Lowering wind speed and a land fall during low tide prevented cyclone Mahasen to hit the coast of Bangladesh hard on the early morning of 16 May.
In the Mephan river delta a storm surge of 2 meter has been reported, causing some 20 chars to flood. Earlier when Mahasen was in full swing, a 5 meter storm surge was predicted.
Broken up over land Mahasen caused heavy wind guts and thunder showers. In and around the coastal cities of Patuakhali and Bhola thousands of thatched houses were destroyed and crops leveled.
The Bangladesh authorities officially reported six death.
Last moment track change During the final 24 hrs before landfall at 06.00 hrs, the cyclcone’s track changed 100 km to the west (map by Deltares)
Just before landfall the cyclone changed its track some 100 km to the west. “That would have resulted in a higher tide in the Meghan river delta, if not for the landfall to coincide with the low tide”, says Maarten van Ormondt of the research institute Deltares.
Ormondt followed the cyclone’s track and made some simulations of the storm surge: “The surge lies somewhat right of the track and would have pushed more water up the funnel-shaped Bay of Bengal, and into the river delta. ”
Mahasen was predicted to head for the more eastern coastal city Chittagong. Here the cyclone had hardly any influence on the high tide. The tidal monitoring data of Chittagong the cyclone only shows up during the low tide. Because of the conjunction with the storm surge, the low tide was a little less than normal.
Mahasen made landfall in the early morning of 16 May some 100 km west of the coastal city of Cittagong where the low tide was a little less than normal.
Constantly changing storm surge
Mahasen proved again how difficult it is to predict the impact of a storm surge. Changes in wind speed, track and conjunction with the high tide have a big influence. Martijn van Ledden of the consultancy Royal HaskoningDHV has been closely involved in the aftermath of hurricane Katrina that hit New Orleans in 2005. He affirms the difficulty for emergency authorities to react to the constantly changing situation.
Hurricane surge atlas
Van Ledden: “Therefore the US Army Corps of Engineers asked us to make the hurricane surge atlas. In an online database we filled 300 different types of hurricanes that may impact the US southern coastline. We combined the potential height of the storm surge of these hurricanes with the land elevation, showing the areas that shall be exposed to flooding. In case of a buildup, the authorities can identify the historical hurricane with the greatest resemblance and quickly assess the maximum storm surge and overtopping potential.”
According to Van Ledden such a quick assessment is of crucial importance when it comes to taking preventive measures.
According to the latest model calculation by Dutch research institute Deltares the cyclone Mahasan will produce a storm surge of 1 to 1.5 meter along the coast between Chittagong and Cox-Bazaar.
Earlier this week when the cyclone was building up over the Northern part of the Indian Ocean a storm surge of 5 meter was predicted.
Less wind speed
An explanation for this down-toned prediction is that the wind intensity has changed considerably. The early calculations were based on wind speeds up to 70 knots. Now it seems that wind speeds dropped to only 45 knots when Mahasen made landfall earlier today.
Mahasan slowed down and changed from a cyclone to a heavy storm.
Hydrodynamic model Delft 3D
Most reports on cylcone Mahasan origin from weather stations that monitoring the complex on wind speeds, width and track. Deltares is one of the few institutes to monitor the cyclone’s storm surge.
The hydrodynamic model has been set up with Delft3D system running in 2D model.
Uncertainty over precise track
During the week different weather models predicted different tracks for the cyclone.
Most recent forecasts show a track more to the north and resulting in the Deltares model to an even lower storm surge.
Deltares therefore notices that the model is only an indication. Rainfall and wave induced set-up are not included in this simulation.
This news item was originally published on the website of Deltares.
A team of Dutch organisations specialized on flood control, headed by the Dutch Delta Program Commissioner, won the 2013 Franz Edelman Award for Achievement in Operations Research and the Management Sciences in San Antonio on April 8.
