Table of contents

The rapid development of Geographic Information System (GIS) and remote sensing technologies have provided opportunities for GIS and remote sensing applications to be integrated into various practical fields over the past decades. Especially, GIS and remote sensing have led to significant breakthroughs in research related to natural resources, environment, disaster risk, geospatial databases, land use change and urbanization. In that context, The National Conference on GIS Application 2022: GIS and Remote Sensing Applications for Environment and Resource Management was held at the Vietnam National University Ho Chi Minh City - University of Science (VNU-HCM) during 11-12 November, 2022. The major objectives of the conference are to create a symposium for scientists, scholars, managers and stakeholders to exchange their research achievements, applications of GIS and remote sensing technologies in various fields of environmental and natural resource management as well as to propose development orientations for GIS and remote sensing technologies in the future.

With a great privilege, we would like to present IOP Conference Series: Earth and Environmental Science to readers. After rigorous reviews, thirty papers from the conference were selected to publish in this special issue. These papers represented cutting-edge research on a variety of subjects, including (a) agriculture and climate change; (b) environmental management; (c) geospatial database analysis; (d) land use change; and (e) natural resources management.

We appreciate the support provided by the Vietnam National University Ho Chi Minh City (VNUHCM) and the University of Science (VNUHCM-US) for the conference. We would like to express our gratitude to all conference participants for their papers and attendance. We also want to express our appreciation and gratitude to all the reviewers who have assisted us in maintain the quality reputation of the articles submitted for publication in the IOP proceedings. Finally, we would like to give special thanks to the conference organizer and to all others whose contributions made the publication of the special issue.

On behalf of editor board

Assoc. Prof. Dao Nguyen Khoi

Faculty of Environment, University of Science

Vietnam National University Ho Chi Minh City

List of Organizing committee, Secretariat, Editor board, List of reviewers are available in this pdf.

All papers published in this volume have been reviewed through processes administered by the Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

1. Type of peer review: Single anonymous

2. Conference submission management system: Morressier

3. Number of submissions received: 33

4. Number of submissions sent for review: 32

5. Number of submissions accepted: 29

6. Acceptance Rate (Submissions Accepted / Submissions Received × 100): 87.9 %

7. Average number of reviews per paper: 2.00

8. Total number of reviewers involved: 27

9. Contact person for queries:

Name: Assoc.Prof. Dao Nguyen Khoi

Affiliation: Faculty of Environment, University of Science, Vietnam National University Ho Chi Minh City

Email: dnkhoi@hcmus.edu.vn

There has been noticed that the Vietnamese Mekong Delta (VMD) is particularly vulnerable to the impacts of extreme weather situations. Some underlying effects of global climate change may cause the hydrological conditions of this delta to shift, and this could eventually cause serious issues for the socio-economic and agricultural systems. Besides, a key part of agricultural productivity is also played by cultivation practices, particularly fertilizer management. Inadequate and inappropriate application of nitrogen will negatively impact the environment and affects the economic value of farmers. Crop simulation models demonstrate their effectiveness in simulating and evaluating nitrogen fertilizer management in order to increase nitrogen use efficiency and prevent environmental contamination. Our research intends to identify how farming and climate affect rice productivity. In this study, the ideal N ratio and the climate change's impact on paddy rice growth stages in Vinh Thanh district, Can Tho City were determined by using the DSSAT-CERES-Rice. With the value of Correlation coefficient (R²) = 0.8 and index of agreement (d-value) = 0.96, the DSSAT-CERES-Rice model was suitable for simulating rice yield, according to research findings. Additionally, rice yield will alter as meteorological parameters change in the future, and temperature will have the greatest influence on rice output. When the nitrogen fertilization rate in the rice cultivation process is changed to 0, 40, 80, 120, and 160 kg ha⁻¹, the research results demonstrate that there is no noticeable distinction when comparing the efficiency of nitrogen use as well as the economic efficiency at the above nitrogen ratios. Nevertheless, research findings clearly indicated that fertilizing with nitrogen at a rate of about 80 kg ha⁻¹ will be more effective economically and in terms of nitrogen utilization than other treatments.

