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Tuesday, May 7, 2013

A TRILOGY OF DISASTER DILEMMAS: A STORY ABOUT FLOODS, HURRICANES AND COASTAL THREATS.


DEREK WALCOTT

Derek’s Poem  - A City’s Death by Fire - recapped his memories of the 1948 fire which he claimed “levelled all but the churched sky”. In the Poem, he asked “Why should a man wax tears when his wooden world fails?” Sixty-five years after the fire, we wonder if Derek were also to recap memories of the onslaught of floods on the city, would he have asked: “Why would the wooden world of Castries city be under threat of failure from God’s tears?”

When we contemplate the persistent “assault and battery” of Castries City by floods over time, we wonder whether water will ultimately be a main cause of the "death" of the capital city.

The city’s flooding dilemma
To the best of living memory, Castries City has historically been subject to a barrage of perennial flooding, primarily because of its location in a flood gut on reclaimed land. Apparently, the engineering interventions designed to respond to the flooding problem have not always produced the desired outcome.

As far as I am aware, engineering consultants have prescribed two major solutions in that regard: (1) the desilting and clearing of the main and parish drains prior to the onset of the rainy season; and (2) the Castries Flood Mitigation Project. Only the later has brought a measure of relief and - we can safely say - were it not for it, the flooding could have been a lot worse for the city. Clearing the drains does not seem to work anymore, as they seem to have become overwhelmed by the indiscriminate disposal of waste and breeding of rodents and pests.

The recent spectacle on Bridge and Jeremie Streets being virtually submerged under flood water rising well above 3 feet at some points and lingering around for more than 14 hours is a potent reminder of the consequences of onslaughts by floods on the city environment. Even the pumps (if they were in working condition) must have been overwhelmed by the sheer magnitude of the flooding.

Sign of things to come
If this year’s early heavy rainfall were to be a reliable predictor of what is to come during the hurricane season, then we seem to be in for major weather challenges; but as I said a previous article, I don’t expect those challenges to stem from a proliferation of category 3+ hurricanes.

In the article titled “Powerhouse Hurricane Review 2013 (published April 13) I argued that, contrary to the scientific predictions by weather experts, I didn’t "believe" that we would have a "hyperactive" hurricane season punctuated by a high frequency of very dangerous cyclones. Assuming that the time frame for the hurricane season has remained constant (June – November) and that there hasn’t been a “season/climatic shift”, then (given that the prevailing rainfall pattern continues) it is also reasonable to assume that there is much heavy rainfall is on the horizon.

I also argued that thermodynamic conditions (which will contribute to the early heavy rains) should also have a mitigating impact on the intensity and frequency of hurricanes. I have boldly thrown out this hypothesis into the public domain for monitoring. Having said this though, I’m also patently aware that my position is mere conjecture – a “modification hypothesis” to the current hurricane paradigm laden with limitations.

Dangerous Rains
Hurricane Tomas in 2010 may be too fresh in our minds to escape attention. We might claim that it was a “rarely-occurring” natural phenomenon which was an exception to the rule; but we can’t run away from its lessons.

One of the painful lessons was the recognition that flooding and landslides can have an equally if not more devastating impact than hurricane-force winds. Traditionally, the perception was high winds were the real danger; but Tomas might have changed that. We now appreciate that both wind and rain can be extremely dangerous, with the realisation that it may be easier to “escape” the onslaught of the high winds of a cyclone than it is to escape floods and landslides associated with the heavy rains.

When Hurricane Ivan hit Grenada in 2004, it laid waste to the island. Hurricane Emily struck her again in 2005 but this time, something of a “minor miracle” happened: It was reported that 100% of the “exposed rafter” roofs retrofitted by Caribbean Metals easily survived category 2 hurricane force winds, while the “non-exposed rafter” roofs toppled around them. That was a lesson worth noting!

Compare that to the onslaught by Tomas: there was nothing St. Lucia could do to escape from the “Titanic” landslides and/or “Noah-type” floods which hit Soufriere, Saltibus, Bexon and the Bar de L’Isle.

