PROJECT ALERT NOTICE (SD) DWSC Flooding

Date: Sat, 23 Mar 2019 09:57:01 EDT

Summary: USGS response to flooding in SD (Day 10).

The extent of flooding in SD has expanded to encompass more of the state as temperatures warm and snow melts. Currently, there are 10 gages at or forecasted for major flood stage, 12 gages at moderate, and 10 gauges at minor flood stage. The most significant changes since yesterday are the confirmed POR conditions on the Keya Paha River in south-central SD. The rating for the Keya Paha station below was extended this morning based on a discharge measurement made yesterday that was twice the highest previous measured flow (36 years of record). Additionally, the forecasted crest for the James River near Scotland was lowered overnight to a level below POR (still major flood stage). Forecasts for moderate flooding in the Moreau River Basin in north-central SD are now available. Releases from Angostura Dam in southwest SD may be increased to 10,000 cfs over the weekend which will cause downstream impacts.

06464100 KEYA PAHA R NEAR KEYAPAHA,SD
https://waterwatch.usgs.gov/?id=wwsa&site_no=06464100

USGS 06478500 JAMES R NEAR SCOTLAND, SD
https://waterwatch.usgs.gov/?id=wwsa&site_no=06478500

USGS 06360500 MOREAU R NEAR WHITEHORSE, SD
https://waterwatch.usgs.gov/?id=wwsa&site_no=06360500

06401500 CHEYENNE R BELOW ANGOSTURA DAM, SD
https://waterwatch.usgs.gov/?id=wwsa&site_no=06401500

Flooding is still expected to be significant in the Sioux Falls, SD area. The forecasts for the following sites are being carefully monitored:

USGS 06481000 BIG SIOUX R NEAR DELL RAPIDS, SD
https://waterwatch.usgs.gov/?id=wwsa&site_no=06481000

USGS 06482020 BIG SIOUX R AT NORTH CLIFF AVE AT SIOUX FALLS, SD
https://waterwatch.usgs.gov/?id=wwsa&site_no=06482020

USGS crews in SD have made 30 measurements this week despite ice and overland flooding challenges. Crews are deployed today and will be measuring flows in Firesteel, Elm, and Medicine Creeks and the James, Bad, White, Keya Paha, and Cheyenne Rivers.

The DWSC has been in contact with the Office of Communications. A media advisory was released yesterday and a live radio interview is planned with SD Public Radio on March 23 (Monday). Stakeholders are being informed of our activities through updates to NWISWeb and NWSChat.