Flood Alert Early Warning System
Previous Flooding Issues
Carmarthenshire County Council (CCC) has responsibility for over 100 trash screens sited on ordinary watercourses across the county. Even with a resource heavy inspection and maintenance programme in place, many of these become periodically blocked with debris and other materials, leading to blockage of flow, and risk of overtopping and flooding to local properties.
For example in 2017 Stradey Park trash screen was blocked leading to localised flooding. There is evidence of several near misses at screens across the County during Storm Callum, due to blockage. As well as residential properties, some of the screens protect the road and highways network.
The Flood Alleviation Scheme
For this scheme a telemetry network has been established at 6 key trash screens around the County, chosen as CCC assets that provide flood protection to a significant number of properties and are mainly located in our priority flood risk management (FRMP2) communities.
The network allows remote monitoring of water levels in response to rainfall in real time. This enables screen blockages and high water levels to be picked up at an early stage and actioned, before they become an issue leading to potential flooding.
The scheme consists of the following components:
1. Installation of 2 water level sensors at each of 6 screens, one upstream and one downstream of the screen. As well as allowing water depths through the screen to be monitored, this allows differentials in water level each side of the screen to be detected, usually an indication of increased debris or gravel/silt deposits on the screen that can lead to blockage.
2. A battery powered telemetered data logger at each location.
3. Real time remote monitoring and alert configuration. Critical water depths and differentials at each screen can be set as “trigger alerts” allowing improved flood risk management.
Scheme design and installation was undertaken between April 2023 and March 2024. Collection, monitoring and analysis of data is ongoing. Critical water depths, differentials and “trigger alerts” are under development.
Benefit
This new scheme provides an improved standard of flood protection for approximately 205 properties.
The telemetry network allows officers to monitor water levels across trash screens in real time. A rapid rise in water levels at a trash screen is normally an indication of flood flows through the structure, and development of a large differential between water levels upstream and downstream of the screen can indicate blockage of the screen.
“Trigger alerts” will be used to target clearance of blockages and, in the case of imminent flooding, warn communities, thus reducing the risks of flooding and associated damage.
Funding
The design, hardware, software and installation works cost a total of approximately £40,000. Welsh Government provided £34,000 of this, with Carmarthenshire County Council funding the remainder.
Previous Flooding Issues
Carmarthenshire County Council (CCC) has responsibility for over 100 trash screens sited on ordinary watercourses across the county. Even with a resource heavy inspection and maintenance programme in place, many of these become periodically blocked with debris and other materials, leading to blockage of flow, and risk of overtopping and flooding to local properties.
For example in 2017 Stradey Park trash screen was blocked leading to localised flooding. There is evidence of several near misses at screens across the County during Storm Callum, due to blockage. As well as residential properties, some of the screens protect the road and highways network.
The Flood Alleviation Scheme
For this scheme a telemetry network has been established at 6 key trash screens around the County, chosen as CCC assets that provide flood protection to a significant number of properties and are mainly located in our priority flood risk management (FRMP2) communities.
The network allows remote monitoring of water levels in response to rainfall in real time. This enables screen blockages and high water levels to be picked up at an early stage and actioned, before they become an issue leading to potential flooding.
The scheme consists of the following components:
1. Installation of 2 water level sensors at each of 6 screens, one upstream and one downstream of the screen. As well as allowing water depths through the screen to be monitored, this allows differentials in water level each side of the screen to be detected, usually an indication of increased debris or gravel/silt deposits on the screen that can lead to blockage.
2. A battery powered telemetered data logger at each location.
3. Real time remote monitoring and alert configuration. Critical water depths and differentials at each screen can be set as “trigger alerts” allowing improved flood risk management.
Scheme design and installation was undertaken between April 2023 and March 2024. Collection, monitoring and analysis of data is ongoing. Critical water depths, differentials and “trigger alerts” are under development.
Benefit
This new scheme provides an improved standard of flood protection for approximately 205 properties.
The telemetry network allows officers to monitor water levels across trash screens in real time. A rapid rise in water levels at a trash screen is normally an indication of flood flows through the structure, and development of a large differential between water levels upstream and downstream of the screen can indicate blockage of the screen.
“Trigger alerts” will be used to target clearance of blockages and, in the case of imminent flooding, warn communities, thus reducing the risks of flooding and associated damage.
Funding
The design, hardware, software and installation works cost a total of approximately £40,000. Welsh Government provided £34,000 of this, with Carmarthenshire County Council funding the remainder.
