INTERNATIONAL WORKSHOP ON WATER AND DISASTER London, Ontario, Canada December 13-14, 2004

Flood Forecasting and Hazard Mapping in Jamaica

Presenter Herbert Thomas

Water Resources Authority Jamaica 1 Content • The cause and nature of flooding • Flood warning/Hazard mapping as risk reduction instruments. • Lessons Learned • Way forward

12/3/2006 2 Jamaica located; 161 km (100 miles) south of Cuba Latitude 17o42′ and 18o31′ N Longitude 76o10′ and 78o22′ W. .

12/3/2006 3 Cause of Flooding

9 Jamaica prone to flooding 9 Topography 30-yr. rain /geology Flood prone areas determines the Housing areas nature of flooding 9 Climate also 'W'W'W $T'W'W 'W$T'W'W 'W$T impacts 'W$T$T'W'W'W'W'W 'W 'W'W'W'W'W 'W'W'W'W 'W 'W$T'W'W'W$T'W'W'W'W$T$T$T $T 'W'W$T $T 'W'W 'W'W 'W 'W'W'W 'W'W'W'W'W'W'W$T'W'W'W'WW''W'W'W'W$T'W$T 'W'W $T $T $T 'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W 'W$T'W'W 9 Man’s impact $T$T$T$T'W $T 'W$T 'W 'W 'W'W'W'W'W'W'W 'W $T $T $T$T$T $T$T'W$T $T 'W'W'W'W 'W 'W'W'W$T$T 'W'W$T'W'W$T$T$T $T'W$T$T$T $T $T 'W'W'W'W 'W'W'W $T$T'W aggravate the $T'W'W$T'W$T'W$T$T 'W'W'W$T$T$T'W$T$T$T$T $T $T$T 'W 'W'W 'W$T$T$TT$ $T$T $T $T $T$T$T$T$T$T$T $T $T $T 'W 'W'W'W 'W 'W'W'W'W'W$T$T$T'W'W'W flooding $T$T$T $T $T 'W 'W'W$T'W'W$T$T 'W'W'W'W'W'W'W'W'W 'W 'W 'W'W$T 'W 'W'W'W$T'W 'W 'W'W'W 'W'W'W'W 'W'W'W'W'W'W 'W $T'W$T'W $T $T$T'W$T'W 'W'W$T $T$T 'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W 'W 'W'W$T'W'W$T $T'W$T'W'W'W$T'W 'W'W'W'W $T 'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W $T$T 'W'W $T'W'W'W'W'W'W'W'W'W 'W 'W 'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W 'W 'W'W'W'W'W'W 'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W'W 'W'W'W'W$T'W'W'W'W$T$T'W'W'W$T'W'W$T'W'W$T'W'W $T $T$T $T 'W 'W 'W 'W'W'W'W'W'W'W'W'W'W'W'W'W'W$T'W'W$T'W'W'W $T $T 'W$T$T$T$T'W'W'W'W'W$T'W'W'W'W 'W $T$T 'W'W'W 'W 'W'W $T 'W$T'W 'WW''W'W$T'W$T$T'W $T$T$T$T$T$T 'W'W'W'W'W $T $T $T'W'W'W'W'W$T 'W'W'W'W $T$T$T$T$T$T$T$T$T$T$T $T$T$T

12/3/2006 4 Nature of the flooding

• Groundwater induced • Depression • Riverine

• Storm Surge • Urban Runoff

12/3/2006 5 Minimising the Flood Risk

What is the Jamaican Experience ?

12/3/2006 6 Existing early warning systems in Jamaica

1992-NF 1999-D 1993-F

1992-year established NF- not functioning F- functioning D-development stage

12/3/2006 7 Future Early Warning Systems

Pencar River

12/3/2006 8 Cave River

12/3/2006 9 Flood Forecast table

12/3/2006 10 Flood Forecasting

20 18 Rainfall 16 Stage Hydrograph 14 12

10 Flood Stage 8 Potential additional 6 Warning time 4 2 0 Preparedness Flood Flooding Recovery Preparedness plan plan Recognition Warning time at stage

12/3/2006 11 Community Based Early Warning Systems in Jamaica

FLOOD GAUGES Blue = Watch mode Orange = Alert mode Red = Critical

12/3/2006 12 Value FEWS to Community

Communities Reliability Loss Is System Reduction still being used

Rio Rivoli 97% yes 97% yes 100% Cobre Thompson 93% yes 100% yes 98% Pen

Cave River (Aenon 44% yes 28% yes 60% yes Town) 16% no 39% no 6% no

ODPEM Field Survey February 2004 12/3/2006 13 RECOMMENDATIONS

Get local govt involved and designate a Lead Agency Revive communication process within communities Improve equipment and monitoring Institute annual drills Upgrade /Maintenance of systems Dedicated Budget Strengthen institutional capacity

12/3/2006 14 Flood Plain Mapping •Flood plain mapping Project, WMO 1980s •Hydrologic Support Unit Project UNDP 1990s •Community Disaster based management Projects UNDP, USAID, DIPECHO, 2000s - to date

1 6 1 Rio Grande 3 2 Yallahs River 4 2 3Hope River 5 4Rio Cobre 5 Rio Minho 6 Black River

12/3/2006 15 Overview of the Mapping Process

ArcView ArcView Input Data Flood DEM plain maps

HEC-RAS HEC-HMS Water Flood surface discharge profiles Rio Cobre Flood Plain Map

12/3/2006 17 Problems with usage

1. No guidelines for their interpretation and use. 2. No national standard for regulatory flood 3. No national guideline prohibiting/permitting flood plain uses. 4. No national standard for the level of protection – depth/or flow velocity 5. Very limited number of flood plain maps available. 6. No flood zoning done - hence need for rigorous analysis to assess cumulative impacts

12/3/2006 18 Legislative Amendments •Amendment of the Water Resources Act 1995 •Repeal of the Floodwater Control Act 1958

The Water Resources (Amendment) Act, 2003 has been drafted. - Floodwater Control Areas - Floodwater Control Plans for those areas. Flood Control Policy to be implemented (regulatory flood, usage regulation, zoning, etc)

12/3/2006 19 THE END

THANK YOU FOR YOUR ATTENTION 12/3/2006 20