MARD Report on the Drought and Saltwater Intrusion in Mekong River Delta

Drought and saltwater intrusion in the Mekong Delta occurred earlier than the dry season 2015-2016. The severity still remain and the situation will continued to be severer in the coming time of the dry season and agriculture production and livelihoods will be continuously affected. Ministry of Agriculture and Rural Development prepare the report on the impacts of drought and saltwater intrusion on agriculture production and livelihoods of people in the Mekong delta during dry 2019-2020.


Farmer in An Thai A commune (Kien Giang province) stared at the severely drought paddy rice

1. SALTWATER INTRUSION

Saltwater intrusion developments since the early dry season.

On the Mekong river basin, 2019-2020 is considered as a low flow year with a serious inflow deficit to the Mekong delta compared to the yearly average, even lower than period 2015-2016. Typically, the average water level since the early dry season at Kratie station (in Cambodia) is only  6.67 m which is 1.43 m lower than the yearly average, 0.5m lower over to the same period in 2016; the water storage volume the Tonle Sap Lake (Cambodia) by 10 February 2019 is estimated only at 1.9 billion m3, i.e. means a storage deficit of nearly 35.7 billion m3 compared to the highest volume (measured on 1 October 2019) and 3.6 billion m3, lower than the  yearly average and a decrease of 30 billion m3 compared to 2018 over the same period. This is the main cause to the early onset, deeper and prolonger saltwater intrusion during dry season 2019-2020.

In fact, saltwater intrusion already very high since December  2020 (during 12 – 15 December 2019); the salinity limit of 4 g/liter  in estuaries of Mekong river can approach as deep as 57km inland (in Ham Luong River) and deeper than the yearly average for 24 km and than the salinity  limit in 2015 for 17km.

In January, the salinity limit of 4 g/liter increased during 6-13 January 2020 which is measured in the basins of 2 Vam Co rivers (Vam Co Dong, Vam Co Tay), i.e. intruding as far as 82-85 km inland,  18-20km deeper than in 2016; the saltwater intrusion depth in Mekong estuary is 45-66km; 6-17 km deeper than in 2016;  48km deep in land in the coast of West Sea and 6 km deeper than in 2016.

Saltwater intrusion forecast

At present, saltwater intrusion is in its high time (during 8 – 16 February 2020) together with the high tide in the mid-January (lunar calendar). This is the most severe saltwater intrusion since the early dry season when the salinity limit of 4 g/liter is measured in estuaries with following depths:

  • Two (2) Vam Co Rivers: Saltwater intrusion extent is 100-110km which is 20-22 km deeper than the yearly average and 4-6 km deeper over the same period in 2016 and 15-17 km lower than the deepest saltwater intrusion extent in 2016.
  • Mekong estuary: Saltwater intrusion extents: Co Chien river 68 km, Ham Luong river: 75 km and Hau river 66 km; 20-30 km deeper than the yearly average; 3- 10 km deeper over the same period in 2016 and 4 km  lower than the deepest saltwater intrusion extent in 2016  
  • West Sea Coast on Cai Lon river: Saltwater intrusion extent is 61 km; 12 km deeper than the yearly average; 5 km deeper over the same period in 2016 and 7 km lower than the deepest saltwater intrusion extent in 2016

During the next period of the dry season, in estuary areas of the Mekong River, saltwater intrusion will continue to rise with high tide, specifically: during 21-27 February, the highest salinity limit will be 55km inland, or a decrease of 20 km compared to the saltwater intrusion during mid-February 2020; during March 7-15, the saltwater intrusion will quite high, the salinity limit of 4g/liter will be measured as deep as 80 km inland which is 5 km deeper than the mid-February saltwater intrusion in mid-February 2020; From late March onwards, saltwater intrusion will gradually decrease as upstream reservoirs will increase their discharge like in recent years. In Vam Co and Cai Lon rivers, saltwater intrusion will continue at high level till late April 2020.

2. EFFECTIVENESS EVALUATION FOR THE MITIGATION MEASURES

In order to proactively cope with saltwater intrusion impacts and to minimize damages to agricultural production and to make sure local people will not suffer water shortage. Some following effective measures have been implemented: 

1. The Ministry of Agriculture and Rural Development has continuously organized monitoring and forecasting of water sources developments since June 2019 to proactively direct and report to the Prime Minister for early directions and resolute responses.The Prime Minister held a meeting with leaders of provinces and cities in the Mekong Delta region to discuss the prevention of landslide and production of Winter-Spring crop 2019-2020 on September 27, 2019 in Tien Giang province; The Ministry of Agriculture and Rural Development issued a Directive in October 2019; the Prime Minister issued Directive 04/CT-TTg dated January 22, 2020 on the implementation of measures to saltwater intrusion, drought and water shortage mitigation measures; on 3 January 2020, Deputy Prime Minister Trinh Dinh Dung chaired the Conference on Prevention of drought and saline intrusion, ensuring agricultural production and domestic uses in the Mekong Delta during the dry season 2019-2020 in Ben Tre province

