PROJECT ALERT NOTICE (ND SD) Dakota WSC Flooding

Date: Wed, 03 Apr 2019 15:24:31 EDT

Summary: USGS response to flooding in SD & ND (Day 21).

Gage-heights at thirty-nine (39) U.S. Geological Survey streamgages in South Dakota (SD) and North Dakota (ND) are exceeding National Weather Service (NWS) minor to major flood stages. The distribution of the thirty-nine sites experiencing flooding in the Dakotas can be observed at the WaterWatch link below.

Eastern ND - A gradual melt will begin to accelerate today through this weekend as warmer air moves into the region. The James River in ND is still mostly ice covered but has reached minor flood stage south of I-94. Overland flooding and runoff into local drainages is actively occurring in the central to southern Red River Basin. Much of this runoff is now making it into the rivers with less water locked-up behind dams of snow and ice. USGS crews have been making measurements at gaps in the ice and are finding shifts from 0 to -4.0 ft. Stations in the southernmost reach of the Red River have crested at moderate flood stage. The Red River at Fargo, ND is forecasted to crest April 7-8 at major flood stage of about 35 ft. (peak of record is 40.84 ft. in 2009). Uncertainty in the peak forecast still exists due to ice. Links to data and imagery for the Red River Basin are provided below:

USGS 05054000 RED RIVER OF THE NORTH AT FARGO, ND https://waterwatch.usgs.gov/?id=wwsa&site_no=05054000

USGS installed a webcam at Fargo, ND with real-time imagery available at https://cida.usgs.gov/stormsummary/timelapse/BasicData/DakotaWSC/DWSC/DAK_Red_River_Fargo_timelapse_videos/frame_gallery/

USGS photos from the field are added daily to (DOI access only): https://drive.google.com/drive/folders/1bNiqh_sBAegZgSJQyocSZ2skHDlsJkVf?usp=sharing

Eastern SD - Attention is now focused on the confluence of the James and Elm Rivers near Aberdeen, SD. Ice and the confluence of flows are resulting in backwater and flow reversals at some stations. The potential exists for breakout flow from the Elm to enter Moccasin Creek which flows through Aberdeen, SD. James River flows south of Aberdeen will remain at moderate to major flood stage this week. In the Big Sioux Basin flows are receding at all stations. Stations near the headwaters are at minor flood stage with the remaining stations at moderate flood stage. Flow in the diversion channel around Sioux Falls was lowered but still remains above previous POR. Webcam imagery of the Sioux Falls area is available at https://siouxfalls.org/flood/webcams

Approximate annual exceedance probabilities (AEP) will be provided for various basins once the peaks have passed.

Since the beginning of flood conditions on March 13, 2019, USGS crews in the DWSC have made 267 measurements despite ice and overland flooding challenges. The eight RDGs deployed in eastern ND are operational. All data section staff in both states are deployed today to measure flows and repair gages. Seven real-time sites are currently having operational issues. Many bubbler lines have been damaged by ice, but non-contact auxiliary sensors are operational at most sites. Crews are actively documenting high water marks at sites. Two water-quality samples were collected this week with more planned for tomorrow.

The Dakota WSC Facebook page has also been updated with recent flood information: https://www.facebook.com/USGSDakotas/

Stakeholders are being informed of our activities through updates to NWISWeb, NWSChat, email, and phone calls.

Dakota WSC Flood Map
USGS Red River Stations