Tidal Lagoon Swansea Bay plc Appendix 7.2 Supporting Technical Information Report Tidal Lagoon Swansea Bay – Environmental Statement Volume 3 Appendix 7.2 . TIDAL LAGOON SWANSEA BAY LIMITED TIDAL LAGOON SWANSEA BAY MARINE WATER QUALITY ASSESSMENT SUPPORTING TECHNICAL INFORMATION Report Reference. P1609_RN3391_Rev1 Issued 21 January 2014 Intertek Williams House 11 - 15 Columbus Walk Cardiff CF10 4BY United Kingdom Tel: +44 (0) 2920 020660 Fax: +44 (0) 1428 727122 E-mail: [email protected] Web Site: www.intertek.com . DOCUMENT. RELEASE FORM . TIDAL LAGOON SWANSEA BAY MARINE WATER QUALITY ASSESSMENT. Title: . SUPPORTING TECHNICAL INFORMATION Client: TIDAL LAGOON SWANSEA BAY LIMITED Report Reference: P1609_RN3391_REV1 Date of Issue: 21 January 2014 Hard Copy Digital Distribution: TIDAL LAGOON SWANSEA BAY LIMITED No: n/a PDF Intertek Energy & Water Consultancy Services No: n/a PDF Prepared By: Emma White, Ann Saunders, Josh Gibson, N Barcock Project Manager: Authoriser: Nick Barcock p.p. Chris Mooij Rev No Date Reason Author Checker Authoriser Rev 0 30/12/13 Original NB AS NB Rev 1 21-01-14 Revisions NB AS NB COPY NUMBER: (applies to hard copies only) Intertek Energy & Water Consultancy Services is the trading name of Metoc Ltd, a member of the Intertek group of companies TIDAL LAGOON SWANSEA BAY LIMITED TIDAL LAGOON SWANSEA BAY MARINE WATER QUALITY ASSESSMENT CONTENTS 1 INTRODUCTION ................................................................................................. 1 2 SWANSEA BAY COASTAL MODEL ................................................................. 3 2.1 MODEL PARAMETERS ............................................................................................. 6 2.2 DISCHARGE SOURCES ............................................................................................ 7 2.3 MODEL APPLICATIONS .......................................................................................... 12 3 MODEL APPLICATIONS ................................................................................. 15 3.1 VALIDATION APPLICATIONS ................................................................................... 15 3.2 SENSITIVITY APPLICATIONS ......................................................................... 15 3.3 MICROBIOLOGICAL MODEL (STORM-IMPACT) ..................................................... 17 3.4 OPTIMISATION APPLICATIONS ............................................................................... 19 3.5 CONSTRUCTION IMPACTS APPLICATIONS .............................................................. 20 3.6 DECOMMISSIONING APPLICATIONS ........................................................................ 23 3.7 DESIGN ITERATION APPLICATIONS ......................................................................... 23 3.8 SUMMARY ........................................................................................................... 24 4 ADVECTION DISPERSION MODEL VALIDATION ......................................... 27 4.1 SURVEY 1 ........................................................................................................... 28 4.2 SURVEY 2 ........................................................................................................... 30 4.3 SURVEY 3 ........................................................................................................... 32 4.4 DISCUSSION AND CONCLUSIONS ........................................................................... 34 5 STORM-IMPACT VALIDATION ....................................................................... 35 5.1 INPUT SOURCES AND ASSUMPTIONS ...................................................................... 35 5.2 VALIDATION AGAINST NRW DSP SAMPLE DATA ..................................................... 35 5.3 VALIDATION AGAINST SMART COASTS EVENT DATA ................................................. 39 5.4 CONCLUSIONS ..................................................................................................... 45 6 WIND SENSITIVITY APPLICATIONS .............................................................. 46 7 MICROBIOLOGICAL SOURCE INPUTS ......................................................... 52 7.1 POINT SOURCES .................................................................................................. 52 7.2 DIFFUSE SOURCES ............................................................................................... 57 8 WFD SOURCE INPUTS ................................................................................... 62 REPORT REF: P1609_RN3391_REV1 21/01/2014 TIDAL LAGOON SWANSEA BAY LIMITED TIDAL LAGOON SWANSEA BAY MARINE WATER QUALITY ASSESSMENT 8.1 FLOW ................................................................................................................. 