The Dutch organisations Delta Commissioner of Holland, Ministry of Infrastructure and the Environment, CPB Netherlands Bureau for Economic Policy Analysis, Delft University of technology, Tilburg University, research institute Deltares, consultancy firm HKV, collaborated on the winning submission, entitled Economically Efficient Flood Standards to Protect the Netherlands against Flooding.
Director of science Jaap Kwadijk of Deltares (photo above) received the award on behalf of the whole team, rom Informs president Anne Robinson (left).
The six finalists competing in the 2013 Franz Edelman Award Competition included teams from Baosteel, Chevron, Dell, Kroger, and McKesson.
Every year, the Franz Edelman competition recognizes outstanding examples of operations research-based projects that have transformed companies, entire industries, and people’s lives. O.R. uses advanced analytical methods to help make better decisions.
Handing out of the Franz Edelman Award 2013 in San Antonio.
Optimal dike heights
The Dutch consortium won the award with a new calculation method developed and used to calculate the economic optimal dike heights for the protection of the Netherlands against flooding. Application of the method of calculation leads to greater efficiency. The computational method used can be deployed worldwide in determining optimal dike heights against flooding.
Deltares conducted for the project, the analysis and wrote the final report ‘Social cost-benefit analysis 21st Century’, which was completed in 2011. The theory, the mathematical model and the software were developed in conjunction with, and in accordance with instructions from, Deltares, by the Dutch Central Planning Office, the country’s Ministry of Infrastructure and the Environment, Tilburg University, Delft University of Technology and HKV consultants.
More efficient spending of public funds
Delta Commissioner Wim Kuijken congratulates the team on winning this important, prestigious award. “Almost 60 percent of the Netherlands is vulnerable to flooding,” he said. “The objective of the Dutch Delta Approach is not to respond to a flood disaster but to avoid it. This innovative project has contributed significantly to improved flood protection in the Netherlands while at the same time steering public funds in the most efficient way.”
Acceptance speech by science director Jaap Kwadijk of Deltares.
(photos by Informs)
The Franz Edelman competition, now celebrating its 41st year, attests to the contributions of operations research and analytics in the profit and non-profit sectors. Since its inception in 1972, cumulative dollar benefits from Edelman finalist projects have reached $190 billion.
Protection against flooding is a vital issue in the Netherlands since 55% of this country is susceptible to flood risk. Each year the Dutch government spends roughly 1 billion euro on protection by dikes and dunes. In total there are 3,500 kilometers of primary dikes in the Netherlands.
Ten-fold increase flood protection standards
The country’s second Delta Committee recommended increasing all protection standards by at least a factor of ten, a highly costly step given limited funds.
Using operations research techniques, the team determined that it is efficient to limit increased standards to only three critical regions. These results, accepted as a basis for policy by the minister of Infrastructure and Environment, led to 7.8 billion euro less investment costs while strengthening the country’s defense against the kind of devastation that cost massive damage in the United States during Hurricane Sandy and resulted in thousands of deaths in Holland during a major storm in the early 1950′s.
About Informs
The Institute for Operations Research and the Management Sciences (Informs) is the leading professional association for professionals in advanced analytics.
Informs is an international scientific society with 10,000 members, including Nobel Prize laureates, dedicated to applying scientific methods to help improve decision-making, management, and operations. Further information about INFORMS, analytics, and operations research is at www.informs.org.
Deltacommissioner Wim Kuijken explains the importance of the new calculation method for flood protection in the Netherlands.
This news item was originally published on the website of Informs and Deltares.
The Jakarta floods of 2013 claimed 20 lives and left 20.000 displaced from their homes. Heavy rainfall on the 15th and 16th of January in and around Jakarta caused massive flooding in the city.
The Flood Management Information System (FMIS) that had been installed by HKV Consultants and research institute Deltares late 2012 was put to the test. The system is operated by the DKI Jakarta Public Works and connected the city’s telemetry to a flood forecasting model. The flood information is disseminated to disaster organizations.
