5 Oct 2020

Below average runoff continues in the upper Missouri River basin

September precipitation was well-below normal in the Missouri River Basin.  As a result, September runoff in the upper Missouri River Basin above Sioux City, Iowa was 69% of average.  Since January 1, precipitation in the upper Basin is well-below normal.  The National Weather Service’s Climate Prediction Center (CPC) is forecasting that below-normal precipitation will continue in October.  The 2020 calendar year runoff forecast for the upper Basin, updated on October 1, is 30.2 million acre-feet (MAF), 117% of average. Average annual runoff for the upper Basin is 25.8 MAF.

3 Sep 2020

August inflows much below average in northern Missouri River Basin

August precipitation was well-below normal in the Missouri River Basin, particularly in the western and far northern portions, which received less than 25% of normal precipitation. The lack of precipitation and dry soil conditions resulted in 74% of average August runoff in the Missouri River Basin above Sioux City, Iowa (upper Basin). The 2020 calendar year forecast for the upper Basin, updated on September 1, is 30.6 million acre-feet (MAF), 119% of average. Average annual runoff for the upper Basin is 25.8 MAF. Runoff in the upper Basin during the remainder of 2020 is forecast to be below average.

20 Aug 2020

PUBLICATION NOTICE: Utilizing Stream Flows to Forecast Dredging Requirements

Abstract: In recent years, the United States Army Corps of Engineers (USACE) has spent an average of approximately a billion dollars annually for navigation channel maintenance dredging. To execute these funds effectively, USACE districts must determine which navigation channels are most in need of maintenance dredging each year. Traditionally, dredging volume estimates for Operations and Maintenance budget development are based on experiential knowledge and historic averages, with the effects of upstream, precipitation-driven streamflows considered via general-rule approximations. This study uses the Streamflow Prediction Tool, a hydrologic routing model driven by global weather forecast ensembles, and dredging records from the USACE Galveston District to explore relationships between precipitation-driven inland channel flow and subsequent dredged volumes in the downstream coastal channel reaches. Spatially based regression relationships are established between cumulative inland flows and dredged volumes. Results in the test cases of the Houston Ship Channel and the Sabine-Neches Waterway in Texas indicate useful correlations between the computed streamflow volumes and recorded dredged volumes. These relationships are stronger for channel reaches farther inland, upstream of the coastal processes that are not included in the precipitation-driven hydrologic model.

6 Aug 2020

Gavins Point releases to remain steady through August

Below-normal precipitation in Montana and Wyoming during July resