For almost a year now, I’ve been a member of the Dutch River Forecasting Service, which is responsible for monitoring and forecasting of water levels and discharges of rivers Rhine and Meuse. For this, we have a wonderful tool available: FEWS Rivers. The tool imports meteorological as well as hydrological observations and forecasts and allows one to run these through hydrological and hydrodynamic rivers to produce estimates of future stage and flow. There is really a wealth of information available, making it difficult sometimes to find one’s way.
So how do I go about making a forecast? Rather than simply looking at the latest available forecasts and choosing one that fits my beliefs, I try to dig a little deeper. Here’s the list of questions I try to answer:
- What does the meteorological history look like?
- What do the meteorological forecasts say?
- What’s the hydrological history?
- What do the hydrological models say?
- What is the current action level? What are the criteria for moving to the next level and have these been met?
Typically, this analysis will take about one hour for each of the two rivers. Usually I only do this at the beginning of my shift, though. Once I (think I) know what the situation is like, I can suffice by looking at incremental information only, which takes a lot less time. Obviously, this is true only if nothing much is happening. If any flood waves are coming my way, analysis takes longer.
If I can find the time, I’ll go a bit deeper into each of above questions.