RWH experience in the Mekong Delta

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Dear all,

The International Fund for Agricultural Development (IFAD) is planning a new project in the Ben Tre and Tra Vinh provinces of the Mekong Delta, Vietnam. Freshwater supply here is increasingly limited by the effects of salinity intrusion in the dry season. Part of a wider range of "climate adaptation practices", a study is proposed on different models of household/community RWH including their financial viability. For this, I would like to hear about your experiences with RWH in the Mekong delta or similar environments, so that the proposed work in these two provinces has a good starting point. Your help would be most appreciated.


- G

Dear G,

Thanks for your contribution - i've sent this reply to you already separately, but would like to share this information with other members of this platform as well hoping that can add on to it.

RAIN does not have anything published on this, but i did came across some information on the internet (see right for documents).

As you might be aware of, a lot of domestic rooftop water harvesting is done in Thailand - using Thai Jars.

I do hope this helps,

Best regards,

- R

Ozdemir et al 2011.pdf


RWC Water Safety Plan Cambodia April 2007.pdf

Thai Jar.avi

Dear G,

Then Warwick PhD student Dr Kumthorncharoen did some studies a decade ago on water security in the Delta, whose rainfall as you know is generous and whose dry season (say under 40mm/day) is fairly short. He noted

- considerable movement of population with the seasons and especially the rice harvest

- use of canal water whose quality declines to bad in the dry months

- use of boats to transport water (up to 400 litres at a time) from government wells on canal levees to houses - this could interleave nicely with roofwater harvesting, in that raintanks can also be used to receive water transported by boat say weekly in the dry season. I think there is some Sri Lankan experience of mixing RWH and water distribution by bowser in the Hambantota dry zone.

However if the shallow groundwater is really going saline, that changes the whole dynamic, effectively leaving only deep boreholes (arsenic?), RWH and surface water treatment (e.g. by screening plus 5 days' storage). How far inland (of the coast or of the prawn lagoons) is this saline intrusion?

Would be interested in experimenting with manually operated community 'riverside filters' if you think them relevant.

- T

Dear G,

The document Domestic-Rainwater-Harvesting-Vietnam-Country-Study (from what is now Relief International) mentioned by R is very comprehensive. It was written in the context of a global rainbag programme leading to the 'Bob' product being piloted in East Africa.

Two points relating to RWH in Vietnam might be mentioned.

Thai Jars. SE Asia has vigorously taken up the Thai Jar for domestic RWH, although in prosperous Thailand itself it is on the decline. Jars are of unreinforced mortar, plastered onto a mould of wood/concrete/or steel-and-rope covered with mud as a release agent. In their 'homeland' in Khon Kaen province, Thailand they were not large (800 litres?) probably because they needed to be lifted onto motorcycle trailers for delivery from workshop to house. Multiple jar-sets are common in Thailand and Cambodia. If construction is on site, it seems one can go up to 2000 litres with unreinforced cement jars - as has (?) been achieved in Nepal. However (we) found great difficulty in Uganda in maintaining adequate quality of Thai jars built 'on site' and not in a workshop.

The Study warns about the danger of, and concern about, dengue being transmitted by mosquitoes breeding in rain tanks. However it is likely that mosquito larval development in tanks (continuing as far as the pupa or adult stage) can be prevented by excluding light from tanks and also by screening out any significant organic content. (No light or nutrients = no algae which are at the start of the mosquito food chain.)

- T

Effects of local and spatial conditions on the quality of harvested rainwater in the Mekong Delta, Vietnam