E894 February 2004 Environmental Assessment Report For the St. Lucia _ . ... -- LC Disaster Management Project 11 Study and Design of Coastal Protection for Dennery Village ii.. ._ Submitted to The Project Coordinator Castries, St. Lucia By r SMITH INTERNATIONAL In association with COASTAL ENVfRONMSNAL ENGINEEUNG 6~EC Public Disclosure Authorized Public Disclosure Authorized Public Disclosure Authorized Public Disclosure Authorized Public Disclosure Authorized Public Disclosure Authorized Public Disclosure Authorized Public Disclosure Authorized
Transcript
E894February 2004
EnvironmentalAssessment Report
For the
St. Lucia_ ..... -- LC Disaster Management Project 11
Study and Design of CoastalProtection for Dennery Village
ii.. . _
Submitted to
The Project Coordinator
Castries, St. Lucia
By
r SMITH
INTERNATIONAL In association withCOASTAL ENVfRONMSNAL ENGINEEUNG
6~EC
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Table of Contents
1. Purpose and Need for the Project ..................................................... 3
2. Legal and Regulatory Framework ..................................................... 4
3. Description of the Proposed Project and Altematives Considered .................................... 5
7. Environmental Management Plan and Construction Monitoring Programme .. 47
7.1 Background .47
7.2 Impacts and Mitigation Measures .47
7.3 Water Quality Monitoring .51
7.4 Summary .51
8. Public Consultation and Review ........................ 52
1. Purpose and Need for the ProjectDennery is a low-lying fishing village on the East Coast of Saint Lucia, which is confined bythe Dennery River in the south and the Trou A L'Eau River in the north. The village hasbeen prone to flooding, storm surge and damage by wave action and high seas, as evidencedduring the passage of such storms as Tropical Storm Debbie (I'S Debbie) in 1994 andHurricane Lenny (HL) in 1999. Most recently, Tropical Storm Lily (September 2002)resulted in significant beach erosion and flooding.
The Government of St. Lucia is committed to providing coastal protection to the village ofDennery and, to this end, commissioned a design investigation to ensure the protection ofthe village from damage or erosion as a result of sea action. This project has been carried outin two phases, as described following
Phase 1 Feasibiliy Stud,
Under this phase of the project, the following general services were required:
* Conducting a study of the coastline of the Dennery Village, including hydrologicalstudies of the Dennery and Trou a l'Eau rivers and maritime movements.
* Developing physical mitigation options with preliminary costs and economicanalysis.
* Carrying out an Environmental Impact Assessment for the proposed options.
Phase 2 Detailed Design
Under this phase of the project, the following general services were required:
* Developing detailed designs, including Bills of Quantities, drawings and technicalspecifications, for the preferred option of possible mitigation measures.
* Developing a project management framework for implementation of any physicalworks, including the role of government agencies, other stakeholders and externalconsultants, as necessary for implementation of the works.
This document summarizes the environmental components of the overall project. Theoverall description of the project, including all options considered, and design details, isprovided in the main report volume.
2. Legal and Regulatory FrameworkEnvironmental requirements associated with the project are defined under St Lucian lawand World Bank environmental policy.
Under St Lucian law, environmental requirements are contained within the Physical Planningand Development Act, No. 29, of 2001. This act empowers the head of the land planningdivision with the authority to develop and enforce regulations relating to land planning,zoning, and environmental management as well as other responsibilities related to land use.The act provides for the requirement of environmental assessments if the consequences of aparticular project are considered significant. Specifically, part 22 of the law provides therequirements for compliance with environmental assessment and monitoring activitiesassociated with a given project.
World bank policy concerning environmental assessment is contained in OperationalDirective OP4.01. The Dennery works project has been classified as Category B under thisdirective as having potential significant consequences. Under this classification, anenvironmental assessment is required.
The revetment structures designed under this project have been designed in accordance withINFRAM Publications Numbers 2 and 3, Geometrical Design of Coastal Structures, J.W. van derMeer (1998) and Application and Stabiliy Criteria for Rock and Anrtficial Units, J.W. van der Meer(1998). In addition, these structures as well as the drainage structures have also beendesigned in accordance with British Standards (BS) Codes.
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3. Description of the Proposed Project and AlternativesConsidered
The primary problems that have been identified for the Dennery shoreline, include:
* An eroding shoreline, with most of the houses along the coastal strip predicted to beseverely impacted or destroyed within the next ten (10) years.
* The potential for 2.5 acres of land along the beachfront zone to be eroded within thenext 25 years. This would result in the sea lapping at the main road (High Street)after that period of time.
* During a 25-year return period hurricane event, it is anticipated that all of the houseswithin the coastal strip (i.e. seaward of High Street) could be flooded, as the stormsurge is predicted to be approximately 2 metres. For the extreme hurricanes, theflooding will be worse.
In order to address these problems, some altematives mitigations strategies have beenproposed. These are presented in Table 3.1 following, and depicted in Figures 3.1 to 3.6.
Table 3.1 Summary of Initial Mitigation Options for the Dennery Coastline.
Mitigation Components Benefits DrawbacksStrategyOption 1 * "Do-nothing" * Extensive loss of land
alternative over the next 25* Requires the years.
preparation of * Requires evacuation ofevacuation plans residents in thefor the village event of passages of
hurricanes that aremore severe thanthe 1 in 10 yearevent.
* Will require theconstruction of arevetment for themain road afterapproximately 20-25years.
* Does not facilitateexpanded tourismactivities.
Option 2 * Sand management * Restores some of * Should include regular(requires that the main sand beach profilewhen the Dennery source to the monitoring as a partRiver is cleared of beach. of the project tosand that this sand * Will assist in the facilitatebe placed on the slow restoration of reassessment ofbeach north of the the beach. shoreline trends.river in thie zone * Results will not beof most erosion) immediate, but
Requires the likely over the verypreparation of an long term.evacuation plan * Will still require
evacuation ofresidents as inOption 1.
* During hurricanesand/or storms,erosion is stillexpected.
Mitigation Components Benefits DrawbacksStrategy
Option 3 * Sand management * Shore protection is * May still require(as in Option 2) implemented, evacuation of
* Construction of a thereby protecting "front-line"275m long the most threatened residents, althoughrevetment just row of buildings damage to propertyseaward of the line during a storm will be minimized.of most threatened event. * Still does not facilitatebuildings. * Some of the main any expansion of
sand source will be tourism attractions,retained on the such as the Saturdaybeach, thereby night fish fiestareducing theongoing erosion.
Option 4 * Sand management * Reduced loss of river * Moderate recovery
* Construction of a sand to the offshore of beach width.170m long regions * May still requirerevetment * More of the primary evacuation of
* Construction of sand source will be residents due totwo breakwaters: retained on shore flooding from storm
* A lOOm long * Erosive power of the surge.structure placed waves at thelOOm offshore southern end of theand opposite the bay will be reduced.river mouth. * "Front-line"
* An 80m long buildings will bestructure placed protected.approximately60m offshore andopposite theworst erodedarea.
Mitigation Components Benefits DrawbacksStrategy
Option 5 * Sand management * Rapid widening of * A larger* Construction of beach. environmental
two breakwaters * Reduced loss of river impact as dredgingas in Option 4 sand to offshore. is required.
* Relocation of * Retention of primary"front line" sand source.residents * Less erosion at
* Nourishment of southern end.beach out to * Greater "buffer"1966-1981 against storm surge.shoreline(requires 30,000 - * Creates vista40,000m3 of sand) ("window") to the
Option 6 * Sand management * As for Option 5 plus: * No window to the
* Construction of o Increased sea createdtwo breakwaters protection * Requires upgradingas in Option 4 for front of front line housing
Constructnof a line stock to take fullConstrucdlgtio residents advantage ofreduced length tourismrevetment as in .u .Option 4 opportunities
* Nourishment ofthe beach as inOption 5
* No immediaterelocation of"front line"residents
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Plans of all options are shown following.
M .1,/C- Arwcpstd eroiono ovet. ' 8'*a 15 -25 year period
Figure 3.1 Option 1
Sand remord from routh ofnwer redistributed in the area
Wedge of sad frorn mouth of 6rvrclearod on a bi-monthrly or quafrteuy basis - --(Approxrrmataly 4004600 m' per occasion
Figure 3.2 Option 2
K
BSnd roniovad from moutf ofr vaedistributed in be area
Sand removed from mouth ofter -,,
calead on a 2 -3 nonth ba. . et
Figure 33 Option 3
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f;~~~/ A'
- o2 , Do Sand Iemove from mouth of5 rwer tedistrbuted in the area
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XF j <¢ D Bre~~Sakvvater
Sand removed from mouth of rwerFi 1 3.4 O ocea4 d on a 2 -3 mont basis,
Figure 3.4 Option 4
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Reoction d rsidensntsm hgh risk zone
; ~~~~~~~Noudshmns of beodz y .- ' with 30000-40,000 m, of sand
.z / > " \ Sand removed ftom mouth ofrrver redistnbuted In the ars
/ t ~~~~~~~Breakwater
Sand removed from mouth of *4ercieared on a 2 -3 monT basis,
Figure 3.5 Option 5
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-y
i~~~~~~~~~~~~ /
Nourithment of beachwith 30.000 -40,000D m of send,
Sand removd from nouth ofA rprer redistnbuted in tMe area
SIrekwater
X ~~~~~~§A'~~~~~
Sand removed from mouth of rfier]( c4nred on a 2 -3 monthbs bas
Figure 3.6 Option 6
The suitability of the various options is described here in a final summary format, includingthe option that was eventually selected.
Option 1
This "no action" option offers no beach recovery and provides no protection for theresidents of High Street. Furthermore, this option provides no potential for tourismdevelopment, and has significant, potential long-term negative environmental impacts. Thisoption is therefore not recommended as the preferred option.
Option 2
Despite a relatively high benefit-cost ration of 0.91, this option only offers a solution thatwill be realized in the long-term. It does not offer ay protection in the near to medium term.
Further, it offers no expansion potential for tourism, nor any significant positiveenvironmental impacts, except for short-term employment and changes in shorelinemorphology. This option is therefore not recommended as the preferred option.
Option 3 (a, b and t)
In terms of the benefit-cost ratio, this option offers the best results. However, the beachrecovery horizon for option 3 is long-term, and there are potentially significant negativeenvironmental impacts from this option, particularly with regard to wave reflection impactson beach stability. Because of this, the sand management component is an integral part ofthis option, as the redistributed sand must be placed in front of the revetment. Based onthese considerations, this option is recommended as a least-cost preferred option.
Option 4
While no major negative environmental impacts characterize this option, neither does it havea convincing benefit-cost ratio, nor a near-term beach recovery horizon. 'There is alsolimited potential for tourism expansion with this option. This option is therefore notrecommended as the preferred option.
Option 5
Despite the 0.45 benefit-cost value, this option offers the most long-term positiveenvironmental impacts. This option also provides a near-term horizon for beach recovery,and good potential for tourism expansion. Option 5 is therefore the recommended option ifrelocation of front line residents is to be considered.
Option 6
This option is similar in makeup to Option 5, however, either no removal of front-lineresidents is accounted for or phased relocation only of the most derelict structures. Becauseof this, a reduced length revetment, as in Option 4, is included. The benefit to cost ratio is0.44, and this option is recommended only if relocation is not feasible.
Option 7
Following public consultations with the people of the village and meetings with theDepartment of Planning Staff, a final revised option was selected that provided the followingopportunities:
* Full protection of all of the front line residents, therefore not requiring thatrelocation of these people be a mandatory component of the project.
* Phasing out of derelict buildings, so that a "windows to the sea" effect could beobtained over time without active relocation taking place.
* Protection of these front line buildings, against storm surge, through theconstruction of an adequately elevated berm.
* Rehabilitation of the northern end of the bay, to its former state.
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* Mitigation, to some extent, of the impact generated by the construction of theFishing Harbour whereby that structure appears to have reduced the build up ofsand in the central areas of the bay.
* The reuse of sand excavated to accommodate the buried revetment, to nourish thebeach in front of the revetment.
A drawing showing this final option is given below.
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, ul _:LL.C, L £ a2 X ii } r
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D , ' ' 5ucxl l£ x,
Figue 3.7 Option 7t.X _
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4. Existing Environmental Conditions
4.1 Land Use PatternsDennery takes its name from the Count d'Ennery, Governor General of the FrenchWindward Islands from 1766 to 1770. Before that it was called Anse Canot, because of thecanoes carved from the large trees that were brought down the river to the coast to belaunched. Since then, Dennery has become prominent as a fishing village and a marketcentre.
Dennery is located just south of the Mabouya Valley, with La Croix Point and the DenneryRiver as its northern and southern limits. The Dennery settlement was initially constrainedby a narrow coastal shelf, with poorly drained low-lying areas to the south and west Thehigh ground, south of the Ravine Trou a L'Eau, with limited vehicular access, presented themain opportunity for expansion. The limited coastal shelf consequently became high densitymixed use development, with unsafe setbacks from the active coastal zone area. Denneryhas, consequently, had a long history of property damage during hurricanes and high seas.
I'he East Coast Road Project, which was completed in 1976, made significant changes to theDennery Village. It provided vehicular bypass to the central village area, and fostered theconditions for draining and backfilling the swampy areas in the south central areas ofsettlement.
The land-use pattern is conditioned by the pre-existing constraints as described above andthe opportunities presented by the East Coast Road Project, which created a bypass to thevillage and effected the means of draining and reclaiming the south central poorly drainedareas. I'he bypass of the central village area has resulted in a reduction in retail activity alongthe central strip of settlement along the coastal area. These central and southern areas havebecome the institutional expansion areas providing lands for recreation, schools, and otherinstitutional uses.
The development of the "Daito", a fish-landing base, in 1997 has been the most significantactivity in the Dennery Village since the construction of the East Coast Highway. Thisfacility, located on the north-central area of the bay, includes two breakwaters, tworevetments, a main building and several ancillary buildings.
4.2 The Ecological Setting
4.2.1 Terrestrial & Coastal Vegetation
The Dennery coastal area has dry scrub woodland covered by xerophytic vegetation, typicalof the St. Lucian coast. This forest type includes Acacia species, some occasional large trees(Coccolobis and Tabebuia species), while dense scrub and thickets predominate.
Along the Dennery River, and nearing the mouth of the River, is the Dennery Mangal, whichis dominated by RhiZophora mangle and Laguncularia racemosa. The mangal has sufferedtremendously from deforestation (for charcoal production) having been reduced to 0.5hectares (1997) from 6.0 hectares (1985). St. Lucia has already lost 40% of its wetlands andthe remaining 60% are under severe stress from a variety of human activities. These include
increased siltation, and pollution (agricultural, domestic and sewage). lThe mangal systems inSt. Lucia play a vital role in maintaining coastal stability, and serve as important breeding andnursery grounds for several fish and bird species.
The Dennery coastal area falls within a "protected landscape" under a system of ProtectedAreas Plan for St. Lucia. This plan was established in 1975, but not much has been done toimplement the recommendations (St. Lucia Biodiversity Report).
4.2.2 Soil
The Dennery Village Settlement is comprised of two basic soil types:
* The agglomerates tuffs, the yellow-white hard material derived from volcanic ashmaterial (that is evident in many cut slopes along the highway.); and
* The alluvium beach and terrace sands that comprise the eastern and southernsections.
Though a large percentage of the lands within the greater area are classified as Class VI andVII (OAS 1984), the Mabouya Valley has significant Class I & II. The Tropical Dry Forestsareas in the higher grounds of the valley are significant water catchment areas. Thecatchment of the Roseau River to the south is classified in the main as VII in terms of landcapability, with small tracks of Class I & II within the floodplain.
4.2.3 Benthos
Although several areas along St. Lucia's west and south coasts have extensive coral reefs andseagrass beds, Dennery, on the east coast has no significant benthic flora or fauna.However, in order to identify the type of community inhabiting the sediment, a non-quantitative benthic survey was carried out. Benthic organisms are sediment or bottomdwellers and because of their generally sessile nature, they act as integrators of the effects ofdisturbances and variations in the environment. Biological information from the benthos(together with water quality and fishery) assessments for a marine area can provide a goodindication of the "status" of the environment at a specific time.
Four (4) stations covering the general bay area were sampled for benthic organisms. At eachstation, a diver using a core sampler collected one sediment sample. Each sample waswashed through a 500mm2 sieve mesh and all the benthic organisms retained on the meshwere washed into plastic containers, stained (using Rose Bengal) and preserved in a 10%formalin solution.
In the laboratory, each sample was re-sieved using a 500mm2 screen mesh and all themacrofaunal organisms were picked out and examined under both binocular and compoundmicroscopes.
These organisms were identified as far as possible to species level to compile a macrofaunalspecies list for the bay (Table 4.1).
The number of individual organisms recorded was small (12), and belonging to eight (8)species. These values are much lower than compared to other bay areas in the Caribbean,although the survey was non-quantitative. Such low values are generally indicative ofstressed or disturbed environmental conditions in coastal areas.
Table 4.1 Macrofaunal species for Dennery Bay
Phylum ANNELIDA Phylum MOLLUSCA
Polychaeta Amphibod sp.a
Paramphinome sp.a Diplodonta sp.a
Scoloplos sp.a Bivalve sp.a
Exogone lourei
Spionid sp.
Syllisgracilis
4.2.4 WaterQualiy
During the period June 23rd to 25th 2002 a field survey was carried out in the Dennery coastalarea. A tremendous amount of garbage/solid waste was observed along the recreationalbeachfront and the main drains from the town were seen bringing a myriad of murkyeffluents (with a strong stench) to the coast. In general, the immediate water quality of theDennery shoreline appeared to be quite poor. This is somewhat in keeping with the findingsof the benthic assessment, which suggested that the nearshore environment in Dennery isstressed.
Additionally, the poor water quality of Dennery is in keeping with findings on the status ofcentralized sewage systems in St. Lucia in 1995: 540/o were in "poor condition" and 46%"good" (Urban population data UN ECLAC; Sewage Treatment Facilities data UNEP). Theresidences on High Street, immediately bordering on the beach do not have access tocentralized sewage, and reportedly dispose of their sewage in the nearshore areas.
Furthermore, the major drains from the town bring effluents to the coastal, fishing (landingsand inshore fishery) and recreational area. This is not only a water quality concern from anecological perspective but also has health implications for people using the beach.
41.2.5 Nearshore Water Circulation
The water circulation patterns inside Dennery Bay are based on current speeds which aretypically less than 0.1 m/s, with the exception of the area behind Dennery Island, wherecurrent velocities are up to 0.2 m/s. To the north of the river mouth along the shoreline,stronger currents occur during the rising tide than during falling tide.
4.3 FisheriesThe commercial fishery of St. Lucia is artisanal with a wide variety of species beingexploited. The major fishing ports/landing areas in St. Lucia are Vieux Fort, Castries,Soufriere, Gros Islet and Dennery, the project area. The fishery includes:
* Shallow shelf and reef fish * Deep-slope
* Large pelagics * Coastal pelagics
* Lobster * Sea urchins
* Seamoss * Flying fish
* Turtles
IThe fisheries information for Dennery as compiled by the Fisheries Division (MAFF)provides good landing and registration information, while Fishbase (1998) on the internet,provides fish species inventories including threatened species.
In 2000 Dennery had a total of 73 fishing vessels registered with the Fisheries Division: 59pirogues, 13 canoes and 1 long-liner. This represents approximately 7.3 % of the totalvessels and 11.6 % of fishermen for St. Lucia.
At Dennery, 235 fishers are registered (year 2000) compared to 330 (at Vieux Fort), 243 (atCastries), 180 (at Gros Islet) and 154 (at Soufriere). At Dennery, approximately 60 % of thetotal registered are full-time fishers with the others, part-time. Figures for 2001 (Dept. ofFisheries, MAFF) show a total of 324 tons of fish were landed (estimates) at Dennery.Coyphaena hippurus (dolphin), Acanthogybium solandri (Wahoo) and Thunnus sp. (iTuna) are themain catch accounting for approximately 93% of the total catch. This total value of fish for2001 was estimated at EC$ 22.4 million with Dennery accounting for EC$3,824,200.00(approx. 17 % of the total value for St. Lucia).
There are no detailed fisheries surveys in terms of species composition done for DenneryBay. Fond D'Or Beach, which is north of Dennery, was declared a marine reserve in 1986(under the Fisheries Act), and is a known nesting site for leatherback turtles.
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5. Existing Socio Economic ConditionsThis section constitutes the findings of a rapid social appraisal exercise of residents of thecoastal area of Dennery village in St. Lucia conducted on August 8 and August 9, 2002.
5.1 Community SettingDennery village is a relatively large, low-income, fishing community situated in the Districtof Dennery on the east coast of St. Lucia. The community is approximately twenty-eightkilometres (28 km) away from Castries, or about thirty minutes drive on the Castries toVieux Fort highway.
5. 1.1 Households
Within the study area (the coastal strip), there are about thirty (30) households. Houses aregenerally small (two to three rooms), and constructed of wood or concrete or a combinationof the two. Most appear to be well maintained, though there were a few very dilapidatedhouses observed, mostly those of elderly people unable to carry out repairs. A number ofabandoned households were also observed in the study area, and according to the CDO, thishas primarily been the result of persons deciding to move further inland to avoid thedamaging effects of wave action and flooding on their properties and household contents,and to ensure their personal safety.
The study area also includes a number of small business enterprises, including several liquorshops, hairdressing salons, small grocery stores and workshops, appearing to be for fumiturerepair.
5.1.2 Utilities and Sernices
Dennery village is fully serviced by electricity and water supply, though some residentsindicated that they experience almost daily water outages. TIhere is a garbage collectionservice, subsidized by the Government of St. Lucia (GOSL), which collects solid waste fromhouseholds in the community twice weekly.
The garbage collection service is taken advantage of by residents as evidenced by the factthat the community is generally free of indiscriminate dumping on roadsides, etc. However,it was observed that there were quite large amounts of debris and other solid waste in theriver channels leading to the sea, suggesting that residents on the hillside areas of the villageare not properly disposing of their waste. Residents also report that there is a lack ofadequate disposal facilities for fish offal and waste oil from fishing boats. As a result,fisherfolk are currently in the habit of disposing of these in the coastal area, contaminatingthe coastal waters for fish and for residents who use the beach for swimming and otherrecreational activities.
Most houses in the study area lack indoor toilet facilities and are served by pit latrines andoutdoor showers. Where these facilities are lacking, residents report that a number ofhouseholds are in the habit of disposing human waste from buckets used in their homes intothe nearshore area, creating a health hazard for other beach users.
5.1.3 Educational FacilitiesWithin Dennery village, there is one (1) pre-school, one (1) primary and one (1) secondaryschool. However, there are several other schools in the wider Dennery District whichstudents from the village have the option of attending. Some students, particularly those ofsecondary school age, attend school as far away as Castries and Vieux Fort.
5.1.4 Communipy Groups andActivities
Dennery village has a number of active youth, adult, sports, cultural and religious groups thatseek to improve the quality of life for residents. These include the Path Finders, theMothers and Fathers Group, Club Sixty, Club Forty, the credit union, the DenneryFishermen's Cooperative, the Fish Vendor's Association, Comfort 2000, the DisasterPreparedness Committee, La Marguerite and La Rose. The Disaster PreparednessCommittee, particularly relevant to this project, is involved in informing residents of theprecautions that should be taken to safe guard against hurricanes, floods and other disasters.
In recent times, with the support of their Parliamentary Representative, Dennery village hasinstituted a Fish Fiesta, which is held on Saturday nights as a means of attracting tourists andpersons from other parts of the island to the community to generate income. Initially, theproject was designed for the benefit of fisherfolk and their families, but other persons havebeen able to capitalize on it as well.
5.1.5 Re4igious Influence
Catholicism is the predominant religious influence in the community, as occurs in the rest ofSt. Lucia. However, there has been recent growth in the Seventh Day Adventists and anumber of smaller churches that meet in the houses of members.
5.1.6 Economic Situation
Unemployment is high in Dennery village, primarily the result of the closure of the garmentfactory Belle Fashions about two (2) years ago. The factory formerly employed close to sixhundred (600) persons, most of them women and many of them from Dennery District.The CDO is working with residents of the community to assist them in the development oftheir own small business enterprises as a way of generating income for themselves and forthe community in general.
5.1.7 Social Conditions
The low employment rate, particularly among women in Dennery, has impacted a number ofother areas, particularly school attendance and a rise in criminal activity. Most families lackthe finances to send young children to pre-school, so that these children are deprived of thebenefit of early childhood education. For those of school-age, finances are often unavailableto provide them with the necessary uniforms, books and meals. A number of villagerslamented that though they are proud of the education system that is available for theirchildren, there are no jobs available for them when they leave school. Some of the youths,frustrated by the lack of employment opportunities, migrate from the area in search of betteropportunities elsewhere. Others have found themselves involved in drug dealing andtrafficking, petty theft and other undesirable activities.
5.2 DemographicsDemographic information was obtained from the Statistical Department in Castries, but ingeneral this was for the entire Dennery District, of which Dennery village is only one area.Information specific to Dennery Village was available from the Preliminary Report of the2001 Population & Housing Census and may, therefore, be subject to change. However,these statistics still serve overall to provide a general understanding of the demographicsituation in the village. This statistical data is further supported by the results of the surveythat was undertaken for this project, and which is presented in the following sub-section.
5.2.1 Population
The entire District of Dennery is comprised of approximately 12,500 persons, according tothe census results. Of these, 52.2% are reported to be male and 47.8% to be female. Of thispopulation, approximately 3,000 live in Dennery Village, 49.9% of them being male and50.1% being female. With respect to the residents of the shoreline area of High Street (bothlandward and seaward sides of the road), there are 204 residents, of which 4 5.6 % are maleand 54.4% are female.
With a land area of 26.9 square miles, Dennery District therefore has an estimatedpopulation density of 466 persons per square mile. Dennery is reported to have 3,753private households, with an average household size of 3.3 persons. The community ageprofile is shown in Table 5.2 below.
Table 5.2 Community Age Structure - Dennery District
Age Group (years) Frequeny Percent
0-4 1190 9.5
5-9 1493 12.0
10-14 1383 11.1
15-19 1319 10.6
20-24 1091 8.7
25-29 955 7.7
30-34 932 7.5
35-39 784 6.3
40-44 653 5.2
45-49 483 3.9
50-54 405 3.2
55-59 351 2.8
60-64 294 2.4
Over 65 1136 9.1
Total 12469 100.0
Source: Statistics Department
This table indicates that sixty percent (600/6) of the population of Dennery is aged twenty-nine (29) years and under.
5.2.2 House and Land Ownership
Preliminary census data indicate that 80.2% of residents in Dennery own their houses, 12%of houses are rented or leased either from private owners or from the GOSL, and theremainder have other unspecified arrangements.
38.0% of properties (land) are owned, 10.3% are rented or leased, 30.5% of persons aresquatting on the land they occupy, and the remainder have unspecified arrangements.
Information provided by the Titles Office indicates that there are a total of 52 propertiesalong High Street. Of these properties, the Crown owns three (3), and ten (10) are registeredto persons living at altemate addresses. This suggests that a majority (75%) of the premiseson High Street are owner occupied.
5.2.3 Income and Emplqyment
Average annual income for Dennery is reported to be EC$10,975.46 compared to thenational average of EC$12,468.74.
The unemployment rate for Dennery is 25 .0%. Disaggregated by gender, the rates are18. 6% for men and 34.3% for women. The national unemployment rate is 18.9% - 16.7%(male) and 21.6% (female).
5.2.4 Demographic InformationThe average number of years reported by respondents that they have lived in Denneryvillage is 32.25 years.
I'he total number of persons in the households interviewed is sixty-nine (69) persons.Twenty-eight (28) of these persons, equivalent to 40.6% are male and forty-one (41) persons,or 59.4% are female. This male to female ratio is a reversal of the trend noted above inSection 5.1 for the wider Dennery District, but it is in keeping with the ratios given forDennery Village. The average number of persons in each household is calculated to be 3.4persons.
The age structure for the sample households is shown in Figure 5.1 following.
The chart indicates that in both the male and female case, around fifty-three percent (530/0)
of persons are aged twenty-nine (29) years and under. This is slightly lower than the figure
for the wider Dennery District but it still indicates that the population of the community is a
relatively young one.
5.2.5 Income and Emplqyment
Figure 5.2 below shows the employment status of the members of the sample
households.
12 - - _
0 8~
o U FemMalesCL6 FE m
2
0 -- r---
Student Unemployed Self- Employed by Retired Disabledemployed others
Employment Status
Figure 5.2 Employment Status of Sample Households
As indicated, the unemployment rate for males is approximately 17.9% whereas theunemployment rate for females is 24.4%. These rates are comparable to the nationalunemployment rates but somewhat lower than the rates for the wider Dennery District.
Of the total households interviewed, only sixty percent (60%) were able or willing to give afigure for average annual income eamed. From the information given, the average incomeearned by these households was estimated to be EC$7,000.00. This is approximatelyEC$4,000.00 (or 36.4%/6) less than the average for Dennery District reported by the StatisticsDepartment.
5.2.6 Perceptions of Environmental and Social Conditions
Table 2.3 shows the responses of surveyed households to questions about their perceptionsof various environmental and social conditions in Dennery village in terms of percentage.
Table 5.3 Householders' Perceptions of Environmental & Social Conditions inDennery (Percentage of total respondents)
Environmentall Very Very
Social Conditions dissatisfied Dissatisfed Average Satisfied satisfed No response TOTAL
Of particular note is that 85% of persons indicated that they are very dissatisfied with theemployment situation in Dennery village; 70% are very satisfied with drinking water supply;45% think drinking water quality is just average, whereas 35% are very satisfied with drinkingwater quality; 50% are very satisfied with the provision of health care; 60% are satisfied withthe garbage collection service provided and with the availability of public transport; and 55%are very satisfied with the level of security in the area.
When asked what kind of improvements they would like to see take place in Dennery village,the following responses were given:
* More job opportunities - 50%
* Protection from the sea/ a seawall - 35%
* Improved social infrastructure, e.g. a technical school, community center,provision of assistance to the elderly - 35%
* Improved services, e.g. regularized public transport, better water supply andsanitation, better roads - 20%
* Improved drainage - 20%
* Building of facilities along the coast to attract tourists to Dennery to spend theirmoney- 15%
* Improved housing - 10%
It can be seen from the results above that the highest priorities for residents of the coastalarea of Dennery village are increased job opportunities, protection from the sea andimproved social infrastructure.
5.2.7 Sodal Value Placed on Living in Dennegy VillageRespondents were asked to indicate what they liked most about living in Dennery village.Responses given were as follows:
* I have lived here all my life - it is a familiar setting/I have family ties/I have culturalties - 50%
* I like the community setting/social interaction - 30%
* I like the coastal environment- 30%
* The cost of living is not high as in other places - 5%
The results above indicate that respondents place a high social value on living in familiarsurroundings, strong family, community and cultural ties, and on living near the sea, whichalso is a cultural issue.
When asked if they would be willing to move to another part of the District of Dennery oranother part of the island, fifty-five percent (55%) indicated that they would be willing if itwere necessary for the safety of their families or if social conditions would be better. Thirty-five percent (35%) of respondents indicated that they would not be willing to move becausethey have a strong attachment to their current location but a majority of them would likeincreased protection from the sea. Ten percent (10%) of respondents could not make adecision in response to the question posed.
5.2.8 Past Damage Incurredfiom Hur,icanes and Tropical StormsA question was posed to respondents to determine what kind of damage they had receivedto their properties in the past as a result of hurricanes or storms. They were also asked toestimate the value of any such damage if they could. Table 3.4 following provides theresponses obtained.
It can be observed from the table that fifty-five percent (55%) of respondents indicated thatthey had received damage to their homes and/or properties during Tropical Storm Debbie,which occurred eight (8) years ago. Some residents reported that their homes and propertiesare in need of repair or upgrading but they are afraid to undertake the expense because itmay be lost to the sea if there is another major storm or hurricane.
Table 5.4 Past Damage Incufred from Hurricanes and Storms
I.D Type of Damage Inairred Estimated Value of When Damage OccurredDamage (EC$)
1 Water damage to household No estimate TS Debbie (8 yrs ago)contents
2 Lost a business, house & boats 100,000.00 TS Debbie (8 yrs ago)
3 No damage No estimate
4 Lost a business 9,000.00 TS Debbie (8 yrs ago)
5 No major damage No estimate
6 Lost part of property (eroded by No estimate TS Debbie (8 yrs ago)the sea)
7 Damaged property No estimate TS Debbie (8 yrs ago)
9 Roof removed, contents of home 10,000.00 TS Debbie (8 yrs ago)destroyed
10 Part of home washed away by the No estimate TS Debbie (8 yrs ago)sea
11 Foundation of the house eroded, 6,000.00 TS Debbie (8 yrs ago)back part of the house taken awayby the sea
12 Part of house lost to the sea No estimate TS Debbie (8 yrs ago)
13 Water damage to household No estimate Hurricane Alan (20 yrscontents from flooding ago)
14 Roof destroyed 5,000.00 Hurricane Alan (20 yrsago)
15 No damage No estimate
16 Damage to home No estimate llurricane Alan (20 yrsago)
17 Household contents damaged by No estimate Occurs sometimes whenflooding tide is high
S l 1 )IAI : ' II ( A\(i 1\ I PRk)I 1(.XBAN II X.I RY\ If 1 S\It. I l I ' 3.\31 29
I.D Type of Damage Incurred Estimated Value of When Damage OccurredDamage (EC$)
18 No damage No estimate
19 No damage No estimate
20 Water damage to household No estimate TS Debbie (8 yrs ago)contents from flooding
5.3 ConclusionsResidents of the coastal area of Dennery village are at risk of experiencing damage to theirhomes and properties from storm activity due to their close proximity to the sea. Despitethis risk, many of these persons place a high social value on living in their present locationsand would prefer to remain there provided that some protective mechanisms are put inplace. It must be concluded that residents understand the magnitude of this risk becausemost have lived in the area for an average of thirty (30) years and have already experienceddamage from at least one major tropical storm system. Other persons have indicated awillingness to move in order to ensure their safety, and some have already relocated, asevidenced by the number of abandoned homes within the study area.
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6. Potential Environmental ImpactsThe selected option (option 7 in Section 4) will have potential impacts on the environment(physical, socio-economic and ecological). These impacts can be identified as positive ornegative, and may have short-term or long-term implications. This section outlines themajor potential environmental impacts of the proposed options both during and afterimplementation, and provides recommendations for mitigating and monitoring theseimpacts.
There are three main components that make up option 7. These include: sand management,the construction of offshore breakwaters, and the construction of a revetment. Theenvironmental impacts are summarized in the following impact matrix, and further describedin this section.
Physical WvaterCirculatlo ShoWeline Mo photogy Sediment Transport _==________=__Wvave Processes _ _ ____ ____Coastal Water Qualibty __*_ _ Freshwater Qualts _ Significant Positive Effect
Social era onal wmnings1 No impactRrecr eational Boating _ TShorlTerm (During ConstructlornVeticeuir tramc I MTbedlumTermlfarlne VssselTratfc L t | t | T Long TermmFishing __
Nolse - - - i-ii - -
AirQuattlty - - - - - - -A estheflcsl l l l lX l l l l Hazardyulnerablilf T r
Impact Matrix
6.1 Physical Imparcts
6.1.1 SeTrment Transport
Negligible impacts on sediment transport are expected during all constr-uction phases of thisproject, as no shore perpendicular impermeable structures are proposed. However, from alonger-term perspective, the positioning of the offshore breakwaters is expected to have a
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positive impact on the sediment transport regime, as the wave climate in the lee of thesestructures will be reduced. In addition, some of the sand brought down to the mouth of theDennery River during floods will be redirected to the central and southern sections of thebeach. In this way, the sediment from the river will not be completely lost to the offshoresubmarine canyon. The most northerly breakwater, is also expected to reduce the waveenergy in its lee, thereby reducing the potential for sand transport and thus contributing tothe slow build up of this beach.
6.1.2 Wave Processes
During storms the waves that affect the Dennery shoreline can have serious negativeimpacts on the beach and adjacent properties. The construction of the three breakwaterswill mitigate the impact of these waves on several areas of the shoreline, and will thereforehave an overall positive impact on the beach stability. The construction of the revetment,however, without any beach nourishment in front of it, could actually have a negative impacton the Dennery shoreline, as the revetment will tend to reflect the wave energy, resulting infurther loss of sand from the beach area in front of this structure. It is for this reason thatthe design calls for the spreading of sand, from the excavation associated with the revetment,in front of the revetment itself. The quantity of this material is expected to be in excess of5,000 m3.
The extent of wave sheltering from the three breakwaters, against waves from the east andENE, are shown in Figures 5.1 and 5.2. These simulations indicate a reduction in waveheights, in the lee of the structures, from 0.3-0.5m down to 0-0.2m.
1SS1A ITHREFDIF /S Simulation for WAWARNERDennery Bay, St. Lucia 'IG ItNT j 5NAA
Figure 6.2 Comparison of Breakwater Performance versus Existing Shoreline - Waves from the East-North-East
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6.1.3 Nearshore Water CiraulationIn order to examine the impacts of the proposed sea defense works on the prevailing currentpattems and water circulation characteristics, a three-dimensional hydrodynamic model wasused. Overall, this process involved the setting up of a finite element mesh, modelcalibration for the existing shoreline configuration and, finally, simulations of the shorelinewith the proposed offshore sea defense structures. The model that was used for theseinvestigations was the RMA-10 suite developed by Ian King.
RMA-10 is a three-dimensional finite element hydrodynamic model for stratified flow (King[1993]). The primary features of RMA-10 are:
* The solution of the Navier-Stokes equations in three-dimensions;
* The use of the shallow-water and hydrostatic assumptions;
* Coupling of advection and diffusion of temperature, salinity and sediment to thehydrodynamics;
* The inclusion of turbulence in Reynolds stress form;
* Horizontal components of the non-linear terms are included;
* A capacity to include one-dimensional, depth-averaged, laterally-averaged andthree-dimensional elements within a single mesh as appropriate;
* No, partial and full slip conditions can be applied at both lateral boundaries;
* Partial or no slip conditions can be applied at the bed;
* Depth-averaged elements can be made wet and dry during a simulation; and
* Either a quadratic parameterization of turbulent exchange, or a Mellor-YamadaLevel 2 turbulence sub-model estimates vertical turbulence quantities.
The mesh construction exercise involved the setting-up of two finite element meshes. Thefirst mesh was developed to represent the existing bathymetric and shoreline configuration(see Figure 6.3). The second mesh represented a modification of the first mesh, to reflect theproposed configuration of the offshore breakwaters. The bathymetry for the primary mesh isalso shown in Figure 6.3. As can be seen, the mesh extends from Anse Povert in the north,to Anse Galet in the south. In an eastward (i.e. seaward) direction, the mesh goes out to the300 to 400-metre water depth contour.
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Figure 6.3 Finite Element Mesh - Existing Conditions
Due to the lack of long-term measured currents, the finite element model for the existingconfiguration was calibrated using the current speeds calculated from two episodes ofdrogue tracking. The fins of the drogues were constructed from aluminum, attached by alength of wire to a spherical float. A photograph of the drogues used is shown in Photo 1.Essentially, the drogues were dropped into the water and tracked using GPS equipment. Ateach position fix, the time was noted. In this way, the water mass movements were evaluated(speeds and directions). Drogues were tracked during both the rising and falling stages of thetide.
