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Opening Section

Foreword and Acknowledgements

Introduction

Part I: The Framework for Monitoring Recreational Water Quality

Part II: Guidelines for Recreational Water Quality

Part III: Explanatory Notes to the Guidelines

Appendices

Further Information

SECTION H: NOTES TO PART II: Guidelines for Recreational Water Quality

Note H(i): Sampling times and periods

Season period

The bathing season period will vary according to location, but will generally extend from 1 November to 31 March. If a beach is used all year round the grade and weekly monitoring should reflect this (i.e. should be based on data for a period relevant to usage).

A Suitability for Recreation Grade (SFRG) is established for each beach in the programme at the beginning of the season. The SFRG is applicable for up to five years, provided there are no significant changes within the catchment that might affect water quality. The grade provides an indication of the overall condition of the site.

Weekly sampling should continue at those beaches graded Good, Fair or Poor. Weekly sampling is required for determining the public health risk at a beach. Beaches graded Very Good may not require ongoing monitoring because of the low risk identified. The same applies to beaches graded Very Poor, as they will generally be unsuitable for recreational use.

Resource limitations may restrict the number of beaches in a region that can be monitored. The grading system applied in these guidelines enables beaches to be prioritised according to their grade, and creates the potential to have all beaches within a region, city or district graded over time.

Number of samples to collect

A minimum of 20 samples should be collected from each site in the monitoring programme, usually at weekly intervals. Additional samples may be taken throughout the season as a result of single-sample exceedances. While these do not contribute to the recommended 20 samples, they should be recorded in the database/spreadsheet with all other samples.

Timing sample collection

Figure H1 shows how a sampling regime may be timed. In this instance it ensures that the results are generated in time to inform the public of the quality of the beach at the time of highest use (the weekend). There may be other peak times when the regime in Figure H1 is not appropriate and staff should design programmes accordingly.

Flexibility in sample timing

In setting up a programme it is important to allow for the minimum number of samples to be collected (20). This will usually require weekly monitoring, depending on season period (which may vary from region to region). As sampling is not likely to take place during conditions which may present a health and safety hazard (e.g. heavy rainfall, storm conditions, large surf), it is important to design a weekly sampling programme that has sufficient flexibility to allow sampling to take place as soon as practical after adverse conditions have abated. This may also better reflect the conditions under which people are swimming.

24-hour re-sampling requirement

Marine waters

For marine waters when sampling returns a result exceeding the action level threshold, the guidelines require a follow-up sample within 24 hours of receiving the first result. The purpose of the follow-up sample is to ensure that the first sample is not an anomaly and that the problem is persistent before initiating a public notification plan.

Ideally, resampling should take place within 24 hours of receiving a high result. While this does not present a problem for urban beaches, logistically it may not be possible for more remote locations. In such instances re-sampling should take place between 24 and 72 hours after receiving a high result.

If a sampling agency has remote sites it may be possible to arrange for another organisation to collect samples and transport them to a local laboratory for analysis. Health agencies, territorial local authorities or community organisations may be able assist with sampling, and could be particularly useful for re-sampling in remote locations.

Freshwaters

No follow-up sample is required to confirm an exceedance of the alert-level threshold. There are two reasons for this: the dilution factor is likely to be less than for marine waters resulting in more extreme exceedances; and potentially higher concentrations and a greater range of pathogens may be present in freshwaters.

Note H(ii): Techniques for taking and analysing samples

Where to sample

Water-quality samples should be taken from the area where swimming occurs. In general, the sample will be taken at approximately 15 cm below the surface at a point where the depth of water is 0.5 metres for marine water, and 30 cm below the surface at a point where the depth of water is 1 metre for freshwater.

Multiple sample sites

Sometimes it may be desirable to take multiple samples along a beach, particularly where a beach extends for some distance and one sample point is not representative of the whole beach. The way multiple samples are incorporated into results will vary. If samples are taken at considerable distances from each other, then each of the samples should be considered an individual sample site. However, if multiple samples are taken from a small beach (e.g. with the purpose of trying to find a potential source of contamination), then these will need to be treated differently, and the highest value should be taken as the maximum for the whole beach.

Sample collection techniques

At the time of sampling, enter in a logbook (for later transcription to a sample sheet) details of weather conditions (wind speed and direction, rainfall), water temperature, salinity, and observations of conditions such as turbidity or discoloration, and any unusual circumstances affecting the site (e.g. seaweed, jellyfish).

The following steps for sampling are recommended.

