For UoCs located in tidal systems, timing of measurements should correspond with high and low tides, to reflect variations related to the tidal regime.

The UoC can conduct DO monitoring immediately downstream of the last site in a waterbody whilst still following the sampling method in Appendix 8 (8.11).

This may reduce sampling costs when there are multiple sites discharging point source effluent releases to a Type B waterbody near each other.

The methods outlined in Appendix (8.11.2 and 8.11.3) shall be used to record DO concentrations used to determine daily diurnal DO (DDDO).

Any missed samples or deviations in sampling time should be accompanied by a written justification.

Records that DO measurements correspond to high and low tides in tidal systems.

The location of the sampling point, demonstrating that measurements have taken place downstream from the outflow point.

Results of daily DO monitoring and DDDO fluctuation calculations.

DO measurements have taken place at high and low tides in tidal systems.

DO measurements have taken place downstream from the outflow point.

The UoC has presented results of the DDDO calculations based on DO measurements collected in accordance with the methods outlined in Appendix 8.11.1 and 8.11.2.

Confirm the fluctuation level based on the DDDO calculation is ≤65% saturation level.

Written justifications were provided if there were any missed samples or deviations in the sampling time.

Methods to measure Total Suspended Solids (TSS) can be found in Appendix 8 (8.12).

Concentration of settleable solids (ml/L) can be measured by calculating the volume of solids that settles to the bottom of a conical cone (Imhoff cone) in one hour.

More sophisticated methods such as spectrophotometer readings can also be used to measure settable solids.

Details and location of the system used to treat effluent prior to discharge.

Evidence regular testing of TSS and settleable solids has taken place. Quarterly testing would demonstrate best practice.

Results from the testing of point source releases which demonstrate ≥65% of TSS are captured and the concentration of settleable solids in effluent water is consistently <3.3ml/L.

A treatment is in place and located prior to the point of discharge.

Results of testing from the UoC which confirm the treatment system captures ≥65% of suspended solids and that the concentration of settleable solids in effluent water is <3.3ml/L.

Quarterly monitoring ensures the UoC can capture any seasonal or inter-annual variations in the data collected.

Measurements should be timed to coincide with, or immediately follow, annual turnover events when the waterbody is not permanently stratified (holomictic).

The UoC should calibrate equipment used to measure DO, TN, TP, SD and Chl-a according to the technical specifications of the equipment.

The UoC should conduct measurements of the parameters in-situ.

Samples may be sent for laboratory analysis, however variability with sample maintenance during transit can lead to inconsistent results. This is particularly evident with DO and Chl-a samples.

Documentation outlining the sampling plan to conduct quarterly monitoring and that is in accordance with Appendix 8 (8.8).

Quarterly monitoring data has been collected and submitted to the ASC Water Quality Calculator. Data should be submitted at least annually.

Evidence that quarterly monitoring data has been timed with annual turnover events (where applicable).

That equipment to measure DO, TN, TP, SD and Chl-a has been calibrated according to technical specifications.

The sampling methodology to conduct quarterly monitoring is in accordance with Appendix 8 (8.8).

The UoC has conducted quarterly monitoring of the water quality parameters and submitted data to the ASC Water Quality Calculator at least annually.

Evidence has been provided demonstrating the UoC has calibrated equipment to measure DO, TN, TP, SD and Chl-a in accordance with the technical specifications.

Paerl, H.W., Scott, J.T., McCarthy, M.J., Newell, S.E., Gardner, W.S., Havens, K.E., Hoffman, D.K., Wilhelm, S.W. and Wurtsbaugh, W.A., 2016. It takes two to tango: when and where dual nutrient (N & P) reductions are needed to protect lakes and downstream ecosystems. Environmental science & technology, 50(20), pp.10805-10813.

Information on the appropriate use of Secchi Disks can be found here: ‘What is a Secchi disk’, accessed November 22, 2023: <https://www.nalms.org/secchidipin/monitoring-methods/the-secchi-disk/what-is-a-secchi-disk/>

Example of a method for Chl-a measurements made using ethanol extraction followed by spectrophotometric measurement at wavelengths 665 and 750nm (using accredited methods: EPA method 445.0: Method 445.0 In Vitro Determination of Chlorophyll a and Pheophytin ain Marine and Freshwater Algae by Fluorescence, accessed November 22, 2023: https://cfpub.epa.gov/si/si_public_record_report.cfm?Lab=NERL&dirEntryId=309417

Cost effective example for measuring using in-situ Chl-a using a field spectroflurometer include the FluoroSense handheld fluorometer manufactured by Turner Designs and the YSI handheld meter with EXO1 (#599080) or EXO2 (#599201) sondes.

Hamdhani, H., Eppehimer, D.E., Walker, D. and Bogan, M.T. (2021) Performance of a Handheld Chlorophyll-a Fluorometer: Potential Use for Rapid Algae Monitoring. Water, 13, 1409: https://doi.org/10.3390/w13101409

Kuha, J., Järvinen, M., Salmi, P. and Karjalainen, J. (2020). Calibration of in situ chlorophyll fluorometers for organic matter. Restoration of Eutrophic Lakes, 847, 4377-4387: <https://doi.org/10.1007/s10750-019-04086-z>

The data collected as part of the 24-month site level monitoring survey is submitted by the UoC to the ASC Water Quality Calculator.

The water quality baseline is based on 24-months of monitoring data from the site level monitoring survey. However, the following phased approach is permitted when sites do not have sufficient data prior to the initial audit:

Harmful algal blooms (HABs) and Adverse Turnover Events (ATEs) are required to be reported as part of the baseline characterisation. The number of ATEs and HABs that have occurred can be recorded by conducting the following:

The methodology and analytical methods used to conduct site level monitoring survey are in accordance with Appendix 8 (8.8).

The sampling methodology for collecting 24-months of data for the site level monitoring survey, if this is not available at the initial audit.

The results of the site level monitoring survey, as determined by the ASC Water Quality Calculator.

The results of the 24-month baseline characterisation, as determined by the ASC Water Quality Calculator.

Records of HABs and ATEs from the last 10 years.

A water quality monitoring survey has been conducted by the UoC. Results are presented from the ASC Water Quality Calculator.

A sampling methodology has been presented for collecting 24-months of data for the site level monitoring survey, if this is not available at the initial audit.

The data collected for the site level monitoring survey followed the methodology and analytical measures outlined in Appendix 8 (8.8).

A water quality baseline has been characterised. Results are presented from the ASC Water Quality Calculator.

The results of the review by the UoC into adverse turnover events and harmful algal blooms in the waterbody.

Vollenweider, R.A., Rinaldi, A. and Montanari, G. (1992) Eutrophication, structure and dynamics of a marine coastal system: results of ten-year monitoring along the Emilia-Romagna Coast (Northwest Adriatic Sea). Marine Coastal Eutrophication, Proceedings of an International Conference, Bologna, Italy, 21–24 March 1990, Pages 63-106: <https://doi.org/10.1016/B978-0-444-89990-3.50014-6>

More information about the equations used for TSI assessment, including the relevant peer-reviewed scientific literature, is provided in Carlson, R.E. and Simpson, J. (1996) A Coordinator’s Guide to Volunteer Lake Monitoring Methods. North American Lake Management Society, 96 p.

Evidence of spatial management at a national/regional level for water quality can be used by the UoC to demonstrate that the intent of Indicator 2.6.8 has been met. To use this evidence, the following should be met:

Examples of outreach can include:

As per Appendix 8, section 8.7, a Terms of Reference (ToR) document shall be drafted and agreed upon by all members of the WQMN upon formation, which includes the following:

An agreed map of the WUM by members of the WQMN, which includes the components outlined in Appendix 8 (8.7).

The map should be updated on an annual basis where required.

Evidence of outreach efforts and responses (where applicable) to ASC Certified site and non-certified sites belong to ASC Certificate Holders if a WQMN needs to be established.

If a WQMN has been established, the UoC presents evidence that they have joined the WQMN or the UoC can demonstrate the spatial management of water quality at a national/regional level.

A ToR has been agreed upon by all members of the WQMN, which includes commitments to the WQMN requirements, as outlined in Appendix 8 (8.7.1).

A map of the WUM has been developed by the WQMN and presented by the UoC, which includes the components outlined in Appendix 8 (8.7).

Evidence of outreach efforts and responses to ASC Certified site and non-certified sites belong to ASC Certificate Holders if a WQMN needs to be established.

Auditor discretion should be used to determine if sufficient levels of outreach has been conducted, when such outreach has not been reciprocated.

Evidence that the UoC has formed/joined a WQMN, or that the UoC presents evidence that water quality is managed at a national/regional level.

