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HQi thao khoa hoc - Hgp tac Qu6c t^ digu tra, nghien cihi tAi nguySti va mfli tmong bi5n THE FIELD SURVEYS AND RESEARCH OF THE COAST LINE AND RIVER MOUTH EVOLUTION IN VIETNAM Nguyen Manh Hung Nguyen Thi Viet Lien Institute of Mechanics, VAST, Hanoi, Vietnam Abstract: In the paper, the results of the cooperation in field survey and research concerning the evolution of the coast line and river mouth of Vietnam in the frame of the Project "The evolution and sustainable management of the coastal areas of Vietnam " code VS/RDE-03 for the periods of 2004 - 2007 and 2007 - 2011, funded by Sida/SAREC have been presented The Project involved the Center for Marine Environment Survey, Research and Consultation (CMESRC) and The Department of Water Resources and Engineering (DWRE) Lund University as implementing and collaborating institutions During the first phase (2004-2007) the Red River Delta coastal zone was chosen as the case study of the coastline evolution (with the emphasis of the erosion in Nam Dinh province's coast line Four synthesis field surveys of each cross shore profiles with stations equipped by the modem apparatus and many periodic beach bathymetry surveys were carry out The second phase (2008-2011) is focused on the beach changes in the RRD coast zone and Thuan An, Tu Hien (Thua Thien Hue province) inlets migration and the effects of the structures on the of topographic change in the vicinity of its The main results of the project are: Enhancing the research infrastructure of CMESRC by high-level sophisticated equipment for field measurements: Field surveys: Collection, compilation, and analysis of data related to beach and shoreline changes in the coastal zone of Vietnam; Mathematical modeling of coast line change in RRD and inlets migration; Research on the mechanism of the coast change; Providing of scientific workshops and seminar relating issues and exchange experiences and knowledge between Vietnamese-Sweden an foreign scientist and other as Nelherlands, Poland, Russian and Japanese researches; Master and Doctoral education; Publication in the Vietnamese and foreign journals the Project's outcomes I INTRODUCTION Vietnam has a coastline that is approximately 3200 km long (excluding islands) and much of it is located below an elevation of m [11] Since the economic activity in Vietnam is mostly concentrated in the coastal areas, it is of a vital importance that the physical and environmental conditions in these areas are well Nguyin Manh Hung 163 Workshop- "Intemational Cooperation on Investigauon and Research of Marine Natural Resource and Environment" understood and may be assessed for a wide range of situations For example, the Red River Delta (RRD) in northern Vietnam, which supports nearly one third of the country's rice production, is under a constant threat from high water levels in the sea causing flooding and intrusion of saline water Such high water levels are typically associated with typhoons or strong wave action during the monsoon periods, although long-term sea level rise due to climate change is a concern as well [11] Furthermore, deposition of river sediment along the coastline in combination with sediment transport by near shore waves and currents induce variability in the shoreline position at many scales in time and space that must be estimated in order to manage the delta and associated coastal areas in a rational manner Almost all of the agricultural, industrial, and urban areas of northern Vietnam are concentrated in the RRD Along the coastline of the RRD there are about 25 segments which are experiencing erosion corresponding to a length of 30 km In contrast, accumulation is typically occurring at the river mouths of the delta In tlie delta the erosion and accumulation processes are very active The' most severe erosion can be found in Xuan Thuy and Hai Hau district (Nam Dinh Province), where since 1960 a segment of 4000 m length and 500 m width and 3500 m length and 1000 m width, respectively, have been eroded In contrast, the area at the Ba Lat river mouth moves in the seaward direction at a rate of 80-100 m/year [10] and the siltation in Hai Phong port needs dredging at regular intervals In order to combat erosion, dikes have been built along the delta but many of these have been destroyed by continued wave action during the monsoon or extreme typhoons In southern Vietnam the Mekong Delta plays a similar prominent role for the socio-economic development as the Red River Delta for northern Vietnam Coastal erosion has often been observed along the Vietnamese coastline, and at present there are more than 300 segments of coastline subject to erosion [10] ir^JJvlJ^T^' ^u' "^"""^ Environment Survey, Research, and Consultation (CMbbKC) and the Department of Water Resources Engineering (DWRE) Lund University initiated collaborative research in coastal processes already at the'end of the 1990s, but only from 2004 the project "The evolution and sustainable management of the coastal areas in Vietnam" Coded VS/RDE-03 undertaken between the two institutions has been approved by the Vietnam Sweden Cooperation Program At present we have completely carry out the first period 2004 - 2007 and coming to the end of the second period (facing out phase) 2008 - 2011 1, 7^^ '^"K^;^^''!?^?''-'^'^''''^ ° ^ * ^ P"'^^^"' P™j«« and of the ongoing cooperation between CMESRC and DWRE is to develop an integrated and sustainable strategy sn rf!!"^f'"fi, t ' " " " " T " ' '" ^'"'"'™ '" * e framework of the [1] More fnllnw ^ ' r n ^ short-term objectives in VS/RDE-03 strives towards arriving at the D m h T ^ ' r ^ l ! , f " ' [ ' ' "^"".'P*'"" of * e coastal evolution in Vietnam and d sc oTion J H ,-r''' '"'''r^^' management of the coastal areas; (2) a the RRD * 1"^" !fi
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