The Lower Mekong Delta is roughly a 39,400 square kilometers triangle stretching from Go Cong in the east to Tan Chau and Ha Tien in the northwest, down to Ca Mau at the southern tip of Vietnam. The region had a population of 17.53 million inhabitants in 2018, nearly 20 % of the country’s population. It has one of the slowest growing populations in the country, mainly due to out-migration. In 2017, Mekong Delta’s gross regional development product (GRDP) growth stood at 7.6 percent, higher than the national average of 6.81 percent (Shira D. 2018; MOIP, 2018).
The Lower Mekong Delta, located in the southernmost region of Vietnam, has been formed for about 6,500 years, mainly from the deposition of fluvial sediment sources of the Mekong River during the process of sea-level rise and lowered sea level (Ngo, 1991) (Fig. 1).
The delta plain can be divided into two parts: an inner delta dominated by fluvial processes, and an outer delta that is affected by marine processes. In geomorphological features, the delta consists of a variety of landscapes, including tidal flats, sand ridges and tidal back swamps in the coastal area, estuaries at river mouths, river flood plains, broad depressions, peat swamps, alluvial levees, and terraces further inland (Thach 1991).
The wetlands are among the richest ecosystems that are important breeding sites for many aquatic species migrating from the upper reaches of the Mekong River. They can broadly be categorized into three groups: (i) saline wetlands including coastal mangrove and saltwater swamps along the east coast and the west coast; (ii) inland wetlands dominated by Melaleuca forest and seasonally inundated grassland habitats, and (iii) estuarine seasonally saltwater wetlands, distributed mainly at the mouths of the Bassac and Tien Rivers.
The annual flood pulse plays an important role in agriculture and fisheries. Large areas in the Plain of Reeds and the Long Xuyen Quadrangle are usually inundated in the flood season. The floods flush and dilute stagnant and polluted waters, recharge groundwater tables, maintain river morphology, sustain the productivity of freshwater fisheries, and floodwaters are retained for use in the dry season, particularly for irrigation. Flood-deposited sediments improve soil fertility across the floodplains. The flood season in the Mekong River Basin lasts from June to November and accounts for 80 to 90% of the total annual flow.
The delta agricultural farming systems applied including rice crops, fruit tree gardens, wood tree plantations, livestock (cattle and poultry), and aquaculture (shrimp, fish). In the past years, the Lower Mekong Delta has developed into a major food-producing area, which plays a central role not only for national food security but also in the regional context through food-related export.
The development of agricultural production has achieved remarkable achievements, in which Vietnam’s rice export volume ranked third in the world in 2017 (MoIT 2018). The delta is considered the largest rice bowl in the country, with an area of about 1.7 million hectares, the annual output of over 25 million tons, accounting for about 50% of national rice production. However, delta people themselves are always tormented with the question: Producing a high amount of agricultural products contributed to bringing Vietnam to the top of the world for rice and fishery export, why the delta people’s lives are still faced many difficulties?
This paper aims to address the fundamental issues that the Mekong Delta ‘s people have faced, especially those affected by climate change.
Lower Mekong Delta development strategy
After 1975, facing the difficulties of national food demand and safety, the state planned and promoted National strategy for socio-economic development focused on reclamation and expanding agricultural production area in the Lower Mekong Delta, which promotes activities as follows:
- Producing rice for national demand and export to the ASEAN region.
- Expanding aquaculture area and intensifying aquaculture intensive farming.
- Promote livestock and poultry breeding activities from households.
- Developing local agricultural production cooperatives.
Aiming to develop a socio-economic plan based on agricultural production, the central and local governments have invested in irrigation systems and saline prevention dikes to reclaimed and expand rice-growing areas in the Plain of reeds, Long Xuyen Quadrangle, Hau River’s Southwest region, Ca Mau peninsular, coastal areas. Besides, flood control dike systems constructed to expand farming areas and increase rice crops in areas of the Long Xuyen Quadrangle and the Plain of Reeds.
Saline intrusion and flood control systems have played a role in expanding areas of rice and other crops. However, brackish ecoregions in coastal areas and seasonally flood plain have been changed and caused considerable impacts on the delta natural ecosystems, which has affected delta people’s lives.
Simultaneously with the development of agriculture, industrial development plans have been developed and implemented mainly around cities and towns. However, the process of industrialization and urbanization has grown significantly since 1995. The urbanization rate in the Mekong Delta estimated at 15.6% in 1995, and the urbanization rate was greater than 21% in recent years. This represents an urbanization rate in delta increased by nearly 37%, greater than that in entire Vietnam (35.5%) during this period.
