tomas damage assessment no pictures

GOVERNMENT OF ST. LUCIA Ministry of Communications, Works, Transport and

Public Utilities

HURRICANE TOMAS DAMMAGE ASSESSMENTHURRICANE TOMAS DAMMAGE ASSESSMENT

REPORT ONE (1)

FDL Consult Inc.P.O. Box 1803

GoodlandsCastries, St. Lucia

Tel: (758) 453-5727 / 5271Fax: (758) 453-7048

E il fdl@fdl ltiEmail: [email protected]

DECEMBER 2010

FDL Consult Inc Hurricane Tomas Damage Assessment Report

December 2010 Page | i

TABLE OF CONTENTS

Executive summary ................................................................................................................................................. 1

1 Introduction ....................................................................................................................................................... 4

2 Immediate Assessment ................................................................................................................................. 6

2.1 Roads ............................................................................................................................................................ 6

2.2 Bridgesand Other Crossings ........................................................................................................... 12

2.3 Water Supply Infrastructure .......................................................................................................... 13

2.4 Watersheds and Rivers ..................................................................................................................... 14

2.5 Landslides ............................................................................................................................................... 15

2.5.1 Natural Slope and Fluvial Processes .................................................................................. 15

2.5.2 Guesneau ........................................................................................................................................ 18

2.5.3 Columbette (Sabby) ................................................................................................................... 20

2.5.4 Barre de L’Isle .............................................................................................................................. 22

2.5.5 Bagatelle ......................................................................................................................................... 22

3 Disaster Response Rationale and Methodology .............................................................................. 25

3.1 Monitoring and Supervision ........................................................................................................... 25

3.2 Rationale and Approach ................................................................................................................... 26

3.3 Emergency Works ............................................................................................................................... 27

3.3.1 Upslope Landsides (Debris Flows) ..................................................................................... 30

3.3.2 Down Slope Failures .................................................................................................................. 30

3.3.3 Bridges and Culverts ................................................................................................................. 32

3.3.4 Rivers and Streams .................................................................................................................... 34

3.4 Assistance to WASCO ......................................................................................................................... 34

3.5 Roseau Dam and Transmission Mains........................................................................................ 35


December 2010 Page | ii

3.6 Millet and Ravine Poisson Intakes ............................................................................................... 35

3.6.1 Canaries Intake ............................................................................................................................ 36

4 The Way Forward ......................................................................................................................................... 37

5 Cost Estimates ................................................................................................................................................ 39

6 RecommendationS ....................................................................................................................................... 40


December 2010 Page | 1

EXECUTIVE SUMMARY

The country’s infrastructure, among other things suffered significant and extensive damage

following the passage of Hurricane Tomas, on Saturday 30 October, 2010. The maximum

sustained winds measured at Hewanorra and GFL Charles Airport were 89(143) and 35

(156.2 mph (Km/h). The total rainfall recorded during the 24 hr period ranged from

533mm (24 inch) at Hewanorra Airport to 668 mm (26.3) inches at Desrache.

The hurricane intensity and duration has been identified by others as about a 1 in 200 year

event, based on hind‐casting (subject to confirmation). However, the occurrence of

hurricanes in recent years, possibly associated with climate change, could require this

statistic to be significantly revised to become a higher frequency event in years to come.

In particular, major sections of the primary and secondary road network were rendered

impassable due to a combination of factors including land slippages, severed bridges and

roads, mudslides, fallen trees and/or utility poles. As a result some communities were

completely isolated or partially accessible overland for several days. The historic landslide

prone areas in Soufriere, Canaries, the Bar de L’isle and Castries North East and East are

worthy of note.

An immediate damage/condition assessment was made by a team of engineers from FDL

Consult Inc. which involved primarily a walk‐through along with an aerial observation of

the obstructed and collapsed roads and bridges.

Generally the bridges/crossings performed well during the passage of Hurricane Tomas.

Many of those which failed were constructed of corrugated pipes. However, most of these

pipes were constructed more than 35 years ago (normal design life for these pipes is

25yrs) and had exhibited earlier signs of structural damage.



Numerous landslides of varying types and magnitude accompanied the Hurricane, the

impact variable, but most intense in the historically prone areas. Some emergency

clearance has taken place to ensure access to all communities and to permit economic and

other activities to resume. The extent and results of the geotechnical assessment will be

elaborated on elsewhere in the report.

The MCWT&PU with the support of FDL Consult Inc oversaw the immediate recovery

works for the country’s road and bridges infrastructure including WASCO. The primary

objectives of the emergency recovery were:

Restoration of accessibility through the primary network

Reinstatement of the water supply network

Enhancing public safety

Providing access to locked communities

Preservation of critical infrastructure most at risk from further damage

The emergency nature of the works, limited access and the attendant adverse impacts on

logistics meant that predominantly all the clearing works were implemented on a day work

basis. A small percentage that involved construction of structures, emergency repairs and

highly labour intensive works were implemented on a works contract basis through a

direct selection based on availability, capacity and qualification based on pre‐existing

criteria. Examples included bridge reinstatement and repairs and construction of Vanard

Intake. The day work rates were pre‐established rates included in the Disaster Response

Plan of the MCWT&PU. All claims for payments had to be submitted to the Command

Centre for review, auditing and processing. A review process was established for the

accurate and timely processing of payments. Taking into account the factors described

above there is a clear need to identify a sensible and reasonable approach to managing the

vulnerability of the existing roads, drainage and structures, which are still exposed to the

slope‐related hazards and consequential fluvial hazards, post‐Tomas. This will require both

remedial and preventative works.



It must be accepted that the existing roads and river crossings will suffer in the future from

some damage and blockage by landslide debris and erosion during prolonged wet periods.

It seems unacceptable that such processes should be permitted to continue in key areas

where there is dense population or vital services infrastructure. Some stretches of road will

inevitably suffer severe damage since preventative work may prove to be too costly, i.e. it

may be more cost‐effective to permit the damage to occur and then rebuild the stretch of

road using a more appropriate design. Monitoring of these areas must be considered;

either as permanent telemetry installations, or frequent site inspections during periods of

prolonged wet weather. Construction of upstream debris control structures must also

feature in this strategy (such as permeable rip‐rap bunds, columns and cable traps).

