K2 K2 K3 K4 K4 K5 K6 K7 K8 K9 NH3N Minimum 0.008 0.009 0.011 0.01 <0.005 0.009 <0.005 <0.005 <0.005 <0.005 <0.005 Median 0.03 0.058 0.028 0.0325 0.0225 0.0255 0.039 0.1233 0.032 0.0243 0.027 Mean 0.0314 0.0601 0.0287 0.0328 0.0482 0.0306 0.0846 0.034 0.0486 0.017 0.0334 SD 0.0173 0.0455 0.0163 0.0132 0.0496 0.0176 0.2057 0.2905 0.0549 0.0230 0.0251 Maximum 0.061 0.14 0.057 0.049 0.16 0.063 0.88 1.2 0.23 0.078 0.081 NNN

Minimum <0.005 0.023 0.016 <0.005 0.012 0.005 <0.005 0.006 0.002 <0.005 <0.005 Median 0.0275 0.048 0.0395 0.02 0.058 0.0385 0.039 0.0624 0.039 0.0353 0.027 Mean 0.0475 0.0714 0.0568 0.0261 0.0668 0.0573 0.0440 0.0495 0.0478 0.015 0.0385 SD 0.0473 0.0486 0.0480 0.0233 0.0534 0.0408 0.0316 0.0533 0.0411 0.0380 0.0377 Maximum 0.14 0.16 0.18 0.064 0.2 0.12 0.12 0.18 0.15 0.1 0.14 DIN Minimum 0.0185 0.035 0.038 0.0285 0.02 0.022 0.0245 0.034 0.0075 0.005 0.017

Median 0.0575 0.108 0.072 0.059 0.0725 0.0695 0.072 0.1857 0.074 0.0596 0.064 Mean 0.0789 0.1315 0.0855 0.0589 0.1150 0.0878 0.1286 0.1145 0.0945 0.043 0.0719 SD 0.0547 0.0892 0.0481 0.0250 0.1018 0.0482 0.2107 0.2832 0.0818 0.0422 0.0427 Maximum 0.198 0.3 0.191 0.103 0.36 0.173 0.938 1.226 0.38 0.144 0.15 TN Minimum 0.15 0.04 0.15 0.19 0.04 0.15 0.12 0.12 0.054 0.07 0.14 Median 0.28 0.16 0.245 0.285 0.245 0.235 0.245 0.3525 0.28 0.2682 0.3

Mean 0.2967 0.1658 0.2350 0.2817 0.2475 0.2892 0.3538 0.24 0.3609 0.27 0.3030 SD 0.1020 0.0689 0.0545 0.0520 0.1202 0.1384 0.3960 0.3962 0.2368 0.1395 0.1013 Maximum 0.51 0.27 0.33 0.38 0.45 0.52 1.8 1.8 1.2 0.61 0.48 TON Minimum 0.052 0.001 0.095 0.125 0.001 0.039 0.053 0.0175 0.0075 0 0.076 Median 0.2185 0.0535 0.149 0.221 0.12975 0.173 0.1765 0.1668 0.23 0.2086 0.205 Mean 0.2178 0.0205 0.1495 0.2228 0.1325 0.2013 0.2221 0.1305 0.2664 0.221 0.2312

SD 0.1046 0.1242 0.0363 0.0607 0.1516 0.1233 0.1898 0.1407 0.2034 0.1613 0.1127 Maximum 0.45 0.155 0.226 0.3505 0.405 0.467 0.862 0.574 0.92 0.5945 0.44 DRP Minimum 0.004 0.003 0.007 0.005 0.007 0.003 0.008 0.009 0.009 0.012 0.009 Median 0.008 0.0105 0.013 0.011 0.015 0.0165 0.014 0.0184 0.019 0.0265 0.016 Mean 0.0113 0.0102 0.0138 0.0117 0.0138 0.0158 0.0160 0.0175 0.0201 0.022 0.0202 SD 0.0064 0.0056 0.0054 0.0047 0.0053 0.0073 0.0094 0.0062 0.0073 0.0174 0.0097

Maximum 0.023 0.022 0.024 0.019 0.023 0.029 0.048 0.03 0.037 0.076 0.051 TP Minimum 0.023 < 0.008 0.013 0.011 < 0.008 0.012 0.015 0.014 0.015 0.012 0.017 Median 0.0315 0.0195 0.0235 0.0385 0.0285 0.0255 0.021 0.0279 0.03 0.0358 0.03 Mean 0.0475 0.0254 0.0276 0.0400 0.0387 0.0355 0.0233 0.0255 0.0353 0.031 0.0369

SD 0.0315 0.0217 0.0093 0.0124 0.0345 0.0234 0.0076 0.0104 0.0195 0.0229 0.0192

Maximum 0.12 0.073 0.048 0.06 0.13 0.096 0.045 0.052 0.11 0.097 0.096

n 12 12 12 12 12 12 17 16 26 11 23

Environment Canterbury Technical Report 13 The quality of coastal water between Kaikoura and Pegasus Bay

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0.00 0.00 1 a b 3 a b 5 6 7 8 9 1 a b 3 a b 5 6 7 8 9 K K2 K2 K K4 K4 K K K K K K K2 K2 K K4 K4 K K K K K Site Site

Figure 3.1 Nutrient concentrations (mg/L) at sites in the Kaikoura area Note: horizontal bar = median, box = interquartile range, whisker ends = % and 95%iles, * = outlier values, o = extreme values

Sites: K1 - behind the supermarket, K2 - just south of Lyell Creek, K3 - Ingles Bay, K4 - South Bay K5 - South Bay, K6 - Goose Bay, K7 - Oaro first reef, K8 - Oaro second reef, K9 - Oaro south of second reef Time: a = 2000-2001 b = 2005-2006

14 Environment Canterbury Technical Report The quality of coastal water between Kaikoura and Pegasus Bay

Nitrate and nitrite nitrogen (NNN) Bay (K3) than just south of Lyell Creek over NNN concentrations ranged from <0.005 to 0.2 2005-2006 mg/L. There was no significant difference in TP NNN concentrations were significantly higher at: concentration between the two sites sampled over • Goose Bay (K6) than south of the second 2000-2001. reef in Oaro (K9) over 1994-1995 • the first reef in Oaro (K7) than south of Other determinands the second reef in Oaro (K9) over 1995- The data for the other measured determinands 1996 are summarised in Table 3.2 and presented in box • the site just south of Lyell Creek (K2) and whisker plots (Figure 3.2). than behind the supermarket (K1) over 2005-2006. Chlorophyll-a The chlorophyll-a concentrations at the sites NNN concentrations were significantly lower in sampled over 2005-2006 ranged from 0.1 to 3.9 Ingles Bay (K3) than behind the supermarket (K1), µg/L. just south of Lyell Creek (K2) and in South Bay (K4) over 2005-2006. The chlorophyll-a concentrations were significantly higher behind the supermarket (K1) There was no significant difference in NNN than just south of Lyell Creek (K2), in Ingles Bay concentrations between sites sampled over 2000- (K2) and in South Bay (K4). 2001, i.e. South Bay (K4) and the site just south of Lyell Creek (K2). Enterococci The enterococci concentrations at the sites Total nitrogen (TN) sampled over 2005-2006 ranged from <2 to 180 TN concentrations ranged from 0.04 to 1.8 mg/L. cfu/100mL. Note: The two highest concentrations (180 and 72 cfu/100mL) were excluded from the TN concentrations were significantly higher box and whisker plot in to get a clearer picture of behind the supermarket (K1) than just south of the concentrations at the sites. 180 enterococci Lyell Creek (K2) over 2005-2006. /100mL occurred just right of Lyell Creek and 72 enterococci /100mL occurred in Ingles Bay. There were no significant differences in TN concentrations between sites sampled over any of There was no significant difference in enterococci the other time periods. concentrations between sites.

Dissolved reactive phosphorus (DRP) Salinity DRP concentrations ranged from 0.003 to 0.076 The salinity at the four sites sampled over 2005- mg/L. 2006 ranged from 28.8 to 35.3.

DRP concentrations were significantly higher in There was a larger range in salinity at the site just Goose Bay (K6) than in South Bay (K5) over south of Lyell Creek (K2) and in South Bay (K4) 1995-1996 and significantly higher in South Bay than behind the supermarket (K1) and in Ingles (K4) than behind the supermarket (K1) over 2005- Bay (K3). 2006. The salinity in Ingles Bay (K3) was significantly There were no significant differences in DRP higher than behind the supermarket (K1), just concentrations between sites sampled over 1994- south of Lyell Creek (K2) and in South Bay (K4). 1995 and 2000-2001. Turbidity Total phosphorus (TP) The turbidity at the two sites sampled over 2000- TP concentrations ranged from <0.008 to 0.13 2001 ranged from 0.8 to 25 NTU. mg/L. There was no significant difference in turbidity TP concentrations were significantly higher: concentrations between sites K2 and K4. • at sites in Oaro (K7 and K9) than in South Bay (K5) over 1994-1995 • at Goose Bay (K6) than in South Bay (K5) over 1995-1996 • behind the supermarket (K1) and in Ingles

Environment Canterbury Technical Report 15 The quality of coastal water between Kaikoura and Pegasus Bay

Table 3.2 Summary of concentrations of other determinands at Kaikoura and Hurunui sites n = number of samples

Sites: K1 - behind supermarket, K2 - just south of Lyell CreeK, K3 - Ingles Bay, K4 - South Bay H1 - Conway Flats, H2, Gore Bay, H3 - Motunau -1st point north of River, H5 - Motunau Sandy Beach, H6 -Motunau south end of Sandy Beach 2005-2006 2000-2001 2005-2006 2000-2001 2000-2001 1994-1996 2000-2001 1994-1996 2005-2006 2005-2006 2000-2001 K1 K2 K2 K3 K4 K4 H1 H2 H3 H5 H6 Chlorophyll a (ug/L) Minimum 0.7 0.2 0.2 0.1 Median 1.2 0.65 0.55 0.35 Mean 1.50 0.65 0.74 0.53 SD 0.93 0.26 0.45 0.52 Maximum 3.9 1.1 1.6 1.7 Enterococci (cfu/100mL) Minimum <2 <2 <2 <2 Median <2 1.5 3 <2 Mean 2.4 16.5 11.5 5.8 SD 3.34 51.50 20.38 11.24 Maximum 12 180 72 40 Salinity Minimum 30.9 28.8 30.7 29.3 Median 34.3 34.2 34.65 34.1 Mean 34.1 33.7667 34.2250 33.7750 SD 1.1544 1.7249 1.2715 1.6723 Maximum 35.3 35.4 35.5 35.3 Turbidity (NTU) Minimum 0.8 1.2 5.3 2.6 4 Median 2.35 4.85 22 12 14.5 Mean 2.5667 6.2167 23.65 10.75 14.24 SD 1.1252 6.3988 14.97 7.70 8.10 Maximum 4 25 51 29 31 n 1210121210121112 12 Water Temperature Minimum 9.5 9.4 9.5 8.5 8.8 8.5 9.9 7.6 8.9 7.4 Median 13.75 13.3 13.5 14.75 12.55 14 14.45 10.8 14 10.9 Mean 13.49 13.01 13.58 14.76 12.42 13.45 13.6 11.7 13.6 11.8 SD 2.89 2.75 3.17 3.81 2.70 3.15 2.7 3.4 3.3 3.7 Maximum 17 17.8 18 19.5 17 17.5 18.1 17.2 18.5 17.8 n 121012121012 109 1010

3.1.2 Over time 3.2 Discussion The nutrient concentrations over time for each site are presented in Figures 3.3 and 3.4. Nutrient and other determinand concentrations differed between sites and over time at sites in the The Kruskal-Wallis ANOVA was used to Kaikoura area. The concentrations of some determine if there was a significant difference in nutrients and/or other determinands were also the concentration of each nutrient, between 2000- more variable at some sites than others (as 2001 and 2005-2006, at the site just south of Lyell evidenced by the range in concentrations Figure Creek (K2) and the site in South Bay (K4). In 3.1). These results indicate site specific, localised South Bay (K4) there was no significant difference influences on coastal water quality. in the concentration of any nutrient over time. Just south of Lyell Creek (K2) the concentrations of TN and TON were significantly higher (TN: p =0.026, TON: p=0.002) over 2005-2006 than over 2000- 2001.

