Determining and predicting changed topographic (shoreline, bottom topographic) under the impact of artisanal saline mining sand at the estuary South Central.
Propose solutions to limit the negative effects of the artisanal saline sand at the estuary South Central towards sustainable development.

Theoretical results: The impacts of the dredging activities of saline sand in the estuaries of the South Central Coast have affected the accretion – erosion of channels in the dry season, inaccessible for boats, so dredging is required. Channels must be degrade periodically, and there must be synchronous engineering solutions to stabilize doors and channels. The accretion in and out of channels erode out on both sides, for estuaries with no impact embankment such as: Cua Dai (Tra Khuc) – Cua Lo (Quang Ngai province), An Hai, Tien Chau estuarys (Phu Yen province). The erosion caused by beach shore protection works can be found at: Cua Dai, cua Lo, Ky Ha estuarys (Quang Nam province ), Da Nong estuary (Phu Yen province), Dam Nai, Dong Hai estuarys (Ninh Thuan province), Lien Huong, Ca Ty estuary (Binh Thuan province).  The erosion - accretion of channel caused by estruary protection : Sa Huynh estuary (Quang Ngai province); Tam Quan, De Gi (Binh Dinh province); Phan Ri Cua, La Gi (Binh Thuan province).
-    The dredging operations to recover saline sands at the South Central estruary has affected the process of erosion - accretion shores on both sides of the estuary and the transformation of chanels in the estuary. The saline sand recovering program often violate as follows: this unit signs advantage of the licenses to exploit outside of the region, in violation of the allowed depth, done improperly to the approved scheme and inadequately listing the volume of minerals recovered and exploited in excess of the licensed quantity. The process of dredging on gave sedimentation of coastal change and energy distribution of the wind, waves, currents, tides, dynamics, the wave coming, geological structures, topographic, which form into a new erosion-accretion process.
-    The region Da Rang estuary need solutions to the accretion of channels of estuaries. Da Rang is still using embankment works torch on either side of the estuary to ensure the channels and regional storm shelter in the Dong Tac fishing port.
Applied results: The basis scientific for the management of mining projects recovering saline sand

There are the causes and mechanisms and solutions in recovering sand in the South Central region.

Scientific papers in referred journals (list):
Pham Ba Trung*, Le Dinh Mau, Tran Van Binh 2019. The effects of projects of dredging and recovering saline sand at estuaries in Binh Thuan - Ninh Thuan provinces . Vietnam Journal of Marine Science and Technology; Vol. 19, No. 4A; 2019: 55–66 .
Bui Minh Chung, Pham Ba Trung , Ngo Minh Thien. Assessment of coastal vulnerability in phu yen province.  Publishing House for Science and Technology,  pp 252-256. DOI: 10.15625/vap.2019.000128.
-    Vu Tuan Anh 1, Pham Ba Trung 1, Kim-Anh Nguyen 2,3, Yuei-An Liou 2,*, and Phan Minh-Thu 1,4 “Human Impacts on Estuarine Erosion-Deposition in Southern Central Vietnam: Observation and Hydrodynamic Simulation”. Sustainability 2021, 13, 8303. https://doi.org/10.3390/su13158303
Technological products (describe in details: technical characteristics, place): including Final report and three thematic reports and topographic topography of shorelines and bottoms in some estuaries in the South Central region of the project VAST 05.05 /18-19. The report showed that the cause of mechanisms and measures and the impact of artisanal saline sand to channel to the door and erosion - accretion of the coast on either side of the estuary.
Other products (if applicable):
Support M.Sc. Bui Minh Chung. Study on geological and hydrodynamic characteristics to determine the coastal vulnerability in Phu Yen province. University of Science - Ho Chi Minh City

Support M.Sc. Cao Van Trieu. Study on characteristics of coastline changes at Da Dien estuary (Da Rang estuary). University of Science - Ho Chi Minh City

The results of the  project are submitted to the Vietnam Academy of Science and Technology and transfer to localities in the South Central Coast through the departments: DOST,  Natural Resources and Environment, Agriculture & Rural Development…

It is necessary to study the changes in topographic morphology of the bank and bottom in detail, synchronized data for each estuary in the South Central Coast under the influence of channel dredging and salty sand recovery.