2. Upon implementing the Prime Minister's direction on speeding up progress of irrigation works to timely prevent and control saltwater intrusion in the early dry season 2019-2020, Ministry of Agriculture and Rural Development and localities speeded up the construction progress of investment projects managed by MARD for 6 to 13 months ahead of schedule and so far 5 projects were put into temporary operation for saltwater intrusion prevention and control in December 2019 and January 2020, such as: Ninh Quoi ship Lock-Sluice (Quan Lo - Phụng Hiep Irrigation System); Xuan Hoa pumping station (Tien Giang province); Tan Dinh, Bong Bot and Vung Liem sluices (Nam Mang Thit Irrigation system), 18 saltwater intrusion control sluices under the Northern Ben Tre Project - Phase 1; Dredging May Phop - Nga Hau Canal etc. These projects have been directly controlling saltwater intrusion for about 83,000 ha and supporting the control of saltwater intrusion impacts on other 300,000 ha. In the coming time, some other going projects will be completed to ensure more proactive and effective control of saltwater intrusion, including Northern Ben Tre, Cai Lon - Cai Be irrigation systems, Long Xuyen quadrangle etc.

3. Regarding rice production, the sowing of Winter-Spring rice crop 2019-2020 takes place 10 to 20 days ahead the schedule compared to previous years; the sowing time is early October and is basically completed in December 2019 to effectively avoid the high time of saltwater intrusion; so far, up to 1,510,000 ha of winter-spring rice has been sown;

  • The ​​sowed area in October 2019 was 473,000 ha, about 300,000 ha more than the same period in the Winter - Spring crop 2015-2016, mainly concentrating in coastal provinces. So far, all these areas have been basically harvested;
  • The sowed area in November 2019 was 714,000 ha, about 150,000 ha more than the same period in Winter - Spring 2015-2016; this rice is in the late stage of tillering and flowering and early stage of ripening: about ​​500,000 ha in the fresh water alluvia fields are not affected by saltwater intrusion; 214,000 ha in the coastal area are not affected by saltwater intrusion;
  • The ​​sowed area in December 2019 was 318,000 ha of rice which are currently in the tillering stage, heading and flowering; about ​​224.000 ha in the fresh water alluvia fields are not affected by saltwater intrusion; 94.000 ha in the coastal provinces is likely to be affected by saltwater intrusion and drought if irrigation water supply is not ensure in the first half of March 202 (Long An 15,500 ha; Tien Giang 2,500 ha; Tra Vinh 21,500 ha; Hau Giang 20,100 ha; Soc Trang 15,000 ha; Bac Lieu 6,000 hectares; Ca Mau 10,800 ha; Ben Tre 2,500 ha). However, for these rice areas, provinces are actively storing water and developing necessary plans to proactively cope with drought and saltwater intrusion in the next coming time.
  • Organize cropping pattern shift for crops planted on rice land susceptible to drought and saltwater intrusion risks: 50,000 ha, including 45,300 ha of annual crops; 3,450 ha of perennial fruit trees and 1,200 ha of and aquaculture. In addition, approximate 100,000 ha are either not cultivated for the crops are delayed;
  • Up to now, total damages of the 2019 Summer - Autumn and Winter-Spring crop 2019-2020 is approx. 29,700 ha (16,000 ha of Summer - Autumn rice, 13,700 ha of Winter Spring rice) which are equal only to 7.3% of the total damages in 2015-2016 (total damaged rice area in 2015-2016 was 405,000 ha).

In the coming time, the harvested winter-spring rice area should not be sowed after that; the sow should only take place as drought and saltwater intrusion are reduced and water supply is guaranteed).

4. Protection of fruit tree areas

The Ministry of Agriculture and Rural Development has issued a manual "Technical guidelines on cultivating fruit trees in drought and saltwater intrusion conditions in the Mekong Delta"; according to which, localities should consolidate dike systems and dikes embanking the garden to prevent saltwater intrusion; not allowed to grow new crops or grow crops in wrong seasons during the drought and saltwater intrusion and especially when fresh water supply for trees is not ensured. So far, fruit trees have not been damaged due to drought and saltwater intrusion impacts.

5. Domestic water supply

There are currently approx. 79.700 households suffering water shortage  during the current drought and saltwater intrusion (Ben Tre: 12,700 households, Soc Trang 24,400 households, Kien Giang 11.300  households, Ca Mau 20.100 households, Bạc Liêu 3.300 households, Long An 7.900 households. There should be urnget solutions. Some of them are being implemented in these localities.

  • Ben Tre Province: has been equipped with RO water filter in 12/35 water supply stations in Ben Tre province to supply enough fresh water for people (people transport water from the water plant to their home by themselves); the Navy squad from High Command No. 2 used their naval ship to carry 250 m3 of fresh water to supply people in 03 communes of Tan Thuy, An Thuy and An Hoa Tay (Ba Tri district) to ease water shortage situation;
  • Soc Trang Province: 115 km of water supply pipeline network has been expanded for about 4,000 households and another 604 km of pipeline will be further installed and completed soon in 2020 to ensure water supply for 22,400 households suffering water shortage. Remaining households (2,000 households) will continue to be supported under other possible sources of funding throuihg the upgrading of water supply works.
  • Kien Giang Province: The province allocated funding for the expansion of water supply pipeline network to raise capacity of water supply plants and water supply for 9,000 households. Remaining households lacking water will use get water from water tank trucks in timely manner during high time of saltwater intrusion. They will be also supported soon using additional and potential sources fundings;
  • Ca Mau Province: Households facing water shortage in the provinces are also one suffer water shortage on annual basis. Currently, local people are proactively using household based water supply solutions;
  • Bac Lieu Province: The province prepared an advance payment to invest in the expansion of 36 km of water supply pipe networks and drill an addition of 04 groundwater wells to supply water to affected households.
  • Long An Province: The province has provided funding to buy 160 water storage tanks (capacity of 1m3) for poor and near-poor households in Can Giuoc district who are being affected by domestic water shortage;
  • In addition, Tien Giang province has installed 50 public taps to completely overcome water shortage of 2,200 households during the high time of saltwater intrusion days.

Enhancing communication, disseminating information on saltwater intrusion and respective prevention and control measures on mass media (VTV, VOV, People's Television, Vietnam News Agency Nam, Vietnam Agriculture Newspaper ..); updated information on water sources, drought, how saltwater intrusion is affecting agricultural production; introduction of drinking water treatment solutions for households during natural disasters; current situation and solutions of daily-life rural water supply. In addition, social networks, phone messages can be used for text messaging (Ben Tre province, Vinh Long province sent SMS, zalo for relevant individuals, mainly on the facebook network..)

3. RESPONSE MEASURES TO BE CONTINUED

In order to limit the damages caused by drought and saltwater intrusion during dry season 2019-2020, some following important solutions should continue to be implemented in the forth coming time:

Immediate solutions

  • Closely monitor the situation, update on daily basis changes of weather, water sources in the upper Mekong and in Mekong Delta; organize measurements and monitor salinity in estuaries and intakes (sluice gates) of irrigation works to promptly detect saltwater intrusion and plan appropriate water intake.
  • Organize proper operation of irrigation works to take advantage of fresh water when salinity level is allowable to store water in fields and in canal systems; urgently close sluice gates to prevent saltwater intrusion during high salinity in water, especially at sluices of Bao Dinh irrigation system (Tien Giang), Nam Mang Thit irrigation system (Tra Vinh, Vinh Long); Quan Lo - Phung Hiep irrigation system; coordinated operation of these irrigation works should be ensured to meet different freshwater and saltwater needs of localities.
  • Continue to accelerate the completion of drought and saltwater intrusion prevention and control works so that they can be temporarily handed over to operators in the dry season 2019-2020, including Ninh Quoi ship lock; Xuan Hoa pumping station, Tan Dinh, Bong Bot, Tan Dinh, Vung Liem sluices; May Phop-Nga Hau canal and Northern Ben Tre irrigation system.
  • Review fruit tree area and orchards throughout the region and especially in the affected 9 provinces; details of these trees are updated to individual district; using agriculture extension documents and propaganda on central and local mass media to provide technical techniques on drought and saltwater intrusion prevention and control for rice cultivation, and fruit planting in water shortage conditions in the Mekong delta; taking most advantage of organic materials (straw, hay, dry leaves, hyacinth ...) or agricultural mulch to cover and keep roots moist. Pruning branches, reducing canopy, pruning buds and flowers to limit evaporation.
  • For aquaculture, it is necessary to enhance environmental monitoring for timely response measures; prepare appropriate breeding plans, do not stock at the time of drought and saltwater intrusion, increasing the use of probiotics to improve water quality to limit frequent water changes; limit feeding when salinity increases; proactively harvest when farmed fish reach commercial size before saltwater intrusion occurs.
  • For rural daily-life water supply:

+ Drilling wells to supplement fresh water sources, extending pipelines from concentrated water plants in fresh water areas to affected population areas, installing public water hoses to supply to affected households; 

+ Calling international organizations and private enterprises to support plastic water storage tanks and household water treatment equipment for the affected people, especially giving priority to the poor, dispersed and riparian households, coastal areas do not have access to clean water yet.