A ToR has been presented, which has been agreed upon by all members of the WQMN. The ToR includes commitments to the WQMN requirements, as outlined in Appendix 8 (8.7.1).

To demonstrate competence, personnel responsible for conducting water quality analysis and defining the WUM should be able to:

The personnel responsible for conducting water quality analysis and defining the WUM have competencies to do so, for example a suitable level of education and/or experience.

Relevant training modules have been completed by the personnel responsible for conducting water quality analysis and defining the WUM.

The personnel responsible for conducting water quality analysis and defining the WUM have the necessary competencies.

Evidence has been presented that relevant training modules have been completed.

The following characteristics should be used to define the Waterbody Unit of Management (WUM):

A map of the WUM which includes the components outlined in Appendix 8 (8.6).

The results of measurements to confirm if the WUM is a HIE (if applicable).

A map of the WUM has been developed and presented by the UoC, according to the method outlined in Appendix 8 (8.6).

The UoC should initially define the boundaries of the Receiving Waterbody (RW) based on hydrological characteristics, which determines its sensitivity to nutrient enrichment.

Marine waterbodies include:

Waterbody types designated under national legislation should be used only if the following are met:

A map of the Receiving Waterbody, which outlines:

A map has been presented by the UoC which outlines the RW, and which supports the classification of the RW.

The results of the HRT calculation and flow rate/TSS measurements conducted by the UoC.

Evidence presented by the UoC, demonstrating the methods used to measure flow rate and TSS, in accordance with Appendix 8 (8.5 and 8.12).

The RW has poor connectivity to deep offshore waters, and/or;

The RW is sheltered from energetic conditions e.g., inflows, currents, exposure to onshore or monsoonal winds, and/or;

The hypolimnion is periodically or permanently poorly flushed.

If measurements of HRT or flow rates are not available, publicly accessible global databases can be used to obtain annual outflow estimates. Data sources include:

Examples of credible secondary sources for flow rates include government flow monitoring and modelling, as well as publicly available databases, including:

Guides on how to calculate cumulative distribution (NORMDIST function) and the 25^th^ percentile/quartile (QUARTILE function) for the flow rate data from secondary sources, using Microsoft Excel:

The UoC should initially determine the depth of the waterbody in comparison to the depth of the cage.

Measurements should take place at the lowest water level and from the bottom of the cage.

Depth should also be measured from the outer circumference of the culture containment space, i.e. excluding predator nets, mortality collection chambers etc.

In tidal systems, the depth should be measured at mean low water spring tide (MLWS).

If the depth of the water column (surface to seafloor) is less than 10m or less than double the cage depth, the UoC should measure the current velocity below the cage to determine whether the >0.1 m/s threshold is met.

Results of measurements which demonstrate that all cages in the UoC meet the depth/current velocity requirements in Indicator 2.6.4.

The UoC has provided evidence demonstrating that all cage systems meet the siting requirements outlined in Indicator 2.6.4.

If mean current velocity is used to meet the requirement, the UoC has provided evidence that measurements were taken during periods with >75% peak biomass.

An example of how to measure current velocity below cages can be found under Section 2.1 of the following document: Marine Scotland (2015): A Technical Standard for Scottish Finfish Aquaculture.

Indicator 2.6.3 complements the other water quality indicators by addressing the direct release of uneaten feed in the form of fines into the environment.

Setting a maximum percentage of fines in the feed addresses the efficient and proper transport, storage and physical delivery of feed pellets to the site.

Poor performance in any of the above phases of feed handling will result in a higher percentage of fines (fine particles of feed) and potentially greater impacts on water quality, due to an increase in suspended organic particles and nutrients released into the environment.

Sampling of feed lots includes feed delivered as material in bulk, big bags and small bags to the site.

Testing by the feed manufacturer to the UoC is permissible where there is no significant risk of feed deterioration during subsequent handling, storage or application.

Rationale for not testing on site should also be reported.

The method used to determine the percentage of fines in feed, in accordance with Appendix 8 (8.3).

The determination and documentation of a schedule and location for the testing of feed.

If testing takes place prior to delivery to the site, the rationale should be documented for not testing on site.

Calibration of sieving machines (if used) in accordance with the manufacturer’s recommendations.

The rationale for the timing and location of feed sampling.

The UoC has appropriate testing technology on site and that, if applicable, it is calibrated as required.

The method used to determine the percentage of fines in feed, in accordance with Appendix 8 (8.3).

Review testing results and confirm that results demonstrate feed contains <1% of fines.