The implementation of the FMIS-system is part of a World bank flood mitigation project. The first phase was completed in December 2012.
Overview of incoming floods Disaster control room at the Indonesia national disaster management authority, BNPB
FMIS: Sudden rise in water level Ciliwung river on January 15
“For the first time in history, Jakarta administration had a full-fledged overview of the incoming floods. And the system proved its value”, says Jurjen Wagemaker of HKV Consultants. He was in Jakarta at the time of the floods. “Authorities had more lead-time to prepare themselves and could anticipate on the flood with better understanding of the situation”.
Room for improvements
According to Wagemakers the recent floods learned that there is still opportunity for improvement: “For example by connecting the system to the systems of the disaster management organizations, emergency aid can be deployed much earlier than is the case at this moment. And flood warnings are still not reaching all citizens, causing great grief for those that have lost their belongings in the floods”.
The Dutch flood expert assures that in the coming years the system will be further developed for effective emergency response.
Collapsed dike
The morning of the 17th, a 30-metre long section of the West Flood Canel collapsed under the pressure of the water, inundating large parts of Menteng, Jakarta’s main business district.
Immediately after the floodings the central Indonesian government announced to have set aside Rp2 trillion (206 million USD) to improve the drainage situation in Jakarta.
These funds will be used in the spillway project to divert excess water from the Ciliwung River to the East Flood Canal. This will reduce the amount of water flowing into the West Flood Canal
More about FMIS
HKV Consultants was awarded to implement the Flood Management Information System Jakarta by the World Bank. In joint venture with Deltares, HKV assists in the upgrade of the existing flood modeling framework and connection to the procedures and IT tools of the disaster management organizations.
With FMIS, disaster managers can take better and more timely decisions in flood prone Jakarta. The project award follows HKVs’ experiences in the Jakarta Flood Management program (2007-2009) and builds on the research done under the Dutch program Flood Control 2015 in Indonesia (2010-2012). HKV consultants has a representative office in Jakarta since 2010.
The services within FMIS include:
- modeling framework especially regarding the upgrade of river and channel capacities to represent recent and proposed dredging and rehabilitation activities of the main rivers of Jakarta;
- telemetric monitoring system, the connectivity and integration with other systems of the climate institutes in Indonesia (online stations, radar and satellite);
- training and capacity building of the specialists at the key agencies in and around Jakarta, to improve the management of flood control systems, communication during flood events, the preparedness by understanding how floods propagate through the city, as well as the technical skills to evaluate proposed mitigation measures.
(also read: Banjir online app Jakarta available on facebook
Jakarta Governor Joko Widodo on location of dike breach Western flood canal
Queen Beatrix of the Netherlands, accompanied by the Prince of Orange and Princess Máxima, visited the Singapore-Delft Water Alliance (SDWA) and NUSDeltares on 25 January during her first state visit to Singapore.
On the occasion of the royal visit, National University Singapore renamed its water research facility the ‘Van Kleef Centre’ in honour of Dutch benefactor Karel Willem Benjamin van Kleef.
NUS water research facility houses the Aquatic Science Centre that is managed by the joint Singapore-Dutch water alliance.
Joint water-releated research programme
Singapore and the Netherlands are global leaders in sustainable water management. The two countries’ complementary strengths in water form the basis for synergistic cooperation, spawning a series of water-related research programmes and projects that have been successfully conducted between NUS and its partners in the Netherlands over the past six years through strategic alliances such as SDWA and NUSDeltares.
After the unveiling of the ‘Van Kleef Centre’, Mr Wong Ngit Liong, Chairman of
National University of Singapore’s Board of Trustees, presented a gift to His Royal Highness the Prince of Orange.
Urban water cycle
SDWA research is centered on the interaction of natural and urban environments embracing water supply systems and the urban water cycle as a core of their research activities. Building on the achievements of SDWA, a new alliance NUSDeltares was established in 2012, with the intention to bring scientific impact to address societal needs in South-east Asia.
Building with nature
The visit was hosted at the NUS Aquatic Science Centre (ASC), which is managed by SDWA, where researchers showcased cutting-edge research work on urban water management and water sensitive urban design, as well as building with nature for inland and coastal water systems.
The ASC is a state-of-the-art environmental observatory and experimental facility for in-depth studies on freshwater processes. Opened in July 2011, the 1,800 sqm outdoor research facility brings together environmental scientists, social scientists, engineers and policy makers to develop integrated and sustainable approaches to urban freshwater management.
The ASC is also used for training, knowledge sharing and public outreach.
Aerial view of the NUS Aquatic Science Centre in Singapore
Dutchman Van Kleef donated aquarium
Professor Tan Eng Chye, Acting NUS President, said: “NUS is deeply honoured to welcome Her Majesty Queen Beatrix of the Netherlands and Their Royal Highnesses and delegation to the ASC, a focal point for many cutting-edge water research projects involving NUS and our Dutch partners under the auspices of the SDWA and NUSDeltares. We are also privileged to rename our water research facility as a tribute to Mr Karel Willem Benjamin van Kleef, who is best remembered for bequeathing his wealth for the construction of the Van Kleef Aquarium, which introduced earlier generations of Singaporeans to the wonders of marine and freshwater life.”
“Since the Van Kleef Aquarium was demolished in 1996, there is no longer any memorial to Mr Van Kleef’s generous gift to the people of Singapore. We are delighted that Professor Tommy Koh led an initiative to rename the physical facility housing the ASC after Mr Van Kleef, so that his spirit of generosity could live on through this NUS research facility bearing his name.”
Associate Professor Vladan Babovic, Director of SDWA, said, “The ASC, which is dedicated to the development of sustainable solutions to urban freshwater management, serves as an important platform to promote research partnerships between Singapore and the Netherlands. The Van Kleef Centre, which houses the ASC, will be an icon that symbolises the long-lasting friendship between the two countries.”
About Mr Karel Willem Benjamin van Kleef
Mr Karel Willem Benjamin van Kleef was a Dutchman who resided in Singapore in the 19th and early 20th century. As a broker, a commission agent and a certified expert in mine drilling, he made a considerable fortune in property and stock in both Holland and Singapore. Upon his death, he donated his wealth to the Municipal Government of Singapore. The gift was eventually used to construct the Van Kleef Aquarium, Singapore’s first aquarium, which was opened in September 1955. The Van Kleef Aquarium was eventually demolished in 1998.
About Singapore-Dutch Water Alliance
Singapore-Delft Water Alliance (SDWA) is multi-national, interdisciplinary research Centre of Excellence for Water Knowledge involving PUB (Singapore), National University of Singapore and Deltares (The Netherlands), established through an initiative of the National Research Foundation in Singapore.
SDWA is hosted by National University of Singapore and provides research home to scientists and engineers from all partner organizations.
As erosion along the Colombian coast accelerates, the Ministry of environment and sustainable development (MADS) is implementing a project to halt the deterioration of Caribbean and the Pacific coastlines.
Research institute Investigaciones Marinas y Costeras (Invemar) carries out the project and the experts are trained by the Dutch research institute Deltares.
One third with erosion problems
According to studies by Invemar in 2006, almost 30 percent of the 3,000 miles Colombian coastline has erosion problems. In five areas where the erosion is most intense the first studies are underway to develop medium and long-term mitigation strategies.
The ministry of sustainable development and Invemar anticipated the important phase of technical consultancy to enhance the capacity and competency at 12 involved corporations autonomous regional (CAR) along the Colombian coastline.
In doing so, the ministry and Invemar started a strategic alliance with the Dutch research institute Deltares.
First workshops
The alliance started in November with a workshop in Santa Marta followed by a course in Delft for a group of Colombians from research institutions and a number of regional government authorities. The workshop was organised by Deltares together with UNESCO-IHE.