+ Invest in public taps, 10 m3 plastic tanks, 15-30 m3 plastic bags located at centralized locations (commune People's Committees, cultural houses ...) to provide water for people in areas not available of concentrated water supply works.

+ Strengthen propaganda and mobilize people to proactively store water in ponds, tanks; economical and efficient use of daily-life water is encouraged;

+ Prepare plans to mobilize mobile trucks to transport fresh water to about 40,000 scattered households in  remote areas, coastal areas, islands in following provinces: Kien Giang, Ben Tre, Long An, Ca Mau and Tra Vinh.

+ Install saltwater and brackish water filtration systems (RO equipment) in rural centralized water supply works that are frequently affected by saline water intrusion in Ben Tre and Tra Vinh provinces.

+ Build a fresh water reservoir at the old dead-end canal and diversion canals and built temporary dams to prevent salt water and keep fresh water for concentrated rural water supply stations in Bac Lieu and Tra Vinh.

+ Review, upgrade, expand, extend the pipeline for adjacent works with surplus capacity to provide clean water to people in affected areas in Soc Trang and Long An. Ca Mau and Kien Giang.

Long term solutions

  • Invest in installing automatic salinity monitoring equipment to timely inform, proactively implement appropriate response measures for each period, especially to cope with extreme weather impacts;
  • Prioritize resources in the construction and completion of closed existing irrigation systems, dredging water conversion canals, constructing low-water head pump stations on canals, building aquaculture infrastructure etc... to proactively control tides and saltwater intrusion; improving existing water intake gates in the tide-affected areas; ensuring proactive operation of irrigation works for fresh water, salt water and water drainage needs. Proposed priority projects: Cai Lon - Cai Be Phase 2, Completing North Ben Tre Irrigation system, South Ben Tre Irrigation system, Nam Mang Thit, Bao Dinh, Nhat Tao - Tan Tru etc.
  • Encourage strong conversion of crop structure and patterns, especially in areas where water sources are not available and where droughts, water shortages, and saltwater intrusion often occur; shifting to diversified agriculture development (aquaculture - fruit trees - rice) to meet market demands; shifting from agriculture quantity to quality focused.
  • Building, upgrading and repairing concentrated water supply works (Ca Mau 30 works, Soc Trang 03 works, Kien Giang 05 works); expand and extend water supply pipeline to nearby household quarters (Long An: for 32,350 households, Ben Tre expanding additional 40 km of pipelines, Kien Giang: 7,880 households), Tien Giang expanding additional 200 km of pipe.
  • - Building fresh water reservoirs from rivers and dead-end canals (Tra Vinh, Long An, Ben Tre and Hau Giang); exploiting groundwater where groundwater quality and quantity are ensured;
  • Proposing the World Bank to support rural water supply and sanitation projects for provinces frequently affected by drought and saltwater intrusion, including the Mekong Delta region; coordinating with the Ministry of Construction in conducting a water supply project for urban areas in the Mekong river delta (with expansion to rural areas)
  • Continue to implement the Government's Resolution No. 120/NQ-CP dated November 17, 2017 on sustainable development of the Mekong Delta to adapt to climate change, accelerate the restructuring of economic sectors, restructure agricultural production; elaborating and reviewing provincial and regional plans in accordance with the Planning Law, elaborating implementation plans, clearly defining capital structure and priority investment projects, including water storage, saltwater intrusion prevention and control, keeping fresh water, urban and rural water supply.

5. RECOMMENDATIONS

In order to enhance the prevention of drought, water shortage and saltwater intrusion in the Mekong Delta region, the Ministry of Agriculture and Rural Development recommends to the Prime Minister:

  1. To continue directing the concerned ministries and branches to coordinate with the Ministry of Agriculture and Rural Development, assisting localities to continue strengthening the prevention and combat of drought and water shortage, and ensuring drought. minimize damage to agricultural production and prevent people from lacking domestic water.
  2. Considering including this subject related to the provision of funding for the implementation of measures to prevent and combat drought and saltwater intrusion into the Resolution of the Government's regular meeting of February 2020 to ensure adequate legal grounds. support from contingency budget for localities. Specifically, on this subject, the Ministry of Agriculture and Rural Development will send a report to the Government Office to summarize key substances and present to the Government (according to Notice No. 16 / TB-VPCP dated January 14, 2020 of the Office regarding the conclusion of Deputy Prime Minister Trinh Dinh Dung at the Conference "Prevention of drought and saltwater intrusion, ensuring agricultural production and livelihoods in the Mekong Delta in the dry season 2019 - 2020 ”).

Source: Ministry of Agriculture and Rural Development