Pic caption: dam holding back the Ulley reservoir in Yorkshire, UK

3D Laser Mapping, the UK based specialists in laser measurement technology and software, has used a state of the art survey system to monitor the risk of flooding amid fears a dam may fail following recent torrential rain.

Engineers trying to reinforce the embankment dam holding back the Ulley reservoir near Rotherham called on 3D Laser Mapping to undertake a detailed survey of the reservoir perimeter in order to maintain the current water level and calculate the capacity of the reservoir in advance of predicted rainfall.

The 3D Laser Mapping team also demonstrated the use of SiteMonitor, a laser scanning system designed to measure and monitor the stability of man made structures, rock faces and landslips, for the ongoing observation of the dam.

South Yorkshire was one of the worst affected areas following extreme weather conditions that saw an entire month's rain fall in just twenty-four hours. Engineers called to the dam site by Rotherham Borough Council signalled a warning, that subsequently saw about one hundred homes evacuated by the Council and South Yorkshire Police in the early hours of the morning and the closure of the M1 motorway, after a scour hole developed on the downstream face of the dam following the collapse of a masonry spillway channel.

Using a Riegl LMS-Z420i, a high performance, long range laser scanner system 3D Laser Mapping were able to provide the on-site engineers from Arup with detailed and accurate measurements of the reservoir perimeter including the surface area of the reservoir and profile of the reservoir banks to the high water mark. These measurements were then used to calculate the capacity of the reservoir in advance of the weekend's predicted rainfall and to assist with the pumping operation to maintain the current water level.

"Laser scanning is an ideal tool for high risk environments such as this," said Dr David Hetherington, Arup Lidar specialist. "Combining accuracy with repeatability for ongoing monitoring, all with minimum risk to personnel."

He continued: "By capturing a detailed model of the reservoir banks we were able to quickly provide the engineering team, Rotherham Council and emergency services the information they needed to manage the ongoing operation and minimise the risk to life and property."

3D Laser Mapping also demonstrated their SiteMonitor software solution for the ongoing monitoring of the dam. SiteMonitor, when used in conjunction with the Reigl LMS Z420i, can obtain measurements that are accurate to 5mm with a distance range of up to 1,000m. Recording and analysing up to 8,000 measurements per second SiteMonitor creates a detailed, accurate and continuous record of the structure.

3D Laser Mapping is a specialist in laser scanning solutions, the Riegl Premier Distributor for the UK, Ireland and sub-Saharan Africa and the leading distributor of TerraScan software. 3D Laser Mapping integrates laser scanner hardware systems with their own software and peripherals to create robust solutions for sectors such as mapping, mining and manufacturing.