The aim was to pass on information and elaborate on possible solutions for tackling the erosion specifically in seven coastal areas with ‘urgent’ status. Leader of the workshop was senior advisor on integrated coastal zone management Joost Stronkhorst of Deltares.
Implementation of measures
According to Director of seas and coasts of the Ministry of the environment and sustainable development, Elizabeth Taylor the strategic alliance with the Deltares is very important for the coastal erosion project. Mrs. Taylor: “Late January the results we will announced of the first study cases and start implementation of measures”.
The City of New York shall have to reconsider its flood defence system. In the aftermath of superstorm Sandy many flood experts have reacted in the media discussing the need of a storm surge barrier, both specifically for New York and in general for coastal cities.
The city has been hard hit twice within a year and the enormous flood damage puts the construction of an expensive storm surge barrier in a new perspective.
New York City has published in March 2011 its ‘Vision 2020: New York City Comprehensive Waterfront Plan’, giving a 10-year vision for the future of its 520 miles of shoreline. The plan does not foresee the construction of a storm surge barrier.
Experts believe that New York will set a trend for other coastal cities as it comes to selecting adequate measures. Both Dutch flood experts Bas Jonkman and Ellen Tromp suggest New York also to consider multi-functional levees. Cities as The Hague and Rotterdam have recently completed flood protection projects with levees succesfully integrated in the urban surroundings.
Big disasters, big measures Professor Bas Jonkman, Technical University of Delft reacted on superstorm Sandy in the New York Times.
The enormous damage caused by superstorm Sandy is a good reason to seriously consider protecting the New York area by means of a storm surge barrier or other flood risk reduction measures, concludes professor Bas Jonkman of the Technical University of Delft in his reaction on the website of The New York Times.
Jonkman has done flood risk management research and consulting in the Netherlands, Vietnam, Cambodia, Indonesia and Romania. At UC Berkeley he worked on the Resin project that focuses on risks and vulnerability of infrastructure in the Sacramento San Joaquin delta.
Closure of the navigable Maeslantkering barrier reduces the flood risk for the city of Rotterdam in the event of a storm surge from the North Sea.
Effective in protection of large hinterland areas
In his reaction he claims these great engineering systems have proven to be effective in protecting large hinterland areas. However, Jonkman also warns for the potential negative effects: the construction and maintenance costs of barriers are high – often billions – and there might be adverse effects for navigation and the environment. The city, state and nation must carefully evaluate costs and benefits of various strategies, such as flexible flood defences in low lying areas and flood proofing of tunnels, he writes on the website of the New York Times.
Always trendy New York
Jonkman is convinced that New York’s reaction, will be relevant for other flood-prone regions in the U.S., like the Houston-Galveston region and Sacramento, as well as deltas in other parts of the world. “Having faced this for generations, the Dutch are eager to share their global experience in the planning and design of effective systems to reduce storm surge risk”, he concludes his comment.
(read the full contribution by Bas Jonkman on the website of the New York Times .
High or low levees Ellen Tromp of research institute Deltares advocates the integration of flood risk reduction and urban development.
For specialist in multifunctional water defences Ellen Tromp at the Dutch research institute Deltares, superstorm Sandy illustrates how urgently New York’s waterfront plan needs to be implemented.
A storm surge barrier will have great impact on the city’s waterfront plan and Tromp draws a comparison with Rotterdam’s navigable storm surge barrier Maeslantkering. Tromp explains that this excisting barrier reduces the impact of a storm surge coming in from the sea. However, levees are still needed in the city itself, but they can be lower and therefore much better integrated in the urban surroundings. According to Tromp this is an important dilemma for New York to resolve.
