Healthy Estuary and Rivers of the City

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3 Healthy Estuary and Rivers of the City Water quality and ecosystem health monitoring programme of Ihutai Suitability of sites for: Contact recreation based on results from the summer of Shellfish safe to eat based on results from 2014 R15/133 ISBN (print) (web) Report prepared by Lesley Bolton-Ritchie May 2015

4 R15/133 ISBN (print) (web) PO Box 345 Christchurch 8140 Phone (03) Fax (03) Church Street PO Box 550 Timaru 7940 Phone (03) Fax (03) Website: Customer Services Phone

5 Table of contents 1 Water quality for contact recreation Introduction Sampling Calculating the Suitability for Recreation Grade Results Water quality for shellfish safe to eat Environment Canterbury Technical Report i

6 ii Environment Canterbury Technical Report

7 1 Water quality for contact recreation 1.1 Introduction There can be health risks associated with immersion in water if the water contains faecal matter from warm blooded animals (birds and mammals). The faecal matter contains disease-causing bacteria, protozoa and viruses. These micro-organisms can cause stomach upsets, skin infections, ear infections and respiratory infections. To reduce the risk of becoming sick as a result of immersion in water, people need to know about the quality of the water for contact recreation so they can decide whether to and where to carry out a recreational activity in or on the water. To determine if there is faecal matter in the water, faecal indicator bacteria (FIB) concentrations are measured. The higher the number of FIB in the water, the higher the likelihood that disease-causing bacteria, viruses and protozoa will be present and hence the higher the health risk. Escherichia coli (E.coli) is the FIB measured in fresh water and enterococci is the FIB measured in sea water. As the water within the estuary is a mix of fresh and sea water, the water in the mid-upper reaches of the estuary is analysed for both enterococci and E. coli. 1.2 Sampling There are seven sites in the Estuary of the Heathcote and Avon Rivers/Ihutai and one site in the Avon River/Ōtākaro and one site in the Heathcote River/Ōpāwaho (Figure 1-1) where the concentration of FIB in the water is monitored each summer by Environment Canterbury to assess suitability for recreation. The faecal indicator bacteria concentrations in the water at each site are measured weekly for fifteen weeks over summer. The estuary sites are sampled around two hours after high tide at Lyttelton. This time difference is because there is an hour difference in the time of high tide between Lyttelton and the inner part the estuary, and to ensure the tide is beginning to go out. Sampling time for the river sites is not determined by the state of the tide. The weekly results are available on the Environment Canterbury website At the estuary sites only the enterococci results are provided on this website. The FIB concentrations at the sites over the summer are in Table 1-1. Environment Canterbury Technical Report 1

8 Figure 1-1: The sampling sites 2 Environment Canterbury Technical Report

9 1.3 Calculating the Suitability for Recreation Grade For each site the FIB results from the summer of were combined with the results from the previous four summers. The 95 th percentile value of these data was calculated and used to give the Microbiological Assessment Category (MAC) which provides a measure of water quality over time. For each site the potential sources of faecal matter to the water are listed. From this list the sources that are likely to provide the highest concentrations of disease-causing micro-organisms are identified; this gives the Sanitary Inspection Category (SIC). The MAC and SIC are used to determine the Suitability for Recreation Grade. The suitability for recreation grades are very good, good, fair, poor and very poor. For each site the updated Suitability for Recreation Grade and the sources that are likely to provide the most faecal matter are shown. The key to the sources are: Birds The picture shows a gull but there are many different types of birds in the estuary Ducks are the most abundant birds in the rivers and drains Stormwater River or large drain Receiving urban stormwater and with a high number of birds The updated Suitability for Recreation Grade is the Grade for the site in 2015/ Results The weekly results for all sites are presented in Table 1-1. The site by site results follow the table. Environment Canterbury Technical Report 3