16 Environment Canterbury Technical Report The quality of coastal water between Kaikoura and Pegasus Bay

4 50

40 3

30 2 20

1 10 Chlorophyll-a concentration (ug/L) concentration Chlorophyll-a

0 (cfu/100mL) concentration Enterococci 0 K1 K2 K3 K4 K1 K2 K3 K4 Site Site

36 25 35 20

34

33 15 32

Salinity 10 31 Turbidity (NTU) Turbidity 30 5 29 28 0 K1 K2 K3 K4 K1 K2 K3 K4 Site Site

Figure 3.2 Concentrations of other determinands at sites in the Kaikoura area Sites: K1 - behind supermarket, K2 - just south of Lyell CreeK, K3 - Ingles Bay, K4 - South Bay

2001 but over 2005-2006 concentrations just 3.2.1 Influences of creeks, streams and south of Lyell Creek were not significantly different rivers to those at the other three sites sampled. Site K2 is just south of the mouth of Lyell Creek. Elevated NH3N concentrations have been found in The range in salinity (28.8 – 35.4) (coastal sea Lyell Creek with concentrations increasing with water in Canterbury is typically 34-35 ppt) at K2 distance downstream (Hayward et al., 2002). indicates that Lyell Creek fresh water affects However, Hayward et al., reported a significant coastal water at this site. Thus, it is possible that trend of decreasing NH3N concentration at SH1 the significant difference in NH3N concentrations over the eight years of monitoring. This finding (2000-2001) and NNN, TN and TP concentrations suggests that over 2005-2006 NH3N (2005-2006), between K2 and one or more of the concentrations in Lyell Creek would have been other sites, is due to the influence of this creek. considerably lower than in 2000-2001. This explanation is not supported by the data because NH3N concentrations were significantly higher just there was no significant difference in NH3N south of Lyell Creek than in South Bay over 2000- concentration over time (between 2000-2001 and 2005-2006) at site K2.

Environment Canterbury Technical Report 17 The quality of coastal water between Kaikoura and Pegasus Bay

0.8 0.8 K1 NH3N K2 NH3N NNN NNN TN TN 0.6 0.6 TON TON

0.4 0.4

0.2 0.2 concentration (mg/L) concentration concentration (mg/L)

0 0

Jul-05 Jul-05 Jan-06 Oct-05 Apr-06 Mar-01 Mar-06 Feb-01 Jun-06 Jan-06 Aug-00 Sep-00 Nov-00 Sep-05 Nov-05 Mar-06 May-06 Feb-06 Nov-05 Aug-05 Sep-05 Dec-05 May-06 Mar1-01 0.8 0.8 K3 NH3N K4 NH3N NNN NNN TN TN 0.6 0.6 TON TON

0.4 0.4

0.2 0.2 concentration (mg/L) concentration concentration (mg/L)

0 0

Jul-05 Jan-06 Jul-05 Mar-01 Mar-06 Feb-01 Sep-05 Nov-05 Aug-00 Sep-00 Nov-00 May-06

Oct-05 Apr-06 Jun-06 Jan-06 Mar-06 Feb-06 Nov-05 Aug-05 Sep-05 Dec-05 May-06 Mar1-01 2 2 1.8 K5 NH3N 1.8 K6 NH3N NNN NNN 1.6 TN 1.6 TN 1.4 TON 1.4 TON 1.2 1.2 1 1 0.8 0.8 0.6 0.6 concentration (mg/L) concentration concentration (mg/L) 0.4 0.4 0.2 0.2 0 0

Oct-94 Apr-95 Oct-95 Apr-96 Oct-94 Apr-95 Oct-95 Apr-96 Jun-95 Jun-95 Feb-95 Feb-96 Feb-95 Feb-96 Aug-94 Dec-94 Aug-95 Dec-95 Aug-94 Dec-94 Aug-95 Dec-95

2 0.8 1.8 K7 NH3N K8 NH3N NNN NNN 1.6 TN TN TON 0.6 TON 1.4 1.2 1 0.4 0.8 0.6 0.2 concentration (mg/L) concentration 0.4 (mg/L) concentration 0.2 0 0

Oct-94 Apr-95 Oct-95 Oct-93 Oct-93 Apr-94 Jan-94 Jan-94 Jun-94 Mar-96 Mar-94 Mar-94 Feb-95 Feb-94 Nov-93 Aug-94 Dec-94 Dec-95 Dec-93 May-96 May-94 May-94 Nov1-93 Nov1-93 0.8 K9 NH3N NNN TN Note: 0.6 TON The y axis scale for K1,K2, K3, K4, K8 and K9 0.4 Is different to that for K5, K6 and K7

0.2 concentration (mg/L) concentration

0

ay-94 ov-95 ec-94 ug-94 eb-95 Jul-95 Oct-93 Oct-94 ov1-93 Jan-94 Mar-96 Mar-94 F N A D M

Figure 3.3 Concentrations (mg/L) of NH3N, NNN, TN and TON over time at sites in the Kaikoura area

18 Environment Canterbury Technical Report The quality of coastal water between Kaikoura and Pegasus Bay

0.2 0.2 K1 DRP K2 DRP TP TP 0.15 0.15

0.1 0.1

0.05 0.05 concentration (mg/L) concentration (mg/L) 0 0

Jul-05 Jan-06 Jul-05 Mar-01 Mar-06 Feb-01 Nov-00 Nov-05 Aug-00 Sep-00 Sep-05 May-06 Oct-05 Apr-06

Jan-06 Jun-06 Mar-06 Feb-06 Nov-05 Aug-05 Sep-05 Dec-05 Mar1-01 May-06

0.2 0.2 K3 DRP K4 DRP TP TP 0.15 0.15

0.1 0.1

0.05 0.05

concentration (mg/L) concentration (mg/L)

0 0

Jul-05 Jan-06 Jul-05 Mar-01 Mar-06 Feb-01 Nov-00 Nov-05 Aug-00 Sep-00 Sep-05 May-06 Oct-05 Apr-06 Jan-06 Jun-06 Mar-06 Feb-06 Nov-05 Aug-05 Sep-05 Dec-05 May-06 Mar1-01 0.2 0.2 K5 DRP K6 DRP TP TP 0.15 0.15

0.1 0.1

0.05 0.05

concentration (mg/L) concentration (mg/L)

0 0

Apr-96 Apr-96 Apr-95 Oct-95 Apr-95 Oct-95 Oct-94 Oct-94 Jun-95 Jun-95 Feb-96 Feb-96 Feb-95 Feb-95 Aug-95 Dec-95 Aug-95 Dec-95 Aug-94 Dec-94 Aug-94 Dec-94 0.2 0.2 K7 DRP K8 DRP TP TP 0.15 0.15

0.1 0.1

0.05 0.05 concentration (mg/L) concentration (mg/L) 0 0

Oct-93 Oct-94 Apr-95 Oct-95 Apr-94 Oct-93 Jan-94 Jan-94 Jun-94 Mar-94 Mar-96 Feb-95 Mar-94 Feb-94 Aug-94 Dec-94 Dec-95 Nov-93 Dec-93 May-94 May-96 May-94 Nov1-93 Nov1-93

0.2 K9 DRP TP 0.15

0.1

0.05

concentration (mg/L)

0

ay-94 ug-94

Jul-95 Oct-94 Oct-93 ov1-93 Jan-94 Mar-96 Mar-94 Feb-95 Nov-95 Dec-94 A M N Figure 3.4 Concentrations (mg/L) of DRP and TP over time at sites in the Kaikoura area

Environment Canterbury Technical Report 19 The quality of coastal water between Kaikoura and Pegasus Bay

Another possible explanation is that the sea water concentrations and turbidity in the Kowhai River (n in South Bay over 2000-2001 was diluted by low =68) are: NH3N concentration fresh water. That is the NH3N NH3N <0.005 – 0.076 mg/L concentrations just south of Lyell Creek were not NNN <0.01 – 0.84 mg/L TN <0.08 – 1.1 mg/L elevated over 2000-2001 rather the NH3N concentrations in South Bay were lower than TP <0.008 – 0.82 mg/L typically occurs in sea water in the Kaikoura area. Turbidity 0.3 – 490 NTU This explanation is not supported by the data because there was no significant difference in Thus Kowhai River water likely accounts for the variability in nutrient concentrations and turbidity NH N concentration over time (between 2000- 3 at site K4. The highest nutrient concentrations in 2001 and 2005-2006) in South Bay. It is possible South Bay did occur over the wetter seasons of that the difference in NH N concentration between 3 the year, i.e. late autumn, winter and early spring, sites K2 and K4 in 2000-2001 results from a rather than in summer (Figures 3.3-3.4). The combination of higher concentrations just south of limited range of salinities recorded precluded Lyell Creek on some sampling occasions and analysis to determine if there was a relationship lower concentrations in south Bay on other between salinity and the concentration of each sampling occasions. nutrient. Stormwater runoff and the fresh water from a small creek flowing from Kaikoura Over 2005-2006, TP concentrations were Peninsula into South Bay could also affect coastal significantly lower and NNN concentrations were water quality at site K4. The nutrient contributions significantly higher just south of Lyell Creek than from stormwater and the creek would also be 2.5 km north at site K1 and 1.8 km south at site related to rainfall. K3. TN concentrations just south of Lyell Creek were also significantly lower than those at site K1. In South Bay the TN and TON concentrations These results suggest that the sea water just were significantly higher over 2005-2006 than south of Lyell Creek may be diluted by Lyell Creek over 2000-2001. There was no significant water, with the creek water having lower TP and difference in TN concentrations in the Kowhai possibly TN concentrations but higher NNN River between 2000-2001 and 2005-2006, but concentrations than sea water. It was found that there could have been differences in the total the highest NNN concentration right of Lyell rainfall and number of significant rainfall events, Creek, occurred in the lowest salinity (28.8 ppt) and hence freshwater volumes to South Bay water; this was not the case for TN and TP. The between time periods. From July 2000 to the end of June 2001 1157 mm of rain, and from July limited range of salinities recorded precluded an 2005 to the end of April 2006 1170 mm of rain, fell analysis to determine if a relationship exists at Snowflake (Snowflake Stream joins the Kowhai between salinity and NNN, TN and TP River). Over the 12 months of 2000-2001 there concentrations. The difference in TN and TP were 32 days and over the 10 months of 2005- concentrations between sites K1 and K2 could 2006 there were 30 days on which > 10mm rain result from elevated concentrations at site K1. fell in a day. Unfortunately the rainfall record for Nutrient sources north of site K1 (oxidation ponds, 2005-2006 is incomplete. However, the Middle Creek, dairy factory discharge) could be indications are that there could have been more responsible for the elevated TN and TP rainfall and more significant rainfall events over concentrations at this site, with concentrations 2005-2006 than over 2000-2001. This could decreasing with increasing distance away from account for the difference in TN concentrations at the sources. That is, site K2 is further from the site K4 between sampling periods. Differences in sources than is site K1. stormwater runoff and creek water discharge between 2000-2001 and 2005-2006 may have Site K4 in South Bay is more than 3.5 km from a also influenced TN concentrations between significant freshwater source (Kowhai River). sampling periods. However, the range in salinity (29.3 –35.5 ppt) at K4 indicates that it is affected by fresh water with The variability in nutrient concentrations at sites the Kowhai River the most likely source. The K5 (South Bay), K6 (Goose Bay) and K7, K8 and sediment-loaded plume from this river extends K9 (Oaro) (Figure 3.1, 3.3 and 3.4) are suggestive north for some distance from the river mouth of the influence of streams and rivers (Kowhai when the river has a high flow and there is a River, Ote Makura Stream (Goose Bay) and Oaro southerly wind (pers. ob.). Nutrient concentrations River respectively) on coastal water quality at and turbidity in the Kowhai River are variable, with these sites. Of particular note are the large spikes high concentrations at times. The range in nutrient in TN concentration at sites K5, K6 and K7 on 9

