Indicator 2.6.9

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System

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Feed Dependent

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Indicator 2.6.9

by Contact on 8 October 2026

Requirement

The UoC shall conduct a water quality survey and determine the water quality baseline, including the trophic status, following the method outlined in Appendix 8 (8.8).

How Do I Interpret This Requirement?

  • 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:

    • The water quality baseline is characterised by the ASC Water Quality Calculator, in accordance with Appendix 8 (8.8).

    • The baseline should be conducted per site and per waterbody. The results should then be shared with members of the WQMN.

    • The baseline determines whether primary production in the waterbody is limited by nitrogen (N), phosphorous (P), or if it is co-limited. Other factors (than N or P) may be limiting primary productivity in a waterbody.

    • The UoC should present evidence of these other limiting factors (e.g. temperature or altitude) where applicable.

  • 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:

    • Reviewing news media and consulting local stakeholders. Alternatively, reviewing data collected by regulatory bodies where available.

    • Reporting the number of ATEs and HABs which have resulted in fish mortality events (farmed or wild) or the mortality of other aquatic species.

    • Reporting instances where fish mortality events or loss of other aquatic species can be attributed to natural phenomena. These instances will not count towards the frequency limits for ATEs and HABs.

    • Reporting the number of ATEs and HABs, as determined by national or regional regulatory/scientific organisations.

Evidence of Implementation

  • 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.

Auditors Should Confirm

  • 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.

Useful Resources

  • 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.