1. Ensure that the bottle is clearly labelled for later sample identification.
2. Immediately before sample collection, remove the bottle cap while ensuring that the inner of the cap is protected from soiling. The laboratory generally supplies sterile containers of a suitable size.
3. Quickly plunge the bottle upside down to the required sampling depth set for the site. (For marine water the sample will be taken at approximately 15–20 cm below the surface at a point where the depth of water is 0.5 metres; for freshwater the sample will be taken at approximately 30 cm below the surface where the depth of the water is approximately 1 metre.)
4. Tilt the bottle until the neck points slightly upwards, with the mouth directed towards the current. The bottle can be moved forward horizontally until filled if necessary. Completely fill the bottle.
5. Rapidly bring the bottle to the surface and pour out a small portion (leave a space of 2–3 cm) to permit proper mixing for analysis. Quickly fit the cap and secure tightly.
6. Record the time of sample collection and check sample identification labelling.
7. Place in a chilly bin containing frozen slicker pads.

Sampling after wet weather

The guidelines relate to samples taken throughout the total bathing season irrespective of weather conditions. Results influenced by rainfall should not be excluded: people do swim shortly after a rainfall event, and it is important to sample when people are likely to be swimming. This may be particularly so for freshwater lakes and rivers.

The separation of dry-weather and wet-weather data is also impractical because the definition of the two is problematic. For example, coastal water can be less polluted in the early stages of a wet spell but more polluted when the weather has become fine just after substantial rainfall; the reverse can be true in estuaries.

Safety

The safety of field officers is vital and should be taken into account when selecting sample sites with respect to entering the water.

Transporting samples

The sample should be transported to the analytical laboratory as quickly as facilities allow, preferably within six hours, but no longer than 24 hours.

When it is not possible to have the samples analysed by the local laboratory, a courier should be arranged well in advance. Courier companies can be requested to make a pick-up from the council in time to courier the samples to the laboratory on the same day or overnight. Samples should be packed in chilly bins (polystyrene bins are sufficient) with ice packs to keep them cool.

It is particularly important that samples analysed for E. coli are analysed within 24 hours of sampling, as bacteria may begin to die or replicate, depending on storage conditions and the status of the water sample.

Documentation of the transport history and of all those who have handled the sample should accompany all samples. This is known as a chain of custody.

On arrival at the laboratory the samples should be placed in a refrigerator, and analysed within two hours of receipt (particularly for enterococci and E. coli; different time factors may be applicable for other micro-organisms). The analytical laboratory should record the times of sample receipt and analysis.

Where analysis for other micro-organisms is required, obtain specific instructions from the analytical laboratory.

Laboratory techniques

Marine studies have generally concluded that enterococci are the indicator of choice for the presence of faecal pollution. The recommended method for their detection in the Recreational Water Quality Guidelines are the Membrane Filter (MF) Test Method for Enterococci in Water as described in Document No. EPA-821-C-97-004, and Enterolert™ (note: Enterolert™ may not be considered suitable for state of the environment monitoring and reporting due to inadequate detection limits).

The above method has been evaluated for marine waters and has the advantage of giving results in 24 hours. Earlier methods gave a result within 48 hours. The value of this for monitoring agencies is to be able to identify alert, and action-level exceedances more quickly.

For similar reasons, in freshwater where E. coli is the indicator of choice, Colilert™ and EPA method 1103.1, 1985 Membrane Filter Method for E. coli are the preferred methods to enumerate Escherichia coli. Both methods give a result within 24 hours.

Quality control

Laboratories conducting testing for monitoring agencies must be able to demonstrate competence. Ideally this means an IANZ accredited laboratory.

It is essential that laboratories have documented quality assurance procedures. This does not have to be in the form of very detailed manuals, but the basic procedures of the laboratory must be written down. It needs to be quite clear what procedures are being used and exactly how the tests are being carried out. All key activities must be documented, and everyone involved in testing – from sample collector to the person reporting the results – must have a thorough understanding of their responsibilities and duties, any problems that could arise, and how they should be dealt with. All activities undertaken must be recorded so that it is quite clear, from the time of collection of the sample to the reporting of results, what actions were taken, by whom and when.

In showing competence, laboratories need to consider participation in an inter-laboratory proficiency programme, spiked samples, split samples, duplicates, positive and negative controls, both within the laboratory and in collaborative tests with other laboratories.

New method validation

New methods must be proven to provide results equivalent in sensitivity and specificity to those of the preferred test methods for the waters being tested. Statistical analysis of parallel test results must show strong linear correlation and no significant difference between the methods by paired t-test analysis.

Note H(iii): Establishing a Sanitary Inspection Category (SIC)

The following steps are required to determine an SIC.

1. Carry out an initial desktop analysis based on historical information.
2. Use Parts A, B and C of the Catchment Assessment Checklist to help identify relevant information about the site.
3. Use Part D of the Catchment Assessment Checklist to identify the presence of sources of faecal contamination likely to cause effects in the water body.
4. If more than one source is present, then choose the most important. Importance is assessed in terms of the susceptibility of the water body to faecal influence. For example, a continual moderate source of faecal contamination may be considered more important than an occasional but high-load faecal source. This may require specific pathogen testing to determine the source of greater impact.
5. Locate the number corresponding to the most significant impact in the SIC flow chart (Figure H2) to determine the SIC.

It is important to recognise there are two questions to be answered in Part D of the catchment assessment checklist. The first is “Is it present”. The purpose of this question is to determine the presence of a potential source of faecal contamination to the recreational site. The second question “Is it likely to cause an effect” determines, after evaluation, if the potential source of faecal contamination actually affects the recreational site, thus posing a risk.

Initial desktop assessment before sanitary inspection

Start the assessment of the sanitary status of a recreational site with a review of its previous history and, where applicable, an assessment of what triggers pollution events, including when and how the guidelines are exceeded.

When considering historical microbiological data to help determine causal relationships, bear in mind the limitations – under some conditions – of the indicator (enterococci/faecal coliform) used. Additional information, such as that set out in Parts A, B and C of the Catchment Assessment Checklist, may be needed to verify the cause of elevated indicator levels, and may already be available in the historical information.

Carrying out a sanitary inspection

Generally, local authorities will have GIS systems or maps to identify the important known discharges and conditions that could cause an issue. The initial emphasis of any assessment should be on potential causes from known discharges and existing conditions, identified using resource information, local data and historical information. In addition, identifying what is not known is important. Gaps in the knowledge about an area can be addressed in a catchment inspection, as well as by reviewing known existing conditions.

To assess the immediate area and catchment data, an annotated map of the beach and catchment is required. The checklist can be used to verify that all aspects and areas that should be included in the map have been added.

Questions that require information for annotation may include:

• number of bathers
• location of oxidation ponds
• duck ponds
• bird-roosting areas (daytime and night time)
• boat anchor and mooring areas
• possibility of septic tank seepage
• location of swamps and mangroves
• location of wastewater treatment and disposal systems and effluent outfalls.

Possible contamination sources (rivers, streams, stormwater drains outfalls) should be included in the map of the sanitary inspection area. Where available, maps of the entire catchment area indicating land use, topography and infrastructure networks (i.e. wastewater and storm drain systems etc.) should also be attached.

Base conditions for establishing a Sanitary Inspection Category

All beaches will have been recognised as having contact recreational activity, so a factor for human-to-human transmission of disease during recreational activity is not included. A single most significant source of faecal contamination has been used to categorise the beach. This is because a second source, even of similar magnitude, can only increase the risk by a factor of two and as such is of limited significance in microbiological terms.

Other impacts not included above may produce an ‘unexpected result requiring verification’ in the grading matrix (Tables D2 and E2). This source should be identified in the ‘more detailed investigation’ suggested in the note to Part D of the Catchment Assessment Checklist.

Note: The Sanitary Inspection Category (SIC) is based on the use of, and monitoring for, faecal indicator bacteria to support risk assessment. As discussed in the introduction, where there are discharges of treated effluent enterococci alone are not an appropriate indicator of public health risk. If pathogen monitoring is carried out then the SIC category for tertiary treated wastewater discharge may be amended.

Note H(iv): Catchment Assessment Checklist (CAC) for marine recreational waters

Catchment Assessment Checklist (CAC) for marine recreational waters (PDF 278 KB)

Note H(v): Microbiological Assessment Category (MAC) for marine recreational waters

The Microbiological Assessment Category is calculated on the basis of five years of historical data (at least 100 data points). Data collected during or immediately following rainfall, as part of routine sampling, should be included in the calculation of the MAC. The purpose of the MAC is to give an indication of general water quality over an extended period, to allow for variations in climatic conditions. The MAC is used in conjunction with the Sanitary Inspection Category (SIC) to determine the Suitability for Recreation Grade, and to confirm that the selected SIC is accurate, based on historical water-quality results.

Note: Follow-up samples from an alert or action mode response should not be included in the data used to generate an MAC. If using the software provided by the Ministry for the Environment to generate grades, follow-up samples will need to be removed from the dataset prior to importing.

See Section D.3 for MAC definitions.

Change in indicators

If a change between indicators is made, there may be limited amounts of data available in the initial years of implementation. To overcome this, correction factors appropriate to local conditions can be applied to historical records. Such conversion factors would normally be based on the results of local analyses.

For many locations there will be a large amount of historical data available that can be used for preliminary recreational water environment classification. If this data includes analysis for enterococci, there will be no problem using the data. However, many recreational water environment managers will have data based only on coliform and faecal coliform counts. Although there is no exact relationship between enterococci and E. coli counts, a relationship expressed by the following equation (WHO 2001) may help in interpreting historical data:

log₁₀(faecal coliform) = 1.028 + 0.601log₁₀(enterococci)

Even more helpful are the following simpler forms of this equation, relating enterococci to faecal coliforms and vice versa:

faecal coliform = 10.67(enterococci)^0.601

enterococci = 0.0195(faecal coliform)^1.67

Using the first formula, a count of 70 enterococci equates to 137.1 faecal coliforms. Using the second formula, a count of 100 faecal coliforms/100 mL equates to 42.7 enterococci/ 100 mL.

