Mục tiêu và đối tượng nghiên cứu Mục tiêu: 1) Đánh giá thực trạng, mức độ ảnh hưởng môi trường của hoạt động khai thác cát và nạo vét luồng hàng hải vùng biển ven bờ Hải Phòng 2) Đề xuất các giải pháp quản lý bảo vệ môi trường vùng biển ven bờ Hải Phòng. Đối tượng nghiên cứu: Các hoạt động nạo vét luồng hàng hải, gồm cả hoạt động nhận chìm có liên quan, khai thác cát và môi trường vùng biển ven bờ Hải Phòng chịu ảnh hưởng của các hoạt động này, cụ thể: sự thay đổi về địa hình, chế độ thủy động lực, vận chuyển bùn cát, biến động bồi xói, và lan truyền, phát tát các chất gây ô nhiễm trong quá trình khai thác cát, nạo vét luồng cũng như biến động các hệ sinh thái Phạm vi nghiên cứu: Nghiên cứu được thực hiện trong phạm vi vùng bờ biển Hải Phòng, giới hạn trong khoảng 15-20km từ bờ/cửa sông ra phía ngoài và trong độ sâu nhỏ hơn 20m. Khu vực nghiên cứu không bao gồm vùng biển Bạch Long Vỹ. Trong đó, khu vực nghiên cứu tập trung vào vùng luồng hàng hải, khu vực các cảng Hải Phòng, các khu vực có hoạt động khai thác cát ở phía ngoài cửa Nam Triệu, cửa Lạch Tray, và cửa Văn Úc-Thái Bình. Để đánh giá mức độ, phạm vi ảnh hưởng của các hoạt động khai thác cát, nạo vét luồng hàng hải đến môi trường khu vực này, phạm vi khu vực nghiên cứu cũng được mở rộng từ các vị trí nạo vét luồng hàng hải, khai thác cát ra phía biển và vào sâu các sông khu vực Hải Phòng (hình 1.1). Vấn đề nghiên cứu: Phân tích, đánh giá và xác định mức độ ảnh hưởng đến môi trường của các hoạt động khai thác cát, nạo vét luồng hàng hải và đề xuất các giải pháp quản lý. Về bản chất ảnh hưởng môi trường, hoạt động khai thác cát và nạo vét luồng hàng hải ở vùng biển ven bờ Hải Phòng giống nhau, đều gây ra các ảnh hưởng môi trường từ việc hạ thấp địa hình đáy biển, lấy đi một lượng vật liệu nhất định, phát tán vật chất trong môi trường nước biển, xáo trộn sinh cảnh đáy biển. Các hoạt động này có điểm khác nhau cơ bản là mục đích sử dụng của con người: nạo vét luồng hàng hải để sử dụng phần đáy biển cố định (được xác định trước) với lượng vật liệu nạo vét có thể được sử dụng cho mục đích khác (giống khai thác cát) hoặc nhận chìm ở biển (khác khai thác cát); khai thác cát để lấy vật liệu cát ở đáy biển sử dụng cho mục đích khác nhau (ở Hải Phòng, chủ yếu để san lấp – tương tự phần vật liệu nạo vét không nhận chìm). 6. Các phương pháp nghiên cứu đã sử dụng: Phương pháp thu thập và phân tích tài liệu; Phương pháp mô hình mô phỏng/dự báo các điều kiện thủy động lực, phát tán chất gây ô nhiễm, vận chuyển bùn cát và biến động địa hình đáy; phương pháp GIS và phân tích đa tiêu chí để xác định các vị trí khai thác cát phù hợp; phương pháp mô hình động lực đáp ứng nhằm phân tích mức độ ảnh hưởng của các hoạt động khai thác cát, nạo vét luồng hàng hải và xây dựng bộ tiêu chí; Phương pháp ma trận Delphi được áp dụng khi xây dựng bộ tiêu chí đánh giá mức độ ảnh hưởng của hoạt động khai thác cát và nạo vét luồng hàng hải đến môi trường vùng bờ biển Hải Phòng. 7. Các kết quả chính và kết luận Ảnh hưởng môi trường của hoạt động khai thác cát, nạo vét luồng hàng hải Các hoạt động khai thác cát và nạo vét luồng hàng hải đang diễn ra ở vùng bờ biển Hải Phòng và có xu thế gia tăng cả về qui mô và cường độ do nhu cầu phát triển KTXH của thành phố, đặc biệt là quá trình đô thị hóa, phát triển cảng và hoạt động hàng hải. Các yếu tố tác động môi trường do nạo vét duy tu luồng hàng hải và khai thác cát bao gồm: sự thay đổi độ sâu (ở vị trí khai thác cát/nạo vét và nhận chìm), thay đổi chế độ dòng chảy, vận chuyển bùn cát, thay đổi cân bằng bùn cát và biến động bồi tụ - xói lở ở các vùng khai thác cát và nạo vét luồng hàng hải, biến động chất lượng môi trường nước biển và hệ sinh vật biển. Ảnh hưởng môi trường do các hoạt động này ở vùng bờ biển Hải Phòng ở mức độ thấp đối với chất lượng môi trường nước biển và các HST RNM, san hô, xói lở bờ biển và hoạt động các ngành kinh tế vùng bờ biển; ở mức độ trung bình đối với HST đáy mềm và địa hình đáy vùng biển ven bờ. Xu thế ảnh hưởng của nạo vét luồng cũng như hoạt động khai thác cát ở khu vực nghiên cứu đến môi trường sẽ tiếp tục tăng lên rõ rệt với các quy mô và cường độ khác nhau tương ứng với các quy hoạch khai thác cát và xu thế phát triển của hệ thống cảng Hải Phòng. Trong dài hạn có thể xảy ra các ảnh hưởng gây xói lở bờ biển, công trình bờ... do tích lũy các tác động của hoạt động khai thác cát và nạo vét luồng hàng hải. Các tiêu chí lượng hóa tác động môi trường của các hoạt động khai thác cát và nạo vét luồng hàng hải ở vùng bờ biển Hải Phòng Để lượng hóa các ảnh hưởng môi trường của các hoạt động khai thác cát ven bờ và nạo vét luồng hàng hải, các tiêu chí đánh giá mức độ tác động của các hoạt động này ở vùng biển ven bờ Hải Phòng được đề xuất trên cơ sở các kết quả phân tích đánh giá hiện trạng/xu thế và tác động của các hoạt động khai thác cát, nạo vét luồng cũng như điều kiện từ nhiên và KTXH ở khu vực nghiên cứu được tổng hợp trong phân tích khung Động lực – Đáp ứng. Mười một tiêu chí được chia theo ba nhóm: Động lực – Sức ép gồm: (1) Nhu cầu khai thác cát của địa phương, (2) Khối lượng bùn cát nạo vét/năm; Hiện trạng – Tác động gồm: (3) Địa hình đáy biển khu vực khai thác/nạo vét, (4) Khả năng phát tán TTLL trong môi trường nước, (5) Khoảng cách từ vị trí diễn ra hoạt động khai thác cát/ nạo vét đến các đối tượng KTXH, (6) Đa dạng sinh học hệ sinh vật đáy, (7) Khoảng cách từ vị trí diễn ra hoạt động khai thác cát/nạo vét đến HST biển, vườn Quốc gia, (8) Khoảng cách từ vị trí diễn ra hoạt động khai thác cát/nạo vét đến ngư trường, bãi giống, bãi đẻ, (9) Chất lượng môi trường nước biển; Đáp ứng gồm: (10) Hiệu quả của các văn bản chính sách hướng dẫn về quản lý hoạt động khai thác cát/ nạo vét, (11) Các chương trình/dự án bảo vệ môi trường biển được triển khai trên địa bàn thành phố. Kết quả thử nghiệm áp dụng bộ tiêu chí đánh giá mức độ ảnh hưởng của các hoạt động khai thác cát ở vùng bờ biển Hải Phòng trên thang điểm 5 cho thấy, tác động của hoạt động này mạnh nhất đến các khu vực có hoạt động kinh tế, đến đa dạng sinh vật đáy (điểm đánh giá mức 4) và hệ sinh thái vùng bờ (điểm đánh giá mức 3,5). Còn các đối tượng khác chỉ bị tác động ở mức độ thấp đến trung bình (điểm đánh giá mức 1 đến 3). Đánh giá chung về ảnh hưởng môi trường của các hoạt động khai thác cát vùng nghiên cứu trong giai đoạn 2015-2020 ở mức trung bình (điểm đánh giá mức 3). Bộ tiêu chí có thể tham khảo áp dụng cho các vùng bờ biển khác có điều kiện và các hoạt động tương tự. Đề xuất các giải pháp quản lý bảo vệ môi trường vùng biển ven bờ Hải Phòng. Trên cơ sở kết quả nghiên cứu đánh giá mức độ ảnh hưởng môi trường và các căn cứ pháp lý, các giải pháp quản lý hoạt động khai thác cát và nạo vét luồng hàng hải ở khu vực nghiên cứu được đề xuất, bao gồm: giải pháp về chính sách pháp luật và thể chế tập trung vào hoàn thiện văn bản pháp qui cấp địa phương và tăng cường cơ chế giám sát, chế tài cũng như phối hợp và điều phối giữa các cơ quan quản lý; giải pháp về xây dựng công cụ quản lý và ứng dụng khoa học và công nghệ, trong đó tập trung đề xuất qui hoạch và phân vùng vị trí và giới hạn khai thác cát (tổng lượng khai thác 9,3-15 triệu m3, không gian khai thác tập trung ở vùng cửa sông Văn Úc và trong khoảng độ sâu đáy biển 6-10m, phân kỳ khai thác 3 giai đoạn với lượng khai thác giảm dần và độ sâu khai thác mỏ khong quá 6m), tránh xung đột sử dụng vùng bãi và biển trong vùng cũng như qui hoạch lựa chọn khu vực nhận chìm chất nạo vét luồng hàng hải ở biển đảm bảo mục tiêu tăng trưởng của hoạt động cảng và hàng hải đồng thời giảm thiểu tác động môi trường, tăng cường ứng dụng khoa học và công nghệ trong quản lý và trong hoạt động khai thác cát và nạo vét luồng hàng hải.
MINISTRY OF EDUCATION VIETNAM ACADEMY OF AND TRAINING SCIENCE AND TECHNOLOGY VIETNAM ACADEMY OF SCIENCE AND TECHNOLOGY - Do Gia Khanh STUDY THE ENVIRONMENTAL IMPACT OF SAND MINING AND DREDGING OF HAI PHONG COASTAL WATERS Major: Environmental and Resource Management Code: 9850101 SUMMARY OF ENVIRONMENTAL AND RESOURCE MANAGEMENT DOCTORAL THESIS Hai Phong– 2022 The thesis was completed in: Graduate University of Science and Technology, Vietnam Academy of Science and Technology Science instructor 1: Assoc Prof Tran Dinh Lan Science instructor 2: Assoc Prof Dinh Van Manh Reviewer 1: Reviewer 2: Reviewer 3: The thesis will be defended at the university's doctoral thesis evaluation council, meeting in the Graduate University of Science and Technology, Vietnam Academy of Science and Technology at hour , date month year 2022 Thesis can be found in: - The Library of Graduate University of Science and Technology - Vietnam’s National Library INTRODUCTION The urgency of the thesis In the issues related to resource management and environment in Hai Phong, there are currently issues of management of dredging/dumping of dredging materials and sand mining With the largest port system in the North of Vietnam but also the coastal area receiving a large amount of sediments from the Red-Thai Binh river system, the dredging activities of dredging materials will always go hand in hand with the operation of Hai Phong regional port system It is estimated that annually, the volume of dredging in hai phong ports is about 2.5-3 million m 3, if including the dredging volume of Lach Huyen port, the annual dredging volume of Hai Phong coastal port system can be up to 3.2-3.5 million m This large volume of dredging takes place every year, not only causing difficulties, reducing the efficiency of seaports in the region but also can affect the ecological environment of the region Therefore, the forecast assessment of the impacts caused by stream dredging as the scientific basis for the management of these activities, improving the operational efficiency of ports, minimizing negative impacts on the water environment is important, both theoretically and practically In addition, with favorable geographical conditions, the accumulation over a long period of time has formed huge sand mines outside the Door of Nam Trieu, Lach Tray and Van Uc-Thai Binh In addition to the economic benefits, these activities can have many environmental consequences, especially in the coming time when the demand for sand mining is further strengthened However, the study assessing the environmental impact of sand mining activities, dredging the coastal waters of Hai Phong is quite limited In the face of this situation, this study was conducted with the title "Studying the environmental impact of sand mining and dredging of coastal waters of Hai Phong" to contribute to building a basis for offering solutions to manage activities The objectives of the thesis 1) Assess the situation and extent of environmental impact of sand mining and dredging of creeks in coastal waters of Hai Phong 2) Propose solutions for environmental protection management and reasonable use of natural resources in coastal waters of Hai Phong The main contents of the thesis The main content groups of the thesis include: - Overview of the area and research issues; - Current status of sand mining activities, shipping channel dredging; - Current status of sand mining activities, shipping channel dredging; - Analyzing and assessing the situation and environmental impact of sand mining and dredging activities - Assessing the level of impact according to the model: Dynamic – Pressures – State – Impacts – Response (DPSIR); - Environmental effects of sand mining activities, stream dredging such as changes in the bottom background, hydroelectric conditions, distribution of suspended sediments, transport of sediments, morphological change, transportation/distribution of pollutants, affecting ecosystems; - Analyze and evaluate the influence trend of sand mining and stream dredging activities - Proposing a set of criteria for assessing the impact of sand mining and stream dredging activities - Proposing solutions to manage sand mining activities, dredging shipping channel Research scope and content Spatial scope: on the basis of the objectives, the research area focuses on the flow area, the area of Hai Phong ports, the areas with sand mining activities outside the Nam Trieu mouth, Lach Tray, and Van Uc- Thai Binh mouth In order to assess the extent and scope of the impact of sand mining activities, dredging shipping channel on the environment of this area, the study research area is also expanded from the locations of dredging, sand mining to the sea and deep into the rivers in Hai Phong area Research contents: Focus on the environmental impact of sand mining activities, stream dredging and proposed management solutions Study subjects: Stream dredging, sand mining and coastal waters of Hai Phong are affected by these activities, including: changes in terrain, hydroelectric mode, sediment transport, erosion variation, and spreading and transport of contaminants during sand mining, dredging shipping channel as well as affect the ecosystems The scientific and practical significance of the project Scientific significance: The research results of the thesis contribute to the development of interdisciplinary scientific research on the marine environment under the influence of human activities in the direction of quantifying the impacts of human activities on the natural environment in coastal areas that have both the potential for socio-economic development and the diverse value in natural protection Practical significance: The results of the assessment of the level of impact, the trend of environmental fluctuations and proposed solutions contribute to building a scientific basis for planning and managing sand mining activities, dredging shipping channel, overcoming limitations in managing coastal areas towards sustainable development in Hai Phong New finding of the thesis - Determining the impact of sand mining activities, dredging of maritime channel on the environment in coastal coastal areas of Hai Phong: low-level effects on the quality of marine water environment and mangrove, coral, coastal erosion and coastal economic activities; moderate effect on soft-bottom ecosystem coastal waters Environmental impact continues to increase in line with sand mining plans and development trends of Hai Phong port system - Proposing criteria for quantifying the environmental impact of sand mining and dredging activities in hai phong coast, including 11 criteria in three groups: Dynamic - Pressure (2 criteria), Status - Impact (7 criteria) and Response (2 criteria); The criteria are applied for sand mining on the coast of Hai Phong and showed that it is quite suitable for use - Proposed limit and scope of sand mining area in Hai Phong coastal area: average annual sand mining amount in the range of 9.3 million to 15 million m3, 5-year diverggity and gradual reduction of the amount of mining from 15 million m3 (to 2025), 10 million m to 2030 and million m3 after 2030; the scope of the mining space is within a depth of 6-10m, the mining depth at the mine is not more than 6m compared to the seabed The structure of thesis The thesis is arranged as follows: In addition to the opening, conclusions and references, the thesis consists of three chapters: Chapter An overview of the area and the issue of research This chapter provides an overview of research issues as well as relevant information on natural environmental and social media characteristics in the research area The preliminary results of the overview of sand mining and dredging activities in the coastal area of Hai Phong have also been presented in this chapter Chapter presents the approach and research methodology for achieving the set objectives of the thesis, including: systemic approach; Interdisciplinary access and inheritance of existing documents Research methods are also detailed in this chapter Chapter presents all the research results, including: environmental impact of maritime channel dredging activities, sand mining; results of assessment of the status of sand mining and dredging of maritime flows in coastal waters of Hai Phong; assess the trend of the impact of maritime channel dredging, sand mining on the environment in the research area and proposals on solutions to manage these activities in the study area In the process of implementing the thesis, the author received comments from scientists, managers, and the encouragement and encouragement of friends and colleagues In particular, the author always receives suggestions and dedicated guidance from Assoc Prof Tran Dinh Lan and Assoc Prof Dinh Van Manh, the author, expresses his deepest gratitude for that help Chapter OVERVIEW 1.1 Natural, socio-economic conditions related to Hai Phong coastal 1.1.1 Related natural environmental features in the study area 1.1.1.1 Geography and topography The research area is located in the waters on the west coast of the Gulf of Tonkin, north of the Eat Sea, in Hai Phong city This is home to sand mines outside the Nam Trieu gate, south of Cat Hai Island, southwest of Lach Huỵen, outside Lanh Tray, Van Uc and Thai Binh In this area, there are also regular dredging activities in the Cua Cam, Bach Dang, Nam Trieu and Lach Huyen 1.1.1.2 Bottom sediment distribution The composition and characteristics of sediment distribution in coastal waters are often quite complex, and depend on the dynamic process and supply According to related studies, surface sediments of the study area include: Small grain sand (Md=0.20-0.10mm); fine silts (Md=0.100.05mm); muds (Md=0.010-0.007mm) 1.1.1.3 Climate Hai Phong coastal area is located in the Tropical Monsoon Belt of Asia, affected by the tropical monsoon climate regime Every year there is a cold-dry winter that lasts from about November of the previous year to April of the following year Hot and humid summers, many rains last from May to October 1.1.1.4 River discharge The amount of water brought to the coast of Hai Phong is affected by the southwest monsoon (summer), tropical cyclone (autumn) and storm (autumn) The multi-water period lasts from July to September, the largest flow from the continent appears in August, the smallest flow appears in January-February every year Every year, the Red-Thai Binh river system supplies about 114 million tons of silt to the coastal region This amount of material is mainly through main inguaries: Bach Dang, Cam, Lach Tray, Van Uc, Thai Binh, Tra Ly, Ba lat, Ninh Co and Day 1.1.1.5 Sea level Water level fluctuations in the coast of Hai Phong are typical with most days in the month being diurnal tides, semi-diurnal tides only appear 2-3 days in poor water periods In one tidal phase there is once large water and once net water 1.1.1.6 Current state of water and sediment environmental quality The results of the evaluation analysis showed that although the majority of water environmental parameters such as Nitrite, Nitorat, Ammonium, Phosphate, Silicate, Dissolved Oxygen, chemical oxygen demand, biochemical oxygen, grease, Coliform and Xianua are still below the permissible threshold (QCVN 10-MT: 2015/BTNMT for aquaculture areas, aquatic conservation), but in the coastal area Hai Phong has also shown local pollution Some areas near discharge points have values that exceed the permissible threshold The content of organic, nutritious and heavy metals pollutants in sediment samples in coastal hai phong is commonly less than the permissible limits under QCVN 43:2017/BTNMT 1.1.1.7 Ecosystems and biological resources Hai Phong coastal area is home to high biodiversity, many endemic species of flora and fauna, and typical ecosystems These are mangrove forests, seagrass, beach sands, reef tidal beaches, brackish lagoons and salt fields, coral reefs, pines, soft bottoms 1.1.2 Related social insurance activities in the research area 1.1.2.1 Ports and maritime The development of Hai Phong city is always associated with activities and services related to seaports Hai Phong Port was built in 1874, now has become a system of different large and small ports, including main harbors: the port area on the Cam River, Dinh Vu port area and Lach Huyen port area 1.1.2.2 Mining Minerals in the research area are mainly sand building materials concentrated in riverside beaches, riverbeds, beach sandbanks, creek-bed sand dunes, ingue sand dunes in Cat Hai, Tien Lang and Do Son areas, with large sandbanks such as Da Bac river, Nam Trieu mouth, South of Dinh Vu, Cua Cam, etc Small, fine, mud-mud and organic matter, brown, gray-brown; The main components are quartz, mica and lightning 1.1.2.3 Tourism activities Hai Phong is a major tourist center of Vietnam Tourism activities and accompanying services in Hai Phong are mainly concentrated in Do Son and Cat Ba Tourism activities in Cat Ba are very exciting In 2012, Hai Phong had only about 100 hotels with 3,900 rooms and 7,340 guest beds By 2019, there are 501 tourist accommodation establishments in the city (up 10% compared to 2018) 1.1.2.4 Fishing and aquaculture According to the Institute of Fisheries Research, Gulf of Tonkin, there are reserves of about 681,166 tons of seafood, of which bottom fish 251,962 tons, floating fish 390,000 tons 1.1.2.5 Marine Nature Conservation For many years, the nature conservation activities on the coast of Hai Phong have been concentrated in Cat Ba Islands, which have been recognized and honored with many national and international titles Cat Ba Islands is a striking example of the conservation potential of Hai Phong coast 1.2 Research overview of the environmental impact of sand mining and shipping channel dredging activities 1.2.1 Overview of sand mining and shipping channel dredging activities in the world 1.2.1.1 Sand mining in the world Sand mining is a common activity in the world, both in developed and developing countries The products of sand mining create cheap materials for socio-economic development needs, especially for leveling, construction materials and other civil sectors 1.2.2.2 Dredging of the world's shipping channel Dredging is an annual activity in the seaport area to maintain the depth needed for shipping routes and ports This activity has always been associated with the operation of the seaport Unlike sand mining, materials obtained from dredging are sometimes not used for leveling, or as building materials, but also dumped into the sea On a global scale, this activity plays an important role in world trade every year 1.2.2 Sand mining and dredging in Vietnam 1.2.2.1 Sand mining in Vietnam With a dense river system, and a very large source of sand sludge from the Red River system (in the north) and the Mekong River (in the south), the riverbeds and coastal estuaries of our country have quite rich sand resources After the period before 2010, sand mining activities in the riverbed areas and coastal inguaries are still quite quiet, but since 2011, such as the increased material demand, sand mining activities are very active 1.1.4.2 Dredging in Vietnam As with other countries in the world, dredging and maintaining the flow into major seaport ports such as Hai Phong, Vung Tau and Ho Chi Minh City are regular activities 1.2.3 Study of the environmental impact of sand mining and dredging in the world Since the mining of leveling materials has a great impact on the water environment and ecosystems in estuary coastal area, there has been a lot of research related to this field 1.2.4 Study assesses environmental impact of sand mining and stream dredging in Vietnam In our country, the study of the effects of stream dredging and sand mining is still quite limited Some recent studies have used mathematical models to simulate the effect of these activities on hydrodynamics condition, sediment transport, morphological change, erosion/deposition 1.2.5 Study of the quantification of the environmental impact of sand mining and dredging Criteria, directives and indicators have been used to quantify the levels of impact, influence or evaluation of the effectiveness of the management process, the sustainability of the ecosystem, the rational use of resources In the study of the rational use of marine and coastal resources, directives and indicators have been developed and applied extensively in the world and Vietnam Chapter RESEARCH METHODS AND MATERIALS 2.1 Approach 2.1.1 Approach to system and integrated management of coastal areas 2.1.2 Interdisciplinary outreach 3.1.4 Inheritance of available research documents and results This thesis will inherit the resources and data from related project topics that have been implemented in this area, especially the group of topics that were implemented in the period 2008-2009, including ĐT.MT.2008.498, ĐT.MT.2008.499, ĐT.MT.2008.500, MT.2015.721 and the results of ĐT.MT.2017.792 10 2.2 Research methods 2.2.1 Method of collecting and analyzing documents Collecting and analyzing existing documents: inheriting and leveraging existing data from topics, scientific research tasks and statistical documents, socio-economic reports about the natural, socioeconomic and environmental conditions in the research area that have been carried out 2.2.2 Model method This study uses the Delft3d model This is a 3D composite model, consisting of basic modules such as Delft3d-Flow, Waves (Delft3dWave), sediment transport (Delft3d-Sed) and other modules This model can well simulate the conditions of hydrodynamics - waves, transport of sediments, water quality in the coastal zones In this study, the model method was used to simulate the effects of sand mining, dredging shipping channel on hydrodynamics conditions, transport of sediments, dispersion of contaminants, erosion fluctuations in the study area 2.2.3 GIS methodology and multi-criteria analysis The multi-criteria evaluation method is an analysis technique that combines different criteria to produce results that need attention The development of the two fields of GIS and multi-criteria analysis contributes especially importantly in solving the problem of spatial multicriteria decisions Multi-criteria analysis in GIS is carried out only after having identified and gathered all the necessary information to achieve the set goal The multi-criteria analysis model for determining the sinking location will include: + Identify the goal: find the location suitable for the conditions of social insurance and environmental resources + Identify the criteria: to pay attention to social insurance, resources and environment The criteria are not a simple variable but a combination of different properties and geometry data These criteria are attributed to the values of the number in the object's properties + Data standardization: each criterion and criteria are of different importance to the purpose set and each criterion has different attributes of different importance Therefore, they need to be standardized in terms of the same type of value depending on the purpose set to be comparable There are two approaches to standardizing data: Boolean style and classification type 2.2.4 Dynamic – Pressures – State – Impacts – Response analyze 14 between 0.03-0.26m/s For the most part, the flow at the time of high peak is reduced, while the low minimum increases compared to when there is no sand mining activity, but this difference is not much, less than 0.07m/s In strong wind conditions, the flow tends to increase at some point (maximum, minimize), with the value increasing by about 0.03m/s However, at some times the flow tends to decrease compared to when there is no sand mining activity (the largest value is 0.04m/s) Under the influence of SE winds, the area southwest of Van Uc, the flow tends to increase at peak and low times (largest 0.06m/s), except in the rainy season under normal wind conditions at some point trending down (0.05m/s) Similar to flow fluctuations in the northeast region, the flow tends to decrease when affected by sand mining activity At the coastal points far from Bach Dang gate to the southwest and northeast) there is a trend of a slight decrease in flow when affected by sand mining activities, however, the southwest area is more affected The flow in the southwest region decreased by about 0.1m/s, especially at peak times of the flow, while points in the northeast decreased by only 0.03m/s The area near the mouth of the Bach Dang River fluctuates slightly at the time when the flow reaches its peak, while at times the stream's extremes are not much different when sand mining activities take place Affecting the height of waves on the coast of Hai Phong Sand mining activities under current conditions can increase the wave height in the Van Uc mouth gate area, the largest of which is the southwest gate with a value that can reach 0.05m Wave heights in the northern area of Do Son also tend to increase slightly (0.01-0.03m) under the influence of NE and SE wind fields after sand mining activities 3.1.4.3 Affects the distribution of suspended sediment During the rainy season, the average suspended sediment concentration in the areas after the above activity tends to decrease slightly (0.1-2.0mg/l) compared to before this activity Meanwhile in the dry season, when the flow of mud and sand from the river decreases, the effects of these activities on the distribution of suspended sediment concentration under the influence of the NE wind field are clearly shown the trend of reducing the concentration compared to the rainy season The effects of sand mining, dredging and sinking also make suspended sediment distribution less uniform in areas where this activity takes place While increasing suspended sediment concentration in some locations, it also reduces suspended sediment concentration in nearby locations where 15 these activities are present These manifestations are more pronounced in the bottom layers of water During dredging, sand mining, turbid water blocks form from pinched sites, sand mining can form and move out around these areas Suspended sediment concentration due to sand mining can be increased from 2-8mg/l In particular, the value of elevated suspended sediment concentration (from 5-8mg/l) is limited to a very small range right at the sand mining site, while in the area outside the sand mine, the increased suspended sediment concentration does not exceed 5mg /l mainly affecting the northwest (inside the river) and southeast of the sand mine (the area outside the sea) The calculation results modeled on different scenarios showed that the turbidity from the sand mining site did not have a significant impact on aquaculture areas (at the mouth of Lach Tray, Van Uc), Do Son beach area and Cat Ba’s Sea The amount of sand sludge transported to the area outside the mine during sand mining is also analyzed, accordingly: in the rainy season, the amount of suspended sediment going outside the sand mining area is only about 52m 3/day and this value in the dry season is very small (only about 6m 3/day) These values are very small compared to the average amount of sand mined on a day (about 2668 m3/day) 3.1.4.4 Affects the balance of the sediments transport The results of analysis for different cases (the intensity of the impact wind field, the direction of the wind, the seasonal factor) were carried out The results of the analysis showed that sand mining activities have significantly reduced the flow of sediment transport from the shore to the sea In addition, the flow of mud and sand along the shore up to the northeast of Do Son Peninsula and southwest of Van Uc river mouth also tends to decrease after sand mining activities The extent of this mudflow decline varies according to the dynamic and meteorological conditions of the region, with levels ranging from about to over 50% This may explain, as the bottom terrain due to the dredging/sand mining activity increases in depth, which will increase the ability to deposit and retain sediment in areas where sand/sediment is removed 3.1.4.5 Affecting the bottom of the area After the process of dredging the stream, sand mining ends up forming wormholes due to these processes acting as sediment traps Under the influence of dynamic conditions, the flow of transporting sand sludge tends to move towards low-click terrain (sinkholes deeper than other areas) As a result, the rate of sedimentation tends to increase in sand 16 mining areas, dredging the stream While the surrounding areas are sand mining, stream dredging, the rate of sedimentation decreases slightly After sand mining takes place, this area appears acceeration zones in areas with sand mining activities with an additional accetion rate of 515mm per month In addition, in addition to the acceeration areas in the area where sand mining activity occurs, there appear erosion areas with an increased rate of bottom erosion, while reducing the rate of acccession in the vicinity due to the mud in those areas is lost to balance the sand sludge in areas that have been removed due to sand mining In the conditions of strong winds, the rate of erosion changes more strongly, the effects of sand mining will also be more evident than normal weather conditions In addition, during the rainy season, the rate of accction in areas with sand mining activity is significantly greater than in the dry season 3.1.4.6 Transporting and distributing certain contaminants The results of calculations simulating the spread/distribution of some contaminants during sand mining under the assumption that the amount of sand mined has only reached about 30% of the total licensed sand openings shows that the increased COD content from the sand mining area can range from 0.015-0.025mgO2/l; BOD content in water in sand mining areas can be increased to 0.01-0.02mgO 2/l The soluble nutrients of nitrogen and phosphorus may also increase near sand mining sites, where NH4+ can increase, and popularity ranges from 0.0004-0.001mg/l; PO42- can also increase to 0.0002-0.001mgP/l Sand mining can also release some heavy metals back into the water environment For example, near sand mining sites, as content increases to about 0.001-0.003μg/l; Pb can increase by about 0.0005-0.003 μg/l; Hg increased mainly in the range of 0.0005-0.0015 μg/l; and Cd content increases due to around sand mining sites with a common value in the range of 0.001-0.002 μg 3.1.5 Affecting ecosystems in Hai Phong coastal area Impact on reef ecosystems: Turbid waters arising from stream dredging and sand mining mainly affect within about 0.5-1km of water from the point of dredging the stream, sand mining Meanwhile, the distance from the location of the coral reef (in Long Chau Islands and southeast cat Ba) is also quite far from these areas: the nearest stream dredging/sand mining area is about 18-27km from the coral reef site in Southeast Cat Ba Therefore, it can be said that the impact of sand mining activities, dredging shipping channel on coral reef in Hai Phong coastal area is very small, almost negligible 17 Impact on mangrove ecosystems: Indirect impacts from dredging shipping channel as well as sand mining will risk indirect impacts on mangrove forest through increasing the process of bottom erosion, reducing sedimentation for forest foundations Normally, after the process of dredging shipping channel and sand mining ends the depth at these locations will increase significantly compared to the current conditions These changes will change hydrodynamics conditions, sediment transport, strengthen sand sludge from the surrounding to the dredging sites, sand mining degrades the source of accolination for the remaining areas This can lead to a decrease in accretion rate, increased erosion rate, affecting the development of mangrove forest in the region As such, the impacts on mangrove forest due to dredging shipping channel and sand mining activities are mainly negative but not great impact because mangrove tree sites are quite far away from the places where these activities take place Impact on marine grass ecosystems: In addition to the indirect impacts from pollution, turbid waters appearing due to dredging, sand mining affecting marine ecosystems, the indirect effects of these activities on marine grass ecosystems are mainly through the release of turbidity and pollutants The results of the evaluation analysis show that the effects of dredging and sand mining on seagrass ecosystems are very small, negligible Impact on phytoplankton species: Sand mining and dredging activities can affect the development and survival of phytoplankton species However, these effects in hai phong coastal mouth are not large because the scope of cloudy dispersal of sand mining and dredging activities is limited to small areas, so the effects on phytoplankton species are also quite small Impact on bottom species: Bottom organisms are directly affected by maintenance dredging activities (including sinking of dredging materials in the sea) and sand mining These activities cause a disturbance of the bottom, loss of habitat of organisms at those locations Therefore, when the dredging of shipping channels as well as sand mining takes place, it will definitely cause certain impacts on the bottom plants and animals in some parts of the region 3.1.6 Analysis of the impact of operations of mining, dredging of maritime flow according to the DPSIR model 18 3.1.6.1 Synthesis of environmental impacts The extent of the