To assess the impact of the Bellawaddy River on the microbiological quality of the bathing waters of Enniscrone Beach, Co. Sligo, Ireland.
With new Bathing Water regulations commencing in 2015, retrospective environmental management of bathing waters is now not adequate enough to protect public health. As part of the process to ensure or even improve bathing water quality status, pollution sources need to be evaluated and management measures implemented to protect bathers from short-term pollution (STP). Following intense rain, streams discharging to bathing waters can cause STP. Pollution of bathing waters is monitored by measuring levels of indicator bacteria present in the water.
In this project the Bellawaddy River was assessed to see if it is a source of STP at Enniscrone’s bathing waters. Discharge of the river was measured using an automatic water level data logger in conjunction with an ascertained rating curve. Indicator bacteria levels were measured in the river and the bathing area. Daily rainfall data was obtained from a local rainfall station. The river was seen to produce hydrograph responses to heavy intense rainfall events. Very large concentrations of indicator bacteria were measured in the river after these hydro-meteorological events. These results showed strong correlation to highly elevated levels of bacteria (STP) in the bathing water. It is concluded that the Bellawaddy River is a primary source of bacteria for the STP events.
Data generated and gathered for this project was further assessed to ascertain whether any aspect could be utilised to indicate a high risk of STP in the bathing water. One environmental aspect was identified as a precise indicator. This involved the use of Enniscrone’s combined sewer system and its storm water retention tank, as a large rain intensity meter. Following heavy intense rain, levels of storm water rose sharply in the tank. These peaks showed strong covariance with the incidences of STP at the bathing water. Any discharged storm water did not affect the quality of the bathing water.
This innovative method to indicate STP, in conjunction with appropriate management methods, will:
• Protect bathers’ health
• Strengthen the water quality status of Enniscrone
The process used in this study, where local environmental data and aspects are evaluated to see if they indicate STP, could be replicated quickly and cheaply elsewhere in the country. Where appropriate this would give beach managers a new decision tool to protect bathers’ health.
Telemetric hydrometric instrumentation along with local rainfall used in an Integrated Catchment Management approach is also identified as a method to indicate STP.