The Port Authority of Jamaica (PAJ) wishes to expand the infrastructure capacity at the Trans-shipment Terminal at Port Bustamante. This, with a view to increasing the berthing capacity (number and size) for ships at the port, as well as providing more container storage space. This will be done in two phases. This report deals with the Environmental Impacts of Phase 1.
Phase 1 involves:
A) The dredging of Channel and Turning Basin
It is proposed to dredge the east channel, which is exposed to strong and long swells to a depth of 17.4m. Part of this exercise involves the removal of a part of Rackhams Cay (20%) in order to provide a minimum channel depth of 18m through the opening between Rackham and Gun Cays. The width required for the east channel to safely accommodate the design ship is 230m. The outer harbour channel (less exposed to swell) would be dredged to 16.4m; while the inner harbour channel (protected from swell) would be dredged to 15.7m. Some of the dredged spoil would be used to reclaim a section of Hunt’s bay to increase the storage capacity for containers.
The proposed options for disposal of the dredged material are as follows:
1. Place all of the dredged material in the proposed Hunts Bay reclamation platform.
2. Dispose of all the material at a suitable marine disposal site.
3. A combination of the above options with some material being placed in the Hunts Bay reclamation platform or some other land bank location.
B) Reclamation of Hunts Bay
The reclamation work for Hunt’s Bay would involve the placement of suitable Rock Armory to create containment berm for fill material. Suitable dredged material would be used as fill for the proposed reclamation area, which is on the south east, adjacent to the Portmore Causeway. It is also proposed to reclaim the north-western corner of Gordon Cay.
In addition to supporting prime waterfront property, Kingston Harbour and its environs are known to contain several ecologically as well as economically important habitats. These environments are important to the short and long-term stability of the shoreline and therefore the sustainability of activities in and immediately around the environs of the harbour. Some of these lands have the potential to support shipping and container storage activities and at present support one of the premier transhipment ports in the region. The nearby barrier and fringing reefs around the Port Royal cays, the natural wetland ecosystems located nearby, the Hunts Bay/Fort Augusta area and surrounding water bodies support vibrant fishing communities of Helsinki, Hellshire, Greenwich Town, Rae Town and Port Royal.
ECOLOGY
Along with existing data from previous reports, six locations generating twelve different sampling transects were established to generate information that would serve to add to the database for the purpose of comprehensively evaluating the ecosystems involved:
Hunts Bay (marine - north, middle, south & terrestrial east/west) - Transects 1, 2 , 3 & 4
Gordon Cay (west & east) - Transects 5 & 6
Ship Channel (east of Fort Augusta & west of Port Royal) - Transects 7 &8
Rackhams Cay (north to south & east to west) - Transects 9 & 10
Gun Cay (east to west) - Transect 11
Farewell / Sea Buoy - Transect 12
Data on the substrate was obtained by a visual examination of the substrate at the various stations Examination of the terrestrial habitat in the vicinity of the proposed Hunts Bay reclamation site was carried out by sampling the vegetation along 20m transects within each sample site. Avifauna were sought by direct observation or by searching for indicators such as nests. Physical descriptions and vocal peculiarities of any bird that could not be immediately identified were noted and later verified with field guides.
The main impacts associated with dredging and disposal activities relate first of all to direct loss of habitat. Secondary effects are assumed to relate to the formation of sediment plumes which may affect fish or benthos because of the smothering (clogging) effect of highly turbid waters on the gills of bivalves or fish, inability to detect predators or the limiting of the photosynthetic process in corals and plants. Nets placed in very silty areas tend to accumulate fine mud particles on their weave and fish can see the net and avoid it or they slide easily off the net instead of becoming entangled in its mesh.
The Hunts Bay Habitat
Because of the already impacted nature of the south eastern shoreline and immediately adjacent waters and sublittoral area it is not anticipated that any significant impact would occur in this area due to reclamation activities. It is possible however that changing the contour of the shoreline could affect the existing circulation patterns within the bay. This might result in a shift of the hypoxic (or highly polluted) conditions westwards into the main body of the bay with the resulting degradation of the existing fishing grounds used by the fishermen. This would reduce their catch levels even further and be considered a negative, indirect, highly significant, long term impact.
Another scenario is that decreasing the space available in this eastern corner of the bay might decrease the retention time of water in Hunts Bay. This could create a more direct flow of water (with its entrained pollutants) into the main harbour and increase the levels of contaminants affecting the fauna in the seagrass beds, mangroves and water column in and around the Port Royal mangroves. No impact on the avifauna or marine life of Hunts Bay is anticipated from loss of the mangrove trees on the eastern margin. Loss of this small and already impacted stand of vegetation is not considered significant to the ecology of the bay.
Kingston Harbour Fishery
The dredging of the areas H1- H3, will undoubtedly release quantities of sediments containing high levels of heavy metals such as Lead, and Chromium. But the direction of sediment movement would most probably be out of the harbour, i.e. moving off to the south and being slowly carried off the west in the longshore drift. The effects on fishable resources at the mouth of the harbour would be largely speculative at this juncture. It is possible that spring flood tides may briefly slow and possibly even reverse the flow of sediment and water from the western dredge sites.
Other considerations include the reported comments from fishers in Port Royal which suggests that where dredging is widespread or unconstrained, normal night time land breezes could move sediment plumes into the Port Royal mangrove area. Bivalve mortality could possibly occur in the short term.
Annual visits into these mangroves in the period September through November over the past 20 years (1980 to 2000), strongly suggest that mangrove prop-roots bivalve resources are becoming somewhat scarcer and more stressed, probably due to increased solid waste originating from Kingston. During the major annual rainfall seasons from October through to November and in May, the increased runoff from the Rio Cobre estuary and from the Sandy Gully, if combined with dredging in the H1 to H4 sectors, could produce conditions of high turbidity in the Port Royal mangroves for variable periods. The residence time of this sediment-rich water may be long enough to cause detrimental effects to biota including fishable resources in the Port Royal mangrove complex.
The proposed clearing of coral hummocks in the east ship channel just north and NW of Southeast cay is of some interest to fisheries. It is known that most daytime fishers traditionally avoid this area due to maritime traffic. Instead, this channel is used by Port Royal hook-and-line fishers as a night-time access route directly to the edge of the south island shelf near to the extreme eastern end of the Eastern Approaches, where the drop-off into deeper water (> 300 m) occurs. Clearing of the coral in the Eastern Approaches area by dredging would not adversely affect fishing activities to any significant degree in the short or long term.
Kingston Harbour, Hunts Bay and the adjacent Port Royal mangoves-seagrass complexes provide modest fisheries production. These catches are mainly based on the capture by nets of sprats and herring and other surface-dwelling fish species, as well as shrimp (Hunts Bay only). Fortunately, most of the gill-net fisheries activities in the harbour are located in the centre of the basin. Nocturnal handline fishing at the entrance to the Eastern Approaches supports many of the fishers at Port Royal township. Parts of the Port Royal mangroves with their adjoining seagrass beds are known to act as nursery areas for various types of fishable resources. However, the majority of these nursery areas lie outside and to the east of the sites identified for dredging activities. During heavy rainfall, it is likely that some turbidity from dredging could affect the Port Royal mangroves and adjacent seagrass bed resources in the outer harbour.
Rackham’s Cay
This site is confirmed as a minor site for the securing of baitfish for hook-and-line purposes. If a part of this area was lost, the remaining bait-rich areas would include the other five Port Royal cays. Each of these possess shallow sandy areas over which small baitfish are regularly found. Quite apart from this, the major baitfish area of the Port Royal mangroves would still be available. Thus the partial loss of Rackhams Cay and the short-term sediment problem in the Eastern Approaches, should not be a major problem to fishers, as there are alternative areas. Any "loss" of baitfish areas nearby would represent a minor percentage of the whole. An approximate loss estimate would be less than 10% of the present baitfish areas.
The major problem with losing a part of Rackhams Cay is the effect on the reef, which would suffer a significant loss from the coral, gorgonian, sponge, seagrass and urchin communities. This impact can be mitigated.
Gun Cay
Negligible impacts are anticipated at this site as a direct result of dredging activities at Rackham’s Cay.
