A phone chain to spread flash-flood news

In the haor, flash floods from upstream arrive suddenly. Many people hear late, when there is no time to cut paddy or move cattle. Choose one contact for every ten houses in the para. When upstream news or an official announcement comes, that person tells their ten houses by phone or voice. Where there is no phone, use the mosque or temple loudspeaker or bell. Once a month, test whether everyone got the news. You need a few responsible people and a list of phone numbers.