Drought is a natural disaster that has severe economic and environmental consequences. In the Dak Lak province, drought has frequently occurred in recent years, causing severe water scarcity in the dry season. Therefore, drought forecasting information will be essential to take timely response measures for water resource management and agricultural production. This study used machine learning methods for drought forecasting in the Dak Lak province. The three machine learning models used in this study include Artificial Neural Network (ANN), Support Vector Regression (SVR), and Random Forest (RF), combined with the use of the Standardized Precipitation - Evapotranspiration Index (SPEI) to predict meteorological droughts. Results showed that the ANN models give high accuracy in the drought prediction for the study area.

The objective of the present study was to map the agro-climatic zone for Robusta coffee crop in the Srepok River Basin. In this study, the trends of temperature and precipitation were identified using by the Mann – Kendall non-parametric test, the water deficit was calculated based on the CROPWAT model, and the agro-climatic zones for Robusta coffee crop were mapped using geographic information system (GIS). Results showed that the average annual temperature and the average annual rainfall had increasing trends. In addition, five agro-climatic zones were identified in the study area, including very appropriate, appropriate, neutral, restricted and inappropriate. Most of the territory was classified as Moderately Suitable for Robusta coffee. Suitable areas for the coffee cultivation were found in the east of the basin. Agro-climatic zoning will help managers and farmers improve crop yields effectively, avoid climate risks and maximize local advantages.

Application of machine learning algorithms in simulating crop yield has attracted more attention from plenty of scientists in recent years. The objective of this study is to estimate the coffee yields in Dak Lak province by using three machine learning algorithms, namely, artificial neural network (ANN), support vector regression (SVR), and random forest (RF), respectively. Input data in simulating processes includes maximum and minimum temperature, effective rainfall, reference evapotranspiration, and crop water requirement in the period 2000-2020. In which, the percentage of data in the training and testing phases is 70% and 30%, respectively. The results indicated that three machine learning models (i.e., SVR, ANN, and RF) have reasonable performance in simulating the coffee yield, out of which, the RF model performs best with NSE values of approximately 0.918 for the training phase and 0.818 for the testing phase.

This study implemented an index-based approach to monitor drought in the Vu Gia – Thu Bon river basin using remote sensing data and Google Earth Engine (GEE) cloud computing services. Landsat's time-series remote sensing data are effectively used to calculate various drought indices. In this investigation, we evaluated the performance of various remote sensing-based drought indices (RSDI) utilizing the cloud-based Google Earth Engine (GEE) computing platform. Results indicated that there was a significant correlation between RSDI and the in-situ Potential Evapotranspiration (PET) and the soil temperature. The empirical results of this study demonstrated the possible utility of remote sensing data in drought monitoring for data-scarce regions.

Drought is one of the extreme weather events that has been occurring with increasing frequency and complexity as well as having negative effects on water resources and agricultural production. The focus of the present study is to investigate the climate change effects on agricultural drought in the Be River Basin. The SWAT model was applied to simulate the soil moisture content and Standardized Soil Water Index (SSWI) was utilized to estimate the characteristics of agricultural drought. In addition, the future climate conditions for the three periods (2022–2040, 2042–2060, and 2062–2080) were generated by the delta change method based on the outputs of five global climate models. The results show that agricultural drought is anticipated to increase in the frequency, intensity, and duration (up to 168.82%, depending on time and emission scenarios). Moreover, drought events and water shortage in the dry season tend to be more likely to happen soon in the Be River Basin. These results are consistent with the changing trends of related soil moisture. Besides, the results contribute reliable scientific evidence to help managers and policy makers having appropriate plans in the future.

Ninh Kieu District is an urban district with a rapid urbanization rate and a complex dimension. This factor has made urban flooding in this district very serious. Metro Residential Area is one of the areas currently being strongly affected by urban flooding in Ninh Kieu District. This research is conducted to apply GIS and SWMM model to assess urban flooding in Metro Residential Area. GIS is used to digitize the drainage system, while SWMM model is used to simulate urban flooding in the study area. Research results have shown the flood level, flood time, flood volume, flow velocity and frequently flooded locations in Metro Residential Area. This is an important basis for the development of solutions to reduce flooding, thereby reducing the impact of urban flooding and improving the quality of life of the residential community living in the study area.