20 Environment Canterbury Technical Report The quality of coastal water between Kaikoura and Pegasus Bay

October 1995. There was heavy rainfall in the DIN concentrations were higher in this part of the Kaikoura region on 9 October 1995 (Environment coast than in the other four areas sampled. The Canterbury rainfall records). Hence freshwater likely sources of the DIN are the three listed in the inputs are the likely source of the high TN paragraph above. DIN concentrations from Middle concentrations at these sites on this sampling Creek over 2005-2006 ranged from 0.5-3.7 mg/L. occasion. There are no salinity data to support These DIN concentrations are higher than those this possible explanation. in the Kowhai River and Lyell Creek over the same time period (Appendix V). The DIN The significant differences in NNN, DRP and TP concentrations in the oxidation ponds over 2004- concentrations between some of the sites (K5 – 2006 ranged from 15.3 – 29.3 mg/L. There are no K9) over one or more of the sampling periods DIN data for the dairy factory wastewater could be related to differences in the nutrient discharge. concentrations in the streams and rivers discharging into the sea in proximity to the sampling sites. There are no Environment The highest chlorophyll-a concentration recorded Canterbury data on nutrient concentrations in Ote at site K1 was 3.9 µg/L (0.0039 mg/L). A Makura Stream and the Oaro River to support this chlorophyll-a concentration of 0.005 mg/L has assumption. been found to cause physical discolouration of surface waters (Eppley et al., 1977). Thus chlorophyll-a concentrations that would discolour 3.2.2 Other influences surface water did not occur at the times of At site K1 behind the supermarket there was sampling. considerable variability in TN and TP concentrations over the year of sampling. This site is approximately: 3.2.3 Site K3 in Ingles Bay • 2.5 km south of the seepage from the The variability in nutrient concentrations at site K3 oxidation ponds was considerably less than at the other sites • 2 km south of Middle Creek sampled over 2005-2006 (Figures 3.3-3.4). This suggests that the coastal water at this site does • 1 km south of the dairy factory not receive any significant nutrient inputs. wastewater discharge However, there is potential for the coastal water

quality in Ingles Bay to be impacted by stormwater These are all potential sources of TN and TP. discharged during rainfall. The TN concentrations in the oxidation ponds over 2004-2006 ranged from 22 – 43.7 mg/L while concentrations in Middle Creek over 2005-2006 Ranged from 1.2 – 3.9 mg/L. There are no TN data from the dairy factory discharge. TP 4 Hurunui results and concentrations in Middle Creek ranged from 0.011 – 0.54 mg/L over 2005-2006. There are no TP discussion data for the oxidation ponds or the dairy factory discharge. Oxidation ponds typically have high TP 4.1 Results concentrations. For example the median and maximum TP concentrations in the Bromley oxidations ponds over 2004 were 6.95 and 11 4.1.1 Between sites mg/L respectively (Bolton-Ritchie and Main, 2005). These results suggest that if oxidation 4.1.1.1 Nutrients pond seepage reaches the coast it would be a The data for the nitrogen- and phosphorus-based significant contributor of TN and TP to the coastal determinands collected in the Hurunui area over water. the period July 1993 to June 2001, are summarised in Table 4.1. The data for each At site K1 the chlorophyll-a concentrations were nutrient at each site are presented in box and significantly higher than those at any of the other whisker plots (Figure 4.1). For sites H3, H4 and H6, where up to eight samples were collected sites sampled over 2005-2006. Chlorophyll-a is a over a year-long period for each of two years, the measure of phytoplankton abundance. data have not been separated by year. Phytoplankton abundance is generally limited and regulated by DIN (NNN + NH3N) concentrations. Thus the chlorophyll-a result suggests that the

Environment Canterbury Technical Report 21 The quality of coastal water between Kaikoura and Pegasus Bay

Table 4.1 Summary of nutrient concentrations (mg/L) at each Hurunui site, based on all the data collected between 1994 and 2001

H1 - Conway Flat, H2 - Gore Bay, H3 - Motunau - 1st point north of river, H4 - Motunau - 40 m north of river, H5 - Motunau - Sandy Bay, H6 Motunau - south end of Sandy Bay

2000-2001 2000-2001 1994-1996 1994-1995 2000-2001 1994-1996 H1 H2 H3 H4 H5 H6

NH3N Minimum <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 Median 0.029 0.027 0.034 0.078 0.035 0.0325 Mean 0.0616 0.0511 0.0738 0.1014 0.0554 0.1154 SD 0.0696 0.0502 0.0879 0.1454 0.0476 0.2210 Maximum0.220.160.290.450.170.91 NNN Minimum 0.005 0.005 0.008 0.03 0.005 0.007 Median 0.024 0.0485 0.067 0.067 0.0355 0.0695 Mean 0.0578 0.0590 0.0745 0.0765 0.0554 0.0681 SD 0.0654 0.0561 0.0537 0.0423 0.0577 0.0418 Maximum0.190.190.180.140.210.14 DIN Minimum 0.0075 0.0075 0.039 0.0395 0.0075 0.021 Median 0.08 0.07 0.127 0.1325 0.077 0.1205 Mean 0.1194 0.1101 0.1483 0.1779 0.1108 0.1835 SD 0.1120 0.1040 0.1170 0.1531 0.1031 0.2113 Maximum 0.34 0.35 0.43 0.521 0.38 0.938 n 1112218 1220 TN Minimum0.120.040.140.220.090.18 Median 0.185 0.17 0.37 0.555 0.21 0.38 Mean 0.2330 0.1982 0.4081 0.5025 0.1982 0.4510 SD 0.1083 0.1112 0.1612 0.1732 0.0767 0.2086 Maximum 0.41 0.44 0.83 0.67 0.3 0.9 TON Minimum 0 0.005 0 0.041 0 0 Median 0.1203 0.0680 0.2620 0.3955 0.0810 0.2738 Mean 0.1357 0.1099 0.2598 0.3246 0.1119 0.2676 SD 0.1000 0.1038 0.1328 0.2082 0.0883 0.1772 Maximum 0.33 0.326 0.593 0.545 0.269 0.576 n 1011218 1120 DRP Minimum 0.004 0.005 0.003 0.003 0.005 0.005 Median 0.006 0.009 0.021 0.021 0.007 0.0215 Mean 0.0085 0.0088 0.0214 0.0229 0.0098 0.0238 SD 0.0046 0.0027 0.0077 0.0135 0.0048 0.0113 Maximum 0.017 0.013 0.036 0.043 0.018 0.062 TP Minimum < 0.008 < 0.008 0.023 0.026 0.018 0.028 Median 0.084 0.0405 0.055 0.0575 0.086 0.0725 Mean 0.0802 0.1008 0.0525 0.0609 0.0744 0.0705 SD 0.0451 0.1645 0.0199 0.0303 0.0353 0.0261 Maximum 0.17 0.6 0.089 0.12 0.13 0.12 n 1112218 1220

22 Environment Canterbury Technical Report The quality of coastal water between Kaikoura and Pegasus Bay

1.0 0.3

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0.0 0.0 H1 H2 H3 H4 H5 H6 H1 H2 H3 H4 H5 H6 Site Site

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0.0 0.0 H1 H2 H3 H4 H5 H6 H1 H2 H3 H4 H5 H6 Site Site

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P 0.02 0.2

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D 0.01

0.00 0.0 H1 H2 H3 H4 H5 H6 H1 H2 H3 H4 H5 H6 Site Site

Figure 4.1 Nutrient concentrations (mg/L) at sites in the Hurunui area Note: horizontal bar = median, box = interquartile range, whisker ends = % and 95%iles, * = outlier values, o = extreme values

H1 - Conway Flat, H2 - Gore Bay, H3 - Motunau - 1st point north of river, H4 - Motunau - 40 m north of river, H5 - Motunau at Sandy Bay, H6 Motunau - south end of Sandy Bay

Environment Canterbury Technical Report 23 The quality of coastal water between Kaikoura and Pegasus Bay

No statistical analysis was carried out to determine if there were significant differences in nutrient concentrations between all six sites 60 because the periods (years) of sampling differed between sites (Appendix I). However, the 50 Wilcoxon two-tailed signed rank test was applied to the data from sites sampled over each specific 40 year-long period to investigate differences in nutrient concentrations between specific sites. 30 The periods were 1994-1996 (sites H3 and H6) and 2000-2001 (sites H1, H2 and H5). 20

Ammonia nitrogen (NH N) (NTU) Turbidity 3 NH3N concentrations ranged from <0.005 to 0.91 10 mg/L. 0 H1 H2 H5 There were no significant differences in NH3N Site concentrations between sites sampled.

Nitrate and nitrite nitrogen (NNN) NNN concentrations ranged from 0.005 to 0.2 Figure 4.2 Turbidity at sites in the Hurunui 1mg/L. area

Note: horizontal bar = median, box = interquartile range, There were no significant differences in NNN whisker ends = % and 95%iles, concentrations between sites sampled. * = outlier values

Total nitrogen (TN) Sites: H1 - Conway Flats, H2 - Gore Bay, H5 - Motunau at Sandy Bay TN concentrations ranged from 0.04 to 0.9 mg/L.

There were no significant differences in TN concentrations between sites sampled. 4.1.2 Over time

Dissolved reactive phosphorus (DRP) The nutrient concentrations over time for each site DRP concentrations ranged from 0.003 to 0.062 are presented in Figures 4.3 - 4.4. mg/L. Hurunui sites H3 and H6 were sampled over There were no significant differences in DRP different year-long periods but were not sampled a concentrations between sites sampled. sufficient number of times over each period to allow for a statistical comparison of the data.

Total phosphorus (TP) TP concentrations ranged from <0.008 to 0.6 4.2 Discussion mg/L. The variability in nutrient concentrations at some

of the Hurunui sites (as evidenced by the range in There were no significant differences in TP concentrations Figure 4.1) indicates that there are concentrations between sites sampled. site specific, localised influences on coastal water

quality.