10 4 Environment Canterbury Technical Report Table 1-1: Enterococci and E.coli concentrations (MPN/100mL), Date sampled E.coli - > 260/100 ml highlighted by light blue, > 550/100 ml highlighted by dark blue Enterococci - > 140/100 ml highlighted by orange, > 280/100 ml highlighted by red The dates highlighted in green are when re-sampling was required. At the river sites where there is permanent signage there is no re-sampling Spit tip Penguin Street Enterococci concentrations (MPN/100 ml) South New Brighton Park Humphreys Drive Mopunt Pleasant Yacht club Beachville Road Moncks Bay Penguin Street South New Brighton Park E.coli concentrations (MPN/100 ml) Humphreys Drive Mopunt Pleasant Yacht club Beachville Road Avon River/Ōtākaro at Kerrs Reach 17-Nov-14 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 10 < Nov <10 <10 10 < Dec-14 <10 <10 <10 <10 <10 <10 <10 < <10 < Dec-14 < <10 10 <10 < <10 < Dec-14 <10 <10 <10 <10 10 < Dec Dec < < < Jan-15 < <10 <10 <10 < <10 20 < Jan <10 < <10 < <10 > Jan-15 <10 < <10 < < Jan Jan Jan < <10 < < Feb < <10 < Feb <10 <10 10 < < Feb-15 <10 10 < < Feb-15 <10 <10 < Mar-15 < Mar Mar Heathcote River/Ōpāwaho at Catherine Street Healthy Estuary and Rivers of the City

11 SPIT TIP Potential sources of faecal contamination Suitability for recreation for 2015/2016 This site is graded GOOD This means this site is satisfactory for swimming most of the time. Exceptions may include following rainfall. Environment Canterbury Technical Report 5

12 PENGUIN STREET Potential sources of faecal contamination Suitability for recreation for 2015/2016 This site is graded FAIR This means this site is generally satisfactory for swimming, though there are many potential sources of faecal material. 6 Environment Canterbury Technical Report

13 SOUTH NEW BRIGHTON PARK Potential sources of faecal contamination Suitability for recreation for 2015/2016 This site does not have a grade. It has only been sampled for one summer and at least three summers of results are needed before it can be given a grade. Environment Canterbury Technical Report 7

14 HUMPHREYS DRIVE Potential sources of faecal contamination Suitability for recreation for 2015/2016 This site is graded POOR This means this site is generally not suitable for swimming, as indicated by historical results. 8 Environment Canterbury Technical Report

15 MOUNT PLEASANT YACHT CLUB Potential sources of faecal contamination Suitability for recreation for 2015/2016 This site is graded FAIR This means this site is generally satisfactory for swimming, though there are many potential sources of faecal material. Environment Canterbury Technical Report 9

16 BEACHVILLE ROAD Potential sources of faecal contamination Suitability for recreation for 2015/2016 This site is graded GOOD This means this site is satisfactory for swimming most of the time. Exceptions may include following rainfall. 10 Environment Canterbury Technical Report

17 MONCKS BAY Potential sources of faecal contamination Suitability for recreation This site is graded GOOD for 2015/2016 This means this site is satisfactory for swimming most of the time. Exceptions may include following rainfall. Environment Canterbury Technical Report 11

18 AVON RIVER/OTĀKARO at KERRS REACH Potential sources of faecal contamination Suitability for recreation for 2015/2016 This site is graded VERY POOR This means this site is not suitable for swimming as indicated by historical results. 12 Environment Canterbury Technical Report

19 HEATHCOTE RIVER/OPĀWAHO at CATHERINE STREET Potential sources of faecal contamination Suitability for recreation for 2015/2016 This site is graded VERY POOR This means this site is not suitable for swimming as indicated by historical results. Environment Canterbury Technical Report 13

20 2 Water quality for shellfish safe to eat Cockles and pipis are collected from the estuary for human consumption. These shellfish filter the overlying water to get their food. When filtering the water they can also ingest bacteria, protozoa and viruses and accumulate these on their gills and in their gut. Large quantities of these micro-organisms in the shellfish can make people who eat the shellfish sick. To determine if the shellfish are suitable for human consumption we measure the concentration of the FIB faecal coliforms in the water overlying shellfish and compare the results to MfE/MoH (2003) guideline values. Faecal coliforms concentrations were measured over the summer at Beachville Road. Faecal coliforms concentrations were also measured monthly (as part of the water quality monitoring programme within the estuary) in 2014 at sites in the estuary where shellfish are known to occur. The state of the water quality for shellfish safe to eat at the five monitored sites are presented in Figure 2-1. Figure 2-1: State of the water quality for shellfish safe to eat Red water quality does not meet the guidelines Green water quality does meet the guidelines Orange water quality meets the guidelines at high tide but does not meet the guidelines at low tide 14 Environment Canterbury Technical Report

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