62 8.2 DISSOLVED OXYGEN, BOD AND AMMONIA LOADS .................................................. 64 8.3 NUTRIENT LOADS ................................................................................................ 68 8.4 TEMPERATURE AND SALINITY ................................................................................ 69 9 REFERENCES .................................................................................................. 72 REPORT REF: P1609_RN3391_REV1 21/01/2014 TIDAL LAGOON SWANSEA BAY LIMITED TIDAL LAGOON SWANSEA BAY MARINE WATER QUALITY ASSESSMENT TABLES TABLE 2-1: LIST OF WIND CONDITIONS USED IN MODEL APPLICATIONS ....................................... 7 TABLE 3-1: ESTIMATED DREDGING AND CONSTRUCTION RATES APPLIED TO MODEL. ................. 21 TABLE 4-1: SUMMARY OF SMART COAST TRACER SURVEYS (2011) ........................................ 27 TABLE 5-1: COMPARISON OF STORM-IMPACT PREDICTIONS AND BATHING WATER SAMPLES AGAINST RBWD STANDARDS: 2008-2011 ....................................................................... 36 TABLE 7-1: LIST OF POINT SOURCES, REPRESENTATIVE MODEL DISCHARGES AND CONCENTRATIONS .......................................................................................................... 52 TABLE 7-2: LIST OF DIFFUSE SOURCES, REPRESENTATIVE MODEL DISCHARGES AND CONCENTRATIONS .......................................................................................................... 57 TABLE 8-1: MODELLED FLOWS .............................................................................................. 62 TABLE 8-2: MEASURED AND CALCULATED FLOWS – RIVERS TAWE, NEATH AND AFAN .............. 63 TABLE 8-3: MEASURED AND CALCULATED FLOWS – MINOR RIVERS ........................................ 63 TABLE 8-4: MINOR WWTWS FLOW STATISTICS ...................................................................... 63 TABLE 8-5: MINOR WWTWS FLOW STATISTICS ...................................................................... 63 TABLE 8-6: LIST OF POINT SOURCES AND CONCENTRATIONS ................................................... 65 TABLE 8-7: LIST OF DIFFUSE SOURCES AND CONCENTRATIONS ............................................... 67 TABLE 8-8: WINTER BOUNDARY AND BACKGROUND CONCENTRATIONS ................................... 67 TABLE 8-9: DISSOLVED OXYGEN (DO), BIOCHEMICAL OXYGEN DEMAND (BOD) AND AMMONIA LOADS ........................................................................................................................... 68 TABLE 8-10: SUMMER BOUNDARY AND BACKGROUND CONCENTRATIONS ................................ 68 TABLE 8-11: LIST OF NUTRIENT CONCENTRATIONS ................................................................. 69 TABLE 8-12: BOUNDARY AND BACKGROUND CONCENTRATIONS .............................................. 69 TABLE 8-13: LIST OF POINT SOURCES AND WINTER CONCENTRATIONS .................................... 70 TABLE 8-14: WINTER BOUNDARY AND BACKGROUND CONCENTRATIONS ................................. 70 TABLE 8-15: LIST OF POINT SOURCES AND SUMMER CONCENTRATIONS ................................... 71 TABLE 8-16: SUMMER BOUNDARY AND BACKGROUND CONCENTRATIONS ................................ 71 REPORT REF: P1609_RN3391_REV1 21/01/2014 TIDAL LAGOON SWANSEA BAY LIMITED TIDAL LAGOON SWANSEA BAY MARINE WATER QUALITY ASSESSMENT FIGURES FIGURE 1-1: GEOGRAPHICAL OVERVIEW OF SWANSEA BAY ..................................................... 2 FIGURE 2-1: MODEL DOMAIN, GRID AND BATHYMETRY .............................................................. 5 FIGURE 2-3: SCHEMATIC REPRESENTATION OF THE HYDROLOGICAL MODEL............................. 11 FIGURE 2-4: SCHEMATIC REPRESENTATION OF MODEL AND DATA INTERFACES ........................ 13 FIGURE 2-5: SCHEMATIC REPRESENTATION OF MODEL STEPS ................................................. 14 FIGURE 4-2: MODELLED AND MEASURE TRACER CONCENTRATIONS MEASURED AT SWANSEA DSP SURVEY 1, SINGLETON PARK STREAM RELEASE ..................................................... 29 FIGURE 4-3: MODELLED AND MEASURE TRACER CONCENTRATIONS MEASURED AT SWANSEA DSP SURVEY 1, TAWE RIVER RELEASE .......................................................................... 29 FIGURE 4-4: MODELLED AND MEASURE TRACER CONCENTRATIONS MEASURED AT SWANSEA DSP SURVEY 1, CLYNERIVER RELEASE .......................................................................... 30 FIGURE 4-5: MODELLED AND MEASURE TRACER CONCENTRATIONS MEASURED AT SWANSEA DSP SURVEY 2, AFAN WWTW RELEASE ........................................................................ 31 FIGURE 4-6: MODELLED AND MEASURE TRACER CONCENTRATIONS MEASURED AT SWANSEA DSP SURVEY 2 TAWE RIVER RELEASE ..........................................................................