| A newsletter on water, environment & health | No.1 2009 |
| Water | Environment | Health |
|---|---|---|
| Water | ^ |
The Danish harbour at Thyborøn has in the recent years experienced increasing problems with large waves in the approach channel as well as damaging overtopping of the outer protection structures.
It is particularly during and after periods with strong westerly and north-westerly winds that the waves at the harbour become very large. This phenomenon was not observed earlier where the prevailing conditions were acceptable under almost all weather situations
The study carried out by DHI has initially focused on why the problems have arisen.
The study has revealed that bathymetry at the outer part of the Thyborøn entrance channel and just outside the harbour has changed in later years. The water depth has been reduced in an area outside and north of the harbour. At the same time the water depth has increased along the eastern side of the channel.
The bathymetry has changed significantly over the last four years
As a consequence of changes in the bathymetry waves from the North Sea propagate differently as compared to what they used to do. The waves propagate towards the harbour instead of just passing it.
For further information please contact Peter Sloth at prs@dhigroup.com or see the full article here.
The EKO Atlantic City project involves reclaiming over eight square kilometres of land adjacent to Lagos, Nigeria. The new reclaimed area will give room for a mix of residential, commercial, financial and tourist accommodation. The project also aims to restore the land lost to coastal erosion over the last 60 years and provide a permanent solution to the problem. Construction is scheduled to begin early 2009. Upon completion EKO Atlantic City will to provide residential accommodation for 250,000 people. The development is also expected to provide employment for at least 50,000 people.
A successful visit convinced project owner, contractor, consulting engineers and authorities that the tested design in the DHI laboratory is a safe design. Witnessing tests gives DHI clients very valuable insight into the performance of the studies of structure interaction with extreme wave climates
For further information please contact Flemming Schlütter at fls@dhigroup.com or see the full article here.
In a novel approach to represent the coupling between the land surface and atmosphere, DHI and DMI (Danish Meteorological Institute) are exploiting OpenMI technology to link hydrological and climate models. Modelling the effects of climate change on the hydrological cycle requires a proper understanding of the water and energy exchange between the atmosphere and the land surface. This exchange is a process that can have a significant impact on the hydrological cycle under a changing climate. OpenMI provides a practical way of linking the achievements of the meteorological and hydrological modelling community.
While there is evidence of increases in both severe droughts and heavy rains, and changes in the magnitude and distribution of both precipitation and evapotranspiration, there is still considerable uncertainty in quantifying the effects on hydrological systems from climate change.
To develop improved methods for assessing the effects of climate change on water resources, a coupled hydrological and climate modelling system is being developed using two state-of-the-art model codes: the climate model code HIRHAM and the hydrological model code MIKE SHE. OpenMI technology is used to link these two existing model systems.
OpenMI is ideally suited to linking hydrological and climate models and allows linking with different spatial and temporal representations and across different platforms. This new technology will also be effective in linking the meteorological and hydrological modelling communities.
For further information please contact Michael Butts at mib@dhigroup.com, Sara Maria Lerer at sml@dhigroup.com, Jesper Overgaard at jov@dhigroup.com or see the full article here.
The Urumea river catchment area which is located in the Basque Country in the northern part of Spain has historically been seriously affected by flooding. The districts most affected by the frequent inundations are the municipalities of San Sebastian, Astigarraga and Hernani. As recently as October 2008 a minor flood was experienced in Hernani. In 2006 and 2004 major flood events with significant damage occurred.
To improve this situation, the Department of Environmental Affairs of the Basque government will in the coming years invest 60 million € in construction of 18 preventive measures. The overall objective of the project is to "Let the river breathe" and consequently reduce the frequency of flooding of the Urumea River.
The preventive measures include substitution of a number of exciting bridges, which at the moment are obstructing the river flow, establishment of by-pass channels, enhancements of the riverbed in defined sections, and creation of public recreational areas. All actions amid at increasing the flow capacity of the river, while respecting the environment and natural flow path of the river.
In order to investigate in detail these 18 predefined interventions, DHI was contracted to set up a 2D model (MIKE FLOOD) of the 15 km stretch from Hernani in the south to San Sebastian in the north.
In the First phase of the study a model of the actual situation was established, incorporating all relevant bridges and hydraulic structures.
In the second phase the 18 corrective measures was incorporated into the model, and simulations of the T=10, 100, and 500 years return periods was carried out.