Industrial development has facilitated high-paying jobs for workers. However, as a result of industrial development and urbanization, rural workers have left the countryside to live and work not only in the delta cities but also in other areas.
Achievements of socioeconomic development
The population density in the Mekong Delta was quite low before 1975, especially in rural areas. Therefore, a migration program for people living in the North and Central regions to the delta for agricultural production was going on for over 15 years. Besides, the exiles also returned to their homeland after the war. The population started from the 1980s, in which the percentage change of urban population in the entire delta between 1995 and 2018 accounts for about 5.8 % (Fig.2)
As a result of the reclamation of the expansion of the rice cultivation area and the application of scientific advances to agricultural production that has achieved certain achievements as follows.
The results of the renovation and expansion of rice area and the application of scientific advances to agricultural production have achieved the following achievements. The area of rice cultivation has increased rapidly since the 1980s. Between 1995 and 2018, it was shown that the agricultural production area accounted for 47% of the national agricultural area (Fig. 4), mainly rice production, accounting for 56% of the national rice output (Fig. 5), and about 90% of the rice amount produced in the Mekong Delta was exported to the world markets (Vietnam statistics, 2019)
The Mekong Delta is Viet Nam’s most important fishery production area by fisheries and aquaculture. The main fishing grounds include coastal areas, estuaries, and inland wetlands.
In addition to natural coastal and estuaries fishing, during the flood season, abundant fish sources from the upper Mekong River reaches the Long Xuyen Quadrangle, the Plain of Reeds, and a part of southwestern region of Hau River. Local communities have benefited from this natural fishery harvesting and this is their main source of livelihood during the flood season.
Coastal aquaculture is a familiar landscape model of local communities, including intensive model, and shrimp - rice farming system or shrimp - mangroves model. For riparian wetlands, being a large area along the Bassac and Tien Rivers, and the low-lying areas of Plain of Reeds and Long Xuyen Quadrangle have been used as catfish farming areas. The area of catfish farming in the Mekong Delta has increased significantly in recent years.
Aquatic production has increased greatly since 1995 (Fig. 6). Aquatic products account for 40% of output, approximately 60% of the seafood export output nationwide, especially farmed shrimp output in coastal areas (Fig. 7).
Issues of unsustainable development
Besides the achievements of economic development in recent years, many issues have arisen regarding the sustainable development and life of people in the Mekong Delta (Fig. 8). While the output of agricultural products increases year by year, people’s lives are still more difficult due to many reasons including inadequate land-use planning, inappropriate policies for rural, degraded natural resources, and polluted environment.
Limited appropriate policies and investment; Appropriate and timely policies and investments facilitate the development of an important region such as the Mekong Delta. However, assessments from ministries and provincial governments show that both of these important issues have had too many limitations over the years.
- Lack of appropriate policies for agricultural development in disadvantaged areas of the delta, especially in poor rural areas.
- Lack of convenient transportation networks in production areas to facilitate goods transportation.
- The facilities used for production and post-harvest are limited, so it is difficult to ensure the desired quality of the produce.
Unsuitable development plan; Some components of development plans have been unsuitable for variable natural conditions and local community characteristics of each region of the Mekong Delta. The overlap between components of development plans proposed by each line ministry implemented to the delta.
At the central level; Currently, there are 10 development plans approved by the Vietnamese Government, including the master plan of the economic development of the Mekong Delta. At the local level; So far there have been nearly 2,500 master plans, of which 773 rural development plans and more than 490 specialized plans approved by localities (MoPI 2017).
The implementation of such inappropriate development plans has resulted in several problems to sustainable development in the delta:
Coastal brackish ecosystems were planned to shift to rice cultivation instead of aquaculture development. Such conversion has disturbed and degraded natural ecosystems. Also, the coastal mangrove ecosystems, which are important to protect coast, have been seriously degraded due to the exploitation and expansion of the shrimp farming area (Fig. 9).
Uncoordinated sectoral approaches; Sector-wide approaches have been an important part of the global effort to deliver sustainable development results for more than a decade now (Kohlmeyer 2005). Concerning the participation of sector ministries in sectoral approaches, various scenarios of development must be considered as well. However, it has concerned a little only during the proposal process of sector plans resulted in ineffectively applied across sectors in coordinating activities of socio-economic development in the Mekong Delta.
