This proposal is seeking new APN support to build upon our previous 2-years APN project: ‘Mega-deltas of Asia: Conceptual Model and its Application to Future Delta Vulnerability’, conducted successfully in 2003/04.  The mega delta project under Capacity Building Networks involves 15 countries, of which 9 are developing nations.  In total >150 participants were involved and are in agreement that our work, while successful, was incomplete without the full integration of climatological controls on the Asian mega-deltas.

During the previous project, a delta conceptual model for forming various deltaic patterns was developed, including that encompassing high-discharge flow and high sediment-load pattern of the Ganges-Brahmaputra, Yellow and the Yangtze deltas, high-discharge but low sediment load pattern of the Pearl River delta; strong tidal and wave dominated Mekong and Red River deltas, high-discharge, but low coastal dynamics of the Chao Phraya delta and Irrawaddy delta.  Also, a number of key controls in contributing delta formation were validated, including sea-level fluctuations, vertical ground subsidence, sediment dispersal dynamics offshore and climate effect.  These together have determined the Holocene deltaic deposition, and as a consequence the framework for modern coastal environmental systems.  Accordingly, the vulnerability of deltaic settings was assessed and effectively circulated through our website (http://www.megadeltas.ecnu.edu.cn ), two project conferences, conference proceedings and many peer-review publications.  Also, communication between scientists and government administrators and policy-makers was very effective.

The monsoon circulation on the Asia mega-deltas was also discussed and incorporated into the megadelta conceptual model establishment.  However, due to complexity these systems, in terms of their temporal and spatial dimensions, all participants recommended that monsoon dynamics and related hazard assessment be brought into the forum at millennial to seasonal scales.  We note that non-Asia megadeltas have not been affected largely by the monsoon circulation.  From the LGM to the post-glacial, the rapid global climate warming strengthened the monsoon circulation over the Asian continent, including deltaic coasts, and this forcing continued when the climate furthered its warming during what is called the mega-thermal period in the early and mid-Holocene.  Many previous studies indicate that this monsoon-associated climate change played key roles in delta topographic evolution, and hence susceptibility to sea-level change.  Historical records from existing database have also shown that tremendous precipitation and huge discharge on centennial to seasonal scales has resulted in extensive inundation of the lower delta plain where most people, agriculture, and industry exist.

Nowadays, in the East Asia and Southeast Asia delta systems, the strong western Pacific summer monsoon extends into these lower delta-plain settings and even further inland along the river valleys to the deltaic-sediment source areas. This external forcing has brought about tremendous rainfall to the river basin, shaping river-delta topography through sediment transport.  For example, more than 4000 mm/y rainfall on average have poured into the Mekong River, which has modified the entire coastal landscape in the past 5000 years.  The well-known Tonle Sap lake in Cambodia was built specifically by the over-siltation along the former coast.  Also, in the Yangtze River valley, there has been more than 2000 mm/y precipitation that had dramatically changed the coastal land by bringing tremendous quantities of sediment to the coast. In this way, the large depression of Taihu lake, about 50 km away from the coast was formed by this monsoon-related morphological aggradation.  Inundation prevailed in the basin and delta coast region, with tremendous loss of land properties and people livelihood. 

The similar case has happened in the Ganges-Brahmaputra delta, where it is strongly affected by Indian Monsoon.  Strong seasonal precipitation meets often with tropical cyclones on the delta coast to trigger huge floods with devastating inundation.  During that time, coastal plain topography has been considerably modified via strong sediment transport onto the coast, and to offshore linked by a huge submarine channel system.  As recently as 1991, over 100,000 people were killed by coastal flooding generated by a cyclone.  The Bengal coast has since been spared a major storm, but the general population remains no better equipped than nearly two decades ago.

Fairly speaking, we understand in a broad sense the impacts of monsoon mechanisms and hydro-circulation, and its impact on coastal topography.  However a large knowledge gap still exists between monsoon circulation processes over different time dimensions and their associated hazards.  Notably, these include 1) spatial and temporal distribution of monsoon precipitation on various Asian delta coasts; 2) similarity and dissimilarity of the monsoon effect on the megadeltas; 3) the resultant interaction between SE Pacific monsoon and Indian monsoon on those Southeast Asian deltas, especially, the Mekong, Red and Pearl deltas; 4) monsoon-proxy and its prediction via modeling; and 5) high-flow and high sediment flux and nutrient disperse to estuarine basin and offshore; and 6) the monsoon circulation in relation to El Nino and/or La Nila.  Thus, we propose a 2-year project that will seek to: 1) establish a comprehensive database through our delta specialists from various deltas.  This will serve as a fundamental base to approach the goal of this project; 2) enhance understanding of the mechanisms of coastal landform change in response to monsoon circulation; and 3) focus on monsoon-triggered delta hazards on centennial to seasonal dimensions.