The projects design return period was set to T=500 year, which means that the planed flood protection measures should be capable of withstanding a flood that statistically should happen once every 500 years.
For further information please contact Peter Torp Larsen at ptl@dhigroup.com or see the full article here.
| Environment | ^ |
The Danish Spatial and Environmental Planning Agency (BLST) has published a report, which suggests that restoration of boulder reefs in coastal waters, a protected habitat type under the EC Habitats Directive, could also serve as a ‘supplementary measure’ and hence support implementation of the EU Water Framework Directive.
2 km2 of boulder reef = ÷ 800 tons N. How can that be? As in many other EU countries, Denmark has focused exclusively on reduction of nutrient loads as a means to fulfil the environmental quality requirements of the Water Framework Directive. Meanwhile other, perhaps equally important methods are neglected in coastal waters. It is indisputable that there have been significant increases in nutrient loads but it is also very likely that the conditions in fjords and coastal waters have been affected by fishing and by extraction of raw materials. Large rocks/boulders have been deliberately removed e.g. for building harbours and smaller stones have been removed unintentionally by trawl-fishing.
Consequently there has been a less developed population of perennial macroalgae, which are often limited by access to hard substrates. Subsidiary effects have been reduced oxygen production in benthic waters and hence worsened hypoxia and fauna mortality.
Numerical modelling has been used to investigate the effects on hypoxia and "internal N-loading" following a "virtual" re-establishment of hard substrate in Løgstør Bredning (an open, shallow area) in the Limfjord. A number of assumptions are made in the models, the most important of these based on observations and measurements in the Limfjord over the last 10 years (the same density and production of macroalgae as at present but over a greater area, reduction in N-release from sediment when oxygen concentration is increased, etc.)
Establishing boulder reefs reduces the extent and, in particular, the duration of anoxia and N-release from sediment. On the basis of a series of model scenarios, it was concluded that establishing 2km2 of reef spread over a number of smaller areas was most cost-effective.
For further information please contact Flemming Møhlenberg at flm@dhigroup.com, Jesper H. Andersen at jha@dhigroup.com or see the full article here.
| Health | ^ |
We think we’re fighting infection in man and keeping down bacteria by using antiseptic hand soaps and disinfecting cleaners in the home and hospital. But, in fact, in the very same bacteria we’re promoting resistance to essential antibiotics that doctors use to cure those bacterial infections.
DHI is now part of a 4-year international research project aimed at understanding how antiseptics and disinfectants bring about antibiotic resistance. The case is clear for a few of the disinfectants, or biocides as they’re called in the European Union. For instance, the chemical triclosan is a very common disinfectant/biocide world-wide. When a bacterium meets triclosan in the home or hospital environment, the bacterium can resist triclosan’s killing effect by establishing a pump in the cell membrane that pumps every molecule of triclosan out that diffuses in. Unfortunately, scientists have recently found that exactly the same pump is what makes bacteria resistant to antibiotics used against tuberculosis and against staph. skin infections. Now it is important to be able to predict which disinfectants should be avoided in order to avoid antibiotic resistance. This is what the DHI project will attempt to do.
DHI’s research project runs from 2009 to 2012 and is with partners at the University of Copenhagen, the Danish Technical University, the Hvidovre Hospital outside of Copenhagen, plus some meat industries and producers of disinfectants.
For further information please contact Stephen Wessels at sww@dhigroup.com or see the full article here.
At the end of 2008 the European Parliament and the Council adopted a new Regulation on classification, labelling and packaging of substances and mixtures (CLP). The CLP-regulation came into force 20 January 2009. CLP is an implementation of the Globally Harmonised System (GHS). Although GHS is introduced as a global system it is still possible to make national or regional adaptations when GHS is implemented around the world.
GHS/CLP will affect everybody who produce, sell or use chemicals. In practice all chemical substances and mixtures must be evaluated, classified and labelled according to new criteria. The first deadline to be met is 1 December 2010.
For further information please contact Henriette Christiansen at hc@dhigroup.com or see here.
DHI hosts and participates in a wide range of events worldwide. A list is available here
Training, capacity and institution building – DHI courses around the globe
For a number of years DHI have offered a variety of courses worldwide. The courses range from short and intensive standard software and vocational training courses to dedicated, specialised training matching individual clients' specific needs and requests.
For further information on courses and training activities please contact DHI International Course Secretariat (courses@dhigroup.com) or consult our websites.
DHI has offices around the global. For contact details please see here
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