COMMENTARY: Flooding and infrastructure rehabilitation projects in the Caribbean

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COMMENTARY: Flooding and infrastructure rehabilitation projects in the Caribbean
Recent flooding in Castries, St. Lucia
Flooding in Castries, St. Lucia

As we approach a new year, we should expect the usual passage of storms, hurricanes or extreme rainfall events such as those occurring this Christmas Season. I wish to extend my condolences to the people of Saint Vincent, Dominica and Saint Lucia.

The passing of any person at this time is especially more difficult considering that it is a time of joy. We should always try to inspire and donate year round and not just in the month of December.

With the Disasters taking lives in the eastern Caribbean on Christmas Eve and Christmas Day I felt the need to warn the countries who will be seeking post disaster relief in the form of rehabilitative works and programs to save a life, following the heavy rainfall over the Christmas bank Holiday.

In retrospect, the public needs to be mindful of their activities once weather warnings or watches are issued and cooperate with the personnel whose duties supersede those of normal activities. These include any personnel from the emergency services of the country.

As a West Indian, I would be most concern now about any project which foresees major construction activities such as those associated with rehabilitation of infrastructure damaged during major Storm events;these being Storm Otto, Storm Ophelia and Storm Tomas and recent heavy rainfall during the Christmas season of 2013.

Infrastructure is defined by the Oxford Dictionary as the basic physical and organizational structures and facilities (e.g. buildings, roads, power supplies) needed for the operation of a society or enterprise. To rehabilitate is defined as, to restore (someone)/building to health or normal life by training and therapy after illness / destruction.

If you are a patient and have suffered a trauma such as fractured bones then one would tend to see a medical specialist to undertake surgery. An orthopaedist or orthopaedic surgeon, trained to deal with problems that develop in the bones, joints, and ligaments of the human body. What an analogy for rehabilitative infrastructure?

Let me give you another definition Hydrology/Flood Hydrology. According to the USGS, “Hydrology is the science that encompasses the occurrence, distribution, movement and properties of the waters of the earth and their relationship with the environment within each phase of the hydrologic cycle.

Hydrology relies on computers for organizing, summarizing and analyzing masses of data, and for modeling studies such as the prediction of flooding and the consequences of drainage failures, water capture or reservoir releases or the effect of leaking underground oil storage tanks.” It includes such subjects as infiltration, channel storage, floods and droughts, direct runoff, and base flow. Surface-water hydrology shares with meteorology the study of precipitation and evaporation.

Also, surface-water hydrology shares with geomorphology the study of the shape, size, and number of river channels; because river channels are formed as a consequence of the rates and quantities of water they must carry.

Some of the tools used in Hydrology studies and application of surface-water hydrology are unit hydrographs, flow-duration curves, flood-frequency curves, and correlation. Floods pose a different set of hydrologic questions.

The height of levees and the size of reservoirs needed to restrain floodwater must be determined if these structures are to be used to reduce flood damage. Flood damage can also be reduced by the proper design of homes and factories which are built on the flood plain, often in ignorance of flood danger. Highway bridges and culverts are other structures that are often damaged by floods.

The objectives of many assignments are to provide the affected country with options for the reduction of storm-water flood risk to a particular catchment through the assessment and analysis of surface area, slope, soil, and general drainage conditions during high rainfall events.

In addition, the assignment will map levels of risk, identify cost-effective drainage improvement measures, develop drainage policy and plans, as well as enhance the capacity of the respective Governments to better manage flood hazards. So let’s put this in context of infrastructure rehabilitation due to heavy rainfall events. In the public domain a few months ago several request for expression of interest for participation in Hydrology studies were advertised.

For any credible post study following heavy rainfall disaster or flooding, a summary of information is useful. Articles from events such as past Storms like Otto or Tomas indicated, that damage assessment teams visited a number of sites throughout the affected country. Information regarding flooding and landslides was prominent. I expect this will follow the events in Saint Vincent, Saint Lucia and Dominica.

Most assessments conclude that the main causes of flooding or slope failure are usually attributed to the intense nature of the rainfall event, when ghuts / river channels overflow in a short time period over which large amount of rainfall accumulated. The short time along with heavy rainfall and poor drainage and lack of understanding of the natural system compounded by anthropogenic changes often result in high economic damages and even death. Each catchment has it owns correlation.

Useful summaries of infrastructure statistics are often short of data in many Caribbean countries. Data could be quantifiable documented damaged as in the number of bridges and highways, residential /business properties, the precise affected area in square km, the flood data associated with the event both observed and measured, intensity curves, and the documented dimensions of the affected infrastructure and priority areas.

