Statistical summaries of streamflow in Montana and adjacent areas, water years 1900 through 2002

Abstract

In response to the need to have more current information about streamflow characteristics in Montana, the U.S. Geological Survey, in cooperation with the Montana Department of Environmental Quality, Confederated Salish and Kootenai Tribes, and Bureau of Land Management, conducted a study to analyze streamflow data. Updated statistical summaries of streamflow characteristics are presented for 286 streamflowgaging sites in Montana and adjacent areas having 10 or more years of record for water years 1900 through 2002. Data include the magnitude and probability of annual low and high flow, the magnitude and probability of low flow for three seasons (March-June, July-October, and November-February), flow duration of the daily mean discharge, and the monthly and annual mean discharges. For streamflow-gaging stations where 20 percent or more of the contributing drainage basin is affected by dams or other large-scale human modification, streamflow is considered regulated. Separate streamflow characteristics are presented for the unregulated and regulated periods of record for sites with sufficient data.

Model‐Based Nitrogen and Phosphorus (Nutrient) Criteria for Large Temperate Rivers: 2. Criteria Derivation

“…The 14‐day duration reflects the most likely time it takes to achieve NB in shallow parts of the river if nutrients are elevated (fewer days would be more protective, more days less protective), while the five‐year recurrence frequency is close to USEPA's long‐standing recommendation (i.e., once in three years) while being slightly protective. In addition, the design flow coincides with low‐flow statistics regularly reported by the U.S. Geological Survey (McCarthy, ). The provisional 14Q5 for the Yellowstone River is 118.7 m 3 /s at Miles City (at gage no.…”

Model‐Based Nitrogen and Phosphorus (Nutrient) Criteria for Large Temperate Rivers: 1. Model Development and Application

“…Like other rivers at temperate latitudes, the Yellowstone River has a strong summer snowmelt signal followed by a low and stable base‐flow period when nutrient excursions are most evident. Water yield is 334 m 3 /s annually (USGS 06309000 Yellowstone River at Miles City, Montana), whereas base flow is 177 m 3 /s (McCarthy, ; see Figure later), thereby reducing the assimilative volume for dilution during the summer low‐flow period. Of the major influent tributaries (e.g., Bighorn, Tongue, and Powder Rivers), only the Bighorn River contributes appreciably to streamflow during the summer months (releasing stored irrigation water from Yellowtail Dam).…”

“…http://www.ncdc.noaa.gov: Accessed May 21, 2009). (b) Streamflow hydrology (m 3 /s) which was between the 5th and 25th percentile (shaded gray), or roughly equivalent to 5‐10 year low‐flow frequency (McCarthy, ).…”

A computer program for estimating instream travel times and concentrations of a potential contaminant in the Yellowstone River, Montana

“…At Corwin Springs (station 06191500), the upstreammost station in the reach, the average channel slope (reach slope) is 13.9 ft/mi, the drainage area upstream from the gaging station is 2,619 mi 2 (U.S. Geological Survey, 2005), and the mean-annual discharge is 3,120 ft 3 /s (McCarthy, 2005). At Sidney (station 06329500), the downstream-most station in the reach, the average channel slope (reach slope), is 2.5 ft/mi, the drainage area upstream from the gaging station is 69,083 mi 2 (U.S. Geological Survey, 2005), and the mean-annual discharge is 12,300 ft 3 /s (McCarthy, 2005). Between Corwin Springs and Sidney, seven major tributaries join the Yellowstone River: Shields River, Boulder River, Stillwater River, Clarks Fork Yellowstone River, Bighorn River, Tongue River, and Powder River (table 2, fig.…”

“…2 Low-flow discharges are the 1-day, 2-year annual low-flow discharges (McCarthy, 2005). The computed mean-annual discharge might not consistently increase in the downstream direction, primarily because the period of record is not the same for all streamflow-gaging stations.…”