Monitoring Plan for Dredging & Disposal Operations for Killybegs Harbour

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1 Monitoring Plan for for Killybegs Harbour Produced by AQUAFACT International Services Ltd On behalf of AQUAFACT INTERNATIONAL SERVICES LTD., 12 KILKERRIN PARK, GALWAY. tel +353 (0)

2 Table of Contents 1. Turbidity / Suspended Solids Monitoring Sites Harbour Offshore Control McSwyne s Bay St. John s Point/ Mouth of Inver Bay Disposal Site Phytoplankton and Zooplankton Sediment Chemistry Benthos... 6 List of Figures Figure 1: Environmental sensitivities in the vicinity of the dredging and disposal operations Figure 2: Location of proposed monitoring sites Figure 3: Grab stations for benthic monitoring surveys in Donegal Bay Figure 4: SPI locations for monitoring surveys List of Tables Table 1: Coordinates of propose monitoring sites... 3

3 1. Turbidity / Suspended Solids This monitoring programme is intended to cover the initial pre-dredging (baseline monitoring) phase, the dredging and disposal and post-disposal phases. The proposed monitoring sites are identified below followed by the pre, during and post-monitoring requirements at each. All monitoring locations shown are subject to change depending on the model outputs Monitoring Sites The monitoring sites are selected based on environmental sensitivities in the area. Figure 1 shows potentially the most environmentally sensitive sites in the area. These consist of csacs, SPAs and aquaculture sites. The Appropriate Assessment prepared for the dredging and disposal operations shows that, based on modelled outputs of the dredging and disposal plumes, no impact is expected on the reef habitats in csacs IE000181, IE000189, IE000625, IE001680, IE000428, IE and IE due to distance and the insignificant levels of deposited and/or suspended sediments. In addition, any impact on bird populations due to the dredging and disposal operations will be negligible. The identified sensitivities in the area that require monitoring are the aquaculture sites in Inver Bay and McSwynes Bay and the St. John s Point csac (IE000191). In addition to these, it is best practice to monitor the area surrounding the dredging operation i.e. Killybegs Harbour and to monitor an offshore control for the disposal site outside the influence of the disposal operation. On the basis of this, 4 static monitoring locations have been selected: 1. Killybegs Harbour 2. Offshore control site east of the disposal site 3. Mouth of McSwynes Bay 4. St. John s Point/ Mouth of Inver Bay All potential monitoring locations can be seen in Figure 2 with coordinates shown in Table 1. Prior to deployment, the location of the buoys will be agreed with the relevant authorities e.g. Irish Lights, Coastguard, Harbour Master, KFO etc. to ensure navigational and fishing lanes are not impacted. Each of the buoys will be fitted with appropriate lights and radar reflectors. 1

4 Figure 1: Environmental sensitivities in the vicinity of the dredging and disposal operations. Figure 2: Location of proposed monitoring sites. Disposal site outlined in green. 2