The following are recommendations which should not be considered exhaustive:

Review of the recommendations and level of implementation of existing watershed

and environmental management plans. A new plan may be required in light of new

observations and climatic data;

Geotechnical assessment of all major landslides;

Update of landslide hazard map;

Reconstruction of Bois D’orange, Choc, Crestlands, Grand Ravine and Canaries

bridges;

Structural assessment of all bridges;

Retrofitting of bridges where required

Immediate de‐silting of rivers in Bexon, Marc, Deglos and Soufriere River;

Immediate lope stabilisation works on all failures affecting the primary and

secondary road network and major tourist attractions.



1 INTRODUCTION

The country’s infrastructure, among other things suffered significant and extensive damage

following the passage of Hurricane Tomas, on Saturday 30 October, 2010. The maximum

sustained winds measured at Hewanorra and GFL Charles Airport were 89(143) and

35(156.2 mph (Km/h). The total rainfall recorded during the 24 hr period ranged from

533mm (24 inch) at Hewanorra Airport to 668 mm (26.3) inches at Desrache.

The hurricane intensity and duration has been identified by others as about a 1 in 200 year

event, based on hind‐casting (subject to confirmation). However, the occurrence of

hurricanes in recent years, possibly associated with climate change, could require this

statistic to be significantly revised to become a higher frequency event in years to come.

In particular, major sections of the primary and secondary road network were rendered

impassable due to a combination of factors including land slippages, severed bridges and

roads, mudslides, fallen trees and/or utility poles. As a result some communities were

completely isolated or partially accessible overland for several days. The historic landslide

prone areas in Soufriere, Canaries, the Bar de L’isle and Castries North East and East are

worthy of note.



the obstructed and collapsed roads and bridges. The major failures are reported below in

terms of affected roads1.

The water treatment and supply systems were disrupted significantly, as major catchment

areas were affected by high levels of siltation and debris, destruction to pumps and main

pipes severed. The John Compton Dam, which supplies water to about 100, 000 users

during the peak tourist season was non‐operational for 15 days/weeks The result was a

national shortage of potable water and reliance on importation from neighbouring islands.

1 Road names used are consistent with the directories of Primary, Secondary and Tertiary Roads (Version 4: 1 Sept 2003).



The water situation was exacerbated by reduced access to the water catchments and

distribution points to conduct thorough assessments and undertake appropriate and

timely action. Emergency, temporary and in a few cases more permanent works have been

undertaken to help restore the water supply. At the time of reporting most communities

had had their potable supply restored, though not necessarily to the pre Hurricane Tomas

level.

Many bridges were also completely or partially destroyed, in particular the Choc and Bois

d’ Orange bridges linking two major commercial zones, Castries and Gros Islet, and the

Fond St. Jacques bridge. The approaches to or support mechanisms for other bridges and

crossings, such as Troumassee were also severed, some immediately following the

hurricane, others overtime, due in part to prolonged and intense rainfall episodes coupled

with an already volatile situation.

Numerous landslides of varying types and magnitude accompanied the Hurricane, the

impact variable, but most intense in the historically prone areas. Some emergency

clearance has taken place to ensure access to all communities and to permit economic and

other activities to resume. The extent and results of the geotechnical assessment will be

elaborated on elsewhere in the report.



2 IMMEDIATE ASSESSMENT



the obstructed and collapsed roads and bridges. The major failures are reported below in

terms of affected roads2.

2.1 ROADS

A number of roads were rendered impassable by landslides on both the upslope and down

slope. Additionally some bridges and crossing were washed away.

Choc – Cap Estate

This is the primary link to St. Lucia’s major commercial and touristic centre. There are

alternative routes but are limited geometrically to use by goods vehicles. Moreover, the

bypass routes are not designed to carry the vehicle volumes presently carried by the

primary link.

The two major crossings at Bois D’orange and Choc constructed of large diameter

corrugated pipes were damaged. The fill over the pipes was eroded by the corrosive power

of the flood waters. In both instances the water undermined the fill after breaching spaces

between headwall and pipe or scoured the fill through the roof of the pipe which had

previously collapsed from corrosion.

Cul de Sac – Ravine Poisson Marc Deglos

All the roads, primary, secondary and tertiary were inundated with silt and debris as the

rivers were rechanneled on these roads for reasons discussed in other sections of this

report. The silt was up to 2m high in many areas rendering some areas inaccessible. There

2 Road names used are consistent with the directories of Primary, Secondary and Tertiary Roads (Version 4: 1 Sept 2003).



was considerable loss of private and some public property. The Bexon School was

surrounded with silt while the pedestrian access was completely washed away.

Barre de L’isle – Hill Top Dennery

Historically the Barre De L’isle is known for its instability. There were a number of slope

failures over the entire length, approximately 2km, of the north side of the ascent from

Ravine Poisson. On the southern descent which is along a ridge a high number of down

slope failures occurred. Therefore, most of the clearing was required on the North side

while retaining structures are required on the south side.

The landscape of the lower portions of the Barre de L’isle on the Ravine Poisson side has

been transformed. Steep hillsides above the road which were once covered with lush

vegetation have been stripped bare.

The remedial long term solution to prevent future landslips could be a combination of

slope stabilisation options.

The Grand Ravine Bridge which is a low crossing also overtopped with at least 2.00 m of

debris during high intensity rainfall.

Praslin Bridge – Fond Bridge

This section of road was virtually intact except for the erosion of the fill over corrugated

pipe at the crossing near the Lombard intersection. This pipe had significantly less

discharge capacity than an upstream bridge along the old ECR alignment. The failure could

have been attributed to the clogging of the culvert and the subsequent force and erosive

power of the water. A culvert with a larger discharge capacity must be considered for this

area.



ECR (Troumassée Bridge – Wanier Bridge)

The road was eroded pre Hurricane Tomas in the area of two culverts along the strait to the

Troumassée Bridge. One culvert was already damaged and earmarked for replacement.

These crossing were also constructed of multiple corrugated pipes which should be

replaced with clear span culverts.

Subsequent rainfall on Thursday 11th November 2010 exacerbated the erosion of the

southern abutment of the Troumassée Bridge. Scour from below caused the collapse of the

backfill to the abutment.

Quart Chemin – Soufriere

This section of the West Coast Road is known for its instability. The upper northern section

(Bouton to Colombette) succumbed to a series of landslides over a 0.5 km span. LUCELEC

lost the only section of the 66 KV lines in that area. The details of the slide are discussed in

another section.

Amazingly the road carriage remained intact for most of the road.

A number of slides also took place between La huat and Soufriere town section.

Choiseul Village – Myers Bridge

Most of the landslides occurred at the known areas of instability, namely Ravine Cacoa, and

Victoria to Myers Bridge. A number of 11KV utility poles were also grounded by slides.

