Abstract
To provide accurate and reliable information on sediment
near the Fargo-Moorhead metropolitan area, the U.S. Geological
Survey in cooperation with the U.S. Army Corps of
Engineers conducted a study in the spring (March–May) of
2010 and the spring of 2011 to examine sediment concentrations,
loads, and particle-size distributions at nine selected
sites in the Red River and its tributaries. Samples of suspended
sediment, bed material, and bedload were collected at the nine
sites at various time intervals during the high-flow events.
Suspended-sediment concentrations varied spatially during
the 2011 spring high-flow event sampling period. Most
tributary streams had substantially higher suspended-sediment
concentrations compared to suspended-sediment concentrations
in the main stem of the Red River, especially at the
Sheyenne River sites. Suspended-sediment concentrations on
the Red River ranged from 45 to 126 milligrams per liter near
Christine, North Dakota and from 49 to 197 milligrams per
liter near Fargo, North Dakota. In comparison, the suspendedsediment
concentrations ranged from 239 to 1,180 milligrams
per liter at the Sheyenne River above Diversion and from
199 to 1,130 milligrams per liter at the Sheyenne River below
Diversion. The Buffalo River had the lowest concentrations
among the sites; suspended-sediment concentrations in the
Buffalo River ranged from 21 to 61 milligrams per liter. Peak
measured suspended-sediment concentrations were slightly
higher in 2011 at the Red River near Fargo, Sheyenne River
above Diversion, and Sheyenne River below Diversion
compared to measured suspended-sediment concentrations
in 2010. Peak measured suspended-sediment concentrations
were lower in 2011 at the Red River near Christine, Maple
River, and Wild Rice River compared to measured suspendedsediment
concentrations in 2010.
Total sediment loads measured during the 2011 spring
high-flow event at the Red River and its tributaries near the
Fargo-Moorhead metropolitan area were mainly composed of
suspended sediment and were greatest at the Sheyenne River
above Diversion compared to the loads at the other eight sites.
The calculated total sediment load during the entire event
ranged from 3,040 tons at the Lower Branch Rush River
(April 7–21) to 188,000 tons at the Sheyenne River above
Diversion (April 8 to May 16). The peak daily total sediment
loads calculated for the 2011 spring high-flow event ranged
from 825 tons per day in the Lower Branch Rush River to
13,209 tons per day in the Sheyenne River above Diversion
More than 90 percent of the measured suspended
sediment was composed of fine-grained material less than
0.062 millimeters in most of the suspended-sediment samples
collected during the 2011 spring high-flow event, except for
the Sheyenne River. Samples from the Sheyenne River above
Diversion had 19 to 43 percent of the suspended sediment with
particle sizes greater than 0.062 millimeters and the Sheyenne
River below Diversion had 10 to 30 percent of the suspended
sediment with particle sizes greater than 0.062 millimeters.
Most of the bedload samples had particle sizes in the
0.5 to 1 millimeter and 0.25 to 0.5 millimeter ranges from the
Maple River, Wild Rice River, Rush River, Buffalo River, and
Red River sites. The Rush and Lower Branch Rush Rivers also
had a greater portion of larger particle sizes in the 1 to 2 millimeter
range. The Sheyenne River sites had a greater portion
of smaller particle sizes in the bedload in the 0.125 to 0.5 millimeter
range compared to the other sites. The bed material
in samples collected during the 2011 spring high-flow event
demonstrated a wider distribution of particle sizes than were
observed in the bedload; the coarsest material was found at the
Red River near Christine and the Lower Branch Rush River
and the finest material at the Sheyenne River sites.