Highlighted River Recreational Sites

River recreationists often ask questions such as - What were the big years at this river site and how big were they?...or conversely, what were the low years? Ranked for each highlighted river site below are the five highest and lowest annual peak mean daily flows and the years in which they occurred for the April - July flow period window. Since reservoir regulation plays a major role in determining observed peak flows, the highest flows have been analyzed over two different historical periods: the post regulation period alone (after upstream regulatory reservoirs were in-place) and the entire period of record (including both pre- and post-regulatory data). As would be expected, higher (but more short-lived) peaks were generally observed in the pre-regulatory era.

Streamflow varies dramatically over the course of the snowmelt season. To characterize the magnitude of a year with a single seasonal peak sometimes can be an oversimplification. Illustrating that point are the hydrographs (or graphs of mean daily flow versus time) for several years shown below. Included are plots for a sample low year (1977), sample high year (1983), and last year (1997).

To help river runners approximate their travel times, information on average river velocities at various flow levels is presented for the highlighted river sites. When utilized with the river reach (distance) information displayed earlier, recreationists can make a ballpark calculation (time = distance/velocity). River velocity actually varies with depth and proximity to the channel boundary, but if considered collectively at all points in a cross-section, it can be expressed as an average. These data, as much of the information in this report, were obtained from the U. S. Geological Survey.

Snowmelt Peak Flow Forecasts - 1998
Colorado Basin River Forecast Center (http://www.cbrfc.gov)
Last Modified: Tuesday, 03-Mar-1998 08:12:52 MST