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Assessment Tools for SEA

Assessment Tools for SEA

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Assessment Tools for SEA

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  1. Workshop on Strategic Environmental Assessment Assessment Tools for SEA Freeman Cheung Chairman, Hong Kong Institute of Environmental Impact Assessment 18 June 2005

  2. Introduction • More sophisticated assessment techniques are now available for environmental assessment • The recent development of the computer modelling techniques using Geographical Information System (GIS) has assisted the development of assessment tools for EIA • Regional Air Quality Model • Noise Mapping Software • GIS-based Habitat Map

  3. Air quality models for EIA • simple Gaussian dispersion models • other numerical models (plume/puff models of various complexity) • physical modelling (wind tunnel) • regional photochemistry air dispersion model

  4. Pollutants in the Atmosphere and their Transport over Hong Kong (PATH) • PATH Modelling System commissioned by EPD in 1996 and delivered in 2001 • state-of-the-art system, custom-built for HK from existing US components and thoroughly validated

  5. AIVS Aircraft Inventory Verification Study • Airborne meteorological and air quality measurements • A total of 14 flights in November 1997 • Results used in PATH verification • Comparison of pollutant fluxes on the inflow and outflow • SAR borders provides a check on the total HK emissions

  6. PATH modelling domains • five nested domains • grid spacing of 0.5, 1.5, 4.5, 13.5, 40.5 km • 49 x 49 grids and recently extended to 97 x 97 grids • unequally spaced vertical layers extend up to 25 km a.g.l. The lowest layer only 20 m deep

  7. SAQM 49x49 nested grids

  8. Emissions • comprehensive HKSAR and regional emissions databases • separate datasets for: • point sources • motor vehicles • marine emissions • biogenic emissions • all other area sources

  9. Example: wind field & O3 concentrations 20 August 1996 4.5 km grid

  10. Examples of Regional Air Quality Modelling for SEA • Site search and EIA for the proposed HEC 1800 MW power plant at Lamma Extension • CTS-3 SEA: Assess impacts of different vehicular emissions control measures, and different transport and population development scenarios by means of comprehensive air quality modelling • PATH was used to assist in the development of emission control strategy for the Pearl River Delta Region

  11. HEC 1800MW Power Station EIA Study • PATH modelling of HKSAR air quality impacts • several emissions scenarios developed • AQO compliance demonstrated for the worst case meteorological scenario (1 hr and 24 averages) and by means of the PATH ‘annual average episodes’

  12. Base case SO2 time series for 26-28 June 1995, assumed as the worst-case scenario for the HEC power station EIA

  13. SEA for the Third Comprehensive Transport Study (CTS-3) • many transport and population development scenarios tested • detailed, 10 vehicle-class traffic forecast for each model grid cell used to estimate vehicular emissions under different growth scenarios • separate scaling up or down of other emissions (power stations, area sources, marine) • innovative use of model results for assessment: modelled increments (2016 scenario – 1997 base case) added to actually measured 1997 concentrations

  14. NO2 annual conc. 2016 – 1997 high growth (high end) CTS-3 scenario

  15. Noise Exposure System • ERM was commissioned by EPD in 2000 to undertake a two years Study “Investigation Study for Review of the Acoustical Environment Due to Infrastructure Projects in Hong Kong (Contract 39/2000)” • The worldwide trend to communicate environmental noise information to the public

  16. Requirements of the Noise Exposure Model • Collate noise information for the territory • Identify and quantify the scale of noise problems • Evaluate the effectiveness of mitigation measures

  17. Data Inventory for the NES • Digital Elevation Model (DEM) • Road Network (Linked to BDTM and ATC data) • Building Locations and Heights • Podiums • Enclosures • Barriers • Ground Surface • Weather Stations • Noise Grids for 4 heights for Lden, Ln, Ld, Le and L10

  18. Some Statistics…. • 2,000km trafficable road (>2,000 AADT) • ~1,100 km2 study area • 6.8M inhabitants • 80,000 residential buildings • 0 – ~1,000 m elevation

  19. Road Treatment Illustration

  20. Road Treatment (Traffic Composition)

  21. Model

  22. Reality

  23. Railway tracks Road centreline Airport Building footprints Podiums Barriers Enclosures Spot heights Contour lines Rivers Slope tops/bottoms Vegetation (ground absorption) Processing Overview Input Processing Output Obstacles Noise Exposure Software Level of exposure estimated for various areas G I S Emitters Decisions made on mitigation/planning based on results Calculates noise levels in different areas using inputs Traffic Model • # of vehicles • Speed • Vehicle weight

  24. Road Noise Contour @ 4m above ground level

  25. Conflict Map

  26. 4m above ground 18m above ground 40m above ground 80m above ground

  27. Noise Exposure • Project requirement to estimate percentage of population exposed to excessive noise • Assigning noise levels to each building facades • Data used include Census Map and Building Type Dataset • Use street block population data and building block volume to estimate number of people affected

  28. Histogram of Noise Levels vs Population

  29. No. of People Exposed to Road Traffic Noise Levels > 70 dB(A)

  30. Summary • One of the largest scale noise mapping exercises in the world • Integrated GIS and Noise Model for better visualisation of the noise environment • A very useful tool/platform to develop 3D graphical presentation of information to encourage public participation

  31. GIS-based Habitat Map

  32. Habitat Type Freshwater/Brackish Wetland Fishpond/Gei Wai Mangrove Seagrass Bed Fung Shui Forest Intertidal Mudflat Natural Watercourse Lowland Forest

  33. Ecological Assessment for NENT Study • Effects on Species of Conservation Concern • Habitat fragmentation/ isolation • Noise/ human disturbance • Water quality • Determine amount of habitat lost • Refer to total habitat in area of Hong Kong • Ecological value of habitat • Presence of rare species

  34. Conclusions • GIS based assessment tools are non-dispensable tools in strategic environmental assessment and planning • PATH is a useful tool to compare air quality impact from different development scenarios and to develop control strategies • Noise exposure system is capable of producing population exposure forecast for different districts for future land use planning • GIS-based habitat map is used to provide calculation of habitat loss for assessment of the potential ecological impact for strategic environmental assessment