- Assessing the current state, changing and influence of natural processes, human activities to expanding accretion process and sedimentation rates on tidal flats in the Red River delta.
- Predict erosion, expanding accretion and sedimentation rates of tidal flats in relationship with climate changes and sea level rise. Propose solutions and sustainable use of tidal flats.

Theoretical results:
Tidal flats in the Red River delta were determined sedimentation rates by radioisotope techniques 210Pb and 226Ra, over 100 years undergoing development tidal flats have passed alternately accretion, erosion processes. Sedimentation rates are range from 0.34 to 1.71cm/year, on tidal flats seeing high sedimentation rate suddenly over 14cm/year in short time. By overlay of information map layers in period 1930-2003, expanding rates of intertidal flats at mean sea level (MSL) and lowest astronomical tide (LAT), during 1930-2003 at MSL zone expand 32.8m/year and LAT zone expand 31.8 m/year. Following expand of MSL zone and LAT zone, area in tidal flats increase 410.0 ha/year at MSL zone and 398.1 ha/year at LAT zone. Beside accretion in most tidal flats, erosion on tidal flats are seeing on Hai Hau areas, loss over 2.7 ha/year.
The script predicted of sedimentation rates and expanding rates of tidal flats in relationship with climate changes and sea level rise note by Ministry of Natural Resources and Environment published in 2009 (MONRE) shown that most high and midle tidal flats will be eroded from 2050 to 2100. Particularly at Ba Lat area from high to midle tidal flats until 2050 not erosion, to 2100 will be erroed. The result expanding area and horizion forecast of tidal flats in relationship with sea level rise by climate changes published by MORE in 2009 shows that the areas has been continue expanding, but although the expanding areas will be decreased significantly in compared with expansion area in the static sea level rise script.
Applied results
The potential of tidal flats in the Red River delta is huge, from the past to present have contributed significantly in development economic and disaster prevention, the tidal flats are always expanding and forwarding to the sea in the next years, create expanding land for economic development. These potentials have now been used by humans in the development of tourism, aquaculture and conservation. However, the darns from the human impact to tidal flat areas as environmental pollution, loose area is ongoing and will continue in the future, they should be solutions using efficient and sustainable.

Sedimentation rates on tidal flat are calculated by radioactive techniques for high precision, this technical assessement sedimentation rates by time. Calculate the areas, fluctuation areas of tidal flats during 1930-2003. Predict sedimentation rates and expand rates of tidal flats in relationship with scenario sea level rise due to climate change issued by MONRE 2009.

• Scientific papers in referred journals (list): 3 papers

1. Dang Hoai Nhon, Hoang Thi Chien, Nguyen Thi Kim Anh, Bui Van Vuong, Nguyen Ngoc Anh, Pham Hai An, Vu Manh Hung, Phan Son Hai, 2011. Sedimentation in the Bang La and Ngoc Hai intertidal zone, Hai Phong. Journal of Marine Science and Technology, Vol. 11, Issue 1, p. 1-13. Publishing House for Science and Technology, Hanoi.
2. Dang Hoai Nhon, Dinh Van Huy, Nguyen Mai Luu, Nguyen Dinh Khang, Dinh Van Nhan, Phan Son Hai, Pham Tien Duc, 2011. Sedimentation rate and accumulation metals in sediment of intertidal zones of Red river delta. Procceding of the 5th National Conference on Marine science and Technology, Hanoi, Vol. 3, p.544-555. The Publishing House for Science and Technology, Ha Noi.
3. Dang Hoai Nhon, Tran Duc Thanh, Dinh Van Huy, Nguyen Thi Kim Anh, Nguyen Mai Luu, Nguyen Dinh Khang, Phan Son Hai, Nguyen Manh Ha, Pham Tien Duc, Lai Thi Bich Thuy, 2013. The sedimentary processes on tidal flats in the North of Vietnam: initial results and implication future. Proceedings of VAST – IRD Symposium on Marine Science. Haiphong, Vietnam. p.164 – 178. The Publishing House for Science and Technology, Ha Noi. ISBN 978-604-913-162-2.