environmental impact of sand mining and maritime channels dredging depends on the size and duration of the extraction, the mode of extraction, and also the sensitivity of the surrounding environment to the mining activity 3.1.6.2 DPSIR model analysis Dynamic and Pressures Pressure can be described as the mechanism that causes any part of the ecosystem that can alter the state of the environment In the dynamicresponse framework analysis, the physical and chemical pressures associated with the operation or motive of the impact are considered pressures caused by mining activity, dredging shipping channel leading to a change in the status quo of ecosystems Status and impact The results of calculations comparing the flow speed near the sand mining area, dredging tends to increase slightly, about 1-5cm/s compared to the current situation The increase in flow velocity can be explained by an increase in depth, however from the location from the sand mining area, dredging the flow over 300m or more, the impacts on the flow velocity are almost negligible Deposition - erosion Bottom terrain fluctuations and erosion in project areas are directly affected by hydroelectric characteristics and the transport of sediment For sand mining and dredging sites, the rate of accoessation increases slightly at the extraction site due to the increased depth in those locations, which facilitates the surrounding mudflow to move in However, the extent of the impact is only within a narrow range of about 500m around the sand mining area For the locations of sinking of dredging material flowing at sea, the seabed is cowboyated depending on the amount of dumping material Water environment According to the results of the meta-assessment, accumulation under different scenarios to transporting mud and sand, the release of suspended sediments carried out in recent research shows that 19 the average suspended sediment content in areas with sand mining activity tends to increase as the level of sand mining increases, similar to dredging shipping channel There is also a significant decrease in the flow of sediments from the shore to the outside and the flow of sediment along the shore from the area where sand mining activities are available to other areas This result is also relatively consistent with multi-year water quality monitoring data in the Do Son area Marine life Sand mining and dredging of maritime currents not only have a direct impact on the bottom ecosystem but also affect the ecosystems in these ecosystems The ecosystem's response to the pressure from mining is reflected by state changes In the context of ecological impact assessment, the state change reflects ecosystem responses to changing environmental conditions Pressure is the mechanism of change, leading to a change in the physiological and ecological state Socio-economic Affecting the socio-economic activities of sand mining, dredging of maritime flows in Hai Phong waters including causing noise pollution to the surrounding environment, increasing the flow of ships at sea due to sand transport activities to the gathering place, posing potential risks to traffic safety at sea Response Until recently, sand was mined mainly from land mines and riverbeds, but due to strong mining and because this practice has been banned in many regions and environmental regulations have become much stricter and no longer allow this sea sand mining operation to be regulated more closely by global law, region and country The United Nations Convention on the Law of the Sea (UNCLOS) (Musah, J A., 2009), the Environmental Impact Assessment Directive (85/337/EEC, 2016) and the Deep Sea Fishing Act 2014 are a few examples of international regulations that address the impact on sea sand mining In Vietnam, legal document responses relating to sea sand mining and maritime stream dredging include provisions in the Law and guiding decrees related to mining activities 3.1.7 Proposed set of criteria for assessing the impact of sand mining and dredging of marine streams on the environment The proposed set of criteria consists of 11 criteria divided into groups: 1) The group of criteria for dynamic and pressure of sand mining/dredging activities; 2) Group of criteria for status and impact of sand mining/dredging activities; 20 I Group of motivation and pressure of sand mining /dredging activities - Criterion 1: Local sand mining needs: - Criterion 2: Volume of sand sludge dredged / year: II Group of criteria for the status and impact of sand mining /dredging activities - Criterion 3: Seabed terrain in the mining/dredging area: - Criterion 4: Ability to disperse sediment suspended in the water environment - Criterion 5: Distance from the location of sand mining / dredging activities to socio-economic objects - Criterion 6: Bottom bio biodiversity - Criterion 7: Distance from the location of sand mining activities dredge to marine ecosystems, National Park - Criterion 8: Distance from the location of sand mining/dredging activities to fishing grounds, breeding grounds, spawning grounds: - Criterion 9: Quality of marine water environment III Criteria for response - Criterion 10: Effectiveness of guiding policy documents on management of sand mining/dredging activities: - Criterion 11: Marine environmental protection programs/projects implemented in the city 3.2 Trends in the impact of sand mining and dredging activities on the environment 3.2.1 Trends in sand mining and stream dredging The results of the analysis in section 3.1.1 show that the level of sand mining in Hai Phong coastal area is still quite small compared to the demand and capacity of mining In the coming time, as the demand for sand as a leveling material increase, the annual amount of sand mined will gradually move towards the planned sand reserves The trend of sedimentation in Hai Phong port area continues to increase in the future To ensure the maintenance of port and maritime operations in Hai Phong, dredging operations in this area are inevitable and will continue to take place 3.2.2.1 Trend towards bottom terrain due to sand mining, stream dredging 21 Both sand mining and stream dredging cause a change in terrain, increasing depth in areas where these activities take place and reducing depth in the dredging sink area However, the change in depth in sand mining areas is much greater in scale and intensity than in the stream dredging and sinking areas According to the approved plan, the sand mining area is concentrated mainly outside Van Uc mouth (southwest Do Son), the area outside Lach Tray mouth, Nam Trieu mouth and southern Cat Hai Changes in terrain due to dredging and exploitation vary depending on the size and operation of each project Therefore, the deformation of the bottom terrain also occurs differently in each area and increases with the increase in scale, intensity of sand mining, dredging 3.2.2.2 Trends affecting hydroelectric conditions in areas where dredging and sand mining activities are present In areas such as the coast of Van Uc and Cat Hai-Nam Trieu, the flow rate increased after the exploitation of all sand mines as planned The increased flow rate is shown at times when the velocity reaches its maximum value, the value increases in the range of 2-8cm/s However, the increase of flow velocity in the case of 100% exploitation of licensed projects and 100% of planned projects does not have a large difference This shows that it is possible