Tide Gauge 00,04 13, /09/90 03J9 15, /09/ /09/90 03,44 16,09 04,44 16,19 05,14 17,04

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1 DATE Tide Tables Tide Gauge Tide Tables Tide Gauge 30/08/90 00,lO 12,52 00,04 13, /08/90 02,03 14, /09/90 03,12 15,16 03J9 15, /09/90 03,57 15,59 03,44 16, /09/90 04,33 16,36 04,44 16, /09/90 05,06 17,11 05,14 17, /09/90 06/09/90 07/09/90 08/09/90 09/09/90 10/09/90 05,38 17,46 06,12 18,23 06,47 18, ,38 07,59 20,18 08,37 21,03 05,39 17,39 05,54 18,14 06,44 18,54 07,14 19,29 07,59 20J4 08,34 21, For inspection purposes only /09/90 09,23 21,57 09,24 22, /09/90 10,22 23,11 10,44 23, /09/90 11,49 11, Table A1-2 Camparison of High Water prediction in Westport Bay from Tide Tables and Automatic tide Gauge. 0621B EPA Export :23:44:12

2 >- c a3 + K 0 a. + U) LLI 3 I LLI 0 3 c 0 W a H t For inspection purposes only. EPA Export :23:44:12

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4 TIDE GAUGE - WESTPORT BAY For inspection purposes only. flug 13 Figure A1-3 Aug 14 YEAR Aug 15 Klrk McCLure Morton EPA Export :23:44:12

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14 APPENDIX 2 Wind Data The mean daily wind speed and direction for the survey period 12 August to 12 September 1990 was obtained from a land based anenometer positioned at Bertra Island. Wind data was also obtained from the closest meteorological stations to the site at Belmullet and Claremorris. A comparison of the daily wind speeds showed that the site was subjected to wind strengths in the order of 15% less than that recorded at Belmullet and around 40% greater than that recorded at Claremorris. The recording station at Behullet, having an open coastal location, was therefore considered to be the most representative of Westport Bay. The wind data from Belmullet was also generally consemative with respect to the dispersion effects of wind generated currents on the release of effluent from the proposed 0utfaJ.I in Westport Bay. Wind records from Belmullet in the form of mean hourly wind speeds and the number of occurrences for a series of directions over the 20 year period, January 1963 to December 1982, were used as the base data for the study. This is because the much longer period of data available was statistically more representative of long term conditions and included the influence of the critical months for shellfish harvesting, October and November. For inspection purposes only. The wind data from Belmdet is presented in the form of a wind rose in Figure A2-1. In the preparation of this wind rose, the raw data was reduced into 30' sectors and classified into three speed groups. The length of each sector represents the percentage frequency of winds blowing in that direction. It can be seen from the wind rose that the prevailing wind direction is from the south-westerly sector. The winds are less than Beaufort Force 4 (5.5 ds) for 38% of the time, irrespective of direction, while winds of strength force 4-6 blow for 37% of the time from the south and west sectors and 11% of the time from the north and east sectors. Strong winds, Beaufort Force 7 and greater occur for 2.4% of the time from the southerly and westerly directions and only 0.2% of the time from the northerly and easterly directions.

15 Tables of percentage frequency and number of occurrences of wind direction and velocity are presented in Tables A2-1 and A2-2. A probabilistic analysis of this data was undertaken to estimate the wind speeds which are likely to occur during storms of extreme intensity. The results are shown in Table A2-3. For a storm with a return period of 1 in 50 years, the mean hourly wind speeds are calculated as 32.0 m/s for a south-westerly storm, 28.6 m/s for a westerly storm and 27.5 m/s for storms from a north-westerly direction. Storms of such an intensity have a 63% chance of occurring once in 50 years and a 2% chance of occurring in any one year. For storms which have a 1 in 1 year return period, the mean hourly wind speeds are reduced to 26.5 m/s for a south-westerly storm, 22.5 m/s for a westerly storm and 20.8 m/s for storms from a north-westerly direction. For inspection purposes only.

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17 Return 150 1:lO 1:l 1:0.5 Period (Years) Direction For inspection purposes only. Wind Speeds in metrdsecond Table A2-1 - Summary of Probabilistic Analysi eed D

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20 APPENDIX 3 Confirmatory Soundings within the Study Area Confirmatory soundings were undertaken within the study area to check the accuracy of both the Admiralty Charts and Source Data Sheets. The survey was carried out using a continuous trace echo sounder. Position king was made by both sextant and EDM Total Station (Electronic Distance Measurement). Additional information was also obtained &om aerial photographs and surveys carried out by the Queen's University of Belfast. The survey concluded that the bathymetry of the Inner Westport Bay, to the east of Pigeon Point, was generally accurately depicted by the Admiralty Charts and Source Data Sheets. However, significant changes to the seabed topography were observed within the outer bay, particularly around: (1) Bertra Spit. (2) The Dorinish Complex. (3) The Annagh Island Complex. The coastal processes which have given rise to the changes in bathymetry are described in the "Morphology of Westport Bay" section of this Report. For inspection purposes only. The changes to the bathymetry of Westport Bay as depicted by the confirmatory soundings were used to update the digital ground model of the Study Area.