PROJECT ALERT NOTICE (SD) Flooding in South Dakota

Date: Fri, 22 Jun 2018 09:10:07 EDT

Summary: Minor to major flooding continues in the southern half of South Dakota.

A widespread 2.5-5 inches of rain early this week in western South Dakota continues to runoff through the Cheyenne and White Rivers resulting in minor to moderate floodings. In the last 48 hours, up to six inches of rain near the border between South Dakota and Iowa has produced minor to major flooding in the southeast corner of South Dakota.

Major flooding is occurring on the Vermillion and White Rivers in southeast SD. The annual exceedance probabilities (AEP) for the flood crests at the USGS streamgages on the Vermillion and White Rivers ranged from 0.10 ("10-year recurrence interval") to 0.04 ("25-year RI").

All streamgages are operational.

Field staff from Rapid City, Pierre, and Huron (8-10 crews) are completing discharge measurements using conventional and acoustic equipment. Staff will continue work this weekend to measure the peaks on the Big Sioux.

Stakeholders are being informed of our activities through updates to NWISWeb. Local media has contacted the USGS office in Rapid City for information.