Representing Complex Structures and Operational Rules, England
- Alastair Sheppard
- Oct 14, 2015
- 2 min read
Updated: Mar 13
What our customers say:
“The ability to run multiple variations of the hydraulic model using Flood Modeller’s 1D solver, without compromising the accuracy of the results, was essential throughout the course of this event.”
Rob Fraser, Chief Engineer, Black & Veatch
The Somerset Levels and Moors are a managed catchment, with water flow controlled by a network of structures and pumping stations. During the winter of 2013-2014, the catchment experienced widespread flooding, which was modelled using Flood Modeller’s 1D solver.
The flood event began in mid-December 2013 and continued for two months. During this period, there was only one day without rainfall, leading to over 500 million cubic metres of water entering the lowland area of the River Parrett catchment.
The Environment Agency for England estimated that there were over 65 million cubic metres of floodwater on the land, covering an area of 65 square kilometres. The Agency carried out the largest pumping operation ever experienced in the United Kingdom, introducing temporary pumping units alongside permanent stations.
Black & Veatch were appointed by the Environment Agency to provide expert input and advice during the flood event, including the hydraulic implications of various intervention options. A 1D hydraulic model was used to perform ‘what if’ scenarios, supporting responses to questions from the incident team, residents, media, and government. Results of these scenario tests were often required with minimal warning and within a very short timeframe. Therefore, the ability to run multiple variations of the model using Flood Modeller’s 1D solver, without compromising accuracy, was essential throughout the event.
Key Facts
The area experienced significant flooding, with 500 million cubic metres of water entering the lowland region of a key catchment.
'What if' scenarios were performed to quickly simulate a long-duration flood event without any loss of accuracy.
The 1D model consisted of 4,668 nodes and 40 separate pumps, each with up to 32 operational rules.
Using a standard desktop computer, the model can simulate a three-month flood event in less than 16 hours while maintaining the required level of accuracy.
The model used for these assessments was reviewed by an international expert panel during the flood event. It has been, and will continue to be, used to support the assessment of interventions within the 20 Year Flood Action Plan.
Following the flood event, the model was further enhanced with new data, including channel surveys, bank surveys, and revised hydrology. The final model contains 4,668 nodes, representing over 135 km of channels and the associated moors.
The model includes 40 separate pumps, each with up to 32 operational rules, and 270 km of banks represented by spill units. These elements are critical to the system's overall performance, and significant time and data were invested to ensure suitable discharge coefficients were selected. The final model can simulate a three-month flood event in 16 hours of computer time while maintaining the required level of accuracy.