However, this equivalence is not exact as it is based on the relationship between faecal coliform and faecal streptococcal/enterococci counts in United Kingdom bathing waters after censoring zero values. If possible, local recreational-water environment managers should define the relationship that exists in their own waters.

Note H(vi): Suitability for recreation grade for marine recreational waters

Explanation of grades

Beaches are graded by considering microbiological monitoring results from previous years in combination with the factors in the catchment that may contribute faecal contamination to the beach. It is a risk-associated grading of the beach, meaning that it provides an indication of what the likely condition of the beach will be on any day. The following general explanation provides a description of each of the beach grades.

Very good

Water-quality tests and assessment of potential contamination sources indicate beaches within this category are considered to have very good water quality (see Table D2 for details). There may be some run-off from low-intensity agricultural/urban/rural catchments, but there are likely to be no significant sources of faecal contamination.

Recommendation: Considered satisfactory for swimming at all times, and therefore may not require monitoring on a regular basis.

Good

Water-quality tests and assessment of potential contamination sources indicate beaches within this category are considered to have generally good water quality (see Table D2 for details). On occasions (such as after high rainfall) there may be an increased risk of contamination from run-off. Such sites receive run-off from one or more of the following sources and may contain animal or human faecal material:

• river discharges impacted by tertiary treated wastewater, combined sewer overflows, intensive agricultural/rural catchments, feral bird/animal populations
• river discharges impacted by; run-off from low-intensity agricultural/urban/rural catchment
• stormwater not contaminated by sewage.

Recommendation: Satisfactory for swimming most of the time. Exceptions may include following rainfall. Such beaches are monitored regularly throughout the summer season and warning signs will be erected if water quality deteriorates.

Fair

Water-quality tests and assessment of potential contamination sources indicate beaches within this category are considered to have generally fair water quality (see Table D2 for details). Events such as high rainfall increase the risk of contamination levels from run-off. Such sites receive run-off from one or more of the following sources and may contain animal or human faecal material:

• river discharges impacted by tertiary treated wastewater, combined sewer overflows, intensive agricultural/rural catchments, feral bird/animal populations
• river discharges impacted by run-off from low-intensity agricultural/urban/rural catchment
• stormwater not contaminated by sewage.

Recommendation: Generally satisfactory for swimming, though there are many potential sources of faecal material. Caution should be taken during periods of high rainfall, and swimming avoided if water is discoloured. Sites are monitored weekly and warning signs erected if water quality deteriorates.

Poor

Water-quality tests and assessment of potential contamination sources indicate beaches within this category are considered to have generally poor water quality (see Table D2 for details). These sites receive run-off from one or more of the following sources and may contain animal or human faecal material:

• tertiary treated wastewater
• urban stormwater, marinas or moorings, intensive agriculture
• river discharges containing untreated / primary / secondary treated wastewater or on-site waste treatment systems
• river discharges impacted by tertiary treated wastewater, combined sewer overflows, intensive agricultural/rural catchments, feral bird/animal populations.

Recommendation: Generally not okay for swimming, as indicated by historical results. Swimming should be avoided, particularly by the very young, the very old and those with compromised immunity. Permanent warning signs may be erected at these sites, although councils may monitor these sites weekly and post temporary warnings.

Very poor

Water-quality tests and assessment of potential contamination sources indicate beaches within this category are considered to have very poor water quality (see Table D2 for details). These sites receive run-off from one or more of the following sources and may contain animal or human faecal material:

• untreated/primary/secondary treated wastewater
• on-site waste treatment systems
• tertiary treated wastewater
• urban stormwater, marinas or moorings, intensive agriculture
• river discharges containing untreated/ primary/secondary treated wastewater or on-site waste treatment systems.

Recommendation: Avoid swimming, as there are direct discharges of faecal material. Permanent signage will be erected at the beach stating that swimming is not recommended.

Note H(vii): Catchment Assessment Checklist for freshwater recreational areas

Catchment Assessment Checklist for freshwater recreational areas (PDF 296 KB)

Note H(viii): Microbiological Assessment Category for freshwater recreational areas

The Microbiological Assessment Category is calculated on the basis of five years of historical data (at least 100 data points). Data collected during or immediately following rainfall, as part of routine sampling, should be included in the calculation of the MAC. The purpose of the MAC is to give an indication of general water quality over an extended period, to allow for variations in climatic conditions. The MAC is used in conjunction with the Sanitary Inspection Category (SIC) to determine the Suitability for Recreation Grade, and to confirm that the selected SIC is accurate, based on historical water-quality results.

Note: Follow-up samples from an alert or action mode response should not be included in the data used to generate an MAC. If using the software provided by the Ministry for the Environment to generate grades, follow-up will need to be removed from the dataset prior to importing.

Note: See Section E.3 for MAC definitions for freshwater.

Note H(ix): Suitability for recreation grade for freshwater recreational areas

Explanation of grades

Beaches are graded by considering microbiological monitoring results from previous years in combination with the factors in the catchment that may contribute faecal contamination to the beach. It is a risk-associated grading of the beach, meaning that it provides an indication of what the likely condition of the beach will be on any day. The following general explanation provides a description of each of the beach grades.

