Research Spotlight: New method to estimate daily flow rates at streams that lack gauges



[1] Records of daily streamflow rates can help scientists estimate future runoff volumes or determine whether fish and other aquatic species have enough water to survive an upcoming season. Many streams are monitored by gauges; however, the sheer number of catchments throughout the United States makes it impractical to have instruments at every stream. As a result, scientists and water resources managers often face the problem of needing to know flow rates within ungauged streams. Archfield and Vogel have developed a method to estimate such flow rates. Using southern New England as a case study, the authors first selected a gauged stream and then, using statistical methods, compared the record of daily streamflow rates from that stream spanning the past 50 years to 27 other streams in the area. On the basis of this comparison, they made a map that marked out the region surrounding their stream where rates at the gauged stream were correlated to other streams about 98% of the time. The researchers then drew borders around the area where their stream matched other streams 95% of the time. Through a series of decreasing percentages of correlation, the authors built a spatial view of how closely their reference-gauged stream matched other streams in the region. (Water Resources Research, doi:10.1029/2009WR008481, 2010)