Sample unit stratification and aggregation- Water quality sampling was stratified into sample units by water type as per the AfN Method. However, some less extensive water types with few sample sites (especially estuaries) were aggregated to meet the sample requirements of the Method. The main effect of aggregation is to reduce the spatial resolution of the Account. Combining sample units will have a minor impact on overall condition scores because calculations were performed per site using location-specific water type benchmarks.

Seasonal data collection- The data presented in this account was collected during a single season (winter) and condition scores should be taken to only apply to that season. The account does not reflect seasonal variability in condition at this stage. Future accounts will present the results of seasonal sampling, which will better reflect the condition and variability of waterways in the Burnett Mary Region.

Timeframe of datasets- Due to availability of data, water quality, ecological flow and riparian extent present data for different time periods. Water Quality data was collected in June 2022. The estuary component of water quality presents the average of data collected monthly over the 2021-22 financial year. Ecological flow presents data for the 2021 calendar year. Riparian extent presents data derived from 2019 spatial models and remote sensing data, meaning there is a time-lag of 3 years from data collection to reporting.

Weather conditions- Floods and above-average rainfall delayed the survey and prevented collection of data from some sites. Furthermore, hydrographic data have been collated from a year in which numerous flooding records have been set. The data presented in the first year of the Environmental Account may therefore be atypical of dry-season, low-flow conditions with subsequent effects on condition scores, especially for water quality.

Site access- Adverse weather also affected access to some sites. For safety reasons, not all data was collected from all sites therefore planned sampling intensity was not achieved in the first year of the Environmental Account. Several sites in the Upper Mary catchment were unable to be sampled and only two upland freshwater sites are presented in this account. These sites will be included in subsequent accounts if survey conditions allow.

Riparian Extent- The most recently available dataset is for 2019. This time-delay means that there is a lag between NRM management interventions such as riparian tree planting and documentation of changes in condition.

Insufficient samples for some assessment units- Due to access constraints in some water quality sample units, we were not able to collect sufficient samples to meet the guidelines outlined in the Method for the Upper Mary and Kolan Estuary sample units. The level of statistical confidence may therefore be lower in these areas. However, sampling requirements were exceeded significantly for most assessment units and therefore the net impact on confidence level for the Account will be minimal. For future accounts we will endeavor to gain access to additional sample locations on private land.

Chlorophyll-a analysis- Chlorophyll-a was measured in the field using a sonde field sampler, rather than via lab analyses. We have discussed with the Method Author who is of the opinion that the results are comparable and acceptable to use.