Understanding Sandbar Dynamics in the Lower Platte River

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Among the various habitat types within a river corridor, sandbars are highly dynamic and quite sensitive to changes such as channel width, streamflow, and riparian woodland expansion. As people, infrastructure, and other factors encroach upon the Lower Platte River, we are exploring variation in the height and area of sandbars to better accommodate all of these uses without jeopardizing these critical habitats.

Among the various habitat types within a river corridor, sandbars are highly dynamic and quite sensitive to changes such as channel width, streamflow, and riparian woodland expansion. As people, infrastructure, and other factors encroach upon the Lower Platte River, we are exploring variation in the height and area of sandbars to better accommodate all of these uses without jeopardizing these critical habitats. The lower Platte River is important because it provides nesting habitat for the interior least tern and piping plover. Because the lower Platte River provides habitat for these two Federal and State protected birds, as well as being within the most populous counties in Nebraska, economic, infrastructure, and resource development needs to be balanced with conservation of important physical and aquatic habitat.

Photos showing examples of sandbar height in the lower Platte River, NE
Top photo: May 7, 2011. Discharge was 283 cubic meters per second. Bottom photo: May 27, 2011. Discharge was approximately 1,262 cubic meters per second.

In 2011, the USGS Nebraska Water Science Center began monitoring locations and geometries of sandbars along a 55-mile segment of the lower Platte River. Our goal is to answer these science questions:

  • To what height are sandbars deposited relative to the river stage that formed them?
  • Do sandbars tend to form in the same places or are they randomnly distrbuted?
  • How long do sandbars remain present/barren after formation?

This study has been completed in phases, beginning with the pilot study in 2011. These sandbar surveys have been completed:

  • April, July, and November 2011: Salt Creek to Plattsmouth
  • April and September 2012: Fremont to Plattsmouth (Drought year)
  • July/August 2013: Columbus to Plattsmouth
  • July/September 2014: Columbus to Plattsmouth

Sandbar geometry was measured on the "dry crown" of each sandbar. The highest area on the sandbar was identified while in the field and 5-9 evenly spaced measurements were taken with GPS (Global Positioning System). Additionally, 9 time-lapse cameras were installed along the river to provide visual information about how sandbars erode and emerge from the river during the various seasons and at various streamflows.

Results from the final phase of this study are being synthesized and will be released as a journal article.

Location map for the Lower Platte River, NE sand bar study