Myers Bridge – Soufriere

Ladera to Soufriere section can be regarded as the section of the South Coast Road with the

highest level of slope instability. This proved true during hurricane Tomas as it was the

site of some significant slides of over 10000 cubic meters with boulders up to 10 tonnes.

Large boulders are characteristic feature of the slopes and geology in this area.



Anse La Raye – Canaries

This section had one major slide coupled with the collapse of a gabion wall. The Anse Gallet

crossing along that route was also completely blocked with the collapse of a large diameter

corrugated pipe. The river channel was completely silted as a result of the blockage forcing

the river to be diverted in two branches.

Soufriere Crestlands – Fond St. Jacques

The Crestlands area was severely hit as it is traversed by several streams that converge

into the Soufriere River. A number of the streams changed course transplanting large

boulders onto the road and through houses. A small bridge was washed off its foundation.

There was on major slide along the route which brought thousands of tonnes of debris

comprising silt, rocks and trees at crossings.

Bagatelle – Castries

The upper Bagatelle section had two major landslides on the upslope which forms the

down slope to the Morne – Guesneau Road. The largest slide was triggered by uncontrolled

roof water charging the slope. Slope stability options are necessary to preserve both the

integrity and safe use of the two aforementioned roads.

Guesneau Ti Rocher – Four Roads

A huge down slope occurred at the junction to Forestierre. It is reported that several

houses collapsed with the slide along with utility poles and lines. The details of this slide

are discussed in sections to follow.



The following tables present a summary of the observed immediate and critical damages to

the various classes of roads:

TABLE 1: SUMMARY OF CRITICAL DAMAGE PRIMARY ROADS

Road Description of Damage Outcome

Choc – Cap Estate Collapse of Choc and Bois D’Orange crossings

Route impassable at crossings ‐

Cul de Sac – Ravine Poisson

Landslips and heavy siltation Route impassable

Barre de Lisle –Hill top Dennery

Major landslides, fallen telecommunication lines. Bridge at Grand Ravine overtopped with 3m of debris

Route impassable

ECR (Praslin Bridge – Fond Bridge

Collapsed crossing Route impassable

ECR(Troumassée Bridge –Wanier Bridge)

Partial collapse of two culverts Single lane traffic

Quarte Chemin Soufriere

Major landslides ‐ fatalities Route impassable

Choiseul Village Bridge –Myers Bridge

Major landslides between Ravine Cacoa and Myers bridge

Route impassable from Victoria toMyers Bridge

(Anse La Raye Canaries)

Major Landslide(Anse La Verdue), Collapsed culvert at Anse Gallet

Road impassable

Myers Bridge Soufriere

Major landslides Road impassable



TABLE 2: SUMMARY OF CRITICAL DAMAGE –SECONDARY AND OTHER ROADS

Road Description of Damage Outcome

Soufriere Crestlands Fond

St. Jacques

Major landslides ,

Collapsed Bridge

Road impassable

Saltibus Main Road Downslope landsides Single lane traffic

Deglos Trois Piton Major Landslide Single lane traffic

Talvern Cacoa Guesneau Major Landslide Road impassable

Guesneau Ti Rocher Four

Roads

Downslope landsides Single lane traffic

Debrieul Myers Bridge Downslope landsides Single lane traffic

Bagatelle Castries Major Landslide Road impassable

Roseau Vanard Millet Major landslides Road impassable

Soufriere Hospital Road Completely eroded Road impassable



2.2 BRIDGES AND OTHER CROSSINGS

Generally the bridges/crossings performed well during the passage of Hurricane Tomas.

Table 3 below provides a summary of the major bridge failures. Many of those which failed

were constructed of corrugated pipes. However, most of these pipes were constructed

more than 35 years ago (normal design life for these pipes is 25yrs) and had exhibited

earlier signs of structural damage. Anse Gallet was, however, constructed in 1993 and its

failure was not due to aging but initial poor maintenance (The crossing was damaged by

previous severe weather systems). The raging water entered the space between the head

wall and pipe which may have existed prior to Tomas.

The Mon Repos failure could have been avoided with the provision of a head wall.

Additionally a number of bridges/crossings were loaded with debris.

TABLE 3: MAJOR FAILURES – BRIDGES/CROSSINGS

Location Type Description of Failure Crestlands Reinforced concrete slab Washed away Fond St. Jacques Bailey Washed off abutmentBois D’Orange Corrugated pipe culverts Erosion of fill and west

retaining wall Choc Corrugated pipe culverts Erosion of fill Morn Repos Corrugated pipe culverts Erosion of fill above pipeAnse Gallet Corrugated pipe culverts Collapsed pipe Troumassée Composite deck with central

pier founded on steel piles Erosion of southern approach

Marc Community Reinforced concrete Collapsed



2.3 WATER SUPPLY INFRASTRUCTURE

There are 28 water production facilities in Saint Lucia which produce

17 million gallons per day (MGD). The main damage sustained varied from destruction to

pumping facilities to silted intakes. A tabular summary of the damages of some of the

infrastructure investigated FDL Consult Inc. follows.

TABLE 4: DESCRIPTION OF DAMAGE: SOME WATER FACILITIES

Facility Summary of Damage John Compton Dam Inaccessibility due to landslides;

Raw water pumping faculty was inoperable.; Damaged incoming electrical supply; Damaged electrical panels; Damaged back up A slab on the spillway was dislodged; Minor structural damage to the service buildings

Grace Intake Excessive siltationBeausejour Intake Excessive siltationCanaries Intake Washed away;

Partial loss of transmission line

Anse La Raye Siltation of intake;Partial loss of transmission line

Millet Intake Landslide;Siltation of intake

Vanard Intake Siltation of intakeRavine Poisson Siltation of intake



TABLE 5: MAJOR FLOODING RIVERS

Name Description of Failure Outcome

Ravine Poisson Bexon Silted to top of bank,

Bank erosion,

Realigned in sections

Extensive flooding of

surrounding lands; major

property damage

Marc River Silted to top of bank,

Bank erosion,

Realigned in sections

Extensive flooding of

surrounding lands

Soufriere River Silted next to footbridge,

Realigned,

Bank erosion

Extensive flooding and siltation

of Soufriere town

Anse Gallet River Silted to top of bank,

Realigned at crossing

Flooding of surrounding

agricultural land

Fond River Excessive debris at bridge

Canaries River Siltation and realignment in the

upper reaches

2.4 WATERSHEDS AND RIVERS

A number of slides occurred in watershed areas. Consequently, the debris ended up in the

rivers and streams which deposited them along the length of the rivers and plains.