The development of GIS brings several advantages for environmental protection and management in Binh Dinh province. This technology has huge potential to overcome the disadvantages of ground-based monitoring sites and can provide additional information on the geographical representation of environmental quality at the regional level. The objective of this study is to use GIS technology to develop a map for rapid identification of the emission coefficient Kv (Kv), coefficient Kq of receiving water (Kq), and wastewater discharge with columns A and B in national environmental regulations. This study also used the ArcGIS tool and map overlay method to merge data with several GIS' layers. The results show the maps of emissions coefficient Kv in the province are as 5 regions with a coefficient Kv = 0.6; 0.8; 1.0; 1.2; 1.4 based on the current state of urban development, socio-economy, industrial zones, special-use forests, natural heritages, historical and cultural relics, urban areas, rural areas. For the coefficients Kq (Kq = 0.9) corresponding to the flow rate (Qmean) of receiving water of all rivers, streams, canals, and channels in Binh Đinh province (Qmean < 50 m³/s). The other result shows that the wastewater river basin from the downstream of the river to the estuary or lagoon usually is the zoning of wastewater discharge column B.

The rapid urbanization of Ho Chi Minh City (HCMC) is a huge pressure upon the surface water quality as well as its self-cleaning capacity. Every day, a large amount of domestic wastewater is discharged directly into the canal system with concentrations of toxic pollutant components. The assessment of the quality and self-cleaning capacity of canal water by the oxy declining process is a basic foundation for the planning and management of waste water drainage and treatment system in the City. With the application of oxy declining and osmotic experiential coefficient formulas into the oxidation process equation (Streeter-Phelpse), the self-cleaning capacity are determined and classified at any time and positions. The self-cleaning capacity depended on the hydraulic and quality condition of canals. The research of self-cleaning capacity is implemented for urban inner canal system of HCMC in the period 2012 – 2021. Based on the assessment's results, the distribution of self-cleaning capacity levels is mapped to analyse the changes and zone. The zoning maps expressed suitability the distribution levels of self-cleaning capacity with high visualization. And they are a valuable basis for planning and decision making on the solutions to improve environment quality of the relative management agencies of HCMC.

Bac Lieu is one of the provinces with the fastest rate of socio-economic development and urbanization in the Ca Mau Peninsula and the coastal areas of the Mekong Delta Region (MDR). Like many other urban regions in Vietnam, Bac Lieu has always faced significant challenges in the management and treatment of municipal solid waste (MSW) and controlling greenhouse gas (GHG) emissions from landfills. This study was carried out to analyze and assess the profits gained from the scenario of minimizing GHG contributions in the Hoa Binh landfill, which is one of the largest landfills in Bac Lieu Province. On the basis of the circular economy orientation and planning MSW management with a vision to 2030, the EnLandFill 2019 software (ENvironmental information – model integrated system for air emission and dispersion estimation from LandFill) was applied. The highlight outcomes presented that from 2020 to 2035, the total GHG emission potential for the landfill gas recovery scenario was 19.270 thousand tonnes of CO₂-eq, which was 7.978 times lower than the case of no recovery. Furthermore, the benefits achieved from the maximum capacity of electricity generation potential in 2032 are up to 1.932 million kWh/year with a power plant size of 220.540 MW. The research provided theoretical and practical implications, playing a crucial role as a driving force in promoting the development of provincial public policies and investments. Moreover, thereby oriented with a multi-objective approach to an integrated relationship of environment, economy, and society, as well as toward an urban of sustainable development.

Thu Duc City (TDC), a sub-city of Ho Chi Minh City (HCMC), Vietnam, has undergone rapid transformation in land use - land cover (LULC) over the past few decades. Flooding is one of the biggest challenges to the sustainable development of the city. Quantifying excess runoff induced by urbanization and climate change is essential for developing an efficient flood risk management strategy. This research aims to evaluate the effects of the impervious surface expansion (a key indicator of urbanization) and the rainfall increase caused by climate change on the excess runoff depth in TDC. The dataset derived from LANDSAT satellite images was used to explore the spatial-temporal dynamics of impervious surface areas from 1985 to 2020. The EPA-SWMM urban rainfall-runoff model was employed to investigate the effects of increased impervious surface and climate change on excess runoff depth. The satellite data showed that TDC has 24% of the impermeable surface area currently, much lower than 75.6% in areas located in the central districts such as Nhieu Loc – Thi Nghe (NL-TN) basin, and that impermeable areas have expanded rapidly in the north-south and west-east directions since 2010. The simulated results indicated that impervious surface development increased excess runoff depth by 14.0mm between 1985 and 2020. It also showed that increasing rainfall due to climate change could raise the average excess runoff depth by 18.2%, 64.0%, and 49.4%, respectively, at the beginning, the middle, and the end of the century compared to the current stage. It suggests mainstreaming stormwater retention and detention systems into urban development plans for adapting to the future uncertainties of urbanization and climate change. It also recommends that the impervious surface areas must be maintained within design thresholds to control runoff and mitigate floods in practice. The research findings could assist policymakers and stakeholders in formulating a long-term vision to propose an efficient urban stormwater management strategy in TDC and similar growing cities.