Urban development including water defence
Tromp advocates multifunctional water defence as an effective and sustainable solution, particularly for major coastal cities like New York, which have to utilise every inch of space. It is also in line with the city’s vision of focusing on the sea and including water in urban development rather than trying to work round it. “A good example of one of the multifunctional water defences that Deltares worked on is the coastline of The Hague. It was achieved by combining dike reinforcement with the redevelopment of the coastal boulevard”.
Increasingly popular in cities
Tromp notices that these kind of flood defence systems are becoming increasingly popular in major cities, including in London, Sydney and Melbourne. “What’s more, in the long term a multifunctional water defence is a cheaper option than many other hydraulic solutions, like a storm surge barrier, for example”, says Tromp.
She is looking forward to attend a workshop in New York next year about multifunctional water defences, where the participants will exchange knowledge and experiences on combining water safety with urban development.
Recent raising of a flood defence wall as part of an redevelopment project of the coastal boulevard of The Hague, the Netherlands
The current view of the coastal boulevard of The Hague after the underground flood wall has been raised to meet future sea level rise.
Artist’s impression of a multifunctional water defence in the harbor of Rotterdam (Urbanisten)
More information
Technical University of Delft
Bas Jonkman (s.n.jonkman@tudelft.nl)
Delft, the Netherlands www.hydraulicengineering.tudelft.nl
Deltares
Ellen Tromp (ellen.tromp@deltares.nl)
Delft, the Netherlands
+31 88 335 7340 www.deltares.nl
Connecting Delta Cities/C40 cities
Rotterdam, the Netherlands www.deltacities.com
New York City, Department of City Planning
waterfrontplan@planning.nyc.gov www.nyc.gov
A series of top events on flood risk reduction will take place in Rotterdam, the Netherlands from 19 till 23 November. Three international conferences will be held in conjunction:
Geotextile positioned vertically in a dike can stop piping. That has been proven by an experiment in a real-size test dike on the IJkdijk location in
Bellingwolde, Netherlands. The experiment was conducted by research institute Deltares in the last week of September on behalf of the water board Rivierenland.
Good alternative for widening of dikes
Waterboard Rivierenland has to upgrade many kilometres of dike because of the risk of piping, a process that has a major impact on the stability of a dike.
The current measures, the widening of dikes or the installation of sheet piling, are expensive and they take up a lot of space. Geotextile could be a good alternative: it is cheaper, easier to install and it doesn’t take up any extra space.
Now the experiment has been successful, the Rivierenland water authority will be looking to see whether the textile can be tested next year on a longer section of dike in the Rivierenland area.
Special geotextile
For the purposes of the experiment, the ‘GeoDetect filter and detection system’ supplied by Ten Cate, was installed over a width of 15 m and a height of 0.5 m in the clay layer of the dike.
GeoDetect measures and follows the strain in soil and enables transmission of a warning signal as soon as its elongation reaches a preset limit.
Geotextile has been used in hydraulic engineering for some time now but using it for piping is new.
Pressure on the test dike
Once the textile was in place, the pressure on the test dike was increased to induce piping. Clear piping was soon seen below the clay dike on the downflow side of the textile but the geotextile was successful in stopping the further development of the piping channel.
The geotextile stopped piping for eight days, after which the experiment was terminated.
Little rinsing of sand and clay
Ulrich Förster, a Deltares dike specialist, was closely involved with the test. He is very enthusiastic about the result: ‘We had already conducted lab trials with the geotextile and the results were very promising. So we had high hopes for this experiment and we haven’t been disappointed.”
The outcome was surprisingly good to Förtser: “Even less sand and clay than I expected was rinsed out. We stopped after eight days because, in practice, that is usually how long high water lasts, with a risk of piping as a result.”
Previous experiments at the IJkdijk location
The first major experiment at the IJkdijk test location was a macro stability test in 2008 showing that 42 hours prior to the actual breach the deformation had started precisely at the position where the dike finally collapsed. Sensor equipment had detected the premature subsidence in the dike.
