MEKONG DELTA REGION

MEKONG DELTA REGION: Accentuation of Difference (2015-18)

Location: Mekong Delta Region, Vietnam
Designers: RUA, Superjacent (January-April 2016) as consultant to SISP (Southern Institute for Strategic Planning) Kelly Shannon, Bruno De Meulder, Claudia Rojas Bernal, Christina Hood, Donielle Kaufman, Michael Waibel, Tracy Collier, Erik Heikkila, Molly Fancler. Kelly Majewski, Anthony Paradowski, C.hris Torres

Commissioned by: Ministry of Construction, Hanoi

Area: 4,060,400 ha
Period of Design: 2014– present
VIETNAM

The Evolving Challenges of the Mekong Delta

The Mekong Delta is a cultural landscape formed and transformed by its sophisticated and dynamic water management. However, the contemporary paradigm of land and water management is currently undergoing a fundamental shift that climate change will inescapably further articulate. Living with floods (in opposition to a defensive living behind dykes) and the interconnected canal system is no longer as evident.

The entire hydrological regime of the Mekong River has been and continues to be re-engineered by Vietnam’s riparian neighbours. The delta is already bearing witness to the impacts of climate change, including sea level rise, saline intrusion, massive inundation, and periods of intensive drought and rising temperatures.

Basin and Delta

The Mekong River originates high up the Tibetan Plateau, flows through six countries and enters the East Sea through Vietnam's Mekong Delta Region. Inundation is expected to severely affect the Plain of Reeds in the northwest of the delta, while saline intrusion will be extreme along the coastal area. The new plan stresses water-based infrastructure and recommends the cancelling of planned World Bank and Asian Development Bank-financed roads that will be inundated (shown in yellow). The identity of Mekong Delta is grounded in its landscape: six main ecological/geographic regions. As well, six think-tank centers, one for each ecological region, are identified as experimental centers for new productive landscapes.

Accentuating Differences

Three distinct morphologies are developed: coastal areas that take into account sea level rise and saline intrusion and are protected by massive new mangrove afforestation; freshwater alluvial area that need qualitative upgrading; and the extended Plain of Reeds which will have to deal with high degrees of inundation. Productive landscapes work to accentuate the qualities of the soil and water conditions and create a differentiated, yet ecologically rich and economically profitable yield from the territory.

Sedimentation Flow for Natural Reclamation

The Mekong deposits 160 million tons per year into the East Sea. Part disappears in the deep sea, but a substantial part can be captured to build land. The systematic implantation of breakwaters could break the existing streams deposits, slow down the water current and halt it locally. This strongly enhances sedimentation and consequently induces an accelerated formation of sand banks that ultimately results in a land gaining process, which can be further consolidated by the systematic planting of mangroves. This will not only strengthen the ecological structure of the Mekong Delta, but also increase its resiliency.

Land Reclamation Project

Two flagship projects, international airport and deep-sea port, are integrated into the reclamation. This way, the key projects neither require (any) land expropriation nor imply the loss of valuable productive land. On the contrary, they will be embedded within a land reclamation program that offers space for ecological development (coastal protective mangrove afforestation) and productive landscapes (fish and shrimp farms, oyster banks and other seafood nurseries that can be combined with new sustainable coastal settlements and new state-of-the-art fishery ports).

Mangrove Afforestation

The coastal area will be significantly affected by saline intrusion and sea level rise by 2050. The plan proposes mangrove afforestation to protect against storm surges and to create a healthier brackish water environment. Integrated shrimp and fish farming, in addition to renewable energy production in mangroves would be encouraged, as opposed to exclusively shrimp farming. Restoration of coastal mangrove belt would include the planting of numerous native species, amongst which many plants with uses and applications in medicine.

COASTAL TRANSFORMATION POSSIBILITIES

Impacts of Climate Change on the Delta's Landscape

Sea level rise, saline intrusion, massive inundation, and periods of intensive drought and rising temperatures have begun to affect the region and reveal devastating consequences on productive landscapes and settlements. These changes threaten the traditional water management systems that have defined the region's cultural and economic landscape for centuries. The revision of the plan for the Mekong Delta Region seizes the opportunity of climate change to realign the plan with the evolving characteristics of the territory.

EXTENDED FLOODED PLAIN TYPOLOGIES

New upstream flooded morphologies are premised on the prediction that massive inundation will occur in the coming years and progressively increase over the decades. The hierarchy of topography, infrastructure and settlement is reconfigured in relation to future inundation. Buildings would be on stilts and the central spine of clustered areas of urbanization would be a dike, at a minimum safety height to avoid inundation in the predicted worst-case scenario. Monsoon collection basins would be able to release fresh water into the delta system during the dry season and as well serve as aquaculture landscapes.

ALLUVIAL PLAIN TYPOLOGIES

In the alluvial plain, the existing settlement types would be modernized, densified and clustered: it is the most productive and will be the least affected region of the delta by climate change

COASTAL TYPOLOGIES

In the coastal areas, the new settlement strategy in the coastal area would comprise of clustered, floating buildings that center on floating collective spaces in clearings of mangrove afforestation. Aquaculture (fish-farming and shrimp farming) would be interwoven into a rich mosaic that is able to withstand the tidal pulses from the East Sea and Gulf of Thailand.

Strategic Revisions for the Mekong Delta Plan

The main question of the new proposed regional plan was how to organize a constructive interplay between unavoidable landscape dynamics and the social, economic, and cultural dynamics of the region. The main asset of the delta, especially in view of the expected worldwide food shortage, remains its enormous agri- and aqua-cultural potential.