Although Real-time kinematic (RTK) is a positioning technique with high accuracy at the centimeter level, the investment cost for this positioning technique is relatively high. To reduce the investment cost, low-cost, dual-frequency, multi-Global Navigation Satellite System (GNSS) receivers can be considered. In Vietnam, the Continuously Operating Reference Stations (CORS) network has operated and covered the whole country. Therefore, the combination of low-cost, dual-frequency, multi-GNSS receivers and the CORS network can make RTK positioning easier and less expensive. The aim of this study is to evaluate the potential of applying the RTK positioning technique using a low-cost, dual-frequency, multi-GNSS receiver and the CORS network in Vietnam. In this study, four positioning experiments were performed in static and kinematic modes, and at near and far locations in which the rover was about 3 km and 30 km from the CORS station, respectively. Experiments conducted near the CORS station gave good results with the average standard deviation of 0.2 cm for static positioning and average deviation of 2.2 cm for kinematic positioning, and the FIX rate of greater than 95%. Therefore, the experimental results show the excellent potential of RTK positioning using low-cost, dual-frequency, multi-constellation receivers with the CORS network in Vietnam.

This study is based on the current state of management and legal documents in Vietnam. The documents related to national borders and territories, documents signed by Vietnam, and international treaties to which Vietnam is a member. Administrative boundaries on the mainland have documents guiding the determination of administrative boundaries. The administrative boundary consists of the land part and the sea part. There is no record of defining administrative boundaries at sea. This study proposes a number of options for determining maritime boundaries (internal waters) for the coastal provinces of Vietnam. Administrative boundary records, maps, and national geographic databases are used to build the administrative boundary database. The research results provide suitable technical solutions to determine the maritime boundary, taking into account the morphological features of the coast. The administrative boundary database is fully built, legal, unified, and included in the management system. The administrative boundary database management system is centrally managed and is capable of providing information to organizations and individuals in need.

Authorities of the Ho Chi Minh City have expressed an interest in developing application solutions of UAV (Unmanned Aerial Vehicle) that are able to monitor construction progress at different stages of any project; and to update cadastral maps for improving geospatial information for decision-making. This paper aims to describe new opportunities of using UAV in monitoring and mapping at Thu Duc district, and to address main challenges from different aspects and limitations that help engineers to improve the procedures and accuracy of UAV images processing. Some specific application cases focused on monitoring construction progress, cadastral mapping and updating the database are also introduced for understanding how UAV solutions can be applied as one tool to improve the analysis of land use change and infrastructure management in the urban area. In addition, the analysed results also shown how to develop the flight planning and the suitable Ground Control Points (GCPs) with challenges from different aspects in application solutions in capturing necessary data on monitoring construction progress and updating cadastral maps with large scale (1:200 and 1:500).

Rapid urban growth causes the increase of impervious surface which was converted from vegetation land. This affects the rate of water penetration into soils, the rise of surface runoff, and the lowering of groundwater levels. The expansion of the impervious surface gives rise to a series of changes in the physical environment, affecting the quality of life of people due to a change in the thermal energy balance. Therefore, the purpose of this study is to analyse of changes of impervious surface area Ho Chi Minh City and Ba Ria - Vung Tau province which is the marine national economic hub in the period of 2009-2020 by using Landsat satellite image data. The main methods used are NDWI, PISI indices and ISODATA algorithm. The results show that the area of impervious surface area of Ho Chi Minh City is very high with 18.5% in 2009 and 35% increasing rate from 2009-2020. There are 75% districts in Ho Chi Minh city having over 50% impervious surface area. Ba Ria-Vung Tau has lower impervious surface area with 5.8% in 2009 but having the incredible increasing rate– over 100%.

