Using Dutch expertise in flood control
In the second of this two-part series JOHANNES C Nonner associate professor at the Institute for Water Education of UNESCO-IHE in The Netherlands offers up some solutions based on his vast experience to the huge problem of flooding in T&T after a heavy rainfall.
Trinidad and Tobago is vastly different from The Netherlands. The socio-economic structure, the culture, but also the physical environment of the island states appear to have nothing in common with the Dutch mainland delta area in Europe. Trinidad and Tobago comprises two islands which have rocky mountain ranges and blessed with a pleasant tropical climate, whereas The Netherlands is part of a continent, is predominantly flat and, especially in winter, has a harsh cold climate. Despite this contrast the two countries still have a lot in common. Both states have a long coastline that may be threatened by rising sea levels as a result of climate change, are characterised by sensitive deltaic areas and have a fair amount of heavy rainfall leading to the occasional flooding of urban areas and the countryside.
Both territories also have densely-populated zones and environmental concerns have to be taken seriously. It is better to prevent than to clean up an environmental mess. Flooding by the streams in Trinidad and Tobago is a characteristic of the islands, but seems to have aggravated in the past decennia. As recent as October 2011, the people of Trinidad suffered a series of floods which inundated parts of the urban belt and rural areas bordering the northern mountain range. Although there was no loss of life, the economic and environmental damage was large. Crops on the fields were destroyed and mud currents damaged houses and their interiors.
Human waste in the area, including plastic bottles, bags, cloths, and even pieces of furniture and car tires, were washed down by the flood waters. Indeed, a perfect way to get rid of the local waste, but its transport through the river system to cause environmental damage in the downstream and deltaic areas can never have been the intention of the people concerned. The partly-channelled streams in Trinidad and Tobago with their restricted stream bed areas and insufficient secondary drainage channels which also tend to become blocked heavily contribute to the occurrence of uncontrolled floods and environmental concern. Can the flooding problems in Trinidad and Tobago be reduced and eventually even be resolved?
The obvious answer appears to be to increase the drainage capacity in the flood prone areas by the construction of more drainage channels so that water can discharge quicker to the sea. Although this approach can be very effective, one may also look at the issue from a different angle. Instead of trying to get rid of the floods as quickly as possible one may also consider to store the excess water temporarily in designated areas. For example, the flooding in the urban belt in northern Trinidad could be reduced by widening the natural stream channels, creating water detention areas and considering the realisation of additional stream channels, all set in a natural ecological and environment-friendly context. Operating in this way also enhances the replenishment of the groundwater reserves in the alluvial fan deposits which are underlying the urban belt.
The storage for flood water and the creation of nature along Trinidadian and Tobagonian streams ties in with the concepts of ‘space’ for the river and ‘ecological corridors’ as practised in The Netherlands. Although space will always remain an issue these concepts could work on the islands, even in the heavily-urbanised areas of the country. The introduction of measures to reduce flood risks and to restore the environment means that water managers, hydrologists and engineers should have the knowledge to tackle the issues at stake.
As a contribution to transferring the required knowledge, the Water and Sewerage Authority of Trinidad and Tobago did take the initiative to request a project focusing on water issues.
The project request was worked out by UNESCO-IHE of Delft in The Netherlands and the Dutch Government, the European Union, and Caribbean organisations financially supported the project. The project which is officially named Capacity Building for Water Programmes in Higher Education in the Caribbean started by the end of 2008 and was scheduled to be concluded by the end of 2011. Amongst the many activities of the project, also being executed by the University of the West Indies, the University of Guyana and Costaatt, were short courses on river processes, flood modelling and flood control. Many professionals of the region attended the courses showing the healthy interest the Caribbean has in understanding and solving the problems associated with river flooding and environmental protection.
If you wish to contribute to this guest series send in your ideas to Ira Mathur at [email protected] or [email protected] and join our facebook page on http://www.facebook.com/cleaningupthemess?ref=ts