This plan emphasizes the need to balance the natural water systems with human activities, ensuring that agricultural productivity can be sustained even in the face of significant environmental changes.

Emphasizing the Delta’s Agro-Ecological Identity

Such a territorial identity is largely the outcome of the interplay between land and water, or more precisely: topography (including bathymetry), soil qualities (such as alluvia, saline, and acid sulphate) and conditions, and salt and fresh water parameters (volumes, qualities including carried sedimentation, heights and extents, tides, and seasonal variations).

Recognition and accentuation of the delta’s underlying geography, which has been classified into six broad agro-ecological sub-regions, can re-establish its core identity, counterbalance the relative homogeneity of the region’s urbanism, and re-articulate the productive landscapes of the delta’s dynamic ecological sub-regions.

BRACKISH WATER: MANGROVES, COASTS, ESTAURIES

This species is found along tidal riverbanks in the downstream estuarine zone, and in the lower and middle inter-tidal region (Robertson and Alongi 1992). It occurs as a tree or shrub that grows to 25 m, often around 10 m. It is fast-growing and sprouts easily from coppicing. Both Avicennia and Sonneratia species are the colonizing species on newly formed mudflats in SE Asia (Terrados et al. 1997).

This species is found in the intermediate estuarine zone in the mid-intertidal region. This species tolerates a maximum salinity of 65 ppt and a salinity of optimal growth of 8-15 ppt (Robertson and Alongi 1992). It is a hardy species, and fast- growing. This species can grow to 30 m. This species can be coppiced only in the eastern extremities of its range in Kosrae in The Federated States of Micronesia. In addition, sediment accretion increases the mortality rate of seedlings. This species will not be an efficient colonizer of coastal areas exposed to sudden discharges of sediements such as those of highly erod- ing watersheds (Terrados et al. 1997)

This species is found in the intermediate estuarine zone in the mid-intertidal region. This species tolerates a maximum salinity of 65 ppt and a salinity of optimal growth of 8-15 ppt (Robertson and Alongi 1992). It is a hardy species, and fast-growing. This species can grow to 30 m. This species can be coppiced only in the eastern extremities of its range nge in Kosrae in The Federated States of Micronesia. In addition, sediment accretion increases the mortality rate of seedlings. This species will not be an efficient colonizer of coastal areas exposed to sudden discharges of sediements such as those of highly eroding watersheds (Terrados et al. 1997)

This species is found from downstream to intermediate estuarine zones in the mid to high inter-tidal regions. It is shade intolerant with a maximum porewater salinity of 45 ppt and a salinity of optimal growth of 0-15 ppt (Robertson and Alongi 1992). This species is slow-growing but is a hardy species and is very prolific.

This species is found in the intermediate estuarine zone in the lower inter-tidal region. It is shade intoler- ant with a maximum porewater salinity of 63 ppt (Robertson and Alongi, 1992). This species grows on soft, recently consolidated mudbanks. This species is a tree or shrub that grows to 25 m, but is more often seen at 5-10 m. This species is a fast-growing species. It is a colonizing species on newly formed mudflats in SE Asia. (Terrados et al. 1997) and has a high tolerance of hyper-saline conditions (Tomlinson 1986).

This species is found in downstream to intermediate estuarine zones in the mid-intertidal region. It is shade intolerant with a maximum porewater salinity of 66 ppt and a salinity of optimal growth of 8-34 ppt (Robertson and Alongi 1992). This is a slow-growing species that grows to 25 m height.

This species is found in the upstream estuarine zone in low, mid, and high inter-tidal regions (Robertson and Alongi 1992). It forms extensive belts along brackish to tidal freshwater creeks and rivers. It is very fast growing, especially in fresh water, and is a competitive species.

This slow growing semi-deciduous species can reach up to 20 meters tall. While very tolerant of salt it requires mostly dry well-drained soil. The tree is praised for its beautiful and fragrant flowers that have a long blooming time. The seeds and pulp of the fruit have great appeal to monkeys and birds. The flowers and leaves have medicinal properties while the wood itself is hard and durable for construction applications. (Barwick 2004)

This evergreen species can reach up to 20 meters in height. It lives at the edges of mangroves and brackish swamps where it forms impenetrable thickets by sprawling and rooting as its limbs touch the ground. The wood burns lowly and is a source of charcoal in some areas. (Barwick 2004)

This species has extensive medicinal properties and is promoted for biological insect control. A fast growing evergreen that can grow to a height of 16 meters. Typi- cally found in lowland forests, they are very drought- resistant and have a wide tolerance of soil especially salinity, as long as they are well drained. (Barwick 2004)

This evergreen species thrives with its roots dabbling in the brackish waters of lagoons, inlets, estuaries and seasonally flooded coastal regions. They are nocturnal bloomers and have a Magnolia-like quality. Frequently planted as a shade tree at the beach due to their high salt tolerance. (Barwick 2004)

This very fast growing small flowering evergreen tree can grow up to 10 meters. This species is an excellent choice for dense, sea-worthy screening and hedging. It has been widely used to contain beach erosion, for coastal rehabili- tation, and coastal shade tree. (Barwick 2004)

A slow growing tree that is home to coastal forests and scrubland. This species has medicinal properties, its seed oil is used for cooking and fuel, and is grown commercially for its excellent timber. In addition to its commercial ben- efits it is also a desirable urban and rural ornamental tree. The tree can get up to 35 meters tall. (Barwick 2004)