This study aims to analyze the variation of land surface temperature (LST) and its effect on the urban heat island (UHI) in relation to the urban planning processes of Ho Chi Minh City (HCMC) from the years 2010 to 2020. These changes have impacted the urban environmental conditions and the city development. The study used the time series of Landsat 5 TM and Landsat 8 OLI acquired for the years 2010, 2015, and 2020, and used the algorithms for calculating the land surface temperature (LST), the normalized difference vegetation index (NDVI) and the normalized difference built-up index (NDBI) to investigate the relationships between these phenomena in the city planning processes. The results highlight the increase in land surface temperature was related to the dense of impervious surface area and the decrease of vegetation area. The UHI zones occurred in the areas with high LST and NDBI values, and low NDVI values (concentrated in the central districts and the planned areas) compared to the surrounding areas with lower LST and NDBI and higher NDVI. The recommend planning solutions for the new urban development areas should focus on increasing the amount green areas to combat the UHI phenomenon and environmental problems against the development.

Urban sprawl has changed the land use land cover (LULC) in Ho Chi Minh City (HCMC). It has caused the gradual decline of the natural vegetation and rapid increase of the impervious surface, which leads to the heat storage capacity of the urban surface being on the rise. There is a land surface temperature (LST) difference between the urban center and surrounding areas and it creates the urban heat island phenomenon (UHI). This study used Landsat 4, 5, and Landsat 8 satellite image data from 1990 to 2020 with the GIS algorithms on ENVI and ArcGIS to analyze and estimate the correlation between the LULC and the LST in HCMC. The Kappa coefficients of the LULC classifications were all over 0.8 in 1990 – 2020 period. The total area of impervious surface has increased by 57,338 hectares over the past 30 years; while the total area of natural green has decreased by 19,116 hectares. The LST has remarkably increased in the areas of construction lands, industrial zones, and impervious surfaces, with an average increase from 22°C to 27°C. While the LST in the others such as the vegetation surface and water surface were slower, from 20°C to 23°C. The solution of enhancing the urban green space was suggested to mitigate the increasing LST impact on HCMC.

Surface characteristics are believed to be the primary factor causing spatial variation in land surface temperature (LST), especially in a large and rapidly growing city like Ho Chi Minh City. The study aims to estimate the spatial relationship between land surface temperature (LST) and impervious surface density (ISA) by using three statistical techniques: 1) Optimized hot spot analysis; 2) Global linear regression (OLS); and 3) Geographically weighted regression (GWR). LST and ISA were extracted from Landsat 8 OLI of 2020. According to the optimized hot spot analysis's findings, over 80% of the areas of high ISA values (mean ISA: 0.86, SD: 0.13) overlap with areas of high LST values (mean LST: 36.2°C, SD: 2.04°C), with a correlation coefficient of r=0.775. Likewise, Moran's I index (I=0.82, Z=72, P<0.001) indicates that LST in Ho Chi Minh City has a significantly spatial dependence, so geographically weighted regression (GWR) and global linear (OLS) models need to be taken into account simultaneously. Coefficient of determination R² and AICc (Akaike information criterion corrected) were used to compare the models. R² increases from 0.78 to 0.87, whereas AICc decreases from 8047 to 7033 in OLS and GWR, respectively. GWR has a more substantial explanatory power for the association between LST and ISA and offers superior LST prediction accuracy compared to OLS. Potential urban heat island areas can be accurately detected by combining GWR and optimized hot spot analysis.

In recent years, land use changes in Kon Tum province have been significantly transformation. Hence, there is an urgent need for Land Use/Land Cover (LULC) change assessment in Kon Tum province during two recent decades. The present study employed GIS technique to examine potential changes in different land-use types between 2005-2010, 2010-2015 and 2015-2020 periods. To do this, several LULC maps representing the existing condition of LULC for the years 2005, 2010, 2015, and 2020 were subjected to the GIS technique. The outcomes show that there was significant conversion in agricultural land (NNP), increasing from 10.38% (2005) to 29.87% (2020) of the total study area. Furthermore, about 30.08% of unused land (CSD) and more than 10% of forest land (LNP) area were converted into agricultural land during each period. However, a large proportion of agricultural land (about 25.2%) was converted into other types of land use for the three periods. On the other hand, other types of land use coded as residential land (OTC) and built-up land (PNN) experienced large changes of about 171.66% and 245.67, and CSD exhibited a strong decrease (-99,83%) during 2005-2020 period. Several factors including climate change, international economic integration, science and technology, population growth and human resources, land resources, infrastructure, market, and policies of the local government were identified as driving forces of the LULC change in the province. Overall, it is expected that these findings will be conducive to the establishment of a general framework for land use planning in Kon Tum province.