to make maximum use under the approved plan in the coastal estuary of Hai Phong Due to the depth in sand mining sites, increased flow dredging can reduce the friction at the bottom of the incoming wave and slightly increase the wave height in those areas Analysis of the simulation results, forecasts show that in the 50-year-sized area of Van Uc, wave heights can increase to 2-7cm, depending on the level of sand mining in these areas Meanwhile, in the coastal area of Nam Trieu- Lach Tray, the wave height can also increase by about 2-5cm depending on the conditions and amount of sand mined 3.2.2.3 Trends affecting on suspended sediment distribution Suspended sediment distribution has also changed with various sand mining/dredging scenarios In general, suspended sediment concentration tends to decrease slightly in sand mining areas (about 3-7mg/l) and decrease uniformity in Hai Phong coastal estuaries In particular, the direction of the wind waves that show the most obvious influence is the directions SE, S and E With the impact of the wind field from different directions (such as NE, E, SE, S), the distribution of suspended sediment between exploiting cases (all 100% of licensed projects, 50% exploitation according to the 22 plan and exploitation of 100% according to the plan) also has a small change and most of them show a slight decrease in suspended sediment concentration in the mining areas Sand after these activities are over In particular, the manifestations of decrease in suspended sediment concentration content are more evident at the bottom and gradually increase as the level of sand mining increases The same can happen after the dredging shipping channel and dumping operation is complete but the scale and intensity will be smaller 2.4 Trends affecting the sediment transport and sediments balance In case of increasing the amount of sand exploited in all the planned areas, the flow of sediment from the estuary, the coastal area to the sea continues to decline (from 5-83% of the amount of sand sludge transported through) In particular, the coastal waters outside the sand mining sites will be the place where the flow of sediment transported through the most decreases, then the amount of sediment gradually decreases outwards with depth Besides, the flow of mud and sand moving along the bank to the south of the red river delta also tends to decrease The future decline in sediment transport as the increase in sand mining dredged the shipping channel mainly to make up for the shortage of sediment taken away in sand mining areas, dredging the stream Due to the sudden increase in depth of the places where these activities take place, making those areas become sediment traps, retaining the flow of sand sludge as it moves through, while attracting mud and sand from around the transport to and depositing in sand mining sites, dredge the stream These impacts may not affect offshore waters, but in coastal areas, they can cause mud and sands, increasing the risk of erosion for coastal areas near sand mining sites and dredging the shipping channel 3.2.2.5 Trends affecting seabed erosion fluctuations The trend of accelerating accretion in mining/dredging positions is evident when increasing the amount of sand mined With normal weather conditions, the accretion rate in sand mining areas can increase in the range of 5-15mm per month The process of transporting sediment increases sharply when strong windy conditions appear Therefore, the accretion rate at sand mining sites can be up to 10-20mm per month However, it also sharply increases the rate of erosion in areas close to the sand mining site with a possible bottom erosion rate of over 25mm per month 3.2.2.6 Trends affecting the spread of private pollutants for sand mining 23 As the intensity of sand mining increases with the amount of sand mined as with licensed projects and the entire region has been planned for sand mining (100% of the projects are licensed and 100% as planned), the simulation results show that the content of muscle pollutants tends to increase markedly (COD) increased from the mining area of about 0.0150.03mgO2/l; BOD also increased to about 0.01-0.025mgO 2/l; NH4+ levels increased in popularity between 0.0004-0.002mg/l, and PO 42- levels also increased to about 0.0004-0.001mgP/l Similarly for organic, nutritional groups, the content of some heavy metals such as As, As, Pb, Hg and Cd also tends to increase with increased sand mining activity (all licensed projects and entire regions have been planned) This increased heavy metal content mainly occurs around sand mining sites, and the marine spectrum ranges from 0.001-0.004μg/l The scope of influence and distribution of contaminants varies with the tide phase, the largest impact from 3-8km from the extraction sites: little impact at the time of net or large water; move outwards, southsouthwest during the down tide and up north and northwest during the upand-coming tide phase 3.3 Proposed management solutions 3.3.1 Summary of the grounds as the basis for the proposals Natural conditions of the area Environmental and ecological conditions in Hai Phong coastal area Conditions related socio-economic Conditions related legal documents Analyzing the appropriate levels of sand mining sites and dredging sinking 3.3.2 Proposing management solutions 3.3.2.1 Legal and institutional policy solutions 1) Perfecting the system of legal documents in the management of sand 24 mining activities, paying special attention to provincial and municipal levels 2) Strengthen supervision and sanctions against violating organizations in sand mining and dredging of maritime flows 3) Strengthen coordination between sand mining and dredging units 3.3.2.2 Solutions for building scientific and technological management and application tools 1) Planning and zoning of sand mining areas and sinking of dredging materials in coastal waters 2) Application of science and technology 3) Proposing sand mining limits 4) Increasing the use of advanced technology in sand management and mining and dredging of maritime flows 3.3.2.1 Proposed solution to manage sand mining activities 1) Develop and finalize legal policies in the management of sand mining activities 2) Review the coordination between agencies and agencies in managing sand mining activities 3) Mining activities are quite specific activities, taking place in harsh environments: wind waves, flooding, bottom terrain (depth) of sand mines that change constantly over time Therefore, the regulatory agencies not only follow the reports of the sand mining unit but need the support of specialized agencies in checking and evaluating the authenticity of each report 4) Strengthen inspection and supervision of sand mining status at mines, if enterprises not mine sand as promised may consider revoking sand mining licenses 5) Application of modern technical and technological means in the monitoring of sand mining activities 6) Study the review, planning and demarcation of boundaries between clam farming areas and sand mining areas, supervise the implementation of these plans 7) Research and look for other sources of materials to replace sand 3.3.2.2 Selection of priority location for sand mining, sinking of dredge at sea 25 3.3.2.3 Proposed sand mining limits 3.3.3 Proposed solutions for dredging activities 3.3.3.1 Strengthen supervision of current regulations relating to dredging activities 3.3.3.2 