الفهرس | Only 14 pages are availabe for public view |
Abstract The impacts of global warming on the Nile basin precipitation patterns are examined. Annual historical data sine 1900 is analyzed at different areas on east, west, middle and upper Nile areas. Also, the relation between rainfall and temperature at different regions on the Nile is checked based on historical available daily Mean Areal Precipitation (MAP) and temperature data, since 1977. A strong relation between rainfall and temperature change have been found over the Blue Nile basin. However, the White Nile basin found less sensitive to temperature changes. A relation between temperature and precipitation over the Blue Nile basin have been developed based on 5 years of observed daily data and validated based on the rest of the data. In addition to that, different emission scenarios studied and some of them chosen to be an input to scenario generator model, MAGICC & SCENGEN. Also, 16 GCMs are checked and four of them are used to study the impacts of climate change on the precipitation and temperature changes on the Nile basin. To this end, the long-term anomalies (till 2030) of precipitation changes due to global warming are generated at different regions based on the developed relation and the outputs of the scenario generator. The main findings of this study indicate that the global warming will have positive impacts on i the precipitation rates over the Blue Nile basin and minor impacts on the White Nile basin. The study also indicates that there will be shifts on precipitation season at different areas over J, the Nile basin. The study indicate that the range of precipitation change on the Blue Nile will range from- 2.14% to 10.65% and the White Nile precipitation will change within a range of -1.43% to 9.94% over the next three decade. These changes in precipitation have been simulated using a distributed conceptual rainfall runoff model to study the impacts of these change on the inflows to High Aswan DAM (HAD) then lake Nasser simulation model have been used to simulate the performance of the lake over the next three decade due to these changes. The main findings of the study indicate also, that the inflow to Dongola will change in a range of -14% to 32%. The operation of HAD simulation results shows that the negative scenario indicates that the probability that the lake level will go below 160m is 48% where it will be difficult to generate electricity while the probability that the level will go below 150 (indicator for drought) is about 13%. The model showed also for the optimistic scenario (most probable one) indicates that the probability of the lake level to be around 180m is about 56%, and the probability that the level will go below 166 is only 0.5%. The hydrological elasticity of different catchements has been calculated using the Nile Forecast System (NFS) hydrologic model and it is found that the hydrological elasticity of the White Nile is the lowest and the Blue Nile at Khartoum is the highest. The changes in precipitation developed from climate models have been used as a multiplier to historical monthly precipitation then these data are disaggregated using statistical downscaling to daily precipitation and used as input to the hydrologic model to simulate the impacts on runoff. The reliability, which is a measure of reservoir failure occurrence due to not fulfilling the demand requirements, shows that the had is a highly reliable project for Egypt, specially in drought times, that is represented here in the thesis by the pessimistic scenario (reliability of is 92%), of climate change impact, where the frequency of droughts will be higher. the vulnerability of the had to climate changes ranges from less than 1% up to 12%. the resilience, which is a measure of reservoir system recovery following failure, of had ranges from 50% during droughts where the number of time had will not fulfi II the water requirements of Egypt will increase to up to 99% during wet years. the sustainability index of the had ranges from 40%, in case of drought over the Nile, up to 100% if wetting of the Nile happens. Key words: Hydrological Models, Nile Basin, Climate Change, Downscaling, Scenario Generation, and Emission Scenarios vii |