9 th Session of the Forum on RegionalClimate Monitoring Assessment and Prediction for ASIA (FOCRAII) Beijing, China 08-10 April,2013
Planning and Management of Water Resources in a Climate Change Perspective And Comparison of results of Hydrological Models used by PAKISTAN By Muhammad Ajmal Shad Director Pakistan Meteorological Department Flood Forecasting Division (FFD) Lahore-Pakistan.
Introduction Features and Problems for the models in individual Rivers Results of the Models Conclusion
Responsibilities of Flood Forecasting Division (FFD), Lahore FFD of the Pakistan Meteorological Department plays a pivotal role in the entire flood mitigation process. Hydrometeorological data from the various national and international sources is received in this office which is then processed to produce flood forecasts and warnings to be disseminated outwards to various national organizations
Flood Forecasting Division (FFD) Lahore is a specialized unit of PMD for this purpose.Responsibilities i.Flood Forecasting ii.River stream flow forecasting iiiWater availability Forecast for Dams iii.Assisting Water Management at Dams specially during Monsoon HYDROMETEOROLOGICAL SERVICES AND FLOOD FORECASTING
Burning of fossil fuels due to human activities has leads to increase in greenhouse gases Climate of the globe is warming Frequency of high floods are expected to increase Extreme climate events badly affect the economy of the world Pakistan’s economy highly depends on the water resources of Indus river system
The rivers in Pakistan are distinguished with complex topography, diverse climate and varied morphology which produces specific hydrological characteristics and highly variable discharge in rivers. Difficult orography in northern parts of the country has strong influence on the meteorological situation of the region which ultimately greatly affects river flow.
COMPARISON OF FEWS Model & ACTUAL IN CURRENT FLOOD SEASON
RIVER INDUS: 1.The FEWS Model was run day by day w.e.f 15.06.2010. The Catchments of Indus River and its tributaries received severe rainfall resulting flood peak of exceptionally high magnitude in River Indus and its tributaries was experienced..The Maximum discharge of 6,12,800 Cs on 30-07-2010 at 0500 and 5,50,000 Cs on 10-08-2010 at 0900 were released from Down stream of Tarbela. Rainfall runoff and routing model for Tarbela Upstream and Kabul River has not been developed and incorporated in the Fews Model. Therefore, Fews Model does not generate forecast of Upstream Tarbela and for Kabul River. 2.The gauge at Nowshera on River Kabul was washed away on 29/07/2010 at 18:00 hrs. and data was not received upto 05/08/2010 of 06:00 hrs.
Evaluation of FEWS Model Performance and Operational Real-Time Flood Forecasting (Flood Season 2011)
Discrepancies: 1: The preprocessing Data requires enough time to run the Model. 2: The causing of crashing of the model are not fully defined. 3: The Catchments of FEWS model are not overlay with the radars Catchments. 4: The Grid display modules are not function able (Inundation Maps). 5: Some times U-grib gives negative values of forecasted rainfall which crashes the FEWS Model. 6: Incase of no rainfall, some times FEWS shows negative discharges at the rim stations. 7: The Help in the tool bar of FEWS Model is not functionable.
6.U-grib Negative Value Should be automatically filter. 7. The Source Code of the model should be provided to PMD. 8.As per NESPAK 30 days forecasted hydrograph value is required to obtain 30 days forecast, the forecasted days is minimized, up to 7 days. Because u-grib gives QPF for 7 days. 9.Help module may be activated
LIMITATIONS The catchments of all the rivers lies in the Indian Mountainous Region. The rainfall data of high altitude catchments are not available, due to which water availability at the RIM Stations can not be estimated. The discharge data of eastern rivers (Sutlej, Ravi & Chenab) is supplied by India through Pakistan Commissioner For Indus Water (PCIW) during the flood season only (10 th July to 30 th September)
The Problems of Flood Forecast not merely related to the models but also to the condition under which the models used Every River has unique Flood Forecasting Problems in term of data availability,Physiographic and Hydro Meteorological Conditions The flood flows are extremely unsteady and the models do not readily adopt to the abrupt flow changes
Presently the flood forecasting Models are far from satisfactory. There is dare need to improve the present system in term of data gap(dense Observational Network ) There is need for more reliable rainfall prediction model specially for the runoff forecast at the rim station. Since the available meteorological models are not accurate in temporal and spatial Rainfall prediction Conclusion