4.1.1.2 Other determinands 4.2.1 Influences of creeks, streams and The data are summarised in Table 3.2. rivers

Turbidity At site H1 at Conway Flats there was low The turbidity at the three sites sampled over 2000- variability in NH3N and TN concentrations but high 2001 ranged from 4 to 51 NTU. variability in NNN and TP concentrations when compared to the variability in concentrations at The turbidity at Conway Flats (H1) was significantly higher than at Gore Bay (H2) (p=0.033). The data are shown in Figure 4.2.

24 Environment Canterbury Technical Report The quality of coastal water between Kaikoura and Pegasus Bay

0.8 0.8 H1 NH3N H2 NH3N NNN NNN TN TN 0.6 TON 0.6 TON

0.4 0.4

0.2 0.2 concentration (mg/L) concentration (mg/L)

0 0

Oct-00 Apr-01 Jan-01 Jun-01 Mar-01 Feb-01 Oct-00 Apr-01 Nov-00 Aug-00 Sep-00 Jun-01 Jan-01 May-01 Mar-01 Feb-01 Aug-00 Sep-00 May-01 Mar1-01

Aug1-00 Mar1-01 Aug1-00

0.8 0.8 NH3N H4 H3 NNN TN 0.6 TON 0.6

0.4 0.4 NH3N NNN TN 0.2 0.2 TON concentration (mg/L) concentration (mg/L)

0 0

Jul-94 Jul-94 Apr-94 Oct-95 Jan-94 Jun-94 Oct-94 Mar-94 Mar-96 Jan-95 Nov-94 Dec-95 Sep-94 Mar-95 Feb-95 May-96 Aug-94 Sep-94 Nov-94 Dec-94

0.8 0.8 NH3N NH3N H5 NNN H6 NNN TN TN 0.6 TON 0.6 TON

0.4 0.4

0.2 0.2 concentration (mg/L) concentration (mg/L)

0 0

Jul-94 Apr-01 Oct-00 Jan-01 Jun-01 Apr-96 Jan-96 Jan-94 Mar-01 Feb-01 Nov-00 Aug-00 Sep-00 Nov-95 Nov-94 May-01 Sep-94 May-94 Jun1-94 Mar1-01 Mar1-94 Aug1-00

Figure 4.3 Concentrations (mg/L) of NH3N, NNN, TN and TON over time at sites in the Hurunui area

Environment Canterbury Technical Report 25 The quality of coastal water between Kaikoura and Pegasus Bay

0.2 0.6 H1 DRP H2 DRP TP 0.5 TP 0.15 0.4

0.1 0.3

0.2 0.05 concentration (mg/L) concentration (mg/L) 0.1

0 0

Oct-00 Oct-00 Apr-01 Apr-01 Jun-01 Jun-01 Jan-01 Jan-01 Mar-01 Mar-01 Feb-01 Feb-01 Nov-00 Aug-00 Sep-00 Aug-00 Sep-00 May-01 May-01 Mar1-01 Mar1-01 Aug1-00 Aug1-00

0.2 0.2 H3 DRP H4 DRP TP TP 0.15 0.15

0.1 0.1

0.05 0.05 concentration (mg/L) concentration (mg/L)

0 0

Jul-94 Jul-94 Apr-94 Oct-95 Jan-94 Jun-94 Oct-94 Mar-94 Mar-96 Jan-95 Nov-94 Sep-94 Dec-95 Mar-95 Feb-95 May-96 Aug-94 Sep-94 Nov-94 Dec-94

0.2 0.2 H5 DRP H6 DRP TP TP 0.15 0.15

0.1 0.1

0.05 0.05 concentration (mg/L) concentration (mg/L)

0 0

Jul-94 Apr-96 Oct-00 Apr-01 Jun-01 Jan-94 Jan-96 Jan-01 Mar-01 Feb-01 Nov-94 Nov-95 Nov-00 Sep-94 Aug-00 Sep-00 May-94 May-01

Jun1-94 Mar1-94 Mar1-01 Aug1-00

NOTE: The y axis scale for H2 differs from that at all other sites

Figure 4.4 Concentrations (mg/L) of DRP and TP over time at sites in the Hurunui area

26 Environment Canterbury Technical Report The quality of coastal water between Kaikoura and Pegasus Bay

other Hurunui sites. The NNN and TP results strength, between years. The rainfall influences suggest that there are inputs of both to coastal the volumes of fresh water discharged to the water in proximity to this site. As New Zealand coast. Wind direction and strength affect the state rivers have been found to contribute large of the sea and influence the direction of water amounts of NNN to the coast (Park, 1994) it is movement along the coast. likely the NNN, and probably TP, are from nearby rivers, streams and creeks. The possible The Motunau River is the closest and highest freshwater sources are the Conway River (2.7 km volume freshwater source in proximity to the north), Silvery Creek (160 m south) and Sawpit Motunau sites. Fresh water also flows to the coast Creek (850 m south). Of these the Conway River from Water Supply Creek approximately 2.4 km adds the greatest volume of fresh water to the north, and a small creek approximately 3.4 km sea. There are no data on NNN and TP south, of the Motunau River. Of these freshwater concentrations in Silvery Creek and Sawpit Creek, sources it is the Motunau River that is likely to but concentrations in the Conway River at have the greatest impact on coastal water quality Conway Flats Road over 1994-1999 were: in the Motunau area. There are no water quality or NNN < 0.03 – 0.54 mg/L water quantity data for any of these freshwater TP < 0.008 – 0.27 mg/L sources. However, the variability in NH3N, TN and DRP concentrations (Figure 4.1) at sites H3-H6 That is, NNN and TP concentrations within the likely reflects the variability in Motunau River Conway River are variable and could account for nutrient concentrations and /or water volumes. the variability in concentrations in the coastal water some 2.7 km south of the river mouth. 4.2.1 Other influences The water turbidity at Conway Flats was more At Gore Bay and Motunau stormwater runoff and variable than at Gore Bay (H2) and Motunau (H5) septic tank seepage, from the residences and significantly higher than at Gore Bay. As immediately adjacent to the coast, are potential sediment -laden river water causes high turbidity sources of nutrients, micro-organisms and other in coastal water, the turbidity at Conway Flats contaminants such as metals (for example Zn, Cu, could be due to the influence of the Conway Ni), pesticides and herbicides and hydrocarbons. River. This river transports more sediment during At Gore Bay some 75, and at Motunau some 124 flood events than during normal flows. Hence the residential sections are close to the coast, hence variability in the flows in the Conway River likely any runoff and seepage will eventually end up in has a considerable influence on the variability in the sea. turbidity at Conway Flats. There are no salinity data to support this. Investigation of the impacts of stormwater discharges on coastal water quality would require At site H2 in Gore Bay the variability in NH3N, localised, specifically designed, rainfall NNN TN and TP concentrations was similar to dependent, sampling programmes. Investigations that at site H1, i.e. low variability in NH3N and TN to determine if seepage from septic tanks is concentrations and high variability in NNN and reaching the coast would require intensive and TP. The possible freshwater sources of NNN and specifically designed sampling programmes. TP are the Jed River (800 m north), Buxton Creek (440 m north) and Tweedies Gully stream (540 m south). There are no water quality data for these freshwater sources.

Four sites, H3, H4, H5 and H6, were sampled in proximity to Motunau. A between-site comparison of nutrient concentrations is complicated by the fact that sampling at the sites was undertaken over differing time periods. Site H5 was sampled over 2000-2001 while sites H3, H4 and H6 were sampled over 1994-1996. Thus, while the box and whisker plots for TN and DRP (Figure 4.2) indicate lower concentrations at site H5 than at the other three sites, this difference could be of a temporal rather than a geographic nature. Temporal differences could result from differences in the weather i.e. rainfall, wind direction and wind

Environment Canterbury Technical Report 27 The quality of coastal water between Kaikoura and Pegasus Bay

5 Pegasus Bay results Total Nitrogen TN TN concentrations ranged from 0.12 to 0.56 mg/L. and discussion TN concentrations were significantly higher at 5.1 Results Woodend (P3) and Waimairi (P5) than at Amberley (P1) over 2000-2001.

5.1.1 Between sites Over 2005-2006 TN concentrations were significantly higher: 5.1.1.1 Nutrients • at South Brighton (P7) than at all other The data for the nitrogen- and phosphorus-based sites (P1-P6) except Scarborough (P8). determinands, collected in Pegasus over the • at Scarborough (P8) than at sites from period July 2000 to June 2006, are summarised in Woodend (P3) to New Brighton pier (P5). Table 5.1. The data for each nutrient at each site are presented in box and whisker plots (Figure Dissolved reactive phosphorus DRP 5.1).For sites P1, P3 and P5, where twelve DRP concentrations ranged from <0.003 to 0.082 samples were collected over each of two year- mg/L. long periods, the data from each sampling period are separated (P1a, P3a and P5a (2000-2001) DRP concentrations were significantly higher at and P1b, P3b and P5b (2005-2006)). Waimairi (P5) that at Amberley (P1) and Woodend (P3) over 2000-2001. The Wilcoxon two-tailed signed rank test was applied to the data from sites sampled over each Over 2005-2006 DRP concentrations were specific year-long period to investigate differences significantly higher: in nutrient concentrations between sites. The • at Scarborough (P8) than at sites from periods were 2000-2001 (sites P1, P3 and P5) New Brighton Pier north (P1-P5) and 2005-2006 (sites P1-P8). Over each of the • at South Brighton Beach (P7), New year-long periods there were significant Brighton Pier (P6) and Waimairi (P6) than differences in the concentration of two or more at sites from Spencerville north (P1-P4) nutrients between sites (Appendix III). Total phosphorus (TP) Ammonia nitrogen (NH3N) TP concentrations ranged from 0.009 to 0.28 NH3N concentrations ranged from <0.005 to 0.53 mg/L. mg/L. There was no significant difference in TP There was no significant difference in NH3N concentrations between sites over 2000-2001. concentrations between sites over 2000-2001. Over 2005-2006 TP concentrations were Over 2005-2006 NH3N concentrations were significantly higher: significantly higher at New Brighton Pier (P6), • at South Brighton (P7) than at all other South Brighton (P7) and Scarborough (P8) than at sites (P1-P6) except Scarborough (P8). sites from Spencerville north (P1-P4). • At Scarborough Beach (P8) than at Amberley (P1), Woodend (P3), Concentrations at Waimairi (P5) were significantly Spencerville (P4), Waimairi (P5) and New higher than at Amberley (P1) and Woodend (P3). Brighton pier (P6).

Nitrate and nitrite nitrogen (NNN) NNN concentrations ranged from <0.005 to 0.34 5.1.1.2 Other determinands mg/L. The data for the other measured determinands are summarised in Table 5.2 and presented in box There was no significant difference in NNN and whisker plots (Figure 5.2). concentrations between sites over 2000-2001.

Over 2005-2006 NNN concentrations were significantly higher at Scarborough (P8) than at Spencerville (P4), Waimairi (P5) and New Brighton Pier (P6).