5 Table 1: Coordinates of propose monitoring sites Monitoring Site Longitude (WGS84) Latitude (WGS84) Killybegs Harbour Inver Bay McSwyne s Bay Off shore Harbour It is proposed to carry out static monitoring around the dredge site in the harbour area. One moored buoy will be deployed in the southern part of the harbour area, in a location approved by the Harbour Master. This moored buoy will have a solar panel for power and will be cabled to a probe at a suitable depth. The probe will contain sensors for Turbidity, Dissolved Oxygen, Temperature and Salinity. They will be set to record every 15 minutes with data being relayed back to an onshore monitoring station. This buoy will be deployed for a minimum of 1 month prior to dredging commencing (to provide baseline data) and will remain in place for the duration of the dredging operation. Water samples for suspended solid analysis (for correlation with the turbidity results) will be collected during the baseline campaign from the location of the moored buoy. Samples will be collected every hour for 12 hours for 1 week. Weekly samples will be collected during the dredging campaign. This baseline information will be used to determine the background range for turbidity and suspended solids. The moored buoy will require servicing at c. 6 month intervals but in the case of an emergency e.g. the mooring is moved by strong waves or fouled by a vessel, additional field trips may be required to recover and replace the equipment. Additional monitoring will be required during the dredging operation. A mobile monitoring campaign will be carried out during dredging. It is proposed that 5 points (number subject to change) plus a transect through the dredge plume (every m) will be monitored every two hours during the dredging operation. Again surface, mid and bottom will be monitored for Turbidity, Dissolved Oxygen, Temperature and Salinity. For Turbidity, a trigger level of 50 mg/l above background is recommended. The time interval between sampling sessions may be extended to 6 or 12 hourly intervals if compliance with this trigger level is demonstrated. Exact locations will be selected following review of model outputs. This mobile monitoring should commence at least 2 days prior to dredging commencing, continue every day during dredging and for at least 24 hours once dredging ceases. AQUAFACT can provide costs for this once details are known. Monitoring will cease 24hrs after dredging ceases. It may be advantageous to monitor plumes following ship/trawler movements in the harbour during the baseline data recording phase as these may have an influence on background levels. 3

6 Offshore Control A monitoring buoy is proposed for the offshore control location. This location is in waters of c. 70m deep. A large buoy similar to a navigational buoy in size will be required for the moored monitoring site at this location. This moored buoy will have a solar panel for power and will be cabled to probes at mid and bottom positions. Each probe will contain sensors for Turbidity, Dissolved Oxygen, Temperature and Salinity. They will be set to record every 15 minutes with data being relayed back to an onshore monitoring station. The buoy will be deployed 3 months prior to disposal to provide background data on turbidity. Monitoring will continue for a period of 3 months after disposal operations are complete. An Acoustic Wave and Current profiler (AWAC) will also be deployed on a bottom frame and cabled back to the buoy. Wave and current data will be recorded and relayed to shore. This should be installed as far in advance of the dredging works as possible to get as much background information as possible and left in place 1 month post-completion of the disposal activity. The moored buoy will require servicing but in the case of an emergency e.g. the mooring is moved by strong waves or fouled by a vessel, additional field trips may be required to recover and replace the equipment. During the pre-dredging phase, water samples for suspended sediments will be collected (frequency, times, tides etc.) to calibrate against the turbidity levels and to obtain a background range. It is proposed that samples will be collected every hour for 12 hours for 1 week during the baseline data collection phase and weekly thereafter. No trigger level is required at this site as its purpose is to monitor what is happening so that as much real time information is available in the event of an incident St. John s Point/Mouth of Inver Bay A monitoring buoy is proposed for the area off St. John s Point and at the mouth of Inver Bay. This location is in waters c. 25m deep and has been selected to act as a trigger site for elevated levels of turbidity and suspended solids. This moored buoy will have a solar panel for power which will be cabled to a probe located at a suitable depth. The probe will contain sensors for Turbidity, Dissolved Oxygen, Temperature and Salinity. The probe will be set to record every 15 minutes with data being relayed back to an onshore monitoring station. Monitoring will commence 1 month before operations commence and will continue for the duration of the dredging and disposal campaign and for at least 1 month after disposal ceases. The moored buoy will require servicing at c. 6 month intervals but in the case of an emergency e.g. the mooring is moved by strong waves or fouled by a vessel, additional field trips may be required to recover and replace the equipment. During the pre-dredging phase, water samples for suspended sediments will be collected (frequency, times, tides etc) to calibrate against the turbidity levels and to obtain a background range. It is proposed that samples will be collected every hour for 12 hours for 1 week during the baseline data 4

7 collection phase and weekly thereafter. A trigger level of 50mg/l above background is proposed as this was the value agreed with the aquaculture industry for the previous disposal operation in Mouth of McSwynes Bay A monitoring buoy is proposed for the mouth of McSwyne s Bay. This location is in waters of c. 28m deep and has been selected to act as a trigger site for elevated levels of turbidity and suspended solids. This moored buoy will have a solar panel for power which will be cabled to a probe located at a suitable depth. The probe will contain sensors for Turbidity, Dissolved Oxygen, Temperature and Salinity. The probe will be set to record every 15 minutes with data being relayed back to an onshore monitoring station. Monitoring will commence 1 month before operations commence and will continue for the duration of the dredging and disposal campaign and for at least 1 month after disposal ceases. The moored buoy will require servicing at ca 6 month intervals but in the case of an emergency e.g. the mooring is moved by strong waves or fouled by a vessel, additional field trips may be required to recover and replace the equipment. During the pre-dredging phase, water samples for suspended sediments will be collected (frequency, times, tides etc) to calibrate against the turbidity levels and to obtain a background range. It is proposed that samples will be collected every hour for 12 hours for 1 week during the baseline data collection phase and weekly thereafter. A trigger level of 50mg/l above background is proposed as this was the value agreed with the aquaculture industry for the previous disposal operation in Disposal Site In addition to the above fixed buoys, it is proposed to carry out mobile monitoring from a RIB while disposal is occurring. The purpose of these data collection surveys is to monitor in real-time the dispersion of the plume and to validate the model. Turbidity, Dissolved Oxygen, Temperature and Salinity will be measured throughout the water column. Monitoring will continue for 1 week after disposal ceases. 2. Phytoplankton and Zooplankton Monthly plankton samples will be collected at the same suite of water monitoring stations (Inver, McSwynes, St. John s Pint and Offshore Control). Sampling will be carried out 1 month prior to dredging commencing and continue monthly as long as the buoys are in place. If toxic species of phytoplankton or exceptionally high numbers of medusae are recorded, an increase in sampling frequency e.g. weekly may need to be considered. A 150µ mesh for phytoplankton and a 90μ for zooplankton is recommended. If deemed necessary, a larger mesh (1 cm) can be used to collect large gelatinous zooplankton. A 10 minute surface tow should be undertaken for phytoplankton and a U tow (from the surface down to the sea bed and back up to the surface) should be undertaken for zooplankton. Phytoplankton samples should be stored in Lugol s iodine and zooplankton samples in 5

8 5% buffered formalin for later identification and enumeration in the laboratory. 3. Sediment Chemistry Five samples for sediment chemistry will be collected from the surface of the disposal site prior to disposal for the following analysis: total organic carbon, heavy metals (Aluminium, Arsenic, Cadmium, Chromium, Copper, Lead, Lithium, Mercury, Nickel, Zinc), TBT & DBT, ICES7 CB and USEPA 16 PAH 1. Samples for full particle size distribution will also be collected. The National Laboratory Service will be the analysing laboratory. Results for all analyses will be sent to the Department upon receipt from the laboratory. Consideration should be given to ongoing monitoring of metals/other contaminants at the disposal over the same timeframe as the benthic monitoring (Section 4). Consideration should also be given to monitoring metals/other contaminants at discrete locations around the bay. 4. Benthos A benthic monitoring survey consisting of grab sampling for fauna and sediments and a Sediment Profile Imagery survey will be required 10 days, 6 months and 12 months post disposal and potentially 2 years post disposal (if deemed necessary). The stations sampled and methodology proposed will be the same as used in the baseline surveys. Figures 3 and 4 show the grab and SPI locations respectively. Quantitative grab sampling (0.1 m 2 Day Grab + 1 mm mesh sieve) Identification, enumeration and statistical analysis (using PRIMER) Sediment Profile Imagery Particle size analysis Reports following each survey will be submitted to the Department within three months of survey completion. 1 Sampling and analysis to be in line with analytical and quality requirements set out in the Guidelines for Assessment of Dredged Material (2006). 6

9 Figure 3: Grab stations for benthic monitoring surveys in Donegal Bay. Figure 4: SPI locations for monitoring surveys. 7