Consistent with the location and size of landslides and the amount of rainfall, there was

considerable flood damage in Bexon, Marc and the Soufriere basin. These catchments

recorded high levels of rainfall in excess of 600mm over the 24 hr. period.

Table 5 provides a summary of the major flooding episodes. Most of the flood damage

around the area of the Soufriere Hospital resulted from the construction of the foot bridge

next to the Soufriere Primary School. The concern with the potential implications of the

location of the footbridge was highlighted in the Watershed and Environmental Report

(WEMP) 1997. As indicated in that report, the foot bridge would restraint trees and other



debris which would cause it to over top, directing flows out of the channel into the town. In

fact that same effect was observed on most brides to various extents which also

contributed to flooding level upstream and depositing of silt.

2.5 LANDSLIDES

2.5.1 NATURAL SLOPE AND FLUVIAL PROCESSES

The natural topography of St Lucia has gradually evolved from original volcanic activity

several million years ago. More recent activity (during the past 100,000 years or so, and

historic tropical weathering processes resulted in something resembling the present day St

Lucia topography. The current landform is a reflection of more recent tropical weathering

processes and the presence of the following main rock types: closely jointed andesite or

basalt and volcanic ash/tuff bedrock, other volcanic deposits, and colluvium/alluvium. The

exposed rocks vary from competent, moderately weathered material to completely

weathered, very weak, friable rock/residual soil – generally heavily vegetated except near

man‐made developments, such as roads, agriculture, housing, etc.

The ancient landscape has been incised by large ravines with associated coastal flood

plains (where towns and villages have developed), and there are many other, established,

smaller ravines which are more often dry watercourses. The bedrock may include local

weak planes, which historically have resulted in significant slope failures where the

strata/joint dip is parallel or sub‐parallel to the slopes. The completely weathered rock

(residual soil) is typically 1.5 to 3 metres thick in some exposures; however, in some

locations it is likely to be considerably thicker. Excavations may reveal that there is

evidence that historic slopes failures are present in the flanks of some of the ravines

(where rock‐head has been eroded and replaced with slip debris).

The overall slope processes depict areas of limiting equilibrium with varying degrees of

tree, shrub and other vegetation cover. Exceptional, prolonged rainfall would have



triggered debris flows, mud‐runs and tree falls, temporarily blocking natural watercourses

and creating new ones. These unstable areas would gradually evolve with new vegetation

growth adapting until meta‐stable slope conditions were re‐established.

To summarise, the vegetation and natural topography have evolved through geological

time to produce natural 25 to 45 degree slopes (sometimes much steeper), which are

globally stable (locally marginally unstable) during prolonged periods of heavy rainfall. The

shallow‐depth stability of these slopes probably increases by up to 50% during the dry

season, due to increase in effective stress as a result of the groundwater level dropping, and

negative pore water pressures.

2.5.1.1 INFLUENCE OF MAN‐MADE STRUCTURES ON SLOPE AND FLUVIAL

PROCESSES

The construction of carefully designed roads, drainage, and other development in this type

of terrain, even adopting best practice, will generally be slightly to significantly

detrimental, compared to the long‐term stability and performance of the otherwise natural

slopes.

The construction of ill‐considered roads, drainage and other structures using poor practice

will invariably contribute directly to significant landslides, slumping of sidelong fill, mud‐

runs and serious damage to infrastructure/property. In many instances throughout the

tropical countries this approach to design and construction has proved to be catastrophic –

causing some large areas to be subsequently evacuated and abandoned.

The present situation in St Lucia, post‐Tomas, suggests that, whereas many of the

landslides were probably inevitable, in some areas poor geotechnical design and

construction practice have been adopted in the past. In hindsight, the prevailing ground

conditions and potential impact of changes in rainwater infiltration and run‐off conditions

do not seem to have been addressed in full. As a direct result, uncontrolled run‐off with a

significant debris bed‐load and mud‐runs/log jams has blocked established watercourses,



culverts, and road crossings. These blockages created new river courses resulting in

significant erosion, build‐up of slope debris, and loss of trees (which usually help

strengthen the slopes). If the existing landslide/erosion debris is simply cleared from the

roads and moved to the nearest tip area, then the slopes would continue to deteriorate in

some places during the prolonged wet weather, probably at an accelerated rate. This “do

minimum” strategy may inevitably present an increased health and safety risk at some

stage in the future and additional loss of assets.

The “do minimum” approach to slope remedial works, road maintenance and new‐build is

considered to be unacceptable because of the probable future consequences. Likewise, fully

engineered slope stabilisation works and run‐off control measures, are considered to be

also unacceptable because of prohibitive costs and massive impact on the natural

environment (which is one of the key assets and attractions of St Lucia).

2.5.1.2 COMMENTS ON SELECTED POST‐TOMAS LANDSLIDES

The nature of these selected slides which occurred as a result of the heavy rains of

hurricane Tomas varied in depth and type of movement. They also differ in soil

characteristics and local. However, the common denominator was the exceptional rainfall

event.

Some of the landslides evaluated in this report are characterised by clay soil evident in the

Ti Rocher area and sandy‐clay soil with gravel, cobbles and boulders evident in the two

slides within the Bagatelle area. Steeply inclined bedrock was exposed in small areas as a

result of the landslides. Sabby3 appears at first sight to be less clay content than the

Bagatelle sites. Barre de L’isle is much more variable and will require site specific landslide

soil descriptions.

3 For ease of reference in this report “Sabby” refers to the major landslide at Colombette which resulted in the death and/or disappearance of Sabby’s family.



2.5.2 GUESNEAU

The Gesneau landslide can only be described as “massive” in aerial extent, with an

approximate width and length of substantially affected slope of about 450m. The

approximate maximum depth of the slide is likely to be 20 to 25m below post‐failure

ground profile. However, this has to be confirmed by comparison to pre‐failure

photographs and landslide volume calculations. This slide occurred in a semi‐residential

area where loss of 6 properties occurred. In the past the affected road has been a key link

for through traffic.

The slip surface is exposed in certain areas revealing an exposed rock face which varies

from 0 to 5m below the original ground level. This exposed rock face is evidence of the fact

that the slide mass itself is generally now inactive, with a few areas still at risk of minor

slippage, although the toe of the slip above the ravine has yet to be examined. However, the

main back‐scarp is over‐steep and is likely to continue to back‐sap during wet weather.