Land use regression (LUR) model is a common method for assessing ambient air pollution in metropolis, such as fine particulate matter (PM_2.5). The LUR model utilizes PM_2.5 concentrations as a dependent variable and traffic, topography, and land use variables..., named as environmental data, as independent variables in multiple linear regression analysis. Currently, the PM_2.5 pollution is one of the most concerning environmental issues in Ho Chi Minh City (HCMC). Particularly, in the context of current limited air pollution monitoring resources of the city, the LUR model usage for PM_2.5 pollution assessment at the level of the whole city may be a possible solution. However, the environmental data for using in the LUR model in HCMC is not available. Thus, this study was conducted to prepare environmental data for applying in the LUR model in upcoming studies. The study selected potential environmental variables in HCMC and continued to deal with databases selection for developing these environmental variables. The major result of the study is that a database of environmental data in HCMC was developed, including 26 variables categorized into five groups, including (1) Meteorological data, (2) Traffic-related data, (3) Population data, (4) Land use data, and (5) Social-economic data. Moreover, the study established a conceptual framework for environmental data collection. Finally, environmental data of several fixed sites, where PM_2.5 concentrations were monitored in our previous studies, was extracted as an illustration.

The economy of Vietnam relies mainly on agriculture and the Mekong Delta contributes a crucial part. The region is facing to decline in water resources together with the demand for economic development. Land use changes and policies in agriculture have been implemented in response to natural risks. The study applied a mixed-approach, using both quantitative and qualitative data to explore relations between the status of land use (LU) changes and the implementation of agricultural policies. Multi-temporal Landsat image data including Landsat-5, 7, 8 collected from Google Earth Engine (GEE) database. LU change classification using the Random Forest (RF) method to examine changes in LU in An Giang province from 2000 to 2021. The qualitative data were gathered from individual and group discussions with local authorities, officers and farmers. The results expressed that LU in An Giang province has been changed toward reducing rice areas. Linkages existed between the agricultural policies and the types of LU related to policies of agricultural restructuring. Inappropriate areas for rice have been replaced by upland crops and fruit trees throughout the province. Ecological conditions and specificities of the region contribute to the difference from LU in the province. For agricultural development, value chain and cooperation are necessary to build adaptive and efficient agriculture.

Water resources are increasingly scarce and depleted owing to the effects of local socio-economic development. Hydropower development changes the hydrological regime and the amount of alluvium downstream through the process of reservoir regulation and operation. To evaluate the potential of reservoir effect on river basin flow, we performed a flow assessment in the presence of structures and compared it with control case in which there are no reservoirs. In the Srepok river basin with many hydroelectric power plants built on terraces on rivers. Due to the dense construction surrounding the river, the flow has changed and there have been incidents of hydropower causing damage to crops and households. The results show that, in general, due to the influence of hydroelectric reservoirs, the annual flow is not significantly reduced and the amount of alluvium tends to increase. This research was conducted to provide comprehensive information on hydropower development, and at the same time provide a reliable source of information to help managers make timely and accurate decisions.

One of the five key tasks of the National Strategy on Biodiversity to 2030 is "Investigating, inventorying, evaluating and building a national database on biodiversity". Maps and geographic information systems are two indispensable tools for this task. The objective of this study was to build the map of biodiversity status, focusing on the level of species diversity for Tien Giang province. The input data derived from the results of the available biodiversity statistics combined with additional investigation from the research project of ĐTNN 07/2020. The map layers were compiled from data sources, including (i) secondary data: map of topography, map of land-use status, map of land types, map of sea level rise and flood risk, map of saline intrusion boundary, biodiversity data; and (ii) primary data: survey data on biodiversity and threats. All maps created in this study met the technical process of setting up environment maps in Vietnam (Circular No. 17/2011/TT-BTNMT). This paper has completed 05 thematic maps with a scale of 1:100,000 including: Map of environment for biodiversity conservation; Ecosystem map; Map of species richness, Map of biodiversity conservation status, and Map of threats to biodiversity. This study will help local managers and scientists in managing and looking up detailed information on biodiversity conservation in Tien Giang province more accurately and effectively.