Perfecting the securities and socialization mechanisms related to dredging activities 3.3.3.3 Planning of the area of sinking of dredge material 3.3.3.4 Strengthening the application of science and technology in dredging activities CONCLUSIONS AND RECOMMENDATIONS Conclusion Sand mining and dredging activities are taking place on the coast of Hai Phong and tend to increase in both size and intensity due to the city's social development needs, especially the urbanization, port development and maritime activities Environmental impact factors due to dredging maintaining maritime currents and sand mining include: changes in depth (in the location of sand mining/dredging and sinking), changes in flow mode, transport of sand sludge, changes in the balance of sand sludge and fluctuations in acceeration - erosion in sand mining areas and dredging of maritime streams, fluctuations in the quality of marine water and marine life Environmental impact of these activities in hai phong coastal areas is low for the quality of marine water environment and mangrove forest, coral, coastal erosion and coastal economic activities; at medium for bottom ecosystems and coastal seabed bottom terrain The trend of the influence of stream dredging as well as sand mining activities in the research area on the environment will continue to increase markedly with different scales and intensities corresponding to the sand mining planning and development trend of Hai Phong port system In the long term, there may be effects of coastal erosion, coastal works due to the accumulation of impacts of sand mining and dredging of maritime flows In order to quantify the environmental effects of coastal sand mining and maritime flow dredging activities, the criteria for assessing the impact of these activities in hai phong coastal waters are proposed on the basis of 26 the results of analysis assessing the status/trend and impact of sand mining activities, Stream dredging as well as EIA and social insurance in the research area are synthesized in the Dynamics - Responsive framework analysis Eleven criteria are divided into three groups: Motivation - Pressure including: (1) Local sand mining needs, (2) Volume of dredged sand sludge / year; Status – Impact includes: (3) Seabed terrain in mining/dredging area, (4) Ability to disperse TTLL in water environment, (5) Distance from the location of sand mining/dredging activities to social zone objects, (6) Biodiversity of the bottom organism, (7) Distance from the location of sand mining/dredging activities to marine or national park, (8) Distance from the location of sand mining/dredging activities to fisheries, breeding grounds, spawning grounds, (9) Quality of marine water environment; Responses include: (10) Effectiveness of guiding policy documents on management of sand mining/dredging activities, (11) Marine environmental protection programs/projects implemented in the city The referenceable set of criteria applies to other coastal areas with similar conditions and activities Based on the results of the study assessing the level of environmental impact and legal grounds, solutions to manage sand mining and dredging of maritime flows in the proposed research area, including: legal and institutional policy solutions focused on perfecting local legal documents and strengthening the mechanism for monitoring monitoring, sanctioning as well as coordination and coordination among regulatory agencies; solutions for building tools for management and application of science and technology, which focuses on planning and zoning of locations and limits on sand mining (total mining volume of 9.3-15 million m3, mining space concentrated in the mouth of Van Uc river and within the depth of seabed of 6-10m, 3-stage mining diverging with declining mining volume and mining depth of more than 6m), avoiding conflicts using beach and sea areas in the region as well as planning the selection of marine channel dredge areas to ensure the growth objectives of port and maritime activities while minimizing environmental impacts, enhancing the application of science and technology in management and in sand mining and dredging of maritime flows Recommendations 27 Within the framework of the thesis, PhD students use data on the status of sand mining through the reporting figures of active sand mines However, in practice, the current sand mining capacity may change because some mines have been licensed but not yet operational, moreover, the assessment of sand reserves in areas within a depth of 610m is not of interest while this is an area that can be mined instead of mines at smaller depths This limitation needs to be overcome in further studies The criteria for quantifying environmental impacts are proposed on the basis of research in the coastal area of Hai Phong with two activities: sand mining and dredging of maritime channels Therefore, the criteria are limited when used in extended assessment for other activities or general assessment for hai phong coast as well as other similar coastal areas Therefore, it is necessary to continue this research direction to gradually develop a set of criteria for evaluating the synthesis of activities in coastal areas to the environment and ecology, expanding the scope of application NEW FINDINGS OF THE THESIS - Determine the extent of the impact of sand mining activities, dredging the flow on the environment in the coastal area of Hai Phong - Proposing criteria for quantifying the environmental impact of sand mining and stream dredging activities in hai phong coast - Proposed limit / scope of sand mining area in coastal hai phong area 28 LIST OF WORKS HAS BEEN PUBLISHED 1) Đỗ Gia Khánh, Vũ Duy Vĩnh, Trần Đình Lân, Nguyễn Minh Hải, 2019 Ảnh hưởng hoạt động khai thác cát đến trường dòng chảy dư sóng vùng ven biển Hải Phịng Tạp chí Khoa học Công nghệ Biển, Tập 19, Số 3A; 2019: 33–47 2) Đỗ Gia Khánh, Vũ Duy Vĩnh, Nguyễn Minh Hải, Trần Đình Lân, 2019 Đánh giá dự báo biến động địa hình khai thác cát vùng cửa sơng ven biển Hải Phịng Tuyển tập báo cáo khoa học Diễn Đàn sinh học toàn quốc 2019: Sinh học biển phát triển bền vững NXB Khoa học Tự nhiên Cơng nghệ, tr 694-705 3) Trần Đình Lân, Vũ Duy Vĩnh, Đỗ Thị Thu Hương, Đỗ Gia Khánh, 2019 Đánh giá khả lựa chọn vị trí đổ vật liệu nạo vét luồng vào cảng vùng biển Hải Phịng Tạp chí Khoa học Cơng nghệ Biển, Tập 19, Số 4; 2019: 557–569 4) Do Gia Khanh, Đỗ Thị Thu Hương, Vũ Duy Vĩnh, Trần Đình Lân, 2020 Zoning Marine Disposal for Dredged Material Management: A Case Study in Vietnam Sustainable Marine Structures, [S.l.], v 1, n 2, nov 2020 ISSN 2661-3158 5) Huong, D.T.T., Ha, N.T.T., Do Khanh, G et al., 2021 Sustainability assessment of coastal ecosystems: DPSIR analysis for beaches at the Northeast Coast of Vietnam Environ Dev Sustain (2021) https://doi.org/10.1007/s10668-021-01648-x ... Vĩnh, Trần Đình Lân, Nguyễn Minh Hải, 2019 Ảnh hưởng hoạt động khai thác cát đến trường dịng chảy dư sóng vùng ven biển Hải Phịng Tạp chí Khoa học Cơng nghệ Biển, Tập 19, Số 3A; 2019: 33–47 2)... Nguyễn Minh Hải, Trần Đình Lân, 2019 Đánh giá dự báo biến động địa hình khai thác cát vùng cửa sơng ven biển Hải Phòng Tuyển tập báo cáo khoa học Diễn Đàn sinh học toàn quốc 2019: Sinh học biển phát... Đỗ Gia Khánh, 2019 Đánh giá khả lựa chọn vị trí đổ vật liệu nạo vét luồng vào cảng vùng biển Hải Phòng Tạp chí Khoa học Cơng nghệ Biển, Tập 19, Số 4; 2019: 557–569 4) Do Gia Khanh, Đỗ Thị Thu