I bring this to your attention because as a scientist within the discipline of Hydrology, major infrastructure rehabilitation projects seem to be putting the cart before the horse or the donkey.

There is no doubt that the effects of climate change are being felt within the region and engineering firms who focus solely on the construction of roads, transportation systems, developments for residential and towns are not equipped with the necessary innovative measures which are encouraged by many international organizations such as the World Meteorological Organization, or the World Bank.

After being a part of several training programmes for Government departments throughout the region, substantial gaps exist in executing sustainable disaster management, land management, and thus in protecting the people of the region.

Some professionals are also unaware of how to use intensity duration curves for enhancing the decision making process so that a city would become more resilient in rehabilitation of structures to reduce the damage to the town or community.

During the passage of storms or heavy rainfall in the region it was evident that the structures did not have the required structural integrity to withstand stresses during extreme rainfall events. In addition, the drainage systems demonstrated to be deficient causing disaster and destruction of houses, and loss of accessibility to these communities.

The process of dealing with a natural disaster is really fragile. The success of the any project financing will be determined on the following factors, these are, if no rain falls repeating past magnitudes, if there are no land use changes resulting in further impermeable catchments, if no future developments are approved, if the disposal of waste is reduced, if no pollution or contaminants exit to sea, if no blockages are experienced in the newly built rehabilitative drainage structures, if the capacity of the drainage structures contain all the water which may occur again for the next five years.

The projects will be deemed a failure if a country is lured into securing a loan or technical assistance in rehabilitating infrastructure while still not explaining why the event occurred, why the land management practices and legislation were not considered, why people died , why the rainfall data still has gaps, why no one understands how to analyse these gaps to produce flood hazard maps and update them, why staff and training have not been accomplished, why the bridges and ghuts have not been properly documented or even why have we allowed the land use of an area which was once permeable to be changed to a site where the rates of infiltration, effects of precipitation, evaporation are unknown causing excessive money to be spent annually because no one sought to understand the requirements of a Hydrology Flood risk study.

To date

• Information of flood history is needed to improve the ability of emergency authorities to prepare for future extreme events.
• The lack of maintenance leads to decreased structural safety and systems malfunctioning.
• Bridges and highways need better attention and supervision.
• There is a need for the improvement in advance notification system of the emergency and disaster control agencies.

I must say that I have been apart of collective research teams across the region who have produced tangible results for studies involving flood hazard mapping, rainfall- runoff analysis, early warning systems and much more.

Currently, I am now apart of a new company which is versed in Hydraulics, Hydrology, Disaster Risk Reduction, Policy and more. We use similar methodologies such as those endorsed by FEMA, US ARMY CORPS of Engineers, and advocated by the World Meteorological Organization along with Global Water Partnership-Caribbean. There aren’t many firms who possess the skills in Flood risk Hydrology studies.

According to the information found on regional initiatives, highly praised project across the region have implemented Flood hazard maps, early warning systems; undertaken rainfall analysis to be used for generation of new drainage structures, and have setup committees for better combined institutional management of floods which leads to sustainable development.

Yet we seek to rebuild failed drainage structures, roads and transport systems before comprehensively quantifying the rainfall-runoff estimates, the catchment delineation or hydraulics of structures which were flooded by the use of the methods endorsed by the organizations listed.

I wish to advise the authorities in countries like the Eastern and Westerm Caribbean, that when soliciting Hydrology studies, they should be aware of the requirements of the discipline, the linkages to disaster management and legislation in order to approach the solutions in a holistic manner. Completing construction simultaneously is often not advisable.

By understanding the principles of such you will be able to identify cost effective consultancy services to facilitate the solutions of such projects.

One such solution is to test the measures of rebuilding drainage systems by model programs before re-constructing redesigning and re-habilitating such structures which have failed during events such as Storm Otto or Ophelia and others.

I look forward a new and prosperous 2014. It may just be a rainy one. I pray that on completion of the projects in the Caribbean region, the Disaster and Emergency response systems are not overburdened by the engineering tactics which don’t work because of lack of knowledge of comprehensive disaster management used in flood risk management, hydrology and sustainable development.

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2 COMMENTS

  1. I used to be suggested this web site via my cousin. I am not certain whether this put up is written by
    way of him as no one else recognise such unique about my problem.
    You're incredible! Thank you!

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  2. The Government of St.Lucia should dredge the estuary of the rivers especially those that are located in flood plane areas like Anse-la Raye and the other villages around the island.The dredging of the rivers will prevent then from over flowing their banks and lives will be saved.
    Godfrey Frederick,(st.Lucian} Vancouver Canada

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