Eastern Ship Channel
Negligible impacts are anticipated at this site as a direct result of dredging activities due to the small size of the coral patches/hummocks to be affected.
ENVIRONMENTAL CHEMI\STRY
Kingston Harbour and Hunts Bay are known to receive low quality run-off from gullies as well as poorly treated sewage and industrial waste. In addition the harbour is affected by oil spills associated with operations of the Petrojam refinery and shipping in general. These factors are likely to contribute to the quality of sediment to be dredged.
The indicator parameters considered relevant to the assessment are as follows: total suspended solids (TSS), nitrate (NO3), available phosphate (o-PO4), heavy metals (Pb, Cr, Cu, Cd), chemical oxygen demand (COD), biochemical oxygen demand (BOD), dissolved oxygen (DO), hydrogen sulphide, coliform, and pesticides.
Five sampling stations have been established to provide background information on the following:
Offshore background conditions - Station 1
The channel (near Port Royal) - Station 2
The channel (near Fort Augusta) - Station 3
The turning basin (Gordon Cay) - Station 4
Hunts Bay (near Causeway) - Station 5
Water quality data collected at sites to be dredged, indicate ambient levels of some indicators that exceeded NRCA draft ambient standards, as well as USEPA saltwater quality criteria. This was indicated mainly for two heavy metals, lead and chromium, and biological oxygen demand (BOD). Lead and chromium data appears to be at variance with data collected from a previous study, though some time has elapsed between both determinations. Nevertheless it is considered unlikely that the lead concentration in particular would be so high in the water column. The high nutrient conditions in the harbour identified by previous workers were confirmed, especially for Hunts Bay. Suspended solids were well within the NRCA interim ambient standard for this parameter. Dissolved oxygen levels indicated well oxygenated surface and sub-surface waters.
Sediment from areas to be dredged had levels of lead and chromium which far exceeded the NRCA draft effluent standards, and (BOD) which appeared to be significantly higher than the NRCA Draft stream loading effluent standard. Though the high sulphide levels represent total sulphide, it is expected that a significant portion of this is in the form of toxic hydrogen sulphide.
Environmental Impact
Significant increase in suspended solids levels over background levels is expected. In marine disposal of the spoil. The fact that lead and chromium were much higher in leachate than in pore water would suggest that dissolution of compounds of these metals may be facilitated in oxygen-rich waters. The leachate and pore water had levels of lead and chromium which suggest that the material to be dredged fit the profile of hazardous waste based on a recent classification system developed the USEPA.
The high BOD of the leachate suggests that the material to be dredged would decompose, exerting significant pressure on available oxygen, possibly resulting in an oxygen deficit in receiving waters.
The high level of sulphide in the sediment suggests that disposal of the dredged material could result in the increase of ambient levels of hydrogen sulphide. This could potentially have a negative effect on any fishery in the vicinity at the time of discharge.
The STFATE model was used to simulate the marine disposal of the spoil. The output describes the simulated behaviour of the dredged material discharge at the surface, the sediment plume during descent, the dispersion of contaminants, and the sediment accumulation on the seabed. The model runs were parameterized for the designated offshore disposal site in 350 m water depth, which is the average depth between the 200 m and 500 m contours at the edge of the island shelf. It is assumed that the material is discharged from the trailer barge within 60 seconds and the behaviour of the resultant sediment plume and bottom accumulation is simulated for 1 hour after the material is discharged at the water surface. (Please note that the SFATE output is in feet, hence the results are presented as such).
Based on analysis of contaminant concentrations, the conservative tracer for the long-term simulation computations is lead, with the initial concentration of 156.70 mg/l. The output of the model simulation begins 30 seconds after disposal. The plume has an initial horizontal radius of 45 feet with its centroid at a water depth of 34 feet. The downward decent of the plume initially increases to as much as 16 ft/s within 35 seconds after discharge at the surface, then slows to 8 ft/s 60 sec after discharge, when the plume has increased its horizontal radius to 121 feet, and has a centroid at a water depth of 363 feet. At 95 sec after discharge, the plume is decending at a rate of 5 ft/s with the centroid of water depth at 597 feet water depth, a radius of 176 feet, and a lead concentration of 2.6 mg/l. The plume completes it convective descent 157 seconds after discharge when the centroid depth is 829 feet water depth, with a downward velocity of 2.7 ft/s, a horizontal radius of 230 feet, and a lead concentration of 1.2 mg/l. The bottom is not encountered during convective descent and the diffusion of the plume is greater than the dynamic spreading from the collapse.
The collapse phase of the plume occurs thereafter as the bottom of the larger or heavy sediment begins to encounter the seafloor and the finer sediments lag behind. Within 200 sec after discharge at the surface, the fall velocity reduces to 0.9 ft/s as the width of the cloud expands to 485 feet, having a lead concentration of 1.0 mg/l. At 303 sec after discharge at the surface, the cloud has begins a very slight upward movement as it becomes closer to neutral buoyancy. At this point the centroid of the cloud is 918 feet water depth, having a radius of 612 feet and a lead concentration of 0.96 mg/l. The centroid of the cloud begins to ascend to shallower depths, at a maximum upward velocity of 0.3 ft/s between water depths of 893 feet to 877 feet. The cloud reached neutral buoyancy at a centroid depth of 811 feet, 959 sec after discharge. At this point the cloud has a thickness of 71 feet, a radius of 1185 feet and a lead concentration of 0.56 mg/l.
Pipeline discharge impacts (Eastern Channel)
The cutter dredge to be used in the east channel would discharge waste by a pipeline to the sea floor. A zone of turbulence develops as the material exits the discharge point. This zone of turbulence extends the approximate width of the channel basin (580 m) at the northern end. Settling out occurs quickly, with the percent solids in the centerline of the plume decreasing from 30% at the point of discharge to about 0.3 % (3 g/L) at the end of the turbulent zone located approximately 100m south of the point of discharge. This would be an area of high turbidity at the surface due to the fine‑sized constituents of the effluent. At approximately 120 m away from the discharge point, the plume is interpreted to have descended to the bottom, forming a dense fluid layer that begins underflow spreading with a plume thickness (height) of approximately 6 cm. As the bottom spreading of the dense plume continues, some entrainment of the underflow into the overlying ambient flow occurs, which increases the underflow volume and decreases viscosity, and thus increases spreading along the bottom. At approximately 400 m distance from the initial discharge, the underflow plume makes contact with the east bank. At a distance of about 500 m away from the initial discharge, the underflow plume has a thickness of about 23 cm with a 0.09 percent concentration of solids.
Hunts Bay is an almost fully enclosed basin, open to the sea only by the gap beneath the Causeway, and a few other canals. All the freshwater input must therefore leave through these channels, and this interacts with rising and falling tides to produce the strongest currents situated in the vicinity of these channels.
Reclamation of this area will not impact the overall stability of the bay. The proposed area for reclamation lies in perhaps what is normally the quietest area of Hunts Bay as far as water movement is concerned. However during periods of heavy rainfall these currents will be replaced by strong fresh-water runoff currents produced by input from the large gullies.
Proper stabilization measures of the newly reclaimed area must therefore be implemented to prevent erosion during periods of high storm-water runoff. The same is true regarding the location of the site for land-based disposal of the fines (if this option is selected). Care must be taken in designing the storm water run-off for the proposed area, as a number of drains enter the sea in this area.
SOCIO –ECONOMICS
The socioeconomic impacts assessment (SIA) study area included those areas surrounding the Harbour that might be impacted by the proposed expansion activities. The SIA also took into consideration direct and indirect users of the port (and water) area and other stakeholders. Information on the existing socioeconomic and cultural environment was obtained by desktop research, review of existing reports, and field investigations. The SIA included the description and assessment of the demography; employment; distribution of income, goods and services; merchandise trade and transhipment; fisheries and fishing activities around fish landing sites of Rae Town, Greenwich Town, Port Royal, Hunts Bay at Causeway, Harbour Head and Port Henderson; education, health, housing, solid waste disposal; recreation; community fabric/cohesion; cultural/historic properties; land use; and stakeholders and public consultations.
The stakeholders and public consultation component comprised two distinct activities: a) Public Forum held on 3 August 2000, and b) Follow-up meetings and interviews with representatives from the fishing communities and cooperatives. It was obvious that all stakeholders and users of the Harbour were very genuinely concerned and interested in the proposed development and in the best interest of the people and their environment. Fishermen were concerned about the impacts of dredging and disposal of material on the marine environment and hence their livelihood, given their past experiences of dredging activities in the Harbour. Suggestions and recommendations were taken into consideration and where appropriate, were incorporated into the EIA. Included were:
· Compensation,
· Formation of a watch dog committee,
· An integrated planning approach to the sustainable development of the Harbour and surrounding areas (including comprehensive clean up efforts and community development),
· Public access to the EIA document, and
· The call for the PAJ to organize a second public forum.
Perceived impacts included very significant, direct and indirect positive benefits to national development goals and the strategic development of the Port of Kingston in order to maintain its competitiveness within the region as a premier port. The project would potentially impact economic/employment in a positive, direct and very significant, short and long term manner with the creation of approximately 1,000 new jobs during dredging (200 direct and 800 indirect jobs), plus other employment opportunities during land reclamation, design and construction. No major disruption to fisheries activities or damage to resources would result from dredging as none of any significance existed at the time of field investigation of sectors. The development of the shipping capacity of the Kingston Harbour would also require increased/improved marine policing/security (including drug enforcement capabilities) and customs associated with increased transhipment and container cargoes.
In recognition of the need to move toward a holistic and sustainable approach for the development of Kingston Harbour, a strong recommendation would be the formulation of an Integrated Development, Management and Monitoring Plan (IDMMP), incorporating existing sector plans, initiatives and projects already approved and/or being implemented. The IDMMP should include key action and results areas for the rehabilitation as well as the long-term development of Kingston Harbour, collaboratively with community-based planning and development. It should be supported and owned by all user groups and the public with certain agencies such as the Port Authority of Jamaica, NRCA/NEPA, TPD, KSAC, Ministry of Tourism and Sports, Ministry of Agriculture and Mining, the private sector (such the Port Royal Redevelopment Company among others) and NGOs, positioned to assume certain key responsibilities and lead functions. It was also recommended that most of the unskilled construction and casual laborer positions be filled locally. As much as possible, local residents, especially from the fishing communities, should be given the first opportunity for employment. On the issue of compensation to fishermen (in the event of negative impacts resulting from the project), it was recommended that the NRCA/NEPA and the Fisheries Division in collaboration with the affected Fishing Cooperatives and communities and the PAJ, should agree and discuss reasonable compensation, and the manner of its disbursement should the need arise.
IMPACT OF DISPOSAL ALTERNATIVES
The perceived impacts from the spoil disposal alternatives are positive and negative, as well as national and local in nature:
Alternative 1: Place all of the dredged material in the proposed Hunts Bay reclamation platform
Alternative 2: Dispose all of the material at a suitable marine site
Alternative 3: A combination of the above options with some material being placed in the Hunts bay Reclamation platform or some other land bank location
Disposal to a section of Hunt’s Bay would provide little or no dilution and could be a significant short–term and long-term source of lead and sulphide to the rest of the bay. Through an engineered solution, it may be possible to confine the sediment physically thus eliminating the impact from suspended solids. Preventing leaching to adjoining areas would be more difficult. This alternative would also result in further but marginal loss of habitat in addition to the area to be filled for the port expansion. Terrestrial vegetation lost during this activity would be ecologically insignificant.
Discussions with representatives from the Town Planning Department (TPD) and KSAC indicated that the proposed land use of the reclaimed land would be compatible with surrounding land uses. Once the land was reclaimed, a Site Plan should be developed by PAJ and sent to the TPD and KSAC. Potential impacts would be localized positive impacts related to ‘new’ lands being brought into use and national positive impacts related to the future development of port and transshipment activities and associated economic gains.
The stability of the existing Causeway Bridge needs to be safeguarded and the alignment of the future Causeway Highway needs to be considered. The pre-feasibility study for the new Causeway Highway was done more than 4 years ago including a proposal for the resettlement of the dwellers, fishing community and vendors. It was further understood that the PAJ had been in discussion with the Highway 2000 Team at the Ministry of Transportation and Works, and was given the ‘green light’ to proceed with works in the vicinity of the bridge, as the construction of highway would ‘work around’ the proposed development. Hence, depending on whether the measures to be implemented by the Ministry of Transportation and Works, were done in a timely manner, then potential impacts should be negligible, if not implemented on time, then potential impacts would be negative, short term and direct, until such time that the measures were put in place.
In addition, while fishing activities are minimal at the proposed reclamation site, the westward drift of the plume should be carefully monitored as it could negatively impact handline fishing activities on the western side of the bay. Also, given the composition of the material that would be dredged, and the fact that only a portion of the more compact and non-toxic material may be suitable for land reclamation, the rest of the material would have to be otherwise disposed.
Disposal at sea alone would remove the economic benefits to be gained from land reclamation. It also introduces the complication of the possible effect that toxic substances might have on marine benthic and pelagic flora or fauna. Increased levels of bio-accumulation in these organisms may have immediate or deferred mortality impacts. This alternative would be the least favourable.
A minimum dilution factor (worst case) based only on volume of receiving water and ignoring the dispersive effect of currents was determined to be around 100-fold. Assuming negligible contribution from the receiving water, and using the results of sediment/leachate analyses, maximum temporary contribution of lead from sediment deposited at the dump site could be around 0.5ppm (500ppb), while sulphide could be 5mg/l, and BOD 10mg/l. Based on the total material to be disposed of, average suspended solids could be 6mg/l. It is considered that factors such as prevailing currents as well as interval between discharge events could lessen these values considerably.
A minimum dilution factor (worst case) is determined to be around 1000-fold. Using similar assumptions as in the 200m analysis, it is suggested that a further reduction of at least one order of magnitude would be achieved. It is also likely that at this greater depth, oceanic currents would enable a greater level of dilution. The greater distance that would have to be travelled by the dredge would also provide a longer period between discharge events thus improving dilution even further.
If dumping of the spoil from the Gordon Cay/container port sections H5 to H1 is to occur between the Hope River outfall and Cow Bay, then this heavy metal-polluted material must be placed into very deep water (not less than 1,000 m) and as far south as is feasible in terms of travel time for the barge. This is to avoid the displacement of resident fish species. Cow Bay is known for deepwater fishes such as dolphinfish, kingfish and jacks, and is the site of a very small fishing beach
The heavier fractions will make up the mound of consolidated material and this will be thinner and cover a larger surface area, than if dumping were to take place at 200m. This could result in the complete leaching of all the contaminants from the mound to the surrounding waters taking place in a shorter time. Some finer fractions of the plume may become neutrally buoyant at depth and travel with the prevailing current at that depth.
Other parameters necessary for model input such as temperature, salinity, current regime stratification, have not been measured at these depths, and so we must consider the greater spreading as the worst case scenario.
This scenario assumes disposal of the more contaminated material on land at an adequately prepared site, and “clean” material in the marine environment. This assumes that the contaminated material is surface sediment, and that the quality of sediment improves with depth. For this option dumping could be at the 200m or 1000m contour. This option would be expected to have a minimal environmental impact especially where marine disposal is to the 1000m contour.
Based on the foregoing discussions, this alternative would be the most favourable. This option would take into consideration the concerns of the fishing communities, provide additional land space for the further development of container storage with significant potential economic benefits, and facilitate the disposal of toxic materials in a location that would not negatively or minimally impact on the livelihoods of the surrounding communities under normal circumstances.
MITIGATION
Water Quality
The unexpectedly high values obtained for the trace metals lead and chromium may be adequate reason to repeat these analyses on freshly collected samples. The data base could also be improved by carrying out analysis on the actual sediment dredged at different depths. Though the turn around time for these analyses would limit their usefulness in this exercise, it would assist in refining disposal plans for future dredging operations.
Development of the disposal strategy should take into consideration the possible need to identify different ways of disposing of sediment from different depths (especially in the harbour). Where possible consideration should be given to using sediment as fill for land based projects.
Sediment from the more obviously contaminated areas, namely, Gordon Cay, and the channel near Fort Augusta may have to be disposed of in a different manner than sediment from areas in the outer harbour. The following simple matrix relates sediment type with potential hazards, and disposal options recommended for consideration:
SEDIMENT SOURCE |
POTENTIAL HAZARD ASSOCIATED WITH DISPOSAL |
DISPOSAL OPTIONS RECOMMENDED FOR CONSIDERATION |
|
Outside Harbour |
Increased Suspended Solids |
Ensure safe distance from sensitive ecosystems e.g. seagrass beds, and coral reefs |
|
Ship channel (Port Royal to Fort Augusta) |
Increased suspended solids, possible hydrogen sulphide contamination, organic load |
Ensure safe distance from sensitive ecosystems e.g. seagrass beds, and coral reefs, deep water disposal (>300m) |
|
Ship channel (Fort Augusta to Turning Basin) |
Increased suspended solids, significant hydrogen sulphide contamination, high organic load, possible leaching of lead and chromium |
Land disposal at a sealed site, disposal in very deep water (>1000m), control of discharge rate. |
Ecology
Suggested mitigation for the project includes the following: -
C Curtains placed on dredge to trap sediments and therefore limit the lateral movement of turbid water;
C Spoil dispersion outfall characteristics to be evaluated by collecting grab water samples during dredging operations and operations modified accordingly;
C Dredging to a slightly greater depth than absolutely necessary to pick up more, heavier, material so as to facilitate fallout of dredge spoil when released in open water;
C Dredging to a slightly greater depth than absolutely necessary so as to reduce the need for maintenance dredging;
C No dredging in periods of rapid water movements, for example, in the afternoon when trade winds are strong, or during the rainy season when large influxes of fresh water could move significant volumes of sediment laden waters across the harbour to the Port Royal mangroves;
C The connection of a conical reflective shield to the outlet as silt suppression and dispersion control mechanism;
C Careful mapping of seagrass areas directly affected by the dredge and replanting 130% of area affected to compensate for possible mortality. These techniques are well established for Kingston Harbour waters,
C Reseeding of mussel beds in the Port Royal mangroves to improve the bait population for the fishery;
C Removing corals, seagrasses, gorgonians and urchins at the Rackham’s Cay area and relocating to Gun Cay or some other appropriate site;
C Preventative maintenance of equipment to mitigate negative environmental impacts such as leakages and spillages.
MONITORING PROGRAMME
Monitoring of the Development Programme
A lead role in monitoring should be jointly taken by the NRCA/NEPA and the Fisheries Division. As the Kingston Harbour Rehabilitation Steering Committee already existed, then efforts should be made to utilize existing mechanisms and to build synergy and collaboration. The terms of reference and mandate of the Committee should be reviewed to allow for comprehensive monitoring and accountability of development activities within the Harbour and surrounding areas that might impact on the harbour, including recommendations contained in this EIA. The Committee should comprise members of key government agencies including the NRCA/NEPA, and Fisheries Division, NGOs/CBOs, Fishing Cooperatives and community representatives, Student Network, private sector, international agencies, and the Port Authority of Jamaica.
Monitoring of Dredging Programme
It is recommended that during the actual dredging and disposal procedures, a monitoring program be implemented. This program should include the following:
C An examination of all important environmental parameters should be carried out during the first week of the operation. If no adverse effects are noted, monitoring should be fortnightly. This monitoring will be carried out more frequently during unusual weather conditions, or if adverse effects are noted.
C Turbidity and other sensitive water quality readings should be taken at all sensitive areas outside of the area of the screens initially, and at regular intervals throughout the operation.
C Current readings and examination of plumes should be taken on a spot check basis throughout the area of interest.
· Aerial photographs (unannounced) should be taken regularly to determine if the dredge is operating according to recommendations.
· Soundings should be taken fortnightly at the approved offshore dump site to monitor the effect over the period of deposition.
· A continuous record of wind speed and direction should be made throughout the period of dredging.
Fortnightly reports should be sent to the NRCA on the dredging activities unless conditions develop which warrant more frequent reporting. Spot checks should be done on nearby reefs to monitor any siltation at least once per month, preferably every two weeks