28 Environment Canterbury Technical Report The quality of coastal water between Kaikoura and Pegasus Bay

Table 5.1 Summary of nutrient concentrations (mg/L) at each Pegasus Bay site, based on all the data collected between 2000 and 2006 n=number of samples

P1 - Amberley Beach, P2 - Waikuku Beach, P3 - Woodend Beach, P4 - Spencerville Beach, P5 - Waimairi Beach P6 - New Brighton Pier, P7 - South Brighton Beach, P8 - Scarborugh Beach 2000-2001 2005-2006 2005-2006 2000-2001 2005-2006 2005-2006 2000-2001 2005-2006 2005-2006 2005-2006 2005-2006 P1 P1 P2 P3 P3 P4 P5 P5 P6 P7 P8 NH3N Minimum <0.005 0.005 0.015 <0.005 0.01 0.011 0.009 0.011 0.011 0.015 0.042 Median 0.040 0.023 0.021 0.045 0.024 0.022 0.064 0.034 0.056 0.082 0.072 Mean 0.049 0.025 0.028 0.026 0.031 0.034 0.083 0.052 0.119 0.137 0.127 SD 0.048 0.014 0.014 0.045 0.023 0.024 0.084 0.060 0.145 0.152 0.110 Maximum 0.14 0.047 0.057 0.15 0.085 0.083 0.27 0.23 0.53 0.52 0.36 NNN Minimum 0.005 <0.005 <0.005 0.023 0.0025 <0.005 0.005 <0.005 <0.005 <0.005 <0.005 Median 0.042 0.014 0.025 0.088 0.021 0.017 0.038 0.018 0.020 0.035 0.037 Mean 0.054 0.034 0.034 0.053 0.030 0.031 0.058 0.029 0.028 0.034 0.043 SD 0.056 0.039 0.036 0.091 0.027 0.030 0.050 0.029 0.025 0.024 0.030 Maximum 0.17 0.13 0.13 0.34 0.079 0.084 0.17 0.087 0.067 0.071 0.093 DIN Minimum 0.0075 0.015 0.0205 0.0265 0.0175 0.0135 0.014 0.0175 0.0135 0.0175 0.0495 Median 0.068 0.042 0.062 0.088 0.046 0.045 0.091 0.046 0.096 0.104 0.144 Mean 0.103 0.059 0.062 0.133 0.061 0.064 0.148 0.081 0.147 0.171 0.170 SD 0.101 0.046 0.043 0.111 0.045 0.049 0.123 0.084 0.153 0.164 0.119 Maximum 0.3 0.161 0.177 0.357 0.15 0.138 0.38 0.317 0.563 0.571 0.404 TN Minimum 0.12 0.16 0.13 0.17 0.19 0.21 0.18 0.18 0.17 0.23 0.16 Median 0.190 0.255 0.290 0.292 0.280 0.270 0.320 0.265 0.265 0.345 0.340 Mean 0.195 0.273 0.306 0.250 0.268 0.297 0.325 0.277 0.283 0.357 0.329 SD 0.051 0.078 0.160 0.126 0.060 0.078 0.099 0.074 0.106 0.077 0.093 Maximum 0.3 0.44 0.77 0.52 0.37 0.46 0.47 0.39 0.56 0.55 0.46 TON Minimum 0.039 0.126 0.102 0.0025 0.135 0.1 0.0025 0.073 0 0 0 Median 0.129 0.213 0.224 0.175 0.191 0.234 0.166 0.179 0.157 0.211 0.178 Mean 0.131 0.213 0.244 0.160 0.208 0.232 0.189 0.196 0.135 0.186 0.159 SD 0.058 0.058 0.152 0.128 0.057 0.080 0.142 0.073 0.068 0.114 0.098 Maximum 0.233 0.343 0.683 0.429 0.3525 0.394 0.398 0.348 0.217 0.326 0.297 DRP Minimum <0.003 0.004 0.004 <0.003 0.003 0.005 0.0015 0.006 0.008 0.015 0.014 Median 0.009 0.010 0.011 0.008 0.011 0.010 0.012 0.015 0.017 0.022 0.030 Mean 0.008 0.010 0.010 0.009 0.011 0.012 0.015 0.018 0.025 0.033 0.032 SD 0.005 0.004 0.004 0.004 0.005 0.006 0.012 0.012 0.017 0.023 0.015 Maximum 0.014 0.015 0.017 0.016 0.018 0.024 0.046 0.047 0.057 0.082 0.065 TP Minimum 0.009 0.035 0.029 0.02 0.03 0.03 0.01 0.018 0.01 0.055 0.038 Median 0.041 0.052 0.050 0.072 0.044 0.040 0.094 0.055 0.052 0.077 0.081 Mean 0.065 0.056 0.060 0.058 0.053 0.054 0.102 0.052 0.057 0.088 0.075 SD 0.059 0.016 0.039 0.044 0.023 0.027 0.076 0.018 0.027 0.035 0.023 Maximum 0.2 0.086 0.17 0.18 0.1 0.12 0.28 0.076 0.1 0.17 0.12 n 1212121212121212121212

Environment Canterbury Technical Report 29 The quality of coastal water between Kaikoura and Pegasus Bay

0.6 0.3

)

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L 0.5

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n 0.4 0.2 n

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N 0.1

0.0 0.0 a b 2 a b 4 a b 6 7 8 1a 1b P2 3a 3b P4 5a 5b P6 P7 P8 P1 P1 P P3 P3 P P5 P5 P P P P P P P P P Site Site

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N T 0.2 O 0.2

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0.0 0.0 a b 2 a b 4 a b 6 7 8 P1 P1 P P3 P3 P P5 P5 P P P 1a 1b P2 3a 3b P4 5a 5b P6 P7 P8 P P P P P P Site Site

0.10 0.25

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0.00 0.00 a b 2 a b 4 a b 6 7 8 a b 2 a b 4 a b 6 7 8 P1 P1 P P3 P3 P P5 P5 P P P P1 P1 P P3 P3 P P5 P5 P P P

Site Site

Figure 5.1 Nutrient concentrations (mg/L) at sites in Pegasus Bay

P1 - Amberley Beach, P2 - Waikuku Beach, P3 - Woodend Beach, P4 - Spencerville Beach, P5 - Waimairi Beach P6 - New Brighton Pier, P7 - South Brighton Beach, P8 - Scarborugh Beach a = 2000-2001 b = 2005-2006

30 Environment Canterbury Technical Report The quality of coastal water between Kaikoura and Pegasus Bay

Table 5.2 Summary of concentrations of other determinands at sites in Pegasus Bay n=number of samples

P1 - Amberley Beach, P2 - Waikuku Beach, P3 - Woodend Beach, P4 - Spencerville Beach, P5 - Waimairi Beach P6 - New Brighton Pier, P7 - South Brighton Beach, P8 - Scarborugh Beach

2000-2001 2005-2006 2005-2006 2000-2001 2005-2006 2005-2006 2000-2001 2005-2006 2005-2006 2005-2006 2005-2006 P1 P1 P2 P3 P3 P4 P5 P5 P6 P7 P8 Chlorophyll a (plankton) (ug/L) Minimum 1.2 1.5 2 1.8 2.8 1.5 1.9 2 Median 2.6 3.55 3.95 3.65 5.1 3.3 5.55 3.4 Mean 3.29 15.02 4.53 6.30 6.60 3.44 6.95 3.61 SD 2.20 37.52 2.67 5.07 3.44 1.31 5.39 1.77 Maximum 9.6 13.4 11.8 14.8 12.4 5.5 20.9 7.7 Enterococci (no/100mL) Minimum 1 <2 <2 <2 <2 <2 <2 <2 Median 3 4 2 <2 3 2 9 13 Mean 4.42 5.83 5.50 5.75 26.50 6.54 11.25 19.42 SD 4.29 6.21 7.67 9.14 73.74 9.63 14.88 23.03 Maximum 14 20 28 26 260 32 56 80 n 1212 1212 12121212 Salinity Minimum 27.44 21.3 27.63 29.1 31 31.9 27.8 30.0 Median 32.45 32.5 32.6 33.2 33.1 33.3 32.8 32.9 Mean 32.06 31.0 31.83 32.3 32.84 33.1 32.3 32.2 SD 1.80 3.6 2.053996 1.6 0.78 0.6 1.6 1.3 Maximum 34 33.6 33.6 33.5 33.5 34.1 33.5 33.4 n 1211 1111 11111111 Turbidity (NTU) Minimum 8.5 3.2 3.4 Median 18.5 13 10.5 Mean 19.2 14.4 14.4 SD 8.7 9.3 10.6 Maximum 32 33 39 n121212 Water Temperature Minimum 8.8 8.1 9 9.6 9.4 8.3 10.1 9.1 9 8.9 9.4 Median 14.2 13.1 13.7 15.7 13.7 14.3 14.4 14.5 14.1 14.5 14.9 Mean 13.2 12.6 13.2 14.4 13.6 13.9 14.3 14.0 13.8 14.2 14.5 SD 3.0 3.0 3.1 3.7 3.4 3.7 3.9 3.4 3.4 3.7 3.7 Maximum 17.9 17.5 17.4 20.3 18.4 19.6 22 19 18.2 19.2 19.8 n 1112121112121012121212

Environment Canterbury Technical Report 31 The quality of coastal water between Kaikoura and Pegasus Bay

25 50

20 40

15 30

10 20

(ug/L) Chlorophyll-a 5 (cfu/100mL) Enterococci 10

0 0 P1 P2 P3 P4 P5 P6 P7 P8 P1 P2 P3 P4 P5 P6 P7 P8 Site Site

60 36

34 ) 50

32 NTU ( 40

y 30 30 28 Salinity 26 Turbidit 20 24 10 22 20 0 P1 P2 P3 P4 P5 P6 P7 P8 P1 P3 P5 Site Site

Figure 5.2 Concentrations of other determinands at sites in Pegasus Bay

P1 - Amberley Beach, P2 - Waikuku Beach, P3 - Woodend Beach, P4 - Spencerville Beach, P5 - Waimairi Beach P6 - New Brighton Pier, P7 - South Brighton Beach, P8 - Scarborugh Beach

The Wilcoxon two-tailed signed rank test was applied to the data from sites sampled: Chlorophyll-a • Over 2000-2001 (sites P1, P3 and P5) to The chlorophyll-a concentrations at the sites investigate differences in turbidity sampled over 2005-2006 ranged from 1.2 to 20.9 between sites µg/L (Figure 5.3). • over 2005-2006 (sites P1-P8) to investigate differences in chlorophyll-a, Chlorophyll-a concentrations were significantly enterococci and salinity concentrations higher at: between sites. • Waimairi (P5) than at Amberley (P1), New Brighton Pier (P6) and Scarborough There were significant differences in the (P8). concentration of determinands between some of • South Brighton at the surf club (P7) than the sites sampled over 2005-2006 (Appendix IV). at New Brighton Pier (P6) and Scarborough (P8).