Tidal information was obtained from the CPACC tide gauge, from which a 27-day recordwas used. From this database, the spring and neap tide ranges were extracted. Thecalibration runs were conducted using a neap tide range, as this corresponded more closelyto the actual times of the data collection. Ihe water velocity directions within Dennery Baywere extracted from the RMA-10 results and compared to that of the drogues. Differenttidal boundaries were applied to the north and south ends of the model, in order to bestsimulate the observed tidal currents. During the calibration exercise, the model predictedvery similar current speeds and directions to that of the drogues and hence the model wasdeemed to be adequate for use in a prediction mode. T'he model results are, however,considered to be only applicable within the calibrated region.
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~~~- I
Photo1 1 -,.'___
Pht Drogues used for tracking curfents
T'he results of the hydrodynamtic modeling are shown in Figures 6.4-6.11. Plots are shownof rising and falling tide conditions for both the day-to-day and the 25-year flood flowscenarios of the Dennery River. A hydrograph from the Dennery River was also applied tosimtulate a flood event. Using the results of the hydrodynamic model, an exam-ination intothe current patterns was undertaken to investigate the effects of the proposed breakwaterstructures on the cuffents.
The water circulation pattern for the existing configuration shows that currents insideDennery Bay are typically less than 0.1 m/s, with the exception of the area north of DenneryIsland, where current velocities are up to 0.2 m/s. To the north of the river mouth along theshoreline, stronger currents occur during the rising tide than during the falling tide.Comparing the results for the existing shoreline with those writh the proposed breakwaters(preliminary engineering configuration) in place (see Figures 6.8 and 6.9), it can be seen thatthe proposed structures have the effect of slightly reducing the current velocities that occuradjacent to the shoreline. Offshore in Dennery Bay, no changes to the current pattern areobserved.
'T'he flood conditions corresponding to the 25-year return period were modeled as a 24-hourstorm according to the hydrograph and tide conditions for both configurations. Theresultin plots for the falling and rising tide conditions are shown in Figures 6.6 and 6.7 forthe existing shoreline configuration, and in Figures 6.10 and 6.11 with the proposedbreakwaters in place.
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The plots show minor to no changes during the falling tide phase of the tide, as a result ofthe proposed breakwaters. During the rising tide cycle, however, there is a noticeable changein current patterns. Essentially, for the existing situation, the flood flow moves out in aplume towards the southeast of the bay. It is this flow that carried suspended sediment tothe submarine canyon, where that sediment then becomes lost to the littoral system. Withthe proposed structures in place, the outflow plume is directed to the ENE, and the flowvelocity in the bay in reduced. In this way, the suspended sediments brought down by theriver are retained in the littoral system.
Large-scale water mass movements for the rising tide phase are highlighted in Figure 6.7 and6.11. These show the fundamental differences in the before and after configurations. Bothshow that water is exchanged from the bay, however the mechanism of exchange differs.
Sl IA i Slc , () >I C()\'llI.II .i 1)1 'im llj ' \I 11 I I Sl'. '( I \ P\ , 9
Year 2002 day 18 hour 8.00 L200 _ " ' '
1.0 t!A_ 000 -'''@ Xx'' ''
0.050 t s .t
0.50 - - /br'
0 50 500.55 _060
- -
Figure 6.4 Failing Tide - Existing Shoreline
Year 2002 day 18 hour 16.00200
1.00 000.0500 100 15
0 20
0 300 350 400 450 500 55 W..pp0 60
Figure 6.5 Rising Tide -Existing Layout
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Year 2002 day 1 hour 8.00200. tj,tL A--
I 1I _L0 000 050 SI >0100.150 200 250 300 350.400 450 500 550.60
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6.1.4 Shoreline Morphologv
One of the main objectives of this study has been to address the ongoing erosion andchanges to the shoreline morphology of Dennery Beach. The proposed breakwaters willhave an overall positive impact on the area, by reducing the wave energy in their lee and bypromoting the build up of sand on the beach in the lee of each structure. While anchoringthe shoreline and the buildings at the back of beach, the revetments could have somenegative impacts on the beach morphology by increasing the loss of sand from the beachdue to the reflection of wave energy from the revetment. This potential impact has beenmitigated against by the specification of excavated sand, from the revetment, being spreadon the beach in front of the revetment itself. For the final design stage, it is recommendedthat this placement of sand should replace the consideration of dredging and beachnourishment.
Finally, the sand management component will result in slow beach width changes.
6.2 Socio-Economic Impacts
6.2.1 Recreation
Any recreation activity at the beach will be temporarily impeded during the construction andsand management activities. I'his is a temporary adverse impact, and can be mitigated byadvising the community and public at large of the dates of proposed sand managementactivities.
6.2.2 Fishing
Fishing may be temporarily impacted during the construction of the breakwaters. It isrecommended that all members of the community be advised of the nature and schedulingof the work in order to avoid conflict. This negative impact will be only for the duration ofconstruction.
6.2.3 Vehicular Traffic
Impacts on traffic will be moderate and temporary as far as the extent of the works along theroads leading to the project sites. Traffic impacts along these roads relate more to the typeof traffic (heavy vehicles) and to a lesser extent on the number of vehicles.
Mitigation of this impact should include:
* Schedule deliveries of construction material to avoid peak traffic periods on heavily-trafficked roads;
* Avoid long convoys of trucks making deliveries; and
* Alert commuters as to the closure of any roads well in advance of the start ofconstruction.
I I 1)E .& l)ISlt;X (> \SixI P]'P T( TION Vi 1)[i'i i L\'1 I .$iy l l1\(,1 44
6.2.4 Marine Traffic
The movement of marine traffic may be impeded during the construction phases due to thepossible presence of construction equipment in the nearshore. These impacts areanticipated to only be short-term. However, should the breakwaters be constructed, theroutes for marine vessels may be altered due to the presence of the new structures. This isanticipated to only be a minimal long-term impact. Mitigation of this impact can be attainedthrough the use of appropriate navigational beacons.
6.2.5 Noise
Noise impacts will be only during construction and sand management, and will arise largelyfrom the passage of trucks and the use of heavy construction equipment. The noise is anunavoidable impact of the construction, but is only a short term impact, lasting only as longas the construction and/or sand management activities. In order to mitigate the noisenuisance to the nearby residences, construction activities should be limited to daylight,regular working hours.
6.2.6 Employment
Employment will be primarily a short-term benefit of these works, as they are mostly labour-intensive. The contractors should be encouraged to use as much local labour as is practical.Some longer-term employment may be possible through the sand management componentof the works.
6.2.7 Solid Waste Management
The construction works will generate solid waste, which will consist largely of constructiondebris and packaging material, all of which are suitable for disposal in a landfill. Nohazardous wastes are anticipated during the construction of these works.
6.3 Ecological Impacts
6.3.1 Terrstrial
Except for the mangroves, there are no significant terrestrial habitats occurring along thedefined waterfront zone at Dennery. None of the shoreline protection options will affectthe mangroves, and as a result, there are no major faunal communities or designatedecologically sensitive habitats within the project area. The impact of this project onterrestrial ecology is therefore considered to be minimal to none.
6.3.2 BenthicSignificant viable benthic communities do not exist within the immediate nearshore zone ofthe project site. The impact of this project on the benthos is therefore not considered to besignificant. However, should the breakwaters be constructed, an environment would becreated that would promote the growth of benthic communities. This would, in fact, be apositive impact of these structures.
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6.3.3 AirQualh)
The anticipated air quality impacts are during construction, and are related to dust andexhaust fumes from construction equipment. These impacts are expected to be minimal inextent, and for a short time (only during active construction and sand management).
The mitigation measures to control dust and equipment emissions are:
* Spray dirt surfaces in the construction area with water or other dust palliative dailyduring the dry season;
* Specify and select rock material with a minimum of fine material (rock powder andadhering clay); and
* Ensure that the contractor properly maintains and services all constructionequipment.
6.3.4 WaterQua/iy
The main impacts on coastal water quality will arise during construction, and possibly duringsand management activities, as a result of run-off and sedimentation. The potential sourcesof contamination have been identified as:
* Material stockpiles;
* Silt from rocks being placed in the works; and
* Fuel and lubricants from construction equipment.
