The Government of St Lucia has placed the ECLAC Report done after Hurricane Tomas on their website for the information of the general public. The Report engaged the services of a series of experts during the period November 17th – November 24th 2010. The Report has been described as a Macro –Economic and Environmental Assessment of the Damage and Losses caused by Hurricane Tomas.
The Report is well put together and provides sound recommendations on the way forward in the Post Tomas era. The technical content is excellent and is good reading material for every young engineer. I must say I am surprised that the Ministry of Communications Works Transport & Public Utilities has not pursued the recommendations contained in the report and this is extremely baffling.
The technical team consisted of two engineering experts in the person of Dr. Derek Gay and Dr. David Smith, both of whom I interfaced with as a student at the University of the West Indies. One of the interesting comments in the report on Hurricane Tomas was the effect of the drought on the damage caused by the hurricane.
The report states that in drought conditions the soil contains lower than normal moisture contents and thus on the onset of rains the infiltration is rapid and likely to go to greater depth. One must also note that trees will send their roots deeper to get water during a drought and thus also causing the greater depth of infiltration. With a greater depth of infiltration, it means a greater mass of soil is affected.
The report goes on to indicate that the rainfall during Hurricane Tomas is estimated as a 1 in 180 year event. The probability of a drought and a 1: 180 year flood event occurring in the same year was put at a 1in 1000 yr event!! The drought was largely responsible for the significant amount of slides that took place during Hurricane Tomas.
One believes however that the costing provided in the report may be subject to a significant margin of error due to the limited time frame of the assessment of the damage. This assessment was done almost 3 weeks after the event. The various Government Departments were still very much involved in the recovery phase and could not have completed the assessment of the damage. Comments made this week by the Permanent Secretary of the Ministry of Works suggested that even at this point the design and thus determination of costing is still ongoing.
The cost of infrastructural damage was stated in the report at $ 100.00 million XCD, which ironically coincides with what I had estimated in November 2010 and stated in a previous article. However, in the ensuing period after further review of the damage, I believe this figure may have to be doubled to cover the total damage and replacement cost of Hurricane Tomas. So it is my belief that the ECLAC report is off by 100% in the determination of damage to roads and bridges.
The report however provides sound recommendations on the way forward. One of the recommendations refers to the replacement of bridges and culverts. The report recommends the following for new structures:
- Bridge structure for major rivers should be designed to pass a minimum of a 1:50 year flood event
- The existing bridges should be replaced by open span structures, so that their waterway areas are greatly maximized
- Proper design of wing walls should be incorporated in the design
If one observes the two replacement structures at Anse Galet and Mon Repos, the Ministry has dismissed the recommendations of the report.
The structure at Anse Galet is definitely not designed for a 1: 50 year flood event and more looks like a structure that will overtop every year and the wing walls are an engineering disaster. The structure at Mon Repos is not an open span structure. So it would appear that the excellent work done by the technical ECLAC team is another report that will gather dust in the Gehenna of the Ministry of Works. How sad.
The component of the damage in Hurricane Tomas that has not been discussed in detail in the public fora, is the damage to the Water sector. We have to assume that WASCO has no money to engage in any significant rehabilitation works, and my understanding is that the GOSL was assisting WASCO financially in the post Tomas period. The repair work to WASCO systems therefore will have to be funded by the GOSL.
The report has put the damage to WASCO facilities at $ 53 million XCD. In addition to this sum the report also made recommendations to build resilience to the water supply systems, these works were not costed.
Water security is the biggest challenge St Lucia has to face in the next decade. Government has to place water security in the centre of policy, or else the entire economy can spiral into a tailspin. The three weeks after Hurricane Tomas when there was no water was a wake- up call to put our house in order.
The following are the recommendations in the ECLAC Report to reduce the vulnerability to natural hazards of the water utility:
- A bathymetric survey of the Rosseau Dam to determine the level of sedimentation that occurred during Hurricane Tomas. While the report did not mention it, it must also be noted that there was no work done after Tropical Storm Debbie within the Dam.
- Following quantification of the level of sediment, a suction dredge should be employed to remove the sediment from the Dam,
- Some measures of slope stability need to be done to the slopes of the mountains surrounding the dam
- Lay a new Raw water pipeline from the Junction Tank to Vanard, as this is viewed as a weak link
- The water treatment and distribution systems in the South, specifically Vieux Fort, need to be revamped and updated as required.
We may be looking at another $ 50 million XCD for these works.
The total funding to create a measure of water security is in the order of $ 100 million XCD, and I maintain that this is the greatest challenge facing the nation in the next decade.
You would note that many of the recommendations refer to the Rosseau Dam, which is the major source of water for the North of the island. This area is where 60% of your population reside, and where a huge percentage of your touristic stock is located. The North is seen as very vulnerable with regards to water security.
While there is a huge margin of error in the costings found in the report for infrastructure damage island wide, the ECLAC report has sound recommendations for the nation going forward. It would be a very sad day if this report is not considered in the Post Tomas restoration works.
I strongly urge the Government of St. Lucia to insist that the recommendations of the ECLAC Report are considered in the design phase of all works. We cannot afford as a small nation to be building structures that fail with every storm event. I fully agree with the approach stated in the report, of building resilience and reducing the vulnerability to natural disasters.