After five months of dry season, our plastic water storage pilot in Chiang Rai province is still working! Overall it is functioning well and not losing water. The double-layered bottom of the trench is strong.
One lesson learned is: the design for the top cover, although still keeping condensation from exiting the trench, is not holding up to the weather conditions. On future units we will have to find another material that keeps condensation down while staying durable, which will reduce maintenance costs and time for the average farmer.