The first entry is always the pin's source. Overall confidence is a weighted average of how firmly each reference supports the start and end times used above; a reference counts half as much for every 180 days older than the newest.
Wikipedia[2] gives an exact date: "Water delivery officially began on 22 January 1998," after the Katse Dam was completed in 1996 and its reservoir filled by 1997.
Wikipedia states "Water delivery officially began on 22 January 1998," an exact match to the pin's stored date.
The Lesotho Highlands Development Authority's own site describes the project's dam-building purpose but, per the fetched content, does not specify the exact water-delivery start date, only that "Phase I... was completed in 2003 and inaugurated in 2004" - a weaker, more general corroboration than Wikipedia's[2] precise date.
Something missing or wrong? Say it in your own words: a link that backs this pin up, a different start or end date and why, or a fact it lacks or gets wrong. The AI checks it against this pin's sources, searches for better ones, and adds any page that backs you up. The pin's own sources still count most.