Summary

  • WaterWatch compared river readings with each station's own historical record, making local conditions readable across a national map.
  • Its May 2002 description required at least thirty years of continuous records for a station to appear. The online service had acquired a very long memory.

The web was young. The dots had seniority requirements.

In May 2002, USGS described WaterWatch as a map of current conditions at about 3,000 stream gauges in the United States and Puerto Rico. A station needed at least thirty years of continuous record to qualify. A perfectly serviceable new instrument would have to build its résumé elsewhere.

Those years did a specific job. Each dot compared the river's current flow with historical observations for that calendar day at that station. The colour showed where the reading fell in that local record. The river was being measured against its younger self.

Rivers with their own reference letters

A large river can carry much more water than a small stream while both are having an ordinary day. Put their raw flows side by side and size dominates the conversation. Compare each with its own seasonal history and a different question becomes easy to see: how unusual is today's flow here?

WaterWatch placed the answers on one map. The 2002 legend used green for the middle historical range, warmer colours for lower flows and blues for higher ones, with separate colours for new daily records. The accumulated observations gave those dots something useful to say.

The change addressed an existing chore. A USGS report published in 2005 recalled that individual real-time river readings had been online by the mid-1990s. Users seeking historical context had to examine stations one by one. In mid-1999, a map of streamflow indexes at long-record sites became the centrepiece of WaterWatch.

The browser brought the comparisons together. A reader could start with the national picture, choose a state and open an individual station's graph. The contemporary fact sheet described this as a geographic entrance to NWIS-Web, the agency's online water information system. A coloured dot had a route back to the measurements behind it.

A state could have two problems at once

The 2005 report reproduces a WaterWatch map for 16 September 1999, when Hurricane Floyd made landfall. In North Carolina, the eastern part of the state had record-setting high flows while drought persisted through much of the west. The state boundary enclosed two very different stories.

That is a useful reason to put local comparisons on a shared page. A single description of the state would struggle to accommodate both. The dots let readers find the geographical split and then inspect the relevant stations.

Time had its own choices. WaterWatch offered real-time conditions, the previous day's average and a seven-day average. The weekly view made persistent wet or dry conditions easier to follow. Successive daily maps could also become animations, showing change across the map rather than leaving readers to remember yesterday's arrangement of colours.

All of this was web presentation built around patient observation. The new page made old records useful in the present tense. Its apparent speed rested on people and equipment that had kept measuring long before anyone could click the result.

Internet history is generous to the launch of a website. WaterWatch gives the years before launch a speaking part. Somewhere behind the mouse was a station that had turned up for work, through ordinary days and extraordinary ones, for three decades. The new interface was lucky to have such experienced staff.

Sources