Very good

Water-quality tests and assessment of potential contamination sources indicate beaches within this category are considered to have very good water-quality (see Table E2 for details). This indicates there may be some indirect run-off from low intensity agricultural/urban/rural/bush catchments, but there are likely to be no significant sources of faecal contamination.

Recommendation: Considered satisfactory for swimming at all times, and therefore may not require monitoring on a regular basis.

Good

Water-quality tests and assessment of potential contamination sources indicate beaches within this category are considered to have generally good water-quality (see Table E2 for details). On occasions (such as after high rainfall) there may be an increased risk of contamination from run-off. Such sites receive run-off from one or more of the following sources and may contain animal or human faecal material:

• river discharges impacted by tertiary treated wastewater, combined sewer overflows, sewer overflows, intensive agricultural/rural catchments, significant feral bird/animal populations
• river discharges impacted by; run-off from low-intensity agricultural/urban/rural catchment
• direct discharges from stormwater not contaminated by sewage, boat moorings or marinas
• direct discharges from low-intensity agriculture.

Recommendation: Satisfactory for swimming most of the time. Exceptions may include following rainfall. Such beaches are monitored regularly throughout the summer season and warning signs will be erected if water quality deteriorates.

Fair

Water-quality tests and assessment of potential contamination sources indicate beaches within this category are considered to have generally fair water-quality (see Table E2 for details). However, events such as high rainfall increase the risk of contamination levels from run-off. Such sites receive run-off from one or more of the following sources and may contain animal or human faecal material:

• river discharges impacted by tertiary treated wastewater, combined sewer overflows, sewer overflows, intensive agricultural/rural catchments, significant feral bird/animal populations
• river discharges impacted by; run-off from low-intensity agricultural/urban/rural catchment
• direct discharges from stormwater not contaminated by sewage, boat moorings or marinas
• direct discharges from low-intensity agriculture.

Recommendation: Generally satisfactory for swimming, though there are many potential sources of faecal material. Caution should be taken during periods of high rainfall, and swimming avoided if water is discoloured. Sites are monitored weekly and warning signs erected if water quality deteriorates.

Poor

Water-quality tests and assessment of potential contamination sources indicate beaches within this category are considered to have generally poor water-quality (see Table E2 for details). These sites receive run-off from one or more of the following sources and may contain animal or human faecal material:

• tertiary treated wastewater
• urban stormwater, intensive agriculture, unrestricted stock access, dense bird populations
• low-intensity agriculture, marinas or boat moorings, urban stormwater not contaminated by sewage
• river discharges containing untreated/ primary/secondary treated wastewater or on-site waste treatment systems
• river discharges impacted by tertiary treated wastewater, combined sewer overflows, intensive agricultural/rural catchments, feral bird/animal populations.

Recommendation: Generally not okay for swimming, as indicated by historical results. Swimming should be avoided, particularly by the very young, the very old and those with compromised immunity. Permanent warning signs may be erected at these sites, although councils may monitor these sites weekly and post temporary warnings.

Very poor

Water-quality tests and assessment of potential contamination sources indicate beaches within this category are considered to have very poor water-quality (see Table E2 for details). These sites receive run-off from one or more of the following sources and may contain animal or human faecal material:

• untreated/primary/secondary treated wastewater
• on-site waste treatment systems
• tertiary treated wastewater
• urban stormwater, intensive agriculture, unrestricted stock access, dense bird populations
• river discharges containing untreated/ primary/secondary treated wastewater or on-site waste treatment systems.

Recommendation: Avoid swimming, as there are direct discharges of faecal material. Permanent signage will be erected at the beach stating that swimming is not recommended.

Note H(x): Application of grades and single samples

The risk of becoming sick from swimming at a beach is inferred from the associated grade. Beaches graded Very Good almost always pass the Microbiological Water Quality Guidelines, and there are few sources of faecal contamination in the catchment. Consequently, the risk of becoming sick is low. Beaches graded Very Poor are within catchments with significant sources of faecal contamination, and they rarely pass the guidelines. The risk of becoming sick at these beaches is high and swimming is not recommended. Unless there is a change in the catchment characteristics of beaches graded Very Poor, monitoring is not justified.

For the remaining grades of beaches (Good, Fair, Poor), water quality deteriorates and the risk of illness from swimming increases down the gradient from Good to Poor. The conditions affecting water quality vary (e.g. Good beaches usually pass the guidelines, but occasions such as high rainfall increase the risk of contamination from run-off).

For these beaches it is recommended that weekly monitoring be carried out during the bathing season. The public will be informed when swimming is not recommended (when a sample taken from the beach exceeds the action-level single-sample criteria of the Microbiological Water Quality Guidelines).

Note H(xi): Interim grading

An interim grade is provisional, and dependent on annual review as additional information becomes available until five years of data is obtained. An interim grade is mainly for management purposes, although it may be communicated to the public if it is clearly defined as interim only.

