Sequential events are not specifically required by SQIDEP, and the background to this flexibility is based on three practical challenges;
- If sequential events are required and an equipment failure happens on the 13th or 14th event – should the whole testing restart?
- If a large storm occurred on the 13th or 14th event which meant the hydrograph coverage or maximum concentration criteria weren’t met – should the whole testing restart?
- If two storms occur on the same day and the first has measurable, valid concentrations but the second has concentrations less than LOD (limit of detection) – should the whole testing restart?
However, all rainfall events must be documented and reasons for their inclusion and exclusion provided to evaluators. Similarly, the criteria of 15+ rainfall events across all four seasons must be met. This helps independent evaluators establish the validity of the dataset and reference appropriate commentary to support the reported data.
Many issues may impact data quality during a rainfall event – for example, testing issues arising from large storms, equipment malfunction, detection limits, or testing capacity.
This gets back to the foundation of SQIDEP; independence. Independent third-party organisations perform the testing, data collation and reporting, and they value their professional reputation and want to protect it against claims of arbitrary data selection.
An open, transparent submission made in good faith by an independent organisation, reviewed by 2 independent evaluators, and signed off by the Governance Panel is designed to cover these concerns and ensures that claims with incomplete or inaccurate rainfall data are rejected.