32 Environment Canterbury Technical Report The quality of coastal water between Kaikoura and Pegasus Bay

22

20 P1 P2 P3 P4 P5 P6 P7 P8

18

16 14

12

10

Concentration (ug/L) 8

6

4

2

0

1/07/05 7/04/06 5/05/06 2/06/06 29/07/05 26/08/05 23/09/05 21/10/05 18/11/05 16/12/05 13/01/06 10/02/06 10/03/06 30/06/06

Figure 5.3 Chlorophyll-a concentrations over time at sites in Pegasus Bay P1 - Amberley Beach, P2 - Waikuku Beach, P3 - Woodend Beach, P4 - Spencerville Beach, P5 - Waimairi Beach P6 - New Brighton Pier, P7 - South Brighton Beach, P8 - Scarborugh Beach

Enterococci The enterococci concentrations at the sites The salinity was significantly higher at New sampled over 2005-2006 ranged from <2 to 260 Brighton pier (P6) than at all other Pegasus Bay cfu/100mL. Note: The four highest concentrations sites except Waimairi. (260, 80, 56 and 56 cfu/100mL) were excluded from the box and whisker plot to get a clearer Turbidity picture of the concentrations at the sites (Figure The turbidity at the three sites sampled over 2000- 5.2). 260 enterococci/100mL occurred at Waimairi 2001 ranged from 3.2 to 39 NTU. (P5), 80 enterococci/100mL occurred at There was no significant difference in turbidity Scarborough (P8) and both 56 enterococci/100mL between sites. occurred at South Brighton (P7). 5.1.2 Over time Enterococci concentrations were significantly higher at Scarborough (P8) than at Amberley The nutrient concentrations over time for each site (P1), Waikuku B (P2), Spencerville (P4) and New are presented in Figures 5.4 – 5.5. Brighton Pier (P6). The Kruskal-Wallis ANOVA was used to Salinity determine if there was a significant difference in The salinity at the sites sampled over 2005-2006 the concentration of each nutrient between 2000- ranged from 21.3 to 34.1. 2001 and 2005-2006 at Amberley (P1), Woodend (P3) and Waimairi (P5). At Woodend (P3) and The largest range in salinity was at Waikuku Waimairi (P5) the NNN concentration was (range of 12.3) while there was a small range in significantly higher over 2000-2001 than over salinity at New Brighton pier (2.2) and Waimairi 2005-2006 (p = 0.028 and 0.038 respectively). At (3.5). Amberley (P1) the TN and TON concentrations were significantly higher over 2005-2006 than over 2000-2001 (TN: p=0.01; TON: p=0,004).

Environment Canterbury Technical Report 33 The quality of coastal water between Kaikoura and Pegasus Bay

0.8 0.8 P1 NH3N P2 NH3N NNN NNN TN TN 0.6 TON 0.6 TON

0.4 0.4

0.2

concentration (mg/L) 0.2 (mg/L) concentration

0 0

Jul-05 Jan-06 Jul-05 Mar-06 Feb-01 Aug-00 Sep-00 Sep-05 Nov-00 Nov-05 May-01 May-06 Apr-06 Oct-05 Jun-06 Jan-06 Mar-06 Feb-06 Nov-05 Dec-05 Aug-05 Sep-05 May-06 Mar1-01

0.8 0.8 P3 NH3N P4 NH3N NNN NNN TN TN 0.6 0.6 TON TON

0.4 0.4

0.2 concentration (mg/L) 0.2 concentration (mg/L) 0 0

Jul-05 Jan-06 Jul-05 Mar-06 Feb-01 Nov-00 Nov-05 Aug-00 Sep-00 Sep-05 May-01 May-06 Oct-05 Apr-06 Jan-06 Jun-06 Mar-06 Feb-06 Nov-05 Dec-05 Aug-05 Sep-05 May-06 Mar1-01 0.8 0.8 P5 NH3N P6 NH3N NNN NNN 0.6 TN 0.6 TN TON TON 0.4 0.4

0.2 0.2 concentration (mg/L) concentration (mg/L)

0 0

Jul-05 Jan-06 Jul-05 Mar-06 Feb-01 Nov-00 Nov-05 Aug-00 Sep-00 Sep-05 May-01 May-06 Apr-06 Oct-05 Jan-06 Jun-06 Mar-06 Feb-06 Nov-05 Dec-05 Aug-05 Sep-05 May-06 Mar1-01

0.8 0.8 P7 NH3N P8 NH3N NNN NNN 0.6 TN 0.6 TN TON TON

0.4 0.4

0.2 0.2 concentration (mg/L)

(mg/L) concentration

0 0

Jul-05 Jul-05 Apr-06 Oct-05 Oct-05 Apr-06 Jan-06 Jun-06 Jan-06 Jun-06 Mar-06 Mar-06 Feb-06 Feb-06 Nov-05 Dec-05 Aug-05 Sep-05 Aug-05 Sep-05 Nov-05 Dec-05 May-06 May-06

Figure 5.4 Concentrations (mg/L) of NH3N, NNN, TN and TON over time at sites in Pegasus Bay

34 Environment Canterbury Technical Report The quality of coastal water between Kaikoura and Pegasus Bay

0.3 0.3 P1 DRP P2 DRP 0.25 TP 0.25 TP

0.2 0.2

0.15 0.15

0.1 0.1

concentration (mg/L) 0.05 0.05 concentration (mg/L) 0 0

Jul-05 Jul-05 Jan-06 Mar-06 Feb-01 Nov-00 Nov-05 Apr-06 Oct-05 Aug-00 Sep-00 Sep-05 Jun-06 Jan-06 May-01 May-06 Mar-06 Feb-06 Nov-05 Dec-05 Aug-05 Sep-05 May-06 Mar1-01

0.3 0.3 P3 DRP P4 DRP 0.25 TP 0.25 TP 0.2 0.2

0.15 0.15 0.1 0.1

concentration (mg/L) 0.05 0.05 concentration (mg/L) 0 0

Jul-05 Jul-05 Apr-06 Oct-05 Jan-06 Jun-06 Jan-06 Mar-06 Feb-01 Mar-06 Nov-05 Nov-00 Sep-05 Aug-00 Sep-00 Feb-06

Nov-05 Dec-05 Aug-05 Sep-05 May-06 May-01 May-06 Mar1-01 0.3 0.3 P5 DRP P6 DRP 0.25 TP 0.25 TP

0.2 0.2

0.15 0.15

0.1 0.1

0.05 concentration (mg/L) concentration (mg/L) 0.05 0 0

Jul-05 Jul-05 Jan-06 Apr-06 Oct-05 Mar-06 Feb-01 Jun-06 Jan-06 Nov-05 Nov-00 Sep-05 Aug-00 Sep-00 Mar-06 May-01 May-06 Feb-06 Nov-05 Dec-05 Aug-05 Sep-05 May-06 Mar1-01 0.3 0.3 DRP P7 DRP P8 TP TP 0.25 0.25 0.2 0.2

0.15 0.15

0.1 0.1

concentration (mg/L)

concentration (mg/L) 0.05 0.05

0 0

Jul-05 Jul-05 Apr-06 Oct-05 Jun-06 Jan-06 Apr-06 Oct-05 Jun-06 Jan-06 Mar-06 Feb-06 Nov-05 Mar-06 Aug-05 Sep-05 Dec-05 Feb-06 Nov-05 May-06 Aug-05 Sep-05 Dec-05 May-06

Figure 5.5 Concentrations (mg/L) of DRP and TP over time at sites in Pegasus Bay

Environment Canterbury Technical Report 35 The quality of coastal water between Kaikoura and Pegasus Bay

• Avon-Heathcote Estuary/Ihutai 5.2 Discussion Given that the current flows either northward or southward along the shore, the salinity and water Water movement in Pegasus Bay is influenced by quality at each sampling site will be influenced by the large-scale coastal circulation of the inputs to the sea from both north and south of the Southland Current in combination with the site. influence of tides, wind and waves (Miller et al., 2004). The Southland Current flows northward The lowest salinity (21.3 ppt) was at Waikuku along the east coast of the South Island. Beach (P2). Site P2 is 1-1.5 km south of the However, episodic eddies from the Southland Ashley Estuary mouth and 11.2 km north of the Current do occur in Pegasus Bay (Carter and Waimakariri River mouth. At Amberley Beach (P1) Herzer, 1979 cited in Stevens, 2005). Nearshore, the lowest salinity was 27.44 ppt. Site P1 is 2.8 current flow is predominantly aligned with the km south of the Waipara River and 3 km north of shoreline and the majority of the time the current the Kowai River. The lowest salinities at is a uniform northward or southward flow. The Woodend Beach (P3) and Spencerville Beach tides play a major role in controlling current (P4) were 27.63 and 29.1 ppt respectively. These direction with the current in the lower half of the salinities are attributed to the influence of the water column reversing in phase with the tides Waimakariri River, with Woodend Beach 5.5 km (Cox and Hudson, 2003). The tidal flows are north and Spencerville Beach 4.6 km south of this mainly northward when water levels are above river. The lowest salinities at Waimairi Beach (site mean sea level and southward when water levels P5) and New Brighton Pier (31 and 31.9 ppt are below mean sea level. Wind also influences respectively) could be due to the influence of the direction of surface water currents in Pegasus Waimakariri River (10.7 and 13 km away Bay. However, as the wind energy is not evenly respectively), or the Avon-Heathcote distributed in Pegasus Bay current variations do Estuary/Ihutai (6.2 and 8.5 km away respectively) occur in the bay (Miller et al., 2004). or a combination of both influences. At Waimairi Beach there is also the stormwater from the three The nearshore water in Pegasus Bay is, as outlets that cross the beach. No matter the indicated by the salinity data, influenced by freshwater source, the lowest salinity at these two freshwater inputs. The salinity ranged from 21.3 to sites was at least 1 ppt higher than at any of the 34.1 ppt while the site medians ranged from 32.45 other sites. At South Brighton (P7) the lowest to 33.3 ppt. The salinities that occur further from salinity was 27.8 ppt. Site P7 is 4.4 km from the shore are: mouth of the Avon-Heathcote Estuary/Ihutai and • around 33-34 ppt in the bottom water (at 14.8 km from the Waimakariri River. It is more least 6 m below the surface), 2.5 km from than likely that the salinity at site P7 is influenced shore between the Waimakariri and more by the Avon-Heathcote Estuary/Ihutai than Ashley rivers (KMA, 2003). the Waimakariri River. This will also be the case • 34.1 at the bottom (16 m), approximately for Scarborough Beach located 1.8 km south of 2.8 km from the South Brighton shore the mouth of the Avon-Heathcote Estuary/Ihutai (Zeldis and Gall, 1999) and 16.6 km south of the Waimakariri River. • around 34.5 ppt at 3 m water depth 10 km offshore of the Waimakariri River In Pegasus Bay the Avon-Heathcote Estuary/ mouth (Stenton-Dozey, 2005). Ihutai and the Waimakariri River are considered to be the largest sources of land-based nutrients to The comparison of the near shore salinities with the coastal water. The nutrient contributions from those found further from the shore indicate that all these sources likely account for the significant of the nearshore water in Pegasus Bay is slightly difference in nutrient concentrations between the diluted sea water. The degree of dilution of the sites sampled in Pegasus Bay. sea water by fresh water is affected by the proximity of a freshwater source and the volumes The Avon-Heathcote Estuary/Ihutai is the of fresh water discharged. The notable freshwater receiving environment for tertiary treated effluent inputs to Pegasus Bay (refer to Figure 1.3) are from Christchurch City. The discharged effluent from the following: adds faecal indicator bacteria and, in particular, • Waimakariri River - mean flow of 122 NH3N, DRP and TP enriched freshwater to the 3 m /s and a typical flood flow of 1,500 estuary (Bolton-Ritchie and Main, 2005). Nutrient 3 m /s (Kingett Mitchell Ltd., 2003) and other contaminants inputs also come from the • Ashley River - mean flow of 12.6 m3/s numerous stormwater outlets, four large drains • Waipara River - mean flow of 3 m3/s and the Avon/Ötakaro and Heathcote/Opawaho