The activities of each sector have not been compared together within and among other sectors to avoid duplication and synchronization of activities of plans. They only deal with concerns about their industry’s activities, with little regard for the possible impacts affecting overall development in the Mekong Delta.
The flood control dykes constructed aimed to increase rice crops, from 2 rice crops to 3 rice crops per year, has changed the ecological environment and reduced the amount of natural seafood in the Plain of Reeds and Long Xuyen Quadangle. Dams and culverts constructed in coastal areas have been one of the causes of water pollution and river sedimentation, the case of Ba Lai dam in Ben Tre province is one of the typical examples of changing natural environment affecting people’s life (Fig. 10).
Inadequate land-use planning; Land-use planning is important to mitigate the negative effects of land use and to enhance the efficient use of resources with minimal impact on future generations (Randhir T. 2016). The increasing demand for land, coupled with a limitation in its supplies, is a major cause for more conflicts over land use throughout the Mekong Delta (Quoi, 2018).
The area was dealing with the conflicts between freshwater and brackishwater dependent land use systems (e.g. rice vs. shrimp) and between economic development and mangrove forest conservation (shrimp vs. forest) at both inside and outside of the salinity-controlled area (Ha et al. 2013; Trung 2006; Sakamoto et al. 2009). The situation would become worse under the threats of sea level rise (SLR) in the future (Nhan et al. 2011).
Such unsuitable land-use plans resulted in the interfering application of suitable land-use types to help develop effective local community livelihoods. Besides, the environmental effects and climate changes have affected agricultural production resulted in unreliable yields of crops, therefore, the proposed land use has not been accepted by the local people (Quoi, 2018). Hoanh (1996) and PCBL(2001) stated previously that most of the land use plans in the coastal areas of the Mekong Delta are not sufficient and fail implementation (Hoanh, 1996; PCBL, 2001).
Environmental pollution; Dams, built to prevent saline intrusion for agricultural production, blocked the flow and exchange of water leading to seriously contaminated rivers and canals. Industrial factories built near the riverbank have discharged wastewater into the river, causing water pollution.
Most of the people have been affected quite heavily from polluted rivers and canals over the years. According to local people, the natural fish resources have been degraded or no longer lead to loss of local community livelihoods, making it difficult to raise animals, and unable to wash from polluted river water.
An inadequate transport network; Transport plays an important role in socio-economic development, however, in the Mekong Delta, where more than 17 million people live, investing in transport infrastructure has not been enough for a vast plain. [Only about 40 km of highways constructed until this year].
Lack of transport network has led to difficulties in moving and transporting agricultural products and other goods. The disadvantage of transportation in the Mekong Delta is due to limited investment by the government (Vietnam Ministry of Transport, August 2019).
Water shortage; The management and exploitation of water resources in the Mekong Delta for production and socio-economic development have an extremely important meaning in the overall development of the country. However, the increasing water shortage that resulted from many reasons has affected production and delta people’s lives.
Causes of water shortages include the construction of hydropower dams upstream of the Mekong River reducing a large amount of water moving downstream, and the water storage role of the Plain of Reeds and the Long Xuyen Quadrangle has been lost due to flood control dike network constructed over past years.
The shortage of freshwater has resulted in very negative impacts on all aspects of socio-economic life. Particularly for the agriculture and rural development sector, the lack of water resources will cause great losses and difficulties include lack of water for agricultural production, fruit tree planting, lack of fresh-water for aquaculture and daily life.
Reduce the amount of river alluvium; River alluvium contributes positively to the accretion in the Mekong Delta, and facilitate soil fertile.
About 20 years ago, the amount of sediment moving downstream area was 160 million tons/year, according to recent assessments, there are only about 80 million tons/year, which means about half decreased. It is due to upstream hydropower dams in China and Laos have blocked much of the sediment that once reached the Mekong Delta.
Lack of river alluvial materials resulted in reducing soil fertility. Therefore, to maintain a stable crop yield, it is necessary to increase the amount of fertilizer, and thus, farmers have to spend more on agricultural production.
Drought and saline intrusion; People have pointed to numerous causes converging to create the current situation of drought and saline intrusion, including inconsistent rainfall caused by climate change, the El Nino weather pattern, and the numerous upstream hydropower dams on the Mekong River (David B. 2016).
Shortages of freshwater moving from the Mekong River and the prolonged dry season have caused drought and saline intrusion in the Mekong Delta. Besides, from 2000 to the present, El Nino has affected the Mekong Delta that causing temperatures to rise, shortage of rainfall and this is one of the causes of drought, salt water intrusion that causing heavy damage and continuing serious threat to production and people’s life (Tab. 1, Fig. 11).
