PVC Bags To Prevent Drought And Saltwater Intrusion

[Published on 08/12/2016)

After four months researching and developing solutions for intruded salinity prevention in Mekong Delta, VNUHCM’s research group have introduced to people in saltwater-affected areas in Ben Tre Province the very-first designed water-filled bags. This is known as an immediate solution to halve troubles for people in this regions.

Installing trial PVC bag into cannals in Thanh Phu district. Photo by: Research group

Mobile PVC bags

In March 2016, Mr. Vo Thanh Hao, Secretary of Ben Tre People’s Committee consulted VNUHCM’s research group for researching and providing solutions of drought and saltwater intrusion spreading widely in the province. There were some traditional solutions that Ben Tre province was using to cure the issue, however, they turned out to be temporary, wasteful and difficult to relocate, then, not be considered as effective measures.

At the beginning, VNUHCM’s research group divided into three main directions to approach the implementation. The first group, led by Assoc. Prof. Dr. Huynh Dai Phu (Faculty of Materials Technology, VNUHCM-University of Technology), will immediately solve fresh-water storing issues. Another group, mainly involved Faculty of Environment and Natural Resources, VNUHCM-University of Technology will focus on building the salinity treatment system RO with the capacity 15 cubic per day. Besides, more sustainable solutions will be introduced by the third group, led by MA. Ho Long Phi (Director of VNUHCM-Center for Water Management and Climate Change), which will include a master plan for climate change adaption.

In August 2016, the first group completed the mission by installing four PVC water-filled bags in local community, each bag contains 50 cubic meters locating at schools, health centers, people’s committee offices; and 5 bags containing 10 cubic meters for household use.

To make the outsized water-filled bags, the research group applies PVC material, by using heat fusion technique and adhesive tape. Their capacity can be adjust from 10 to 50 cubic meters. Besides, the bags’ shape is designed to fit locality, particular demands of this region and also users. For example, the cylinder bags are placed at areas with high availability of waterway and irrigation canals. Both dry and watery canals are appropriate to place these bags. Another type of bag, which can be placed at ponds, lakes, fish cages farm, is square-shaped, and be directly installed in saltwater intruded areas.

The later technique can also save an amount of land as it turn saltwater intruded areas into advantage to store fresh water.

The total cost to install 50-cubic-meters bags for household is 33 millions dongs, smaller ones, 5-cub-meters for household is 8.6 millions dongs. Householder can install these by themselves, using their water pumping pile system in house to save 2-3 millions dongs and 6-9 days for installing the new one. The users may self-install by following the provided guidelines, then, they can shut these bags down and store it during flooding seasons.

VNUHCM’s researchers conducted survey of drought and salinity at some regions in Ben Tre on March 2016. Photo by Duc Loc.

Cost-saving and convenient

In Binh Dai District, Ben Tre Province, research group set up the community’s PVC bags with 50 cubic meter capacity, locating at Mr. Bay Deo household, Thua Duc Commune. Mr. Bay Deo supported pumping bags with rainwater in 8 days. He was responsible for taking care of these bags, maintain the pipeline after pumping.

According to Assoc. Prof. Dr. Huynh Dai Phu, installing cost for PVC bags is considerably low, time-saving, high effective by using local resources. These bags are also easy to maintain, repair, which for instance, users can mend them in case of being torn out. When these bags are not in use, users can take it out, fold up and store or use for other purposes.

Mr. Nguyen Van Sach at Quoi Dien Commune (Thach Phu District, Ben Tre Province), who is currently using these new items, said: “This bag is inexpensive and accessible. We want to thank VNUHCM for their prompt support with these valuable bags. They help farmers to store enough freshwater for the upcoming drought.

Dr. Phu added that the endurance of these bags can last from 7 to 10 years and are damage-resistant to insects, crabs and shrimp. Next steps, research group will work on handing over this technique to local people and spread this system to other regions.

The other two groups of VNUHCM are cooperating with local people to produce both mid-term and long-term solutions supporting Mekong Delta people in drought and salinity fighting and also adapting the climate change.



  • Research