An interim grade can be derived using less than the recommended five years’ data where at least 20 data points over the period of greatest recreational use are available. This period will normally be the summer bathing season, but may vary with the types of recreational activity most common in the area.

Circumstances under which an interim grade might be applied include:

• where the data available is incomplete, either with respect to the MAC, or the SIC, or both
• where there is reason to believe that the existing grading no longer accords with changed circumstances, but the data required for completing the grading is insufficient.

Note H(xii): Modifying beach grades

Modifying a beach’s SFRG is justified where occasional and predictable contamination events are identified, and interventions can be demonstrated to be effective in discouraging recreational use. Sites with a modified SFRG should be labelled, and their condition and the effectiveness of management interventions assessed annually.

Modifying an SFRG is particularly relevant to mid-range beaches (Good, Fair and Poor) and where there is disagreement between the SIC and MAC (i.e. a ‘Follow Up’). The process for modifying a beach grade is as follows.

1. Determine whether contamination events are occasional and predictable (i.e. triggered by an event such as heavy rainfall).
2. Implement and evaluate the effectiveness of management interventions to discourage recreational use during known high-risk periods.
3. Reassess the SIC, removing the source of predictable contamination events (provided interventions are effective).
4. Reassess the MAC (where there is sufficient data), excluding results caused by the trigger event.
5. Modify the beach grade according to the revised SIC and MAC.

Data requirements for modifying an SFRG

To reassess the MAC, rainfall-related data should be identified and removed from the dataset. This requires all rainfall data to be marked for easy identification in subsequent years. If removing rainfall data decreases the size of the dataset below the 100 required to generate a MAC, it cannot be modified. Sampling in the subsequent season may be sufficient to generate the required number of samples to reassess the MAC. If not, councils should design a programme to meet this requirement, or stick with modifying the SFRG based on the revised SIC category only. Once sufficient data has been collected the MAC can be reassessed and the SFRG modified accordingly.

The following example illustrates how to modify a grade.

Demonstrating effectiveness of management interventions

Management interventions may range from warning signs to public notices in newspapers. They should aim to reduce beach usage under specific conditions that are known to cause contamination, e.g. after heavy rainfall. It is critical that the effectiveness of these interventions be demonstrated before a beach’s SFRG can be modified. This requires management interventions to be in place for at least one bathing season before a site’s grade can be modified.

The effectiveness of management interventions can be assessed by measuring the decrease in beach use following their implementation. An 80% reduction in recreational use is required for management interventions to be considered effective. Head counts are available from surf clubs to provide baseline information. If no surf club is present, councils or health agencies should collect their own information on beach usage.

Before modified grades are finalised, the monitoring authority should consult other councils and the Medical Officer of Health in their area to gain agreement on the outcome of the regrading. Given their public health protection role, the Medical Officer of Health in particular should concur that:

• there is sufficient documentation to support the original Suitability for Recreation Grade
• there is evidence that management interventions have been effective
• the modified grade is appropriate for the site.

What information to report?

Where site grades have been modified, regional and local councils will report the modified grade to the public. The modified grade provides information on the condition of the site, including when it is not suitable for recreational use (i.e. Good – except for two days following rainfall). While the ‘actual’ water quality at the site hasn’t been improved by removing the source of contamination, the risk has been mitigated through effective management interventions.

The Ministry for the Environment is interested in reporting the original SFRGs, as these reflect the actual water quality and potential for faecal contamination. Reporting the original SFRG will enable the Ministry to pick up improvements to the overall condition of beaches as a result of infrastructural or landuse changes over time.

Note H(xiii): Percentile guideline values for seawater (WHO 2001) and freshwater

Seawater

For marine waters, only faecal streptococci (enterococci) showed a dose–response relationship for both gastrointestinal illness (Kay et al 1994) and Acute Febrile Respiratory Infection (AFRI) (Fleisher, Kay, Salmon et al 1996). A recent reanalysis of this data (Kay et al 2001) using a range of contemporary statistical tools has confirmed that the relationships originally reported are robust to alternative statistical approaches.

The guideline values for microbiological quality given in Table H1 are derived from the key studies described in the previous paragraph.

The cut-off or bounding values (40, 200, 500) are expressed in terms of the 95th percentile of numbers of faecal streptococci per 100 mL, and represent readily understood levels of risk, based on the exposure conditions of the key studies.

For the purposes of water-quality monitoring, the terms ‘faecal streptococci’, ‘intestinal enterococci’ and ‘enterococci’ are considered to be synonymous (Figueras et al 2000). Exposure to recreational waters with these measured indicators refers to body contact that is likely to involve head immersion, such as swimming, surfing, white-water canoeing, scuba diving and dinghy-boat sailing.