36 Environment Canterbury Technical Report The quality of coastal water between Kaikoura and Pegasus Bay

rivers (Bolton-Ritchie and Main, 2005). This has been discharged 1.5 km from shore into estuary is tidal with a mean tidal prism of Pegasus Bay. Stormwater from both Rangiora 8,350,000m3 (Mawson, 1972). As the tide ebbs and Kaiapoi also eventually ends up in the Lower estuary water flows into Pegasus Bay. A Waimakariri River. The nutrient concentrations in considerable portion of the water that ebbs from the Waimakariri River, at the Karaki Yacht Club the estuary floods back in on the next tide (it has near the river mouth, are variable (Appendix VI). been estimated that 32-41% of the freshwater The maximum concentrations recorded (over leaving the estuary (6% of the tidal prism) returns 2002-2006) being NH3N – 0.33 mg/L, NNN – 0.85 on the next tide (Bruce, 1953)). However, the mg/L, TN – 1.4 mg/L, DRP – 0.2 mg/L and TP remainder mixes and moves with Pegasus Bay 0.64 mg/L. The river water that flows into Pegasus water to be dispersed by local and regional winds, Bay forms a plume that extends some distance tides and currents (Miller et al., 2004). out from the shore and north or south, depending on the direction of the wind. The Waimakariri The water plume that leaves the estuary as the River discharge plume is visible because of the tide is ebbing flows either north or south, colour of the river water, with the plume being depending on the direction of the wind. When the most evident when the river is in flood and the plume flows out it influences the water quality at water sediment laden. For river flows up to the sites closer to, than further away from, the mouth mean of 122m3/s, the plume has a weak influence of the estuary. The nutrient data collected from on salinity some 10 km from shore (Stenton- this study indicates that the plume influences Dozey, 2005). The outward extent of influence is water quality at the waters edge and out to at likely to be greater during flood events. There is least 300 m from shore (the length of the New no available information on the along the shore Brighton Pier) to at least 6.2 km north and 1.8 km extent of the influence of this river. However, the south of the estuary mouth. The significantly Waimakariri plume will affect coastal water quality higher concentrations of NH3N at South Brighton at sites both north and south and sites closer to, and New Brighton beaches, the significantly than further away from, the river mouth. As higher concentrations of DRP at South Brighton, evidenced by the salinity data and the fact that New Brighton and Waimairi beaches and the Woodend Beach (5.5 km north) and Spencerville significantly higher TP concentrations at South Beach (4.6 km south) are closest to the river Brighton, that at more northern sites in Pegasus mouth it is nutrient concentrations at these sites Bay, are attributed to north flowing nutrient- that will be most impacted by the Waimakariri enriched estuary water. The significantly higher River. Over 2000-2001 TN concentrations were concentrations of NH3N, DRP and TP at significantly higher at Woodend and Waimairi Scarborough than at, respectively, sites north of beaches than at Amberley Beach. The higher TN Waimairi Beach, New Brighton and South concentrations at Woodend Beach and possibly Brighton are attributed to south flowing nutrient- Waimairi Beach could be due to the Waimakariri enriched estuary water. The results from this River. The nutrient data collected over 2005-2006 study provide information on the extent of the do not show that the Waimakariri River water is along-the-shore influence but not the extent of the impacting nutrient concentrations at Woodend and offshore influence of Avon-Heathcote Spencerville beaches. This could be because: Estuary/Ihutai water on the water quality in • the river plume flows directly out from the Pegasus Bay. However, Zeldis and Gall (1999) river mouth and disperses north or south reported that ~ 2.8 km offshore from with the current some distance from South Brighton, in 16 m water depth, the salinity shore thus minimizing the impact of the and ammonia-nitrogen concentrations indicated river water on nearshore nutrient that surface water at this site was affected by concentrations or water derived from the Avon-Heathcote • the Avon-Heathcote Estuary/Ihutai water Estuary/Ihutai. impacts nutrient concentrations at sites in proximity to the estuary such that The Waimakariri River flows from the mountains significant differences in concentrations through a predominantly rural catchment to resulting from other inputs, such as the discharge to the sea. In its’ lower reaches this Waimakariri River, are masked. river receives the discharge from the PPCS freezing works and the water from the Kaiapoi To determine the along the shore extent of the River and Jockey Baker Creek. Until early 2006 impact on this river on nutrient concentrations will the treated sewage from Rangiora ended up in the require sampling at sites located close to and at Kaiapoi River (via South Brook and the Cam increasing distances away from the river mouth. River) while that from Kaiapoi ended up Jockey To determine that it is Waimakariri River water Baker Creek. Since April 2006 the treated sewage and not freshwater from other sources affecting

Environment Canterbury Technical Report 37 The quality of coastal water between Kaikoura and Pegasus Bay

nutrient concentrations the Waimakariri River (5.1µg/L). These median concentrations are water would need to be ‘traceable’. higher than those from the other six sites. At South Brighton Beach NH3N, DRP and TP The concentrations of the faecal indicator concentrations were significantly higher than at organism enterococci provide information on the many of the other sites sampled. As DIN (NH3N + level of faecal contamination of the sea water. The NNN) and DRP are requirements for potential enterococci sources are the rivers, the phytoplankton growth it is likely that the nutrient Avon-Heathcote Estuary/Ihutai and stormwater. concentrations at this site promote phytoplankton There are three stormwater outlets at Waimairi growth which accounts for the chlorophyll-a Beach and some stormwater outlets including a concentrations that were recorded. At Waimairi large drain at Scarborough Beach. The Beach it is possible that the stormwater enterococci concentrations at all sites were discharged in proximity to the site provides the typically low (medians ranged from < 2 to 13) with nutrients that promote phytoplankton growth. elevated concentrations at times. The highest Stormwater transports fertilisers, nutrients as well maximum concentration of 260/100 mL occurred as pesticides, herbicides, heavy metals, petro- at Waimairi Beach. The water flowing from the chemicals, organic matter, sediment and stormwater pipes could have been the source of microorganisms (Vincent and Thomas, 1997, the enterococci even though it was not raining on Mallin, 2006). The lowest median chlorophyll-a the day the sample was collected. Water does concentration occurred at Amberley Beach (2.6 flow from one or more of the outlets during fine µg/L). This result suggests that that the nutrient weather (pers. obs.). At Scarborough Beach the concentrations at this site are lower than those at maximum concentration was 80/100 mL. The the other sites sampled. water discharging from the nearby large drain could be the source of the enterococci. The chlorophyll-a concentrations at each site Concentrations at this site are also likely to be varied over time (Figure 5.5) with peaks in influenced by the Avon-Heathcote Estuary/Ihutai. concentration in mid September, mid November The maximum enterococci concentrations at and mid April at many of the sites. These peaks South Brighton Beach (56/100 mL) and New are considered seasonal with the spring Brighton Pier (32/100 mL) are likely caused by (September and November) peaks the response Avon-Heathcote Estuary/Ihutai water while the to increases in water temperature, sunlight and maximum concentrations at Woodend Beach possibly nutrient availability. By comparison (28/100 mL) and Spencerville Beach (26/100mL) there was no year-round sampling at offshore are likely caused by Waimakariri River water. sites, such sites were only sampled over one to two months of the year. That is, the offshore Chlorophyll-a concentration is a measure of sampling may have missed the seasonal peaks in phytoplankton abundance. Chlorophyll-a phytoplankton abundance. Then again the concentrations of 0.5 – 2 µg/L occurred 10 km off difference between the nearshore and offshore shore in Pegasus Bay in October- November concentrations may simply reflect between year 2001 (Stenton-Dozey, 2005). Concentrations of differences particularly in weather conditions. 3.7 – 4.0 µg/L were recorded at three sites 2.5 km Variations in phytoplankton abundance can occur offshore in April 2003 (KMA, 2003) and a over time scales of a few days as a consequence concentration of 1.63 µg/L was recorded in of local environmental variation (e.g. river floods), surface water ~2.8 km off South Brighton (Zeldis through to several months as a consequence of and Gall, 1999). The median chlorophyll-a seasonal variability and between years or multiple concentrations recorded at the sites sampled in years as a consequence of global climate this study ranged from 2.6 to 5.55 µg/L, while the variability (e.g. Southern Oscillation cycle) maximum concentrations ranged from 5.5 to 20.9 (Stenton-Dozey, 2005). µg/L. That is, chlorophyll-a concentrations at the waters edge were typically higher than those offshore in Pegasus Bay. The most likely reason for this is that nutrient concentrations are higher 6 Future investigations closer to than further away from the shore. However, temporal differences, i.e. differences and monitoring between years or time of year of sampling, cannot The coastal water quality at sites in Kaikoura, be discounted. Hurunui and Pegasus Bay must continue to be monitored. This monitoring should be for all the The highest median chlorophyll-a concentration determinands measured over 2005-2006 and occurred at South Brighton (5.55 µg/L) with a high suspended solids and dissolved oxygen median concentration at Waimairi Beach concentrations and percent saturation.

38 Environment Canterbury Technical Report The quality of coastal water between Kaikoura and Pegasus Bay

This will allow for an assessment of the matter in surface waters off southern relationships between nutrient concentrations and California and its relationship to primary productivity, nutrient concentrations and phytoplankton. Journal of Marine sediment loads in the water column and nutrient Research 25:671-696. concentrations and salinity. Hayward, S.A., Lavender, R.M. and Meredith, A.S. 2002. Lyell Creek: assessment of water quality and aquatic ecosystem 7 Acknowledgements monitoring, September 1994 to May 2002. The author wishes to thank staff of Environment Environment Canterbury Report Canterbury, including Peter Adams and Julie No.U02/69. 46pp. Edwards for sample collection. The water samples, were analysed by the laboratory staff of IDT (Intelligent Decisions Technologies), 1998. Cawthron Institute and Environment Canterbury. Wqstat Plus. Intelligent Decisions This report was reviewed and edited by Ken Technologies Ltd., Longmont. Taylor from Environment Canterbury. Kingett, Mitchell Limited (KML), 2003. Water

quality in Pegasus Bay. 33 pp.

8 References Mawson, A.H. 1972. Notes on the hydrology of the Avon and Heathcote Estuary. Unpublished paper presented to an ANZECC (Australia and New Zealand Ecology Action Seminar at the University Environment and Conservation Council) of Canterbury, 4 August 1972. 2000: Australian and New Zealand Guidelines for fresh and marine waters. McNicol, J., Shone, M and Horn, C. 2001. Green Australia and New Zealand Environment Globe 21 Kaikoura Community and Conservation Council. Melbourne Benchmarking Pilot Study. Tourism Recreation Research and Education Bolton-Ritchie, L. 2004. Lyttelton Harbour Centre Report No.53. 115pp. /Whakaraupō nutrient status: April 1988 – June 2003. Environment Canterbury Miller, B.M., Glamore, W.C. and Hudson, R.M. Report R04/14. 2004. Christchurch outfall: Twelve months data collection and modelling. WRL Bolton-Ritchie, L. 2005. Akaroa Harbour nutrient Technical Report 2004/14. status: April 1989 - June 2004. Environment Canterbury Report U05/11. NRC, 2001. Clean Coastal Waters: Understanding and reducing the effects of nutrient Bonsdorff, E., Blomqvist, E.M., Mattila, J. and pollution. National Academy Press, Norkko, A. 1997. Coastal Eutrophication: Washington D.C. Causes, Consequences and Perspectives in the Archipelago Areas of the Northern Park, S. 1994. Environment B.O.P. natural Baltic Sea. Estuarine, Coastal and Shelf environment regional monitoring network Science 44 (supplement A): 63-72. coastal and estuarine ecology programme. 1992/93. Environment B.O.P. Bruce, A. 1953. Report on a biological and Environmental Report No 94/6. 137 pp. chemical investigation of the waters in the estuary of the Avon and Heathcote Redfield, A.C., Ketchum, B.H. and Richards, F.A. Rivers. Christchurch Drainage Board 1963. in:The Sea: Ideas and Report. 58pp. Observations on Progress in the Study of the Seas, ed. M.N. Hill. Vol. II. Pp 26-77. Cox, D.R. and Hudson, R. M. 2003. Waimakariri Interscience, New York. outfall oceanographic data collection, 27 May to 25 July 2003. WRL Technical Rosenberg, R. 1985: Eutrophication – the future Report 2003/24. marine coastal nuisance? Marine Pollution Bulletin 16 (6): 227-231 Eppley, R.W., Harrison, W.G., Chisholm, S.W. and Stewart, E. 1977. Particulate organic SPSS, 1999. Systat Inc. Illinois.