One such area includes part of the intact road section which was virtually unaffected by the

slide. The cross section of the road which was made visible by the exposure created by the

slide reveals that the road was constructed on a layer of clay (residual soil or colluvium)

overlying weathered rock. This clay is probably now in un‐drained stress conditions,

however, as pore water pressures approach drained conditions the clay will lose its

cohesion and will experience a significant reduction in available shear strength.

Alternatively it could become saturated in the presence of water ponding causing softening

and loss of un‐drained strength.

The key remaining landslide‐associated risk is that further mass movement could take

place as a result of heavy rainfall or additional loading from back‐scarp failures. The

slipped mass may require several months of dry weather before earthworks and slope

drainage works could start safely. A key aspect is the local stability of the toe of the

landslide at the lip of the ravine. If this area can be stabilised then the main earthworks

could comprise near‐flat wide benches and shallow counterfort drains. Planting of suitable



vegetation would be a vital part of this scheme to control future surface erosion. Local

ground improvement measures near the back‐scarp would enable a reinforced earth

buttress to be constructed to support the back‐scarp and the re‐constructed road.

Even if a permanent road diversion were to be considered, up‐slope of the landslide, then

some work would still have to be undertaken within the landslide to prevent it from

expanding in the future and to control debris flowing into the ravine.



2.5.3 COLUMBETTE (SABBY)

This landslide is a large acute triangular feature, approximately 200m high and tapering

from 10m at the top to 75m at the highway. The volume of debris removed from the event

is likely to exceed 20,000m3 (subject to survey). The remaining potential source of debris

for a future similar hurricane could exceed this figure.

The debris flow is a classic cone shape because concentrated water run‐off has entered the

already saturated slope at one point near the top of the steep slope. This has caused

progressive slope failure and erosion gullying from top‐down.

The Sabby slide was apparently caused by a combination of factors:

Removal of primary vegetative cover due to subsistence farming and a bush fire

in 2009.

Heavy rains, 533mm in 24 hours, probably caused the ground to become fully

saturated; that is ground water table at the surface. This situation would have

reduced the effective shear stress in the residual soil mantel by about 50%,

resulting in the factor of safety against shallow failure dropping to 1.0 or less.

It is not clear at present whether the overall slope failure mechanism was triggered ‘top‐

down’ or ‘bottom‐up’, that is, toe failure first which would undermine the slope causing

regressive upslope failures, or failure of the upper slope which would have loaded the

lower slope causing failure (like an avalanche).

The long term solution for slope stability and debris flow management would be to remove

slipped material and bench the slope. In order to gain safe plant access, benches will have

to be formed in a zigzag up the slope. This will also help control future run‐off provided

suitable debris traps and stilling basins are incorporated into the design. These works

should be carried out after prolonged dry weather. Even so some of the work may require

temporary road closures to safeguard the public who would otherwise use the road.



Alternatively, substantial temporary works protection from material rolling down the slope

during construction work will have to be considered.

The landslide at Sabby’s place is probably still potentially active, and susceptible to even

moderate rainfall. Therefore there will be a need to place a culvert along the newly formed

drainage path to convey water across the road. Also north and south approach drainage

channels to the culvert need to be cleared. As a temporary measure cross road drainage

would be facilitated by a geotextile‐wrapped boulder packed French drain.

The remaining volume of potential slip debris in the slope should be assessed. Whereas the

proposed benched earthworks concept should be capable of preventing a similar

occurrence in the future, it is sometimes prudent to consider implementing a run‐off ‘safety

valve’ feature. This could include incorporating a secondary culvert alongside and at a

slightly higher invert level (with a bifurcation wall), or a slight dip in the road, along with

that area being designed as a spillway.



2.5.4 BARRE DE L’ISLE

Historically the Barre De L’isle has been recognised for its frequent slope failure events.

Hurricane Tomas caused numerous up‐slope failures along the entire road length of the

north side of the ascent from Ravine Poisson. On the southern road descent, which is along

a ridge, numerous down‐slope failures occurred. Therefore, most of the emergency road

clearing was required on the North side while new/strengthened retaining structures will

probably be required on the south side.

2.5.5 BAGATELLE

The two landslides in the Bagatelle area are much smaller than TI Rocher, each having an

approximate width of 50m. However, they have not only damaged the lower road, but now

also pose a serious threat to the upper road.

The landslides (referred to here as Slip 1 and Slip 2) occurred in the form of debris flows

composed of the weathered Volcanic Ash and Tuff (volcanic sandy‐clay mixed with rock

fragments), which crumble quite easily in the presence of water. Based on the observations

made on the site, both slides are considered to be still potentially active in certain areas,

due to the extremely steep incline on the upper and lower slopes, wet areas, and the

presence of trees of large girth. The presence of a competent rock surface can be seen in

certain sections of the upper slopes.

Slip 1

This is a localised slip feature on a steep “natural” slope which persists for at least 100

metres on either side of the slip.

The rubble wall supporting the upper road has at least 20nr 75mm drainage pipes

protruding through the exposed down‐slope face. There is evidence that the v‐drain on the

upslope side of the upper road had been blocked by a small landslip causing run‐off to

cross the road and soak into the verge. There is also evidence of significant flow over the

verge and onto the slope where the retaining wall stops. The slip was probably caused by



complete saturation of the soil mantle and even free water flowing over the ground surface.

Local slumping and erosion would have rapidly developed into an expanding debris flow.

Significant re‐profiling of the slope immediately above the lower road has taken place since

Tomas (as part of the road clearance operations). The ~70 degree new cut slope exposes a

matrix of Grade 5 rock with some soil matrix areas. This is considered to be relatively

stable provided a stub wall, incorporating a road drain, is constructed, and the bare slope is

suitably vegetated.

However, in the central portion of this slip feature the weathered rock profile is not evident

and the slope suggests that a landslide has occurred here in the past. There is a back scarp

a few metres below the upper retaining wall and evidence of an old arcuate backscarp to

the right of that, looking up‐slope. There remains a lobe of about 200m3 which may fail at

any time. The emergency earthworks contractor has recognised this and is considering

whether to wait for the failure event and then clear it, or to remove it now.

There is a perceived risk that further slippage may undermine support for the upper

retaining wall and cause displacement or even failure.