Freshwater

The marine water guideline values have been derived from epidemiological studies, but this type of study is seldom carried out for freshwater and has not been conducted for New Zealand. Instead values are based on a quantitative risk assessment for Campylobacter infection using the results obtained in a recent nationwide study (McBride, Till, Ryan et al 2002). Campylobacteriosis accounts for more than half of New Zealand’s burden of notifiable disease, and for this reason it was selected as the end point for this analysis. Also in that study a reasonable correlation was found between concentrations of Campylobacter and of E. coli.

Note H(xiv): Derivation of alert and action levels for seawater and freshwater

The alert and action levels are management tools, ensuring that risks are kept below illness risks of about 2% per 1000 swimmers. They represent, respectively, 80% and 90% one-sided upper tolerance limits, assuming that the waters are borderline for compliance with previous guidelines and a stated variability applies (measured as the standard deviation of logarithms).

See Appendix 2: Developing the Guidelines.

Note H(xv): State of the environment analysis and reporting

Monitoring and reporting the state of the environment

This section discusses the Ministry’s Environmental Monitoring and Reporting system, which uses environmental performance indicators to report on the state of the environment. The Microbiological Water Quality Guidelines for Marine and Freshwater Recreational Areas serve as the monitoring protocol for the marine and freshwater recreation indicators. In this document the monitoring approach, analysis and data management procedures are described to ensure the generation of robust information for reporting of the indicators.

Good-quality information is increasingly important for central and local government to meet public expectations, be accountable and demonstrate performance. Information is used to produce State of the Environment reports; to review national legislation, regional and district plans; to assess compliance of resource consents; for environmental education, and for the strategic and annual planning process.

Partnerships for monitoring and reporting

The Ministry for the Environment has been working with Regional, City and District Councils, Medical Officers of Health and the Ministry of Health to develop approaches for monitoring and reporting the state of recreational beaches.

Should the Ministry for the Environment want to use the information generated for National State of the Environment reporting then the Ministry would work in partnership with Councils to agree on the principles for information sharing.

Software

The Ministry for the Environment has developed software to assist councils with the process of grading beaches, and calculating the two state of the environment indicators. The software (Bathewatch.exe) follows the same format as the guidelines and uses historical data and information from the Catchment Assessment Checklist to calculate the Microbiological Assessment Category and the Sanitary Inspection Category. The MAC and SIC are used to generate a Suitability for Recreation Grade and percentage compliance with the guidelines for the site.

The software and a user guide can be downloaded from the Ministry’s website: www.mfe.govt.nz.

Data storage and archiving

Most councils store their data as Excel files. The user guide for the Bathewatch software specifies the data file format requirements for loading data into the software. For the MAC component of the SFRG assessment, the data collected from field observations must be stored in a comma-delimited value (*.csv) file format. The data must be stored in this specific file format or it will fail to load properly. It is a simple process to convert files from an Excel format into a *.csv format. The procedure is detailed in the Bathewatch user guide.

It is expected that councils will archive their monitoring data using the council’s normal computer back-up system. The council may wish to consider burning the data onto a CD or an otherwise secure file.

Note H(xvi): Reporting to the public

Public health reporting

If exceedances of alert and/or action levels are recorded during weekly monitoring of recreational beaches, the appropriate responses should be undertaken, as described in section D.4 of the guidelines and Note H(xvii) of these notes.

State of the Environment reporting

The two beach water quality indicators can be reported using the data generated by councils. For:

• the percentage of monitored beaches in each beach grade

the indicator provides a measure of the general state of bathing beaches by combining the risk of contamination from the catchment with the microbiological monitoring at the beach. It reports the overall suitability of beaches for bathing. Beaches will be classified into one of five grades (from very good to very poor).

And for:

• the percentage of the season beaches or coastal areas are suitable for bathing or shellfish gathering

the indicator will give an indication of the amount of time in a season the water quality was considered suitable for bathing or shellfish gathering. It provides a measure of the variation of microbiological quality of bathing waters within a bathing season.

Indicator fit with the pressure-state-response model

The Ministry for the Environment has used the pressure-state-response (PSR) model for developing environmental performance indicators – refer to Note G(iii): State of the Environment Reporting, page G3.

The indicators on which these guidelines are based – percentage of monitored beaches in each beach grade, and percentage of the season beaches or coastal areas were suitable for contact recreation or shellfish gathering – are state indicators that provide general information on the public health risk presented by recreational waters. Pressure indicators would measure the surrounding land use and discharges to water to assist identification of potential causes of changes in water quality. Response indicators would identify management or policy changes (e.g. infrastructural improvements, land-use management policies, national environmental standards) to manage issues for recreational waters.

Note H(xvii): Management responses to exceedances for marine and freshwater

The planned responses to exceedances of the guidelines should be considered and documented when establishing a regional monitoring protocol, and communicated to all agencies that will have a role to play (e.g. regional councils, territorial local authorities and health agencies). Documentation should clearly state who is responsible for carrying out what actions in response to exceedances. If the response varies from site to site, depending on the overall grade, this should also be clearly stated.