Already this year, heavy pre-season rainfall has been sounding serious alarm bells, beckoning us to pay greater attention to flood and slide mitigation.

Are we prepared for the rains?
There is no doubt that Soufriere is still geotechnically fractured and fragile; and I’m not sure that the various slope stability management interventions and their rates of implementation have done justice to gravity of the problem, especially in the context of the early high rainfall, which may have rendered the landscape in those areas even more vulnerable.

Saltibus too is still dangerous territory and poses high risks to residents and road users at some points.

The vulnerability of Choiseul
NEW WEATHER PHENOMENON APPEARED IN CHOISEUL RECENTLY
Choiseul Village, which was generally immune to floods, has now become “risky territory”. In the past, we knew the village to be vulnerable to coastal threats, but the construction of Fisheries Complex brought about much desired coastal protection in that regard; but at the risk of creating a bigger coastal environmental problem of sand depletion caused by the sand mining over time. The environmental impact may not be immediate; but it can be devastating in the long term resulting in the disappearance of beaches. The time may be opportune to compare samples of the sand at the fisheries to samples of the sand from the surrounding beaches to make a determination of the beach or beaches being affected.

SABWISHA BEACH PARK (CHOISEUL)
Just imagine the disappearance of Sab Wisha (l'Anse Louis), the Village beach or l'Anse John from the face of the earth. Also, just imagine, side by side with that, the inconvenience of perennial flooding of the village. If the recent flooding and siltation are not freak phenomena - and when we add hurricanes to the equation - then, the possibility of the threat of exposure to a trilogy of disaster dilemmas is real to the village.

As I said earlier, Choiseul village was considered immune to flooding; but, all of a sudden, a section of it has been put on "vulnerability watch" because of a drainage intervention projection; and some villagers are expressing concern.

TOP OF THE GIANT "MOCO-GEE" GORGE ON TOP OF VILLAGE
It is believed that the cause of that potential vulnerability is related to an apparently poorly designed drainage project running parallel to the Fisheries Complex. The villagers were taken aback by the unprecedented flooding and accompanying siltation which descended on the lower end of JEM Salmon Street after the recent showers of rain. Apparently, the egress of water from (what the villagers call) the “Moco Gee” and “Pa Fond” “passageways” was connected to it. Previously, that water headed straight into the sea; but the design of the Fisheries Complex did not make provision for the continuation of that flow. It is apparent that the new drainage project extending from TG Westal Row to the Moco Gee drain was implemented to apparently address that flaw.

WATER FROM THE MOCO-GEE FLOWS INTO THIS DRAIN
While the project is good in principle, it is also true that the construction and/or design may also have issues.  Firstly, there is the issue of the gradient of the drain inhibiting a smooth flow, resulting in a build up of water spilling unto the road causing flooding. A mere 2% gradient increase might have done the trick. Alternatively, consideration could have been given a “storm drain”, which would facilitated a steadier and greater volume flow rate, hence eliminating the flooding problem.

THE NEW "BOX DRAIN" IN THE VILLAGE
I hope the resulting flooding and siltation do not add to the woes of the besieged Fisheries Complex and the embattled fishermen.

Saltibus/Gertrine, Roblot, Belle Vue and the Victoria/Myers Bridge corridor are the most prone areas to landslides. Geotechnical research into the extent of the vulnerability of those areas with a view to medium/long term engineering interventions is recommended. The problem at Victoria/Myers Bridge, which was especially challenging, have been ameliorated thanks to RDP 01/02; however, threats and risks remain for Victoria/Belle Vue.


SALTIBUS: STILL DANGEROUS TERRITORY
Not all of Choiseul is vulnerable to the trilogy of disaster dilemmas. The West Coast communities are cases in point. Whilst their elevation above sea level makes them highly vulnerable to hurricane force winds, they are relatively free from floods and (of course) coastal threats.  Their problem remains inter-ridge access posed by overflowing rivers over the low bridges during a disaster. In fact, rivers overflowing their banks have been regular phenomena in Choiseul because of the district's "ridged" topography. That problem has been solved between the Village and Laborie, thanks in part to the RDP.

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