Slip 2

This is a localised slip feature on a steep “natural” slope which persists for at least 100

metres either side of the slip. Three houses at the top of the slip have been built in a very

tight cluster, each with its own septic tank and uncontrolled grey water and roof water run‐

off. The acute triangular shape of the slip indicates that this housing development probably

caused concentrated run‐off at this particular point. Upper road run‐off does not seem to

have been a contributory factor because the road is at an apex at this point.

The slip was caused by complete saturation of the soil mantle and even free water flowing

over the ground surface. Shallow, low permeability rock profile would have forced this

mechanism to occur quickly. Local slumping and erosion would have rapidly developed

into an expanding debris flow.



The shallow depth debris flow has exposed steeply inclined bedrock at a few localised

places. It seem obvious that the shallow bedrock must be fully utilised in any remedial

works solution, otherwise alternative could involve large, expensive structures with

considerable volumes of imported bulk fill.

The key issue here is buildability including plant access on very steep slopes. This will be

addressed during the design process. The diagram for Slip 2 below indicates one possible

option that may provide a viable solution.



3 DISASTER RESPONSE RATIONALE AND METHODOLOGY

3.1 MONITORING AND SUPERVISION

The MCWT&PU with the support of FDL Consult Inc oversaw the immediate recovery

works for the country’s road and bridges infrastructure including WASCO. The primary

objectives of the emergency recovery were:

Restoration of accessibility through the primary network

Reinstatement of the water supply network

Enhancing public safety

Providing access to locked communities

Preservation of critical infrastructure most at risk from further damage

All works were undertaken utilizing local equipment and labour resources. The supervision

of all works was managed by a management team lead by the Hon Minister of Works, Guy

Joseph; Permanent Secretary (PS), Allison Jean; Deputy Permanent Secretary (DPS), Ivor

Daniel; Chief Engineer (CE), Lester Arnold; Deputy Chief Engineer (DCE), Albert Jn.

Baptiste; Financial Analyst and Gilbert Fontenard, Civil Engineer and Roger Butcher Civil

Engineer of FDL Consult Inc. The disaster response and management was informed by the

Disaster Response Plan (DRP) of MCWT&PU with expected deviations based on the actual

circumstances. This plan also called for the establishment of a Command Centre which was

established immediately following the passage of the hurricane. The Command Centre was

headed by the Deputy Permanent Secretary with support from Deputy Chief Engineer,

Financial Analysis and Quantity surveyors and requisite administration staff. Weekly

review meetings chaired by the PS with the Minister in attendance were held to review

strategy, successes, failures, priorities, procurement and for decision making. The minutes

of the meetings up to the date of report are appended in Appendix A. The Ministry of

Finance was also represented at subsequent meetings.



3.2 RATIONALE AND APPROACH

The emergency nature of the works, limited access and the attendant adverse impacts on

logistics meant that predominantly all the clearing works were implemented on a day work

basis. A small percentage that involved construction of structures, emergency repairs and

highly labour intensive works were implemented on a works contract basis through a

direct selection based on availability, capacity and qualification based on pre‐existing

criteria. Examples included bridge reinstatement and repairs and construction of Vanard

Intake. The day work rates were pre‐established rates included in the Disaster Response

Plan of the MCWT&PU. A copy of the Plan is included in Appendix B. All claims for

payments had to be submitted to the Command Centre for review, auditing and processing.

A review process was established for the accurate and timely processing of payments.

A critical success factor to the efficiency of the recovery was the availability of fuel to

service heavy equipment. The availability was constraint by lack of access to fuel stations

due to blocked roads, unavailability of fuel at the few accessible stations, lack of access to

site of emergency works and the limited ability of equipment owners (all small businesses)

to finance the high fuel demand for their machines. A further complicating issue was that

the various pieces of equipment on one particular site were of varied ownership. This

would have posed a logistical nightmare for each machine to be fuelled by its own team in

areas of limited access, manoeuvrability and high risk. Considering the challenges

indicated, to facilitate the implementation of the works, a policy decision was taken to pool

the supply of fuel for equipment working in some specific areas. The procurement of the

fuel would be done through the MCWTPU and delivered to three (3) contractors with the

logistical capability to deliver and manage fuel. A system of accountability was established

for the delivery of the fuel.

On December 1st, 2010 it was deemed that the prime objective of the emergency works had

been achieved in some areas and all day works would cease with the exception of certain

areas where progress towards the objective was entrained. However all day works stopped



on 2010. It was agreed that the remaining immediate works would be defined, estimates

developed and appropriated Conditions of Contract adopted based on value and complexity

of work. The estimates would be based on prevailing rates existing at MCWT&PU

incorporating existing conditions.

The focus on the recovery was public infrastructure and WASCO. The MCWT&PU assumed

full responsibility with the support of WASCO staff for the reinstatement of the water

supply in the North and parts of the South. Some of the facilities under the direct

management of MCWT&PU included: Roseau Dam and associated transmission lines,

Vanard, Ravine Poisson, Talvern, Canaries and Millet intakes in the North. Technical and

logistics support were also accorded to the Vieux Fort water supply including the

Beausejour and Grace Treatment plants and the Grace Woodlands Intake and the Fond St.

Jacques intakes in the South. A more detailed discussion of the works follows in

subsequent sections.

It is however recognized that in some areas private properties are still at risk from debris

leaning on structures, landslides above and below structures. Responding to these

circumstances is outside the remit of MCWT&PU although some random interventions

have been undertaken. It is the view of the management team that a special fund be

established by Government with a set of criteria, based on socio‐ economic factors, for

intervention either by MCWT&PU or the Ministry of Housing.

3.3 EMERGENCY WORKS

These works commenced on the evening of October 31st, with the immediate reinstatement

of Bois D’Orange and Choc crossings. The Barre de L’isle was opened to limited traffic by

Sunday November 7th, 2010. On that same date there was access, at least single lane,

through the entire primary road network.



The approach to reinstatement of the infrastructure was governed by the following:

Immediately restore critical components of the infrastructure to ensure access

to basic services

Protect from further damage to components of the infrastructure that are at

great risk to the effective functioning of the country and compromising safety

Replace damaged infrastructure for improved performance

Table 6 provides a summary of some of the reinstatement works and attendant activities.