See Section B for details on who monitors and reports.

Single-sample exceedances

The point of having single-sample limits is to identify variations in water quality within the bathing season that pose an immediate risk to human health.

There are two levels of response to single-sample exceedances.

Alert mode

The first is alert (or amber) mode, and is triggered when a single sample is greater than 140 enterococci per 100 mL for marine waters and 260 E. coli per 100 mL for freshwaters. In this situation, sampling should be increased to daily to improve the information base and identify whether or not the problem is ongoing. A catchment assessment should be carried out to identify all possible sources of contamination. The monitoring authority should inform the Medical Officer of Health and the other council(s) (either regional or local, depending on who is doing the monitoring).

Action mode

The second level of response to a single-sample exceedance is action (or red) mode. In the case of marine waters this is triggered when two consecutive samples are greater than 280 enterococci per 100 mL, and for freshwaters when a single sample exceeds 550 mL E. coli per 100 mL. In this instance the monitoring authority informs the Medical Officer of Health and the other council(s) of the problem. Sampling is increased to daily and a catchment assessment carried out to identify the source of the contamination. The public should be notified of the health risks using appropriate methods identified in the regional monitoring plan. Discussion between the regional council, territorial local authority and Medical Officer of Health should take place to ascertain who is responsible for fixing the problem.

The Ministry for the Environment and Ministry of Health have developed sign templates in consultation with councils and health agencies to use in response to exceedance events and at high-risk sites. (See Appendix 3 for these sign templates.)

High-risk sites

High-risk sites are those sites graded Poor or Very Poor, and will generally have direct discharges, such as sewer outfalls, impacting on them. While the guidelines and notes provide details on assessing these sites and recommend that permanent signs be erected to warn the public of the health risks (see Appendix 3 for sign templates), there is no discussion on remediation work. The agencies responsible for managing the infrastructure or land use affecting water quality, and those responsible for monitoring the sites and public health protection, may wish to discuss and document the remediation work required, and the timeframes, budgets, etc, for achieving this.

Communicating health risks

Communicating health risk is required after exceedance of the action level of the guidelines, as monitoring has identified increased levels of faecal material, which mean the site is unsuitable for recreational use. In order to protect public health, local authorities are required to notify the public of those health risks until the problem has been remedied.

When to issue warnings

The guidelines identify an action level, at which point use of a recreational site is considered unsuitable for contact recreation. For marine waters this is when two consecutive samples taken are greater than 280 enterococci per 100 mL, and for freshwaters when a single sample exceeds 550 E. coli per 100 mL. Warnings should be issued as soon as possible after the results from the sample are available. If contamination is obvious and likely to be ongoing, it is not necessary to wait for results from samples before issuing a health warning.

Other agencies involved in monitoring and reporting should be notified of exceedances before notifying the public of health risks.

Who to contact

The regional monitoring plan will clearly define lines of communication and responsibilities, such as whose role it is to notify the public. Results should be communicated as soon as possible to the agency responsible for public notifications.

What messages to convey

There are several messages to consider when issuing warnings, other than that there is a health risk. These are:

• there is a health risk
• the council is investigating the cause of the problem (i.e. the council is on to it)
• a list of alternative beaches to visit in the region
• an announcement when the problem has been fixed.

How to deliver the message

There are many ways to communicate information to the public. A number of factors will determine the methods chosen to deliver the warnings, including:

• the urgency of the message
• how well informed the community is
• the demographic make-up of the community.

The public awareness and education section provides more detail on establishing the best methods of delivering messages to the public (see Appendix 1), but the most widely used methods for health warnings are:

• signs
• newspaper articles
• radio
• notices in local shops
• websites
• 0800 numbers.

Signs

The Ministry for the Environment and Ministry of Health have developed sign templates in consultation with regional councils, local authorities and public health agencies. These are provided in Appendix 3.

Fact sheets

Fact sheets have been written to help communicate information about the guidelines and monitoring programmes. These generic fact sheets can be used for media releases, handing out at public at meetings, etc. See Appendix 5 for fact sheets on different topics.

Summary

The most important messages to get across are:

• the health risk
• the council is responding quickly to the event.

It is also important to convey the unpredictable nature of this type of problem and the difficulties in isolating the cause.

Once the problem has been fixed, the public should be notified. This will be apparent from the removal of signs, but should be highlighted through use of the media, community meetings, and contact with user groups, etc.

The public education and awareness programme outline (Appendix 1) provides more information on engaging public support for the monitoring programme.

Management interventions for modified grades

Management interventions will vary in type according to the nature of the predictable event leading to the modification and the target audience. Interventions may range from permanent warning signs on beaches, to public meetings (see Appendix 1: Public Education and Awareness Programme Outline). The ability to demonstrate the effectiveness of interventions in discouraging the public from using the site during periods of high risk is critical. This is what will lead to a modified grade. How this is assessed will vary, but must be verified by the Medical Officer of Health.

See Note H(xii) for details on modifying grades.