Workshop on the Strategy and Action Plan of the WMO Flood Forecasting Initiative Geneva, 8 – 10 December 2009 Flood Forecasting Issues in Ghana by J. Wellens-Mensah

FFI Workshop, Geneva, 8 – 10 December 2009 Summary of Main Regional Conclusions for WMO Region I (Africa) contained in Doc.3 are mostly relevant to the Ghanaian Situation Additional Issues specific to Ghana include:  Ghana experiences both urban and rural/widespread flooding  inadequate infrastructure, instruments and equipment to collect and transmit hydro-met data in real time mode;  need for a network of calibrated radars for rainfall prediction and estimation;

FFI Workshop, Geneva, 8 – 10 December 2009  Ghana also experiences flooding from dam spills in upstream country;  These spills are beneficial for filling up reservoirs for hydropower generation, but causes severe flooding on way to the reservoirs -need to synchronise spilling with conditions in downstream channels - need for timely communication of scheduled, controlled and phased spilling from upstream country

FFI Workshop, Geneva, 8 – 10 December 2009  Flood Forecasts must save lives and limit flood damages; therefore forecasts should provide adequate warning and response measures  This, among others, requires delineation of flood plains in relation to flood magnitudes; -need to combine GIS with DEMs -in turn, requires digitised topographic maps at appropriate scale (currently exist in 1:2,500)  Need to control development in delineated natural flood plains eg. siting settlements and villages (keeping people and properties away from flood waters)

FFI Workshop, Geneva, 8 – 10 December 2009  Ghana has streamflow forecasting models for inflows for management of hydropower, potable water supply and irrigation reservoirs;  There is no comprehensive Flood Forecasting System, except for ad hoc warnings based on levels in rivers;  Need to develop end-to-end flood forecasting systems taking advantage of state-of-the art observing systems, data transmission, modelling (eg. using NWP inputs), transmission of flood warnings, scenarios generation and response measures.

FFI Workshop, Geneva, 8 – 10 December 2009 Thank you !