Monsoon circulation has been closely associated with global change.  Climate warming intensifies energy exchange between ocean and land, accelerating hydrological circulation on catchment-coastal land surface.  Flood inundation, coastal erosion, and coastal water level rise while meeting typhoon or cyclone, etc. can potentially threaten environmental safety. Because of intensifying human activity, to understand the role of monsoon processes has become increasingly complicated.  Also, the monsoon variability in different time dimensions makes analysis of database processing more difficult, leading to uncertainties of future predication through modeling.  Thus, we will call for establishing an effective and high-resolution database from the various mega-deltas, which will help differentiate the role of monsoon mechanism from other climatic-related signals, such as El-Nino and summer typhoon, etc. 

In fact, the scientists involved in the proposed study represent almost all Asian mega deltas (seeing above attached TAB) and have done extensive monsoon-related research in the region over the past decade. However, these relatively isolated works have not yet revealed their broader regional significance, which in association with risk assessment is a primary goal of the proposed project. Past failures in coastal planning suggest that the lack of a fundamental monsoon context for risk-assessment studies has harmed our socioeconomic and sustainable development, and this will continue in the future unless better information can be brought to regional planners and managers.

This proposal builds upon our previous 2-years project of Asia mega-deltas under APN Capacity Building Networks.  Involved participants (>150) from >15 countries (9 from developing countries) all support to further our efforts on the mega-delta related project.  Based on the delta conceptual model obtained, we propose this new project, specifically aiming at the monsoon circulation and its impact on societal safety.  The proposed study clearly fits with The Mission of APN through the planned research developments and regional workshops. However, the proposed project also provides critical outreach activities that are based on extensive field-based research conducted by many of our PIs and collaborators during the last decade. Thus, this APN-supported component will allow us bring previous and ongoing basic research results to a broader audience of stakeholders, such as the many developing nations with large coastal areas and major river delta inputs.

This project continues to strengthen our existing long-term collaborative network among delta scientists, who actually have effectively shared their scientific values since the previous APN project.  This network has been running soundly and all participants appreciate the former APN support.  It is clearly shown that the awareness of global change on Asia megadeltas, in terms of physical mechanism and human impact, has been largely risen and disseminated through our project webpage, publication and communication.  We plan to further work together for delta key issues at present and into the future; A website for the proposed project will be established to circulate information and discuss key issues among our coastal scientists, as well as solicit public comments; Workshop proceedings and model results will be published to upgrade academic values, particularly emphasizing the need for a monsoon circulation framework to better assess impacts and hazards in Asian delta systems.

In term of existing 4 working groups, the East Asia working group (China, Japan and South Korea) will contribute the historical monsoonal database on the Yellow, Yangtze, Pearl and Han Rivers; the Southeast working group (Vietnam, Laos and Thailand) will contribute database on the Red, Mekong, Chao Phraya and Irrawaddy rivers; the South Asia working group will contribute their database on the Ganges-Brahmaputra and Indus Rivers, and Oceania (Australia, Indonesia and Philippine) will contribute their database on some river-deltas. 

Our project PI and four co-PI, are responsible for the progress of database collection and establishment, and will keep an effective communication with all colleagues, aiming at the project objectives for our two workshops.  Also, new database will be also contributed to the project, since our project leaders and involved scientists will carry out their own relevant fieldworks and laboratory tests. 

As is well known, the Asian monsoon is the unique driving force that has been shaping not only the delta-coast topography, but also the entire catchment land surface.  This project objective, benefited from our former one, has specifically brought the monsoon issue on the forum to detail its mechanism and related hazards.  The monsoon fluctuation in Asia is the essence of global change, which has largely influenced our societal health.  The summer rainfall processes has become more sensitive to large population on the delta-coast.  Therefore, it is urgent now to study the monsoon for approaching delta-coast sustainable development.

It is obvious that there is a persistent gap between science, assessment, and policy.  Firstly, this study will focus on the establishment of regional database on monsoon-triggered precipitation, discharge, and landform change, etc. Then, a subsequent development on data processing and model critiques will proceed during our Yr.-1 workshop.  Secondly, we will further promote the analysis skills for hazard proxy and criteria with different dimensions.  The results be revisited for discussion and revision at the Yr.-2 workshop, then it will be applied to assess the hazardous impact on delta-coast.  Implications for risk assessment and future delta hazard mitigation will be established on the basis of Yr.-1 and Yr.-2 workshops and of the newly obtained input from key project participants.  The workshop participants are well connected with international-aid and/or government-supported research on Asian coastlines, and thus the project results will have the attention of many relevant policy and advocate agencies.