Background Image
Table of Contents Table of Contents
Previous Page  26 / 36 Next Page
Show Menu
Previous Page 26 / 36 Next Page
Page Background



Modern forecasting systems combine up-to-date

data fromweather stations and information about

river discharges, groundwater and sea level with

hydrological models, establishing a basis for

predicting high-water levels in rivers, sea floods and

imminent drought.

Systems like Delft-FEWS make forecasts faster, and the fore­

casts look further ahead and are more accurate than ever. As

soon as a clear picture emerges of the risks for people, infra­

structure or agriculture, the system issues a precise warning.

This is usually a few days in advance for floods, and even a

few weeks or months for droughts. The emergence of

big data

also makes it possible to draw on more and more alternative

sources of data such as Twitter and satellite images to make

the warnings even more accurate.

The result: more and more time for local authorities to deploy

the emergency services, to organise evacuations or to install

additional protection on rivers or coasts, or to create extra

water stocks to cope with a drought.

Intense rainfall

A good example of a warning system for river floods is the

National Flood Forecasting System for Great Britain and

Wales. The NFFS produces forecasts for floods from the main

rivers, reservoirs, estuaries and seas, taking surface water

and groundwater into account. It does this by combining

hydrological measurements and models with meteorological

forecasts. On that basis, it is possible to state three days

in advance whether the water-level limit will be exceeded

at important locations and what the impact will be on the

surrounding area and the local people.

Even so, the major floods in central England and Wales in

the summer of 2007 resulted in thirteen fatal casualties and

caused material damage amounting to £3.2 billion. During

the evaluation of the disaster, it was found that hydrologists

and meteorologists should have collaborated better. The

result was the Flood Forecasting Centre, a joint agency

bringing together the Environment Agency and the Met Office.

The first major test for the system was in the winter of 2014.

The authorities were able to warn local people in time and

provide them with adequate information, and so injuries and

damage were reduced substantially.

Sea-level rise

On Mauritius, an island republic in the Indian Ocean, sea-

level rise and the increasing intensity of tropical storms are

a threat: they could inflict serious damage in the future on

infrastructure, farmland and housing. Most Mauritians live

on the coastline and so they are particularly vulnerable.

To mitigate the risks of storm surges, the government of

Mauritius set up the Climate Change Adaptation Programme

in the Coastal Zone of Mauritius.

An important part of this programme is a storm-surge

warning system that will be operational for the cyclone

season in January and February of next year. The system

combines oceanography models with meteorological

forecasts. The coastal inhabitants on the side

of the islands where a storm surge is expected

will be warned three days in advance. That gives

them time to evacuate to safe places on the island

and allows the authorities to deploy their limited

resources and emergency services in the best possible

way. The prevention of fatal casualties will be the priority

here and economic damage can also be kept to a minimum.

Peat fires

Both systems operate on Delft-FEWS, a software platform

that will be celebrating its tenth anniversary this year.

Enormous progress has been made during that time. The

available data flows and hydrological models are being used

ever more efficiently. The increasing availability of satellite

data and databases with soil information has resulted in a

major boost for the warning and forecasting systems.

Delft-FEWS is a platform for processing and combining

data flows and it was initially developed for hydrological

forecasting and warning systems. A set of modules make

it possible to develop systems that are tailored to the

specific requirements of organisations in specific regions.

The system can be used in areas such as water-quality

forecasting, groundwater and reservoir management,

operational management and the optimisation of sewage

systems, and even for predicting peat fires.

Social media

A recent development involves using social media for

warning systems. The Floodtags company produces, in

collaboration with Deltares, detailed real-time flood maps of

cities in South-East Asia on the basis of tweets. The maps

show which streets are flooded when the river bursts its

banks and that in turn helps to predict the further course of

the flood.

The recently opened iD-Lab in Delft is another important

new facility where all the available data flows and computer

models can be brought together in a warning and fore­

casting system. During emergencies, the iD-Lab is set up

as a crisis centre that supports government agencies and

emergency services by supplying up-to-date forecasts and


No end in sight

The development of forecasting systems is destined to

continue for a long time yet. Increasing amounts of infor­

mation from the social media, more detailed forecasts,

more efficient software, improved hydrological models and

support for the agencies involved: all these factors means

that forecasting will become even more valuable in the years

to come.

For more information: