Flooding and Development in Low-Lying areas in Jamaica : Impact of Climate Change

Transcription

1 Flooding and Development in Low-Lying areas in Jamaica : Impact of Climate Change Session : Managing Ecosystmes for more Resilient Cities in India, Bolivia, Jamaica Resilient Cities, 2016, Bonn Arpita Mandal Department of Geography and Geology, University of the West Indies, Mona, Jamaica

2 Researchers Dr Matthew Wilson Department of Geography, University of the West Indies, St Augustine, Trinidad and Tobago. Prof Michael Taylor, Dr Tannecia Stephenson, Mr Jayaka Campbell, Mr Alrick Brown Climate Studies Group Mona, Department of Physics, University of the West Indies, Mona Campus, Jamaica. Dr David Smith Co-ordinator, Institute of Sustainable Development, University of the West Indies, Mona Campus, Jamaica. Dr Arpita Nandi Department of Geosciences, East Tennessee State University, Tennessee, USA Dr Christopher Burgess CEAC Solutions Ltd, Jamaica Miss Anuradha Maharaj, Mphil, UWI MONA, Research Associate, CERMES, UWI Cave Hill Campus. Acknowledgement : Coastline damage pictures : Miss Taneisha Edwards, Assistant Lecturer and Ph.D candidate, Department of Geography and Geology, University of the West Indies, Mona Campus, Jamaica.

3 KEY MESSAGES Flooding, a major hydrometeorological hazard in Jamaica has significantly affected major infrastructures located on coastal areas and floodplains. OUTLINE OF THE TALK Flood hazard maps showing present and future flood risk for vulnerable communities at national and sub-national level are hence of particular significance for disaster management and planning for climate compatible development in flood prone areas. Continuous training for local government staff to use geospatial data and understanding its importance in disaster management and climate studies by increased cooperation and data sharing between academia and local and national governments

4 Introduction: Jamaica INTRODUCTION 40 km Jamaica has a tropical maritime (marine) climate. Mean daily temperature ranges from a seasonal low of 26 º C in February to a high of 28º C in August (33 º C in recent years). Islandwide long term mean annual rainfall exhibits a characteristic pattern, with the primary maximum in October and the secondary in May. The main dry season lasts from December to April.

5 Riverine Flood Hazard Potential Map (Nandi et al, 2016)

6 Population density per kilometer Road network Comparing the population density map, road network map with the riverine flood hazard map created by LR. Population vulnerability map shows areas marked in red which are major coastal and inland towns, vulnerable to riverine flooding.

7 FLOODING WOES.. Kintyre, Hope River, Tropical Storm Nicole, Harbour View, Kingston, August 2008 Port Maria, St Mary, after Hurricane Sandy, Oct,2012 Port Maria, St Mary, after Hurricane Sandy, Oct,2012 Effect of tropical storm Nicole, 2010, on beach in Negril, picture shows whole beach gone. Much of the beach was lost in the storm - there used to be at least 15 feet of sand between this wall and the water ( Other pictures from Gleaner Archives and from WRA archives. COURTS STORE MAIN STREET Outram River SHELL SERVICE STATION

8 CLIMATE CHANGE : IMPACTS MELTING OF GLACIERS DROUGHT > AFFECTING WATER AND AGRICULTURE SECTOR FLOODING FROM INCREASE IN INTENSITY OF STORMS HURRICANES SEA LEVEL RISE AND COASTAL FLOODING WATER RESOURCES : DEPLETION DUE TO DECREASE IN DAILY RAINFALL Increase in temperature of the earth s air and oceans, increase in greenhouse gas emissions leading to a warmer climate.

9 Present Climate More storms and hurricanes Nandi et al., 2016 Mandal et al, 2013

10 Future Climate 1 2 Models Scenarios or Storylines of future global development Future Climate Temperature Rainfall Extremes Sea Level Rise

11 Deaths and damages, JMD billions (2010 value) Deaths (# persons) and damages EAD, in JMS billions Future Climate Temperatures still increasing Variable + Drying trend More intense extremes Deaths-present climate Deaths-future climate Damages-present climate Damages-future climate Probability of exceedance Jamaica Present climate 100 year 24 hour 7.0 precipitation depths will become the and 57 year 5.2 RP events by 2100 for NMIA 5.0 and SIA 4.7 respectively Flood risks of deaths and damages are 3.0 expected to increase 11% and 9% 2.0 respectively to ~4.4 persons per 1.0 annum and JMD9.2 billion (USD105.2) 0.0 in 2010 dollars Deaths Damages Presentobserved Presentvalidation Future, 2100 Burgess et al. (2015)

12 Study Areas : Yallahs and South Negril-Orange River hydrometerological events Hurricane Gilbert, 1988 Study Areas Hurricane Ivan, 2004 South Negril-Orange river Watershed Yallahs River Watershed

13 Watershed 1: Yallahs River Upland catchment in south-east Jamaica, draining the Blue Mountains. HEC-HMS model structure, Yallahs River Major riverine flooding associated with Hurricane Gustav (28 August 2008).

