Colorado

StreamStats is now implemented for all of Colorado. This application implements regression equations for estimating instantaneous peak flows with probabilities of occurring in any given year of 50, 20, 10, 4, 2, 1, 0.5, and 0.2 percent. These statistics also are referred to as the 2-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year floods. In addition, StreamStats implements regression equations for estimating annual mean flows, mean flows for each month, the flows exceeded 10, 25, 50, 75, and 90 percent of the time, 7-day minimum flows with recurrence intervals of 2, 10, and 50 years, and 7-day maximum flows with recurrence intervals of 2, 10, and 50 years. All of the equations in Colorado StreamStats are documented in the report:

Capesius, J.P., and Stephens, V.C., 2009, Regional regression equations for estimation of natural streamflow statistics in Colorado: U.S. Geological Survey Scientific Investigations Report 2009–5136, 46 p.

In addition to presentation of the equations, the report also describes the errors associated with the estimates obtained from the equations, the methods used to develop the equations, and the methods used to compute the basin characteristics included as explanatory variables in the equations. StreamStats users should familiarize themselves with the report before attempting to obtain estimates of streamflow statistics for ungaged sites. Application of the equations to ungaged sites assumes that flows at the sites occur under natural conditions. The equations in the above report supersede previous equations that were published in 1985 and 2000 by the U.S. Geological Survey.

Interactive Map

StreamStats for Colorado was developed in cooperation with the Colorado Department of Transportation and the Colorado Water Conservation Board.