In the dry season 2016, severe drought and seawater intrusion affected production and lives in the Mekong Delta. In shrimp farming areas, shrimp could not grow because of saltwater. Oysters died because of the lack of water, while cattle died because of thirst. People living in coastal areas (Ben Tre) province said that affecting by the saline intrusion in the dry season causes damage to crops, livestock, and fisheries, and no source of drinking water for people (Quoi, 2018). The images of people with tears in their eyes because of the cattle deaths and crop failure could be seen in many local newspapers. This disaster has been still haunted communities living in coastal areas.
The shortage of fresh water has forced coastal people to find ways to store water or even buy freshwater for drinking and living in the dry season (Fig. 12).
Ground subsidence process; Many scientists warn the ground subsidence process has been going on in the Mekong Delta (Fig. 13). The problem is thought to be from exploiting groundwater over three decades. Besides, other reasons mentioned soil shrinkage process due to dryness resulted from saline intrusion dikes construction, especially in coastal wetlands (Quoi, 2018). Thuyen (2014) and Philip et al. (2019) stated that in some coastal wetland areas, the ground subsidence from 20 - 30 mm/year. The subsidence associated with raised sea levels will accelerate flood during high tide in the Mekong Delta.
Sea level rise and flooding; The Vietnamese Mekong delta has one of the largest and seemingly lowest elevated delta plains in the world (Syvitski et al. 2009). While ongoing land subsidence increases the rate of relative sea-level rise (Erban et al. 2014; Minderhoud 2017), the sediment load of the Mekong river to counterbalance relative with sediment accretion on the delta plain is dwindling due to upstream dam construction and decreased hurricane activity in the Mekong catchment (Darby et al. 2016). According to climate change scenarios and sea-level rise, the Mekong Delta has been affected by sea-level rise, estimated at 3 mm/year (Fig. 14) (MoNRE 2016).
Sea level rise threatens the viability of agricultural production in the Mekong River Delta. The risk of flooding is likely to be especially severe during the wet season, which is marked by greater rainfall and downstream flow. The wet season lasts from May until November; September and October are already prone to pronounced flooding. By raising the level at which the Mekong meets the ocean, sea-level rise could reduce the river’s slope, decrease its flow, and increase flooding in the delta (Bindoff et al. 2007).
Influences of “ground subsidence” and “sea-level rise” causing severe flooding in the Mekong Delta, particularly in the high tide time. Rising sea levels are likely to infiltrate groundwater aquifers and increase salinity gradients in large parts of the Mekong Delta. Rice cultivation and aquaculture were damaged, and even the livelihoods of urban residents were affected.
A recent study referred to that rising sea levels could flood three times more land than previously predicted (US Climate Central. 2019), of which the Mekong Delta could be underwater by 2050 (Fig. 15), If the study proves accurate. Such, the lives of over 20 million delta people will be affected severely. People are very worried, however, what they will have to do in such a case (Quoi, 2018). Dan Southerland (2019) stated that millions of people living in Vietnam’s Mekong Delta could be forced to flee coastal areas.
Soil erosion and landslide; Land loss has happened very severely along riverbank and coast in recent years. Its consequences cause land loss and serious damage to people’s lives and production.
The root causes resulted from sand mining along the Mekong river (Bassac and Tien Rivers), and lack of sediment flows from upstream of the Mekong River attributed to upstream hydroelectric dams. Besides, changed currents, and strong waves due to tropical depressions from the East Sea resulted in soil erosion alongside shorelines.
According to the announcement of the Ministry of Agriculture and Rural Development (Sept. 2019), up to 512 serious erosion sites occurred along the riverbank, total length of 566 km being, and 52 sites of landslides and erosion alongside the coast with a total damaged length of 268 km.
Landslides and soil erosion cause economic losses and people’s lives. Local people living in areas affected by landslides have to relocate to other places to settle (Tab. 2). However, where they will go is the big question because new lands could not be easy to produce as locals expected.
Lack of rural labor force; Currently, rural labor is an issue for agricultural production, which are concerned by not the only local government but also rural households.
The income of rural workers is quite low while many industrial factories are investing in industrial parks and cities more and more. High incomes while working in factories have attracted rural workers to leave their homelands to work in industrial parks or other jobs in urban. It seems that most rural families that their children study at college have not returned to their homeland after graduation (Quoi, 2018). As a result, the population in the Mekong Delta has declined over the years (Fig. 16).