The potential for short-term degradation of nearshore water quality exists if there is heavyrainfall and leaching from material stockpiles. These impacts are expected to be relativelylimited in extent, and should only persist for short times during the construction phase.
Measures that should be employed to mitigate these impacts include:
* Scheduling the construction work for during the dry season;
* Specifying and selecting rock material with a minimum of fine material. Armourstones for the revetment and breakwaters should be washed properly before beingplaced in the nearshore water;
* The construction schedule should be optimized to minimize the residence time ofmaterial stockpiled on site;
* Fueling and servicing of construction equipment should be carried out away fromthe shore and river banks, and special bunded areas should be provided for theseactivities; and
* A silt barrier should be installed and maintained during the nourishment andconstruction exercises.
6.3.5 SedimentQualiy
One of the primary recommendations coming out of the design is the clearing of sedimentfrom the mouth of the Dennery River and the placement of this sediment on the beach in
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front of the revetment. This activity is expected to yield approximately 500 m3 of sand every3 to 6 months. In order to confirm the suitability of this sand for reuse on the beach, asample of the sand from the mouth of the river was collected and tested for contaminants atthe Sevem Trent Laboratories in Florida. This consideration is important as the river drainsan agricultural catchment and the sediment may contain some traces of pesticides.
Table 5.1 following indicates a listing of contaminants that should be considered for testingand their reference values. Levels below these reference values indicate that the sedimentmay be deposited on land or in seawater without any restrictions. The results of the sandsample testing from the mouth of the river are listed beside the reference values forcomparison.
Table 6.1 Listing of Contaminants, Reference Values and Results
Contaminant (mg/kg of dy matter) Reference Value Measured Results
Chromium 100 2.8
Nickel 35 Not tested
Copper 36
Zinc 140
Cadmium 0.8 Below detection level (BDI,)
Mercury 0.3 (BDL)
Lead 85 16.2
Arsenic 29 5.8
Napthalene 0.01 BDL
Fluoranthene 0.1 BDL
Benzo (a) pyrene 0.1 BDL
Benzo (k) fluoranthene 10 BDL
Mineral Oil Total 50
Pentachlophenol 0.1 BDL
Hexachlorobenzene 0.001 BDL
PCB's 0.01 BDL
Hexachlorocyclohexane 0.001
Aldrin 0.01 BDL
Dieldrin 0.01 BDL
Endrin 0.001 BDL
DDE 0.01 BDL
Endosulphan 0.01 BDL
Chlordane 0.01 BDL
Si LDY & I)i&k(i ()i (1_\z1 iL 1'E" )'47'ilflN \ I' I7)VKil IRX_ \ii I. l .; i S l . I ,LY \ I)y,. 47
7. Environmental Management Plan and ConstructionMonitoring Programme
7.1 BackgroundIn order to implement the final design option that has been put forward, severalconstruction-related activities will have to be undertaken. The main activities in theconstruction of the revetment, and subsequently the breakwaters, are outlined below:
1. Site reconnaissance and setting out
2. Material route establishment
3. Movement of materials
4. Double-handling of materials
5. Site preparation for placement of geotextile fabric
6. Excavation (not applicable for breakwaters)
7. Installation of geotextile fabric
8. Installation of armour rock material
9. Installation of corrugated polyethylene pipe (not applicable for breakwaters)
10. Clean up
These activities could potentially have a negative impact on the Dennery environment, andas such, necessary precautions and monitoring activities will need to be employed. Thissection highlights the main potential environmental impacts during the construction of thestructures, as well as the required mitigation and monitoring activities.
7.2 Impacts and Mitigation MeasuresDuring the construction of the revetment and breakwaters, potential impacts on theenvironment will relate to:
i. Sea water quality, ii. Terrestrial/benthic ecology,iii. Noise, iv. Air quality,v. Employment, vi. Fishing,
vii. Land use, viii. Traffic,ix. Waste disposal, x. Public safetyxi. Recreation. xii. Navigation
Each of these is discussed below. Where action by agencies is recommended, these havebeen highlighted in bold font.
S I ,I I ( ;: (& 1 ()IC 1()\s L (-11()N Ui \F\Nl RI \i 1 J VI x I SR. I'. \ 1Pvs,v1 48
7.2.1 Sea WaterQualiy
Three potential sources of contamination to the Dennery Bay marine water have beenidentified during the construction of these works:
i. Silt from excavated material stockpiles,
ii. Silt from rock being placed in the works, and
iii. Fuel and lubricants from construction equipment.
These impacts are expected to be relatively limited in extent, given the size of the proposedworks. They will also be transient, lasting only as long as construction is in progress.
Several mitigation measures are available to minimize these potential impacts:
1. Stockpile excavated material away from the shoreline, and cover the material sothat rain events do not wash the material into the sea.
ii. Specify and select rock material with a minimum of fine material (rock powder)and adhering clay so that the fine material cannot be washed into the sea.
iii. Ring the offshore works with a proper turbidity barrier, so that any sedimentplumes are contained within the barrier.
iv. Fuel and service construction equipment away from the seashore and river banks,and provide specially confined areas for these activities (to catch and containspills).
It is recommended that enforcement of these measures should be carried out by theMinistry of Communications and Works in coordination with the FisheriesDepartment.
7.2.2 Terrestrial/Benthic Ecology
There are no significant terrestrial habitats occurring along the defined waterfront zone atDennery since the area has long since been exposed to development and the original coastalvegetation has been removed. As a result, there are no major faunal communities ordesignated ecologically sensitive terrestrial habitats within the study area. The impact of thisproject on terrestrial ecology is therefore considered to be insignificant.
Prior to the construction of the breakwaters, and once their locations have been laid out inthe field with markers, a benthic reconnaissance must be done to confirm that no sensitivebenthic organisms will be impacted by the structures. This may be coordinated by theFisheries Department.
7.2.3 Noise
Noise impacts during construction will arise largely from the passage of trucks and the useof heavy construction equipment. These impacts will be temporary, lasting only for theduration of construction activity. To mitigate against any noise, the following should bedone:
* Use temporary sound absorbing barriers around noisy equipment.
* Restrict access to high noise areas.
Sit I ) 1)I K & D ( I ( . \ I PX )I T II J-( )NŽ I I< V IRIY IT I r S Sl, 1 . (I V1 (J1 i 49
* Properly site noisy stationary equipment away from workers and the public.
* In areas where construction works are to be done in relatively close proximity tohouses, construction activity should be scheduled to avoid night hours, and shouldoccur within specified daytime hours.
7.2.4 AirQualiy
The anticipated air quality impacts during construction relate to dust (particularly duringearthworks) and exhaust fumes from construction equipment. These impacts are expectedto be relatively small in extent, and to be transient in nature (only during the activeconstruction period). The mitigation measures to control dust and equipment emissionsduring construction include:
* Spray dirt surfaces in the construction area with water or other dust palliative dailyduring the dry season.
* Specify and select rock material with a minimum of fine material (rock powder) andadhering clay. Wash the rocks as necessary, ensuring that the fines do not enter thesea or nver.
* Ensure that the contractor properly maintains and services all constructionequipment.
7.2.5 Employment
Employment is a short-term benefit of these works, as they are mostly labour-intensive. Thecontractors should be encouraged to use as much local labour as practical. Prior to theconstruction works, the Ministry of Communications, Works Transport & PublicUtilities may consider setting up training workshops, for people in the village, in the area ofbest construction methodologies and practices. In this way, there may be a reasonably well-trained workforce that can be utilised by the contractor at the time of the start ofconstruction. The construction of the revetment is anticipated to last for approximately 4-6months, while the breakwater construction will take approximately six (6) months to becompleted. Even though short-term, this burst of construction activity could be a benefit tothe society.
7.2.6 Fishing
None of these works is of such a nature as to impede fishing activity offshore duringconstruction. Landing of boats may be temporarily hampered during the construction of therevetment. In order to avoid conflict, it is recommended that all members of the communitybe advised of the nature and scheduling of the work.
