Volume 5 Issue 4

Authors: Sibtey Hasan

Abstract: Godavari is the second longest river (1465 Km) of India, draining approximately 10 % of India’s total geographical area. Several studies have suggested that Godavari delta is morpho-dynamically highly active resulting in shifting of its entrance into the sea. Notably, construction of dams and reservoirs on the Godavari catchment has had profound impact on its flow conditions. It is an accepted fact that changes in flow conditions affect the morphology of the river as sediment transport and flow conditions have a non-linear relationship. In the present study we have tried to investigate the influence of varying flow conditions during extreme events on the Godavari entrance. A two dimensional modelling was conducted using Delft3D tool to investigate the local flow hydrodynamics during extreme events and its effect at the entrance of the Godavari River delta. Based on historical data the current study determined the influence of moderate (20,000 m3/s), typical (40,000 m3/s), and extreme (60,000 m3/s) upstream historical river discharge events in combination with offshore tidal fluctuations on local hydrodynamics at the entrance of Godavari delta. Mathematical modelling results clearly indicated that extreme flood events had a significant impact at the entrance of the river. During moderate and typical discharge events, strong current magnitudes were observed around 2 to 4 m/s off north of Godavari entrance. Most importantly during extreme flood event, after 12 hours of simulation, water started breaching from the shallower point of the existing sand bar South of Godavari mouth and the current magnitude exceeded 4 m/s. It is highly likely that due to such higher current magnitudes during extreme flood events the sand bar itself could propagate further offshore or another narrow opening might be created to the south of the existing entrance towards the sand bar.

Keywords: Gautami Godavari River; Hydrodynamics; Discharge; Water Level; Coastal Erosion


Authors: Z. Fuat Toprak; F. Meral Halifeoğlu; Orhan Kavak

Abstract: As well known, the historical structures reflect the language, cultures, religions, and development levels of ancient civilizations. In other words, each historical structure can be qualified as an evidence of its civilization’s history. Furthermore, such structures give information about early age hydrological, meteorological, and geological characters of their region. Therefore protecting such historical structures and recording their information are essentially important. Consequently, 14 of the historical limestone bridges located in Diyarbakir province have been detected and mapped. The architectural, geological, and hydrological properties of these bridges have been briefly presented.

Keywords: Historical Bridges; Diyarbakir; Limestone Bridges; Stream Flow


Authors: Selim Dogan

Abstract: Afghanistan is a drought prone country and located in mostly semi-arid and arid regions of the world. Nomads (Kuchi) and rural farmer communities are the most vulnerable to this natural disaster, because their life is totally dependent on agriculture and livestock. Meteorological anomaly information shows that drought occurs in every 10 or 15 years in southwestern and central areas of Afghanistan. Annual precipitation is very low in these areas and people who live there depend on agriculture. They lost their crops and livestock when drought occurs. Drought forces people to move larger cities first (internal displacement) and then migrate to neighboring countries. Most of the precipitation occurs during the winter as snow and rain. Snow melting is a good water resource during the spring and summer seasons. Melted water is used for irrigation purposes. Farmers and nomads lose their cereal productions and livestock in case of winter season precipitation deficiency. They would face to famine if precipitation deficiency turns into a severe drought. The concerned communities are forced to migrate for food and water safety. Environmental degradation is, exacerbated by climate change and, another concern for farmers and nomads. Political conflict is not the only reason for migration. The phenomenon of drought is another major reason of migration beside of conflict, and droughts trigger civil turmoil and political conflict. Many people in Afghanistan migrated to neighboring countries during 1998-2002 severe droughts. In this study, Afghan refugee numbers in Pakistan and Iran and the precipitation anomalies have been analyzed in order to investigate the teleconnection of drought and migration. Many Afghan refugees prefer these two countries for lingual and cultural similarities, besides easiness of travel. Nowadays Afghan refugees prefer the industrialized world for migration, especially to Turkey and European countries for seeking safer life in better conditions.

Keywords: Drought; Migration; Afghanistan