Comparisons of Current and Historic Streamflows in Colorado

The plot depicts, for each day of the year, the percentage of reporting long-term streamgages operated by the USGS that recorded flows within each of the percentile categories indicated above. For example, on October 27, 2003, 10 percent of the vertical scale is shaded red, indicating that 10 percent of the long-term (30 years or more of record) streamgages that transmitted data to the USGS's Water Watch system recorded an average flow for the day that was a new record low for October 27. The largest percentile category for October 27, 2003 (green) covers about 29 percent of the vertical scale, indicating that about 29 percent of the transmitting streamgages recorded average streamflows that fell within the 25 to 75 percent ranking of all historical values for October 27. The number of streamgages reporting for a given day has been as low as 40 in the winter and as high as 110 in the summer. (See data used for these plots)