As recent news shows, forecasting of rainfall is being taken seriously. The UK’s Met Office has broken news that it has tendered a new supercomputer project, which will cost in the region of £1.2 billion. This will be the largest investment in the history of the Met Office; the next largest investment was for the current supercomputer, costing a mere £97 million. The computer is due to have six times more capability for number-crunching than the existing computer and is due a major upgrade after five years to increase this a further three times!
It will bring a step change in helping the water industry mitigate damage.
The level of investment in hardware shown here signifies that more investment is being committed to further understand the current and near-future patterns of weather within the Earth’s atmosphere. The Met Office currently gathers more than 200 billion observations from different meteorological station points (e.g. satellite information, weather stations & buoys) every day to input into the Met Office numerical modelling systems of the Earth’s atmosphere. Needless to say, the processing power involved in inputting such vast quantities of data, running multiple numerical simulations through both the Unified Model family and the Ensemble models to quantify uncertainty in the predictions, is enormous.
The current resolution of forecasting grids varies across the global atmospheric model; the UK in general works to a 1.5km gridded resolution. Areas of interest in the UK (such as around the UK’s largest airports and much of London) run at a much higher resolution, around 300m gridded resolution. Increasing the computational power of the numerical modelling machine should lead to a much wider rollout of higher resolution gridded forecasting, which means that we can start to get more accurate forecasting certainty in areas where the lower resolution grid squares could not pick up more localised weather events.
So the question is, how can the water industry gain a step change from the promised dramatic improvement of forecasting weather events?
The most obvious point is that you'll be able to feed into your models better-localised weather forecasting, and more accurate predictions of severe weather. With better input information, you'll get better model outputs. Considered to be the brain of the operation, the hydraulic model can leverage its understanding of the catchment to predict exactly what is happening – and what will happen – in the catchment area.
Benefits of Better Weather Forecasting for Modellers
Improvements in the resolution and certainty of weather forecasting will empower operational response teams to understand what is going on in the catchment with significantly greater certainty of the incoming rainfall event (in terms of rainfall intensity & duration profiles), and even in some cases it will forecast the rainfall further ahead of time.
The combination of an operational model and better weather forecasting can provide you with benefits such as:
- Time – If you are alerted ahead of the predicted event and can use accurate high-resolution hydraulic modelling outputs to provide a clear representation of above ground and below ground hydraulic conditions, you will optimise the time to fix a problem should one arise. Be it six hours or sixty minutes, it still enables the operational response team to get on the front foot to either prevent the problem entirely, or to mitigate the extent of the problem’s damage.
- A knowledge of “What’s going on in my area?” – Accurate quantifiable outputs of the catchment area's hydraulic conditions provide users with detailed knowledge of “what is going on” in that environment, providing operational teams with vital knowledge. This could be something as complex as: “How will my inlet mechanisms to my Sewage Treatment Works perform during this forecasted storm event?”, or as simple as: “Which roads will be impacted by sewer flooding, pluvial flooding and/or fluvial flooding within my catchment area?”
- Decision-making support – Improved understanding of “What’s going on in my area” enables operational teams to identify the optimal solution to the predicted outcome ahead of a forecasted storm event. It does not take the final decision-making away from the operational team: rather, it empowers the team to understand the consequences of making different decisions. This is where, utilising a virtual representation of the catchment area, we can send multiple “What-If?” scenarios through the same forecasted storm to understand the difference in hydraulic outcomes. For example, “When, and for how long, should I turn on my storm pumps before I cause additional problems downstream of my area?”
- Automated alert and warning systems – Alerts can be generated, with automatic pre-defined Actions sent out, to alert teams when there is a potential problem observed in real-time or forecasted ahead of time.
However, is improving the resolution of where and when rainfall will hit our catchment areas enough for fully functional operational models to be employed?
How can we fully understand the exact areas where we should implement our action plans when we are not considering how expected rainfall is due to affect multiple sources of flooding? For example, with how much accuracy can we predict the route of flood waters once the river banks bursts? How will the locking of flap valves affect sewer flooding if surcharge within the storm network coincides with peak flows in the river system? How can we ensure that certain roads and urban areas are safe from high floodwater depths if we do not consider the effect of pluvial flooding on the catchment area in conjunction with the effect of fluvial flooding within our area?
ICMLive can help us answer those questions. It can take in data to forecast the impact of rainfall on collection system performance, flooding, and probability of overflow events. This can be forward-looking data such as weather forecasts, near-real-time data such as rainfall radar, and historical such as from a SCADA historian. It means that you can consider the impact of expected rainfall, in 1D (rivers, gullies, pipes) but also in 2D, to show the likely overland flow if the river does overtop. If you're interested, do contact me, or find out more from our website. We have a broad introduction to flood and risk assessment as well as a range of live and on-demand webinars.
A step change
The improvements made to forecasting are significant ones and will be a step change in how models enable us to mitigate damages from predicted rainfall events, by accounting for the full integrated catchment hydraulic impacts.