Besides, based on IPSARD (August 2019), the labour force in the Mekong Delta is getting old. The proportion of labors under the age of 35 decreased from 45.5% in 2012 to 38.9% in 2017, while the labors aged 50 and older increased from 20.7% to 26.8%. In agriculture, the number of labors under the age of 35 decreased from 37.4% to 26.2% and labors aged 50 and over increased from 24.1% to 34.1%.
Facing such a situation, the Institute of Policy and Strategy for Agriculture and Rural Development - IPSARD (MARD) organized a seminar on “Occupation and job creation for rural and agricultural labour in the Mekong Delta” held in August 2019. The purpose of the workshop is to improve the rural labor force.
Affecting the Mekong Delta’s people lives
People in the Mekong Delta have been and will be facing many serious impacts resulting from inappropriate development plans and due to climate change and sea-level rise. Key challenges include the rapid increase in socio-economic development activities and limitations of thinking, development models, planning, planning and limitations of mechanisms, current policies for the Mekong Delta and challenges due to climate change, sea-level rise.
The people, who directly affected, and the local authorities have recognized problems resulted from human activities and climate change that have affected people’s production and lives over the past years. According to people, the effects of climate change are becoming more complex and causing more dangerous impacts, that they are worried about (Tab. 3).
Human impacts resulted from unsustainable development plans and climate change have been damaging natural resources, especially ecosystems and biodiversity in the floodplain.
Over the years, human activities and climate change factors have caused impacts on natural resources and delta local people’s livelihoods to varying levels (Tab. 4).
Hurricane and tropical depression effects; In addition to causing damage to humans, it also cause heavy rains, flooding. Strong wind and waves from the sea that can bring saltwater into the river temporarily, affecting water and soil quality. Thunderstorms - tornadoes cause falls of forest trees, affecting the natural ecosystem.
Saline intrusion affects the quality of water sources and soil salinized. Natural ecosystems and biodiversity are altered due to changing water and soil environments. Saline intrusion affects quite heavily on fruit tree gardens, rice fields, and freshwater shortage for drinking and living.
Drought causes a shortage of fresh-water, the soil is too dry resulted in oxidation of pyritic minerals facilitate the formation of compounds of iron and aluminum in soils. The consequences of oxidation form actual acid sulphate soils will affect natural ecosystems and aquatic species.
Prolonged flooding will affect ecosystems and biodiversity. The growth of some plants will be affected under the prolonged inundated condition.
The anxiety and expectations
People in the Mekong Delta have faced risks that affect production and lives, so they are always concerned about the impacts that could be more happened severely in the future. They also want support for suitable solutions to mitigate potential risks that could be happened (Tab. 5).
Impacts that people have concerned include saline intrusion and drought in the dry season, floods in the rainy season, water pollution, erosion and landslides along rivers and canals. In addition, farmers are expected to have support for changes in the structure of agricultural production, the problem of lack of labor in rural areas, and the problem of agricultural markets.
By inappropriate land use planning, local people have to change land use themselves to adapt to the natural conditions:
- Conversion of concentrated shrimp farming land into “shrimp-mangrove-shrimp” or “shrimp-rice” farming model in coastal areas. The organic shrimp production model has been successful in applying to the coastal saline ecosystems.
- Converting 2-crop rice land into 1 local rice crop and grassland instead of rice cultivation to avoid the risk of saline water intrusion.
The expansion of the aquaculture area has increased shrimp production in coastal provinces (Fig. 17). However, such conversions of land-use have not been allowed by the state management agency. Such activities may be charged with unlawful activity
Through surveys and interviews with communities and local authorities, the expectations of the people are very practical in the natural conditions of the Mekong Delta.
- Restructuring suitable farming systems to adapt to climate change, particularly in the brackish ecosystem.
- Develop an aquaculture system instead of rice in coastal areas, and change of land-use plan to expand aquaculture areas and rice - mangrove or shrimp - rice farming systems.
- People expect a harmonious adjustment of the dams and culverts systems so that they can improve the river water environment and restore natural aquatic resources. This expectation is not only in the coastal areas but also in the floodplains of the Plain of Reeds and Long Xuyen Quadangle.
- Invest water supply network for living and farming in the rural.
- Research to find down new varieties of crops and aquatic that can tolerate salinity and drought, especially in coastal wetlands.
- Supporting the application of science and technology to agricultural production.
- Training for local people on aquatic and crop cultivation techniques in the context of climate change impacts.
- The government should assist in finding a stable market for agricultural products.