TABLE 6 MAJOR IMMEDIATE REINSTATEMENT WORKS

Location Description of Works Status

Choc Bridge Backfilling of culvert, river training, concrete slab, boulder pack for scour protection

Complete

Bois D’Orange Backfilling of culvert, river training, concrete slab, boulder pack for scour protection

Complete

Anse Gallet Limited river training Complete Barre de L’isle Slide clearing, tree cutting, drain cleaning, rock

amour protection

Complete

Quarte - Chemin Soufriere

Slide clearing, tree cutting, drain cleaning, river de-silting, temporary culvert crossing, drainage construction, road reinstatement

On-going

Mon Repos Rock Amour, temporary bypass, guard rail

Paving outstanding

Troumassée River Rock Amour, backfill and river training Scour protection and underpinning required

Choiseul to Soufriere Slide clearing, rock breaking, tree cutting On-going

Crestlands – Fond St. Jacques

Slide clearing, tree cutting, drain cleaning, temporary culvert crossing

On-going

Grand Ravine Bridge Tree cutting, debris removal and de-silting Complete

Guesneau - Ti Rocher - Four Roads

Retaining wall construction On-going

Bexon/Marc Rivers De-silting, log removal and pumping On-going

A significant amount of the works was associated with debris removal. The clearance work

had to be implemented while limiting further damage to the environment. A critical issue

was the location and availability of dumb sites. Albeit the concerns the choice was

governed by proximity and accessibility. The use of some of these dump sites has to be

viewed as short term and require further assessment to determine suitability and potential

to cause further environmental damage. It is also recognized that some of the materials



deposited at the dump sites may contain harmful contaminants. The next sections discuss

the approaches to the various components of the emergency works.

Rapid assessment of each situation was required and undertaken to determine the

condition of the failed slope, extent of damage to the infrastructure, safety of the existing

sites, potential risk to further damage, public safety and whether intervention would

exacerbate any of the preceding factors. This assessment in every case included

3.3.1 UPSLOPE LANDSIDES (DEBRIS FLOWS)

All of these slides deposited the loose material on the infrastructure below and blocked

drains which in some cases triggered downslope slides by redirecting ravaging waters

away from drains into slopes. The assessment for these slides also involved determining

whether clearing would have triggered further slop failures or the landslide mass was

required as part of the solution. Most slides were cleared but Bagatelle, Ti Rocher, Mingy

and Fond St. Jacques were determined to require further analysis.

3.3.2 DOWN SLOPE FAILURES

Most of these failures were cordoned off for safety reasons because in many cases they

reduced the carriageway to a single lane. This scenario is prevalent in the Barre de L’isle

and sections of West Coast Road. There is a section of the Barre de L’isle which was under

threat of further collapse from the initial failure; a rock amour slope stabilisation system

was constructed to facilitate safe passage of vehicles.



In the case of Ti Rocher the intervention required the immediate construction of retaining

walls as the community served by this road has a single access. The alternate access was

obliterated by a huge landslide while the landslides on this road had reduced the

carriageway to single lane with the possibility of further collapse. Further slope

stabilisation works may be required at the toe of the constructed walls.



3.3.3 BRIDGES AND CULVERTS

The emergency intervention was informed by:

Type of Construction

Failure mechanism and type

Availability of alternative route

Cost of short term reinstatement

The Bois D’orange and Choc crossings were constructed of multiple large diameter

corrugated pipes. The failure of the crossings involved primarily erosion of the backfill,

collapse of the headwall and partial collapse of the pipes. The pipes of the former were in a

more advanced stage of corrosion than the latter. There were no collapsed pipes at the

Choc crossing. The construction of bypasses was an option but would be timely and very

costly. The most cost effective approach was adopted which involved backfilling of the

pipes and overlaying with a 200 mm reinforced concrete slab.

The partial collapses at Bois D’Orange meant reduced flow and discharge capacity at the

crossing. A strict monitoring and debris removal programme must be in place at this

crossing to minimise flooding and potential damage to the repairs. A new structure must

be constructed as soon as practically possible.

The repair at Choc has more longevity because of the better condition of the pipe. However

a new structure of a different type of construction should be built in the short to medium

term. It is also likely that the protective corrosion resisting layer has been damaged which

will accelerate corrosion of the pipes resulting in reduced carrying capacity and possible

damage of pipe lining by the erosive force of the flowing water.

A bypass was constructed to the Mon Repos collapsed crossing after a load test was carried

out with single axle 15 ton truck. This option was significantly cheaper than temporarily



reinstating crossing by backfilling the existing crossing. More importantly the bypass

allows for the seamless reconstruction of a replacement crossing.

A bypass was also constructed to the collapsed Crestlands Bridge. This was the only

alternative because of location and damage. This bridge was completely washed away. This

bypass is short term as the bridge must be reconstructed urgently.

The Anse Gallet River crossing was not addressed although the corrugated pipe collapsed.

However the debris inside the pipe provides support to the embankment and road above.

No rechanneling or de‐silting works was carried out on the river because of the blockage of

the pipe. The river was allowed to follow the new alignment as a result of the storm. This

crossing will flood with the lightest of showers as the river is silted up to the banks

resulting in temporary delays to users. A new crossing is required as a matter of urgency.

The Fond St. Jacques Bailey bridge washed off its abutment was dismantled and

repositioned on the abutment. Additional work is required on fixing the structure to the

abutment.

The work done on other bridges focused on removal of the debris load against the bridges,

namely Fond St. Jacques, Grand Ravine and Tomazo. Additionally some of the smaller

culverts on the ECR were backfilled though with impeded flow. These culverts require

immediate replacement before the next rainy season.

A detailed inspection of the major bridges is recommended for possible stresses and early

signs of failure. A number of the bridges may require retrofitting and strengthening.



3.3.4 RIVERS AND STREAMS

Most rivers and streams overtopped their banks causing flooding of the surrounding

communities. This was exacerbated by the heavy debris loads deposited by landslides from

the surrounding hills. The communities of Fond St. Jacques, Soufriere, Bexon, Marc and

Deglos were hit the hardest. The emergency response involved removal of large volumes

of silt loaded with tree trunks and boulders. The initial response involved clearing the

debris and silt from the adjacent infrastructure.

The high level of saturation of the silt in the river channels and along the banks presented a

major challenge to accessing the channels by excavators. It was impossible for excavators

to maneuverer as they became fully submerged in the silt and Debris. Therefore immediate

de‐silting works was not possible following the aftermath of the Hurricane based on the

equipment resource available.

Following the heavy rains of November 18, 2010, significant flooding occurred at Bexon,

Marc, Deglos and Cul‐de Sac. A policy decision was taken albeit the constraints; immediate

intervention was necessary to mitigate future flooding. It was accepted that the process

would be slow, inefficient and costly but further loss of property was not an alternative.

In other cases limited or no de‐silting or rechanneling works have been carried out. The

residents in the lower reaches of Fond St. Jacques were relocated and would not be

impacted by swelling river flows in the short term.

3.4 ASSISTANCE TO WASCO

As discussed MCWT&PU assumed full responsibility for reinstatement of the water supply

network. FDL Consult on behalf of the MCWT&PU undertook the first visit on foot to the

Roseau Dam.



3.5 ROSEAU DAM AND TRANSMISSION MAINS

The emergency response required clearance of major landslides along the access road and

reinstatement of a corrugated pipe culvert. The Ministry also coordinated the restoration of

the electricity supply and cleaning of the pump house, generator and surroundings.

There were three breaks on the transmission which were repaired by WASCO. This

required the construction of thrust blocks which were undertaken by a contractor

appointed by the Ministry. All the associated works including access was undertaken by the

Ministry.

Some of the future considerations are:

Stabilisation of the slopes along the access road

Reconstruction of the existing culvert with a reinforced concrete box culvert

Assessing vulnerability of transmission line between the Dam and Vanard

A comprehensive survey of dam including bathometric survey, backup systems, and

structural integrity of major components.

3.6 MILLET AND RAVINE POISSON INTAKES

Ravine Poisson involved a cycle of clearing followed by immediate re‐silting because of the

volume of landslides upstream. There was also an issue of disposal of the silt to avoid it

being washed back into the intake and downstream into Bexon. The site was also

inaccessible to trucks while the land surrounding the intake was claimed to be private

property.

As a long term solution consideration should involve the construction of a silt trap

upstream. Also the landownership around the intake needs to be clarified as these lands

can be used to manage properly the silt since this intake will be silted continually from

landslides around the watershed.



The Millet intake was inaccessible via the existing access road which was completely

severed by a landslide. An alternative access road was required to get heavy equipment to

the intake. All servicing of that machinery included fuel had to be transported manually

through difficult terrain making the exercise very costly.

3.6.1 CANARIES INTAKE

The intervention involved reinstatement of the access road to the intake site, relaying and

transporting replacement pipes and the partial construction of a temporary intake

structure. Further work on the intake was suspended after the French and American

Government donated small water treatment facilities.



4 THE WAY FORWARD

Taking into account the factors described above there is a clear need to identify a sensible

and reasonable approach to managing the vulnerability of the existing roads, drainage and

structures, which are still exposed to the slope‐related hazards and consequential fluvial

hazards, post‐Tomas. This will require both remedial and preventative works.

It must be accepted that the existing roads and river crossings will suffer in the future from

some damage and blockage by landslide debris and erosion during prolonged wet periods.

It seems unacceptable that such processes should be permitted to continue in key areas

where there is dense population or vital services infrastructure. Some stretches of road will

inevitably suffer severe damage since preventative work may prove to be too costly, i.e. it

may be more cost‐effective to permit the damage to occur and then rebuild the stretch of

road using a more appropriate design. Monitoring of these areas must be considered;

either as permanent telemetry installations, or frequent site inspections during periods of

prolonged wet weather. Construction of upstream debris control structures must also

feature in this strategy (such as permeable rip‐rap bunds, columns and cable traps).

Hence, there is need to identify and categorise the perceived hazards, and then to relate

them to the risks to assets and to disruption to livelihoods. This comprehensive

information will be managed using a GIS computer program, in order to extract vital

information quickly and accurately.

The Landslide Database that FDL is compiling comprises three components: field data

sheets, office technical appraisal sheets, and a computer‐based GIS system (prototype

recently developed by consultants for the Ministry) which will combine the two sets of data

into a user‐friendly platform. This will be a ‘live’ database and will require frequent

updating to reflect events, including remedial works.



This information should also be used to assess planning applications for new construction

and possibly to establish new criteria for planning consent.

At present the most prudent strategy has been:‐

Obtain a photographic record of all slope damage that has had a significant impact

on infrastructure;

Obtain a post‐Tomas land‐satellite digital image of Saint Lucia (or at least Google

Earth prints) and identify the locations and geometry of the slides including the

extent of local catchment, and potential future debris sources;

Using experienced geotechnical and civil engineers identify, prioritise and agree

(including stakeholder agreement) which areas require stabilisation or

management measures (using the database which is currently being completed);

Agree a budget expenditure profile for the next 6 months (say) and carry out a

second iteration of prioritised areas (after the next wet season) having established

budget costs for each element of the proposed works;

Develop sketches and quantities for individual temporary works designs and

provide close supervision of the contractor;

Hold frequent liaison meetings to maintain agreement and support as the work

evolves;

Develop detailed designs and Tender Documents to attract competitive tenders for

the main permanent works schemes.



5 COST ESTIMATES

They include preliminary cost of immediate, short and medium term emergency works.

These estimates are preliminary are subject to change with detailed investigation. The

immediate works are primarily clearing of debris, critical river de‐silting, diversions and

temporary works. They were aimed primarily at restoring immediate access and basic

services. The short and medium term costs represent completing some of the immediate

works and preserving the components of the infrastructure under direct threat of further

damage with consequential paralyzing effect on the functioning of the country and

compromising safety. It is mainly stabilisation works. These represent rehabilitation and

reconstruction cost for the infrastructure to the pre Tomas condition with improvements

to mitigate future disaster risk based on engineering principles. They have not factored the

broad spectrum of disaster risk reduction; for example, while a new bridge may be

designed to reduce risk of damage for a similar type disaster, fully mitigating risk may

involve implementing comprehensive watershed management.

The estimates were arrived at using prevailing construction cost data from MCWT&PU and

recent contracts implemented locally. A physical contingency of 30% should be added

because of the estimating risks both in terms of scope and assumed optimum engineering

solution.

Finally, the indirect costs of the damage are not included and outside the scope of this

consultancy. A detailed cost of the damage is included in Appendix C.



6 RECOMMENDATIONS

The following are recommendations which should not be considered exhaustive:

Review of the recommendations and level of implementation of existing watershed

and environmental management plans. A new plan may be required in light of new

observations and climatic data;

Geotechnical assessment of all major landslides;

Update of landslide hazard map;

Reconstruction of Bois D’orange, Choc, Crestlands, Grand Ravine and Canaries

bridges;

Structural assessment of all bridges;

Retrofitting of bridges where required

Immediate de‐silting of rivers in Bexon, Marc, Deglos and Soufriere River;

Immediate lope stabilisation works on all failures affecting the primary and

secondary road network and major tourist attractions.