Abstract

A study by the U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers was conducted during the 2010 spring high-flow event to determine sediment concentrations, loads, and particle-size distributions at six sites in the Red River of the North and selected tributaries near Fargo, North Dakota. Suspended-sediment (point and integrated samples), bed-material, and bedload samples were collected at the six sites at various time intervals during the high-flow event.

Suspended-sediment concentrations varied spatially during the 2010 spring high-flow event sampling period. Suspended-sediment concentrations in the Red River of the North (Red River) ranged from 74 to 156 milligrams per liter at Red River near Christine and from 81 to 154 milligrams per liter at Red River near Fargo. In comparison, the suspended-sediment concentrations ranged from 476 to 1,120 milligrams per liter at the Sheyenne River above Diversion and from 505 to 957 milligrams per liter in the Sheyenne River below Diversion.

Streamflow and suspended-sediment concentration data collected during the 2010 spring high-flow event demonstrated that the timing of the peak in suspended-sediment concentration varied in relation to the peak in streamflow among the six sites. At the Red River near Christine, Red River near Fargo, Sheyenne River below Diversion, and Maple River, the suspended-sediment concentration peak occurred after the streamflow peak. It appears that the peak suspended-sediment concentration occurred simultaneously with the streamflow peak at Sheyenne River above Diversion and before the streamflow peak at the Wild Rice River.

Total sediment loads measured during the 2010 spring high-flow event mainly were composed of suspended sediment and were the greatest at the Sheyenne River above Diversion compared to the loads in the Red River near Christine, Red River near Fargo, Sheyenne River below Diversion, Maple River, and the Wild Rice River. Total measured bedload contributed less than 1 percent of the total sediment load for all of the sites. The total event sediment load ranged from 31,600 tons at the Maple River to 143,100 tons at the Sheyenne River above Diversion.

The timing of the peak in sediment discharge in relation to the peak in streamflow varied among the six sites during the 2010 spring high-flow event. Peak-sediment discharges occurred simultaneously with, or possibly prior to, the streamflow peak in the Red River near Christine, Red River near Fargo, Sheyenne River above Diversion, Maple River, and the Wild Rice River. The peak-sediment discharge occurred a day after the peak streamflow in the Sheyenne River below Diversion, and the Sheyenne River above Diversion peak-sediment discharge occurred a day before the peak-sediment discharge occurred at the Sheyenne River below Diversion, and simultaneously with the peak streamflow.

For the majority of all samples collected during the 2010 spring high-flow event, with the exception of sites on the Sheyenne River, more than 90 percent of the measured suspended sediment was composed of fine-grained particles (less than 0.062 millimeters). Particle-size analyses from bedload samples indicated material in the Red River and the Maple River was coarser than material in the Sheyenne River and the Wild Rice River. The bed material demonstrated a different areal distribution of particle sizes than observed in the bedload, with the coarsest material found at the Wild Rice River and the finest material at the Sheyenne River below Diversion.

First posted May 4, 2011