Coral reefs are a vital component of coastal and marine ecosystems. They are now under strong environmental challenges and are being harmed by human activities and rising sea surface temperatures, which are reducing the living coral cover. The purpose of this research was to evaluate the mapping accuracy of coral covers using PlanetScope satellite pictures with the Artificial Neural Network (ANN) method surrounding Cu Lao Xanh Island in Binh Dinh province. To adjust for the sunglint effect, the bands were corrected using the Hedley technique. After that, the Depth-Invariant Index technique was utilized to reduce the influence of the water column, and the ANN algorithm was employed for mapping. Hard coral, soft coral, seagrass, deep water, and bare bottom were identified as the five kinds of benthic habitat. The accuracy of the classification results was assessed using field data collected on May 10 and 11, 2022. The results indicated that the artificial neural network (ANN) technique had a higher accuracy, with a total classification accuracy of 89.55% and a kappa value of 0.87. Cu Lao Xanh's coral area is around 68 hectares, with soft corals mostly found west and southwest of the island and hard corals in the east. This finding demonstrates that Planetscope satellite imagery is effective at monitoring shallow coral reefs on small islands, providing a scientific foundation and reliable data for the development of a more comprehensive coral reef ecological monitoring and management.

Wetlands account for about 41% of the total global ecosystem services value; therefore, they preserve a role as the most precious ecosystems on Earth. However, 35% of global wetland areas have been lost since 1970 as many wetlands have been exploited unsustainably. In this context, a hydrogeomorphic delineation approach has been developed to divide a wetland landscape into units which have homogeneous hydrological regime, geomorphology, and soil, named as hydrogeomorphic units (HGMUs). These units are fundamental units of a wetland for functional and resilience assessment of a wetland in different uses; then, to determine optimal management strategies for maintaining its complete ecosystem functions. This study used Tram Chim National Park for applying the hydrogeomorphic delineation approach for breaking a landscape of the park down into HGMUs. The findings showed that the park may be divided as three classes, including depression, riverine, and flat. Each class continued to be subdivided as subclasses. The results showed that there were six subclasses, i.e. six HGMUs, which identified in the park. Based on the results, the study described characteristics of HGMUs and created maps of HGMUs distribution of the park. These results will be a basis for next steps of applying functional assessment procedures for analyzing potential of the HGMUs to perform ecosystem functions in our upcoming study for preservation and management purposes in Tram Chim National Park.

Recently, using remote sensing to monitor water quality has become popular because of its outstanding advantages. Tri An reservoir, since its construction, has always played an important role in the southern provinces; however, the lake is now highly eutrophicated in which the green algae community, which causes this phenomenon, is strongly influenced by the nutrients in the lake. The aim of this research is to estimate the nutrient pollutants concentration (i.e., NO₂⁻, NO₃⁻, NH₄⁺) for the Tri An reservoir on November 14^th 2020 using Landsat 8 OLI images. The study performed correlation analysis between measured nutrient pollutants concentration and spectral reflectance values derived from Landsat 8 image bands. The result showed that they are strongly correlated with each other (Pearson coefficients are larger 0.95 between band 4 and NO₂⁻, NO₃⁻, NH₄⁺ measured concentrations). On that basis, the regression equations estimating the nutrient pollutants concentration in the lake were set up and the optimal equation was chosen (the equations estimated NO₂⁻, NO₃⁻, and NH₄⁺ concentrations had adjusted R² values 0.94, 0.93, 0.94, respectively), consequently, the nutrient distribution maps in Tri An reservoir were established to identify the high pollution areas. This study has clearly revealed the effectiveness of using satellite images for monitoring water quality.

