Water Quality Monitoring
Small headwater streams are a significant habitat resource and play an important role capturing and regulating the flow of water to rivers downstream. These headwaters support a myriad of species but they are vulnerable to pollution and can influence water quality further downstream. Many streams in the Wicklow and Dublin Uplands will also eventually flow into reservoirs that in turn provide drinking water to North County Wicklow and Dublin, e.g. the Poulaphouca, Vartry and Bohernabreena Reservoirs. It is therefore vital to protect and maintain water quality in these headwaters, and healthy habitats support better water quality.
The SUAS Project was keen to monitor water quality across participating sites. The purpose –
- To establish a baseline of water quality before any actions were carried out
- To identify any pressures that could be addressed by habitat management actions
- Follow up monitoring to determine if the habitat management actions had an effect on water quality in the surrounding streams.
Aquatic macroinvertebrate monitoring was conducted across ten SUAS sites at twenty-nine unique sample locations in 2019/2020 and this was repeated in 2022. The samples were assessed according to the Small Streams Risk Score (SSRS). The SSRS is a biological risk assessment system for identifying rivers that are definitely ‘at risk’ of failing to achieve the ‘good’ water quality status goals of the Water Framework Directive (WFD). The presence or absence of specific groups of macroinvertebrates and their relative abundance determines the risk category. The categories are:
- Probably not at risk
- Intermediate (Steam may be at risk)
- Stream at risk
Of the twenty-nine locations sampled most remained unchanged (18) or improved (8) with two locations disimproving. Of the two locations disimproving, low water levels at the time of resampling was found to be an issue at one, and possible nutrient enrichment was suggested as the reason at the second. The 2022 monitoring included a suite of chemical analyses to give a broader understanding of any issues that might arise
The water quality monitoring determined that, in general, the ecological health of the streams monitored on six of the SUAS sites had improved and the remaining four sites remained unchanged.