Another experiment was a unique large scale piping test in 2009 that demonstrated for the first time the occurrence of piping and the actual collapse of a dike.
The piping experiment showed that a drainage pipe in the right place can prevent piping.
On 12 September, the research institute Deltares started building the new wave test facility Delta flume at their premises in Delft. The new facility is unique as far as size and test features are concerned.
The new Delta Flume will be completed in November 2013 and replaces the existing flume at the other test location of Deltares in Markenesse.
Ballast Nedam Infra is building the Delta Flume. MTS System Corp (USA) is responsible for the construction of the wave generator.
Bigger waves
The flume of the new facility will be 300 m long, 9,5 m deep and 5 m wide. Worldwide it will not be the longest one (Forschungszentrum Küste, Hannover, Germany has a flume of 309 m) , but it will be world’s deepest.
This allows the significant wave heights to be bigger, up to 2.2 m.
Single and double crested waves
MTS will install its most powerful wave generator ever build, enabling Deltares to experiment with both regular and irregular waves.
Other experimental facilities
The new Delta Flume will be located next to the other experimental facilities of Deltares, including the Atlantic basin (650 m2) and the Delta basin (250 m2) for investigations related to flow forces, discharge coefficients, specific design details, bed protection and morphological impact of hydraulic structures.
This news item is based on the press released published on the website of Deltares
Impression of Deltares’ current Delta Flume at Markenesse.
More information
Deltares
Delft, the Netherlands
+31 88 335 8273 www.deltares.nl
At the global level, people are using 3.5 times more groundwater than is available. Particularly in Northern America and Asia, groundwater depletion in the major agricultural areas is such that 1.7 billion people find themselves under threat.
This has been shown by a new method developed by Utrecht University and the McGill University in Canada. In the Netherlands, the study was lead by Marc Bierkens, the Professor of Hydrology at Utrecht University who also works for Deltares.
Publication in Nature
The study also drew on Deltares software and data. The results were published recently in the authoritative scientific journal Nature in an article entitled ‘Water balance of global aquifers revealed by groundwater footprint’.
Balance between use and renewal
The researchers developed a method for stating the balance between groundwater use and renewal in a given area: the ‘groundwater footprint’. It can be used globally region by region to see whether groundwater is being used sustainably or whether the resource is being depleted.
Major agricultural areas being depleted
Marc Bierkens: “The groundwater footprint is the surface area needed to establish a balance between groundwater extraction in an area and replenishment by rainwater, while maintaining an adequate river flow to preserve the viability of ecosystems. When the groundwater footprint exceeds one, extraction has reached an unsustainable level and that means that the groundwater resources are being depleted. We found that the groundwater resources in 20 per cent of the major agricultural areas are being depleted to such an extent that 1.7 billion people are under threat. These are mainly areas in Northern America and Asia.”
Taking better decisions
Utrecht University has, together with Deltares, been studying groundwater use for many years. Marc Bierkens believes that the chief benefit of this study is that the problem is presented in a clear way, making it possible to take better decisions about how land is used.
Better groundwater management
Bierkens: “The groundwater footprint clearly identifies regional differences in sustainable groundwater use. As a result, policymakers and government authorities can see where agriculture is depleting the groundwater and where groundwater can still be used to enhance agricultural production. That opens the door to better groundwater management.”
World map groundwater footprint The dark-blue areas have a groundwater footprint of less than 1; groundwater extraction is sustainable here in the long term as well. However, the red areas in Northern America and Asia have a much larger groundwater footprint. The footprint of the Upper Ganges is actually 54 times larger. The area would have to be 54 times larger to capture the precipitation needed to sustain current groundwater extraction. Groundwater in areas with a large groundwater footprint is severely depleted. The bar chart shows that the groundwater footprint is less than 1 for most areas (80%). The groundwater is being used sustainably here.
This news item was originally published on the website of Deltares.
More information
Deltares
Delft, the Netherlands
+31 88 335 8273 www.deltares.nl