14 Tropical Storm Gustav: Results for Yallahs 1hr rainfall Maximum flood depth HEC-HMS Generation of flow data for upstream input and subcatchment inflows LISFLOOD-FP Routing of flood wave along main channel and across floodplain (m)

15 Estimation of current flood risk: results HEC-HMS run for 25, 50 and 100 year rainfall events Flows from HEC-HMS routed through the LISFLOOD-FP model to predict inundation extents and depths Topographically constrained flooding Right: Map of exceedance probability: Green: 4% (25 year return period) Blue: 2% (50 year return period) Red: 1% (100 year return period) Main difference between flood areas

16 Estimation of future flood risk: results No reduction in inundation risk in valley Maps of exceedance probability: Green: 4% (25 year return period) Blue: 2% (50 year return period) Red: 1% (100 year return period) Present annual exceedance probability annual exceedance probability (ECHAM, B1) Lower risk downstream

17 Orange/ Negril Rivers Flood model domain Orange/ South Negril Rivers: Low lying twin catchments in west Jamaica. Important center of tourism. Exposed to storm surge and flood risk associated with storms and hurricanes. Flood model development: LISFLOOD- FP: Orange/ S. Negril catchment flow inputs from HEC-HMS models Rain direct to the floodplain Buildings Orange River S. Negril River Topography: 6 m horizontal and 1 m vertical resolution Digital Elevation Model (DEM) from stereo phogrammetry (Mona Geoinformatix Institute) Bathymetry: Interpolated from GEBCO data

18 1 hourrainfall Tropical Storm Gustav: Results HEC-HMS Generation of flow data for upstream input Maximum flood depth LISFLOOD-FP Routing of flood wave along main channel and across floodplain (no storm-surge included) (m)

19 Estimation of future flood risk: results Buildings at risk: substantially more affected in future rainfall/ sea-level rise scenario Greatest hazard for buildings is along the coast Buildings: probability of inundation Hazard to buildings Haz = Depth * (Velocity+1.5) (DEFRA, 2003) Present annual exceedance probability, surge Future annual exceedance probability, surge/ SLR (high) Future 100-yr, surge + SLR (high)

20 COMMUNITY SURVEY IN YALLAHS : PRE AND POST PROJECT

21 CONSTRUCTION ALONG RIVER BANK IN BROOKLODGE AND GRASSPIECE, COMMUNITY MEETING AND DISSEMINATION OF

22 TRAINING ON FLOOD MODELS TO STAKEHOLDERS

23 DISSEMINATION OF RESULTS : UPLOAD DATA THROUGH OPEN SOURCE PLATFORM CARISKA 24

24 Upload or Download data Decide on what you want to allow people to do with the data you can give different people different permissions View or edit Download Choose who can view or download the data Choose who can edit the data Choose who can manage the data Shapefiles and GeoTiffs can be uploaded 25

25 CHALLENGES Resolution of the existing climate models for the Caribbean (50-25km). How useful are they for predicting rainfall variability at watershed/sub-watershed level? OUTLINE OF THE TALK Loss of data (rainfall, streamflow) from gages during flash floods, damage to the gages. Lack of good quality topographical data for flood plain mapping. Insufficient data on damages from past events, needs more training on data collection, data sharing. Implementation of existing and new policies on water management, disaster management, national building code.

26 Data on site Squatter Communities Major Roads Hospitals Parishes Geology Kingston soils map (preliminary classification) Preliminary data on flood risk for Hope River 27

27 Acknowledgements Department of Geography and Geology, UWI Mona, Jamaica. Water Resources Authority of Jamaica Office of Disaster Preparedness and Emergency Management Meteorological Service of Jamaica Mona Geoinformatix Ltd CEAC Solutions Ltd Funding: CDKN and managed by CARIBSAVE

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