PROJECT ALERT NOTICE (NE) Nebraska Flood Update

Date: Fri, 20 Sep 2013 11:41:57 EDT

Summary: NEWSC has been responding to flooding on the South Platte River.

Western Nebraska (South Platte River Basin)

Flood waters from the South Platte River Basin entered Nebraska on Sept. 18 The USGS Nebraska Water Science Center (NEWSC) has been monitoring the movement of the peak along the South Platte River since Sunday, Sept. 15, 2013, at the Fort Morgan, CO streamgage (06759500), and measured the peak crossing the CO/NE state line (20,200 cfs) on the afternoon of Sept. 18.

Throughout the week, two NEWSC field crews have been flood-hardening streamgages at the South Platte River at Roscoe (06764880) and Platte River at Overton (06768000) in anticipation of the high flows. In addition, the Louisiana WSC provided several Hobo storm-surge stage sensors for deployment.

One USGS crew has been monitoring the rising flows at Roscoe, NE. This is the first USGS streamgage in Nebraska on the South Platte River and one that was briefly shut down due to the sequester. The Twin Platte Natural Resources District is providing funding for the gage through the end of the fiscal year. All USGS measurements except two have been made with hydroacoustics. The USGS will be providing discharge measurement assistance to the Nebraska Department of Natural Resources at several State gages along the South Platte and Platte Rivers, and well as assisting the Platte River Recovery Implementation Program in discharge measurements. The crew at Roscoe has made seven measurements on the rising limb and one on the peak of the flood.

The Roscoe streamgage has been in operation since 1982 (http://waterdata.usgs.gov/ne/nwis/uv/?site_no=06764880&PARAmeter_cd=00065,00060). The previous record peak was 11.29 ft at a discharge of 20,100 cfs in 1995. The gage set a record for stage (12.20 ft), but not for discharge. The crew measured near the peak at 17,700 cfs and a gage height of 12.12 ft.

Five South Platte and Platte River stage-discharge ratings were extended to assist the National Weather Service.

An additional crew from the NEWSC was deployed to Roscoe on Sept. 19 to obtain a high-flow water-quality and sediment sample. The NEWSC also is making a series of measurements in the South Platte River at Roscoe as part of a rating loops study for the Office of Surface Water. Crews will stand down on Saturday, Sept. 21, 2013, and begin assisting the Nebraska Department of Natural Resources at downstream sites.

NEWSC Director Robert Swanson is meeting daily with the Nebraska Emergency Management Agency (NEMA) Emergency Operations Center Planning Committee.

A News release is not planned. The field crews have met with both television and newspaper media.