Groundwater in coastal cities is facing with various challenges such as contamination, salinization and land subsidence due to poor management and climate change. This research is aimed to summary groundwater issues such as groundwater quality, salinization and land subsidence in Bac Lieu City, a coastal city of Mekong Delta. A datasets of wells survey, wells logs and groundwater sampling were utilized for the study. The results show that saline groundwaters (TDS> 1.5 g/L) cover 99 and 54% area of shallow aquifers including Holocene, Upper Pleistocene and 48, 93, and 82% area of very deep aquifers like middle Pliocene, lower Pliocene, and upper Miocene, respectively. Fresh groundwater (TDS <1.5 g/L) is mainly found from 75 to 227 m in upper middle Pleistocene, lower Pleistocene and middle Pliocene aquifers. Groundwater extraction amount increases sharply during the last decades which induced groundwater level decline to 15 m below mean sea level (bmsl). The decline of groundwater level is even observed in the non-extracted aquifers suggesting that those aquifers are hydraulically connected. Land subsidence is observed in some groundwater extraction wells. Groundwater chemical data reflects that 73, 53, 28, 21, 18, 16, and 8% of total 120 groundwater samples show the concentrations of hardness, NO₃⁻, Cl⁻, TDS, Na⁺, NO₂⁻, and NH₄⁺ are greater than those recommended in Vietnam National Technical Regulation on Domestic Water Quality (RDWQ; QCVN 01-1:2018/BYT) suggesting that groundwater in the area should not be used directly for domestic purposes. The occurrence of high Na+, TDS and Cl- concentrations in some groundwater samples may indicate salinization. The observation of high NO₃⁻ is also a strange phenomenon in this area. Finding the sources of NO3 high concentration and salinization are highly recommended for further studies to sustainable practices of groundwater protection and management in the area.

Due to the natural and anthropogenic activities, especially the rapid development of hydropower dams in the upper Langcang Mekong, the sediment flux in the lower Mekong has declined alarmingly. This factor is one of the main reasons causing the river morphological changes in the lower Mekong. In this study, we used the MIKE 21 model to simulate the spatial and temporal morphological changes of the Hau River crossing Tra Vinh and Soc Trang, Hau Giang, and a part of Can Tho and Vinh Long provinces of Vietnam, considering the impact of sediment load decrease from the upper boundary. The models were calibrated and validated using the data of the year 2017, and the scenario of a fifty percent reduction of sediment flux from upstream was considered. The results show that the erosion occurrence in the flood season is more significant compared to that in the dry season. However, the spatial distribution tendency of erosion and accretion was similar in the two seasons. Under the impact of reduced sediment load entering the investigated region, the spatial distributions of erosion and accretion locations were estimated to significantly change during dry and flood seasons. However, the riverbed change level changed apparently. The change is more considerable in the flood season; especially, the erosion was estimated to be more severe in all zone of the study area. The erosion level was estimated to increase up to 0.15m in the flood season in zone 1 compared to that under the historical condition. The accretion level increases up to 0.09m in zone 2 and 0.07m in zone 3 under flood season. The erosion level increases up to approximately 0.1m over six months of the dry season and flood season. The results of the study can contribute to the future management strategy for the local governments in particular and for the whole Mekong region in general.

Tam Hai commune, Nui Thanh district, Quang Nam province, is located in the Tam Ky-Phuoc Son suture zone, which is part of the Kon Tum high metamorphic massif's northeastern edge. Its geology is diverse, ranging from late Proterozoic metamorphic rocks to Quaternary sediments. This location also has a distinct landform in which a spit connects the mainland coast to an island known as a tombolo. Furthermore, the Truong Giang River is unique in that it flows parallel to the sea and is separated from it by a vast expanse of sand dunes. As a result, Tam Hai has unique geological and geomorphological properties. Furthermore, due to the long tradition of a fishing village, this geosite has significant additional value. The Tam Hai geosite is evaluated qualitatively and quantitatively for conservation and sustainable tourism development planning using the methods of literature reviews, geosite assessment, GIS, and field survey. The Tam Hai complex (geological, geomorphological, and hydrological) geosite and surrounding area map were created to highlight the scientific and additional values of the geosites: 1) carved rocky coastline in Ban Than mountain, 2) two islets, Mang and Dua, 3) two accumulation-abrasion coasts, and 4) the Truong Giang river. Our study also identifies and assesses the geosite's risks in order to support the geosite's conservation and protection, as well as tourism development here.