Environment Canterbury Technical Report 39 The quality of coastal water between Kaikoura and Pegasus Bay

Statsoft, 2001. STATISTICA for Windows [Computer programme manual]. Tulsa, OK: Statsoft, Inc.

Valiela, I. 1995. Marine Ecological Processes. Springer-Verlag, NY. Inc.

Vincent, V.C and Thomas, M.P. 1997. Urban runoff pollution: An Overview. Environmental Education and Information 16(2): 185-196.

Zeldis, J.and Gall, M. 1999. Assessment of Bromley sewage effluent on phytoplankton growth at the proposed Pegasus Bay ocean outfall site. Prepared for Christchurch City Council. NIWA Client Report No. CHC99/30

40 Environment Canterbury Technical Report The quality of coastal water between Kaikoura and Pegasus Bay

Appendix I: Details of the sampling sites

Site ID Site label Site description Sampling periods Grid reference

NZMS 260 map series

CRC304878 K1 Behind supermarket July 2005 - June 2006 O31:662-686 July 2000 - May 2001 CRC304176 K2 Just right of Lyall Creek mouth July 2005 - June 2006 O31:664-667 CRC304880 K3 Ingles Bay in front of Panorama Motels July 2005 - June 2006 O31:673-655 July 2000 - May 2001 CRC304175 K4 South Bay opposite Takehe Drive July 2005 - June 2006 O31:660-650 SCY000765 K5 South Bay Aug 1994 - May 1996 O32:660-648 SCY000764 K6 Goose Bay Oct 1993 - May 1995 O32:536-5795 SCY000761 K7 Oaro, first Reef Oct 1993 - May 1995 O32:517-546 SCY000762 K8 Oaro, second reef Oct 1993 - May 1995 O32:516-543 SCY000763 K9 Oaro, south of second reef Aug 1993 - March 1996 O32:515-542 CRC304174 H1 Conway Flats Ngaroma Homestead, near bridge July 2000 - May 2001 O32:474-409 CRC302538 H2 Gore Bay north end of beach July 2000 - May 2001 O33:463-539 CRC303254 H3 Motunau 1st point Nth of Motunau River July 1994 - May 1996 N34:166-952 CRC303253 H4 Motunau 40m North of Motunau River July 1994 - March 1995 N34:163-952 CRC304177 H5 Motunau Beach Sandy Bay Rd July 2000 - May 2001 N34:158-953 CRC303252 H6 Motunau South end of Sandy Bay July 1994 - May 1996 N34:152-954 July 2000 - May 2001 CRC303153 P1 Amberley Beach near Amberley Beach Rd July 2005 - June 2006 N34:921-814 CRC302551 P2 Waikuku Beach at surf club July 2005 - June 2006 M35:875-688 July 2000 - May 2001 CRC302571 P3 Woodend Beach at surf club July 2005 - June 2006 M35:866-632 CRC302514 P4 Spencerville Beach at surf club July 2005 - June 2006 M35:869-528 July 2000 - May 2001 CRC302573 P5 Waimairi Beach at surf club July 2005 - June 2006 M35:878-468 CRC304870 P6 New Brighton Beach off end of pier July 2005 - June 2006 M35:885-4455 CRC302578 P7 South Brighton Beach at surf club July 2005 - June 2006 M35:888-428 CRC302596 P8 Scarborough Beach by the clock tower July 2005 - June 2006 M36:914-372

Environment Canterbury Technical Report 41

2 Environment Canterbury Technical Report 42 The quality ofcoastal water between Kaikoura and Pegasus Bay

Appendix II: Details of analyses included in the water quality monitoring programme

Determinand Analysis provider Method Time Period Detection Limit Units

Nitrate nitrogen CIN Laboratory Cadmium reduction 1993-1996 0.005 mg/L

th Nitrate- nitrite nitrogen (NNN) ECan laboratory APHA 4500 NO3 - F (20 ED) 2000-2006 0.005 mg/L

Total ammonia-nitrogen (NH3N) CIN Laboratory Limnology and Oceanography 1969, Cawthron method 1993-1996 0.005 mg/L

th ECan laboratory APHA 4500 NH3-F - modified (20 ED) 2000-2006 0.005 mg/L

Dissolved inorganic nitrogen (DIN) Calculation (NNN + NH3N) mg/L

Total nitrogen (TN) CIN Laboratory Chem div photo oxidation 1993-1996 0.01 mg/L

ECan laboratory APHA 4500-Norg D (20th ED) 2000-2001 0.08 mg/L

th ECan laboratory APHA 4500-N C modified (20 ED) 2005-2006 0.08 mg/L

Dissolved reactive phosphorus (DRP) CIN Laboratory Ascorbic Acid Mo-Sb reagent, Water and Soil No 3 1993-1996 0.003 mg/L

th ECan laboratory APHA 4500-P B,F (20 ED) 2005-2006 0.001

Total phosphorus (TP) CIN Laboratory H2SO4/K2S2O8 digestion Ascrobic acid Mo-Sb reagent 1993-1996 0.005 mg/L

th ECan laboratory APHA 4500-P B5 (20 ED) 2000-2006 0.008 mg/L

The quality of coastal water between Kaikoura and Pegasus Bay

Appendix III: Comparison of surface water nutrient concentrations between sites in: • the Kaikoura area • Pegasus Bay over each year-long sampling period. Results from the two-tailed Wilcoxon Signed Rank Test

Environment Canterbury Technical Report 43 The quality of coastal water between Kaikoura and Pegasus Bay

Kaikoura area

* - significant difference between sites at p< 0.05 ** - significant difference between sites at p < 0.01 blank cells indicate there was no significant difference between sites

K1 - behind the supermarket, K2 - right of Lyell Creek, K3 - Ingles Bay, K4 - South Bay K5 - South Bay, K6 - Goose Bay, K7 - Oaro first reef, K8 - Oaro second reef, K9 - Oaro south of second reef

1994- 1995 - 1995 Higher Value 1996 Higher Value

K5 K6 K7 K9 K5 K6 K7

K5 TP * TP * DRP * K5 K6 TON * TON * TP *

Lower Value K7 Lower Value K6 TON * K7 K9 NNN * NNN *

2000- 2001 Higher Value

K2 K4

K2 TON * Lower Value K4 NH3N *

2005- 2006 Higher Value K1 K2 K3 K4 K1 NNN * DRP *

TN * TON* K2 TP ** TP **

Chl-a ** Salinity** Lower Value NNN** NNN ** NNN** K3 Chl-a ** DIN ** DIN * K4 Chl-a * Salinity*

NOTE: No significant difference in nutrient concentrations between sites sampled over 1993-1994.

44 Environment Canterbury Technical Report The quality of coastal water between Kaikoura and Pegasus Bay

Pegasus Bay

* - significant difference between sites at p< 0.05 ** - significant difference between sites at p < 0.01 blank cells indicate there was no significant difference between sites

P1 - Amberley Beach, P2 - Waikuku Beach, P3 - Woodend Beach, P4 - Spencerville Beach, P5 - Waimairi Beach P6 - New Brighton Pier, P7 - South Brighton Beach, P8 - Scarborugh Beach

2000-2001 Higher Value P1 P3 P5

P1 TN * TN **

DRP **

DRP * P3

Lower Value P5

2005-2006 Higher Value

P1 P2 P3 P4 P5 P6 P7 P8 NH3N * NH3N ** NH3N ** NH3N ** DIN* DIN ** P1 TN * DRP * DRP ** DRP ** DRP ** TP * TP * NH3N ** NH3N ** NH3N ** DIN* DIN ** P2 TN * DRP * DRP ** DRP ** DRP ** TP * NH3N * NH3N ** NH3N ** NH3N ** DIN* DIN ** DIN ** P3 TN ** TN * DRP * DRP ** DRP ** DRP ** TP ** TP * NH3N ** NH3N ** NH3N ** NNN*

Lower Value DIN* DIN ** P4 TN *

DRP * DRP ** DRP ** DRP **

TP * TP *

NNN* DIN* P5 TN * TN * DRP * TP ** TP ** TON* TON* TON* NNN* P6 TN * TP *

P7

P8

Environment Canterbury Technical Report 45 The quality of coastal water between Kaikoura and Pegasus Bay

Appendix IV: Comparison of chlorophyll-a, enterococci, salinity and turbidity between Pegasus Bay sites over 2005-2006. Results from the two-tailed Wilcoxon Signed Rank Test

46 Environment Canterbury Technical Report The quality of coastal water between Kaikoura and Pegasus Bay

P1 - Amberley Beach, P2 - Waikuku Beach, P3 - Woodend Beach, P4 - Spencerville Beach, P5 - Waimairi Beach P6 - New Brighton Pier, P7 - South Brighton Beach, P8 - Scarborugh Beach

Higher Value 2005-2006 P1 P2 P3 P4 P5 P6 P7 P8

Salinity * P1 Chloropyll-a * Enterococci* Salinity * Salinity * Salinity ** P2 Enterococci* P3 Salinity * Salinity * P4 Enterococci*

Lower Value P5 Chloropyll-a ** Chloropyll-a * P6 Enterococci* P7 Salinity ** Salinity * P8 Chloropyll-a ** Chloropyll-a **

Environment Canterbury Technical Report 47 The quality of coastal water between Kaikoura and Pegasus Bay

Appendix V: DIN concentrations in Lyell Creek, Kowhai River and Middle Creek over 2005-2006

3.5 Middle Creek Lyall Creek 3 Kowhai River

2.5

2

1.5

DIN concentration (mg/L) 1

0.5

0

Jul-05 Jul-06 Apr-05 Oct-05 Apr-06 Oct-06 Jun-05 Jan-06 Jun-06 Mar-05 Mar-06 Feb-05 Feb-06 Nov-05 Aug-05 Dec-05 Aug-06 Sep-05 Sep-06 May-05 May-06 Time

Site details Kowhai River at SH 1 – site CRC303270 Lyell Creek at SH 1 – site CRC303476 Middle Creek at Beach Road - site CRC304557

48 Environment Canterbury Technical Report The quality of coastal water between Kaikoura and Pegasus Bay

Appendix VI: Summary of nutrient concentrations at the Karaki Yacht Club, Waimakariri River mouth (2002 - 2006) (Site CRC300245)

NH3N NNN TN DRP TP Minimum 0.008 0.064 0.120 0.007 0.012 Median 0.064 0.285 0.595 0.019 0.057 Mean 0.075 0.347 0.627 0.042 0.105 SD 0.056 0.213 0.318 0.049 0.116 Maximum 0.330 0.850 1.40 0.20 0.640 n 4848484848

Environment Canterbury Technical Report 49