7.2.7 Land Use
It may be necessary to negotiate easements for construction access and working areas duringconstruction. This will be the responsibility of the contractor, who will make necessaryarrangements for compensation of landowners (if required). To facilitate the process,however, it is recommended that the Ministry of Planning, in concert with the Ministry of
Communications, Works, Transport & Public Utilities alert the villagers as to theupcoming works and the likely routing for construction traffic and general activities.
7.2.8 Traffic
Impacts on traffic will be moderate and temporary as far as the extent of the works. Trafficimpacts relate more to the type of traffic (heavy trucks as opposed to light vehicles) and to alesser extent the number of vehicles. Mitigation measures include:
i. Schedule deliveries of construction material to avoid peak traffic periods on heavilytrafficked roads.
ii. Avoid long convoys of trucks making deliveries.
7.2.9 Waste Disposal
The construction works will generate solid waste and sewage. Solid waste will consist largelyof construction debris and packaging material, all of which are suitable for disposal in alandfill, and should be taken to the nearest approved site. No hazardous wastes areanticipated during the construction of these works. Adequate provision must also be madefor toilet facilities on site for workers (Port-a-Johnis, etc.).
7.2.10 Public Safepy
Public safety concerns an'se within the site of any construction works. These concerns aretemporary, lasting only as long as the construction activity. On this project, the site of theworks occupies almost the entire beach. As it should be adequately demarcated, fenced(where appropriate) and guarded to prevent entry by unauthorised persons. It isrecommended that a public awareness programme be launched prior to the start ofconstruction, under the direction of the Ministry of Planning. This programme shouldinform as to the type of construction; the objectives of the work; the likely impacts; and theneed for people not connected with the works to keep clear of the construction area. Duringthe Saturday night fish fiestas, it may be necessary to use the lands adjacent to the Daito.
7.2. 11 Recreation
Any recreation activity at the beach will be temporarily impeded during construction. TIhis isa temporary adverse impact, and the long-term effect of the project will be to enhancerecreational opportunities in these areas, as the beach will be widened and be more stable.
7.2.12 Navigation
The construction of the breakwaters will have a permanent impact on navigation in the bay.In order to mitigate against these impacts, navigational lights will be constructed within thebreakwaters. It is recommended that the St. Lucia Ports and Airports Authority preparesigns for the interpretation of the navigational lights.
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7.3 Water QualityMonitoringIt is recommended that the turbidity if the nearshore waters be measured prior to the start ofthe construction activities, and then weekly during activities, in order to assess the impact ofthe works on the water quality. Should the turbidity readings exceed 29 NTU above thebackground readings (taken prior to construction), then work should be stopped, and effortsmade to ensure that all dust and sedimentation mitigation measures are being employed.
7.4 Summary
Construction Activity Potential Impacts MonitoringActivitis
Movement of Materials * Noise Turbidity Monitoring
* Waste
* Dust
* SedimentationDouble Handling of * NoiseMaterials Dust
Site Preparation * Noise
* Sedimentation
Excavation * Noise Turbidity Monitoring
* Dust
* SedimentationInstallation of Geotextile * Noise
* Dust
* Sedimentation
Installation of Armour * Noise Turbidity MonitoringRock
* Dust
* Sedimentation
* Fuel &Lubricantspillage
Installation of Pipe * Noise
* Dust
* Sedimentation
* Fuel &Lubricantspillage
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8. Public Consultation and ReviewTwo review and consultation meetings were held for the overall project. The first was heldwith government representatives in Castries, while the second was held in Dennery with thecitizens of Dennery. The comments and concerns that emerged from the meetings wereincorporated into the final design option.
The minutes of both meetings are attached as an appendix to this document.
Appendix
Emergency Recovery & Disaster Management Project
Notes on the Presentation of Preliminary Design Report forStudy & Design of Coastal Protection of Dennery VillageDelivered by Consulting Firm-Smith Warner International
Held on Tuesday April 1, 2003Cara Suites Conference Room
PRESENTHonorable Damian Greaves - Minister for Health, HumanServices & Family Affairs/District Representative forDennery
Mr. Martin Satney - Permanent Secretary, Ministry ofPhysical, Development, Environment & Housing
Chamberlain Emmanuel - Civil Engineer, Ministry ofCommunications, Works, Transport & Public Utilities
Representative from the Department of Forestry & Fisheries
Representative from the Dennery Village Council
Representative from the Dennery Disaster Committee
Representative from the OECS Environmental SustainableDevelopment Unit
Mr. Tom Walcott -Individual Engineer
Mr. Pat Brown- Individual Engineer
Dr. David Smith - Consultant-Smith Warner International
The Presentation began at approximately 10:10 a.m.
The Chairperson, Ms. Cheryl Mathurin welcomed everyone tothe meeting and gave a brief description of the proposedplan for the Coastal Protection of the Dennery Village andformally introduced Dr. David Smith - Consultant from SmithWarner International to the panel. She indicated that theconsultancy was in two (2) phases.Phase 1. - Feasibility StudyPhase 2.- Detailed Design
Dr. Smith gave a brief description of the topography of theDennery Village, and the reasons why the study wasundertaken and the possible outcomes of the study.
An assessment and findings of the erosion of the coastlineof the Dennery Village was viewed by the panel. Thefindings indicated that shoreline positional carried outthrough a historical aerial photographs and shorelinesurveys. The database dated back as far as 1966 andshoreline locations for 1966, 1981, 1992 and 2002 werecompared. The results from the data concluded thatsections of this shoreline within the main bay have beeneroding at rates of lm per year. At this rate of erosion,the main road will be under threat of attack from the seawithin the next 25 years.
An important factor was also highlighted; continuous sandmining from the mouth of the river; this primary sedimentsource has been lost to Dennery littoral system. This islikely to result in the continued and ongoing erosion ofthe beach.
Five (5) options that would rectify the problemsencountered by the Coastal of Dennery were proposed to thepanel.
Option 1* "Do nothing" alternative
* Requires the preparation of evacuation plans for thevillage
Option 2* Sand management* Requires the preparation of a evacuation plan
Option 3* Sand management* Construction of a 275m long revetment just seaward of
the line of the most threatened buildings.
Option 4* Sand management* Construction of a 170m long revetment
* Construction of two(2) breakwaters
Option 5
* Sand management* Construction of two breakwaters
* Relocation of front line residents
* Nourishment of beach out to 1966-1981 shorelines(requires 30,000-40,000 m3 of sand.
Hon. Damain Greaves, District Representative for Denneryexpressed his concerns and clearly emphasized that thenumber one priority should be for the protection of thepeople of the Dennery Village. He continued by adding thatthis problem has to be resolved, and by the end of thispresentation he wanted something solid to take back to thepeople of Dennery, because for too long the people have hadto wait and they are losing interest. He wanted to keepthem stimulated and their interest alive. He enquiredabout a time frame, so he could give the people of Denneryan idea of how long they needed to wait before protectivemeasures could be implemented.
Mr. Greaves added that the drainage on the western side isalso a growing concern and drainage also needs to beaddressed. He continued by saying the younger people alongthe seashores of the village are migrating and there isalso a concern for the older citizens who were endangeredduring the last Tropical Storm.
Mr. Greaves suggested that option three (3) which involvesthe following
Option 3* Sand management
* Construction of a 275m long revetment just seaward of
the line of;should be explored immediately followed by option five (5)
in the futureOption 5
* Sand management
* Construction of two breakwaters
* Relocation of front line residentsNourishment of beach out to 1966-1981 shorelines(requires3O,OOO-40,000m3 of sand)
Mr. Greaves indicated that Dennery has lots of potential to
develop Tourism and that the villagers would like to seetourism develop in their Village.
Dr. Smith agreed, and demonstrated that this would be
possible if Option five (5) is implemented.
It was clear that, that after a few clarifications from Dr.
Smith that the panel agreed that Option three (3) and five
(5) is the way forward for the people of Dennery.
Mr. Greaves also made a point that mitigation also needs to
be looked at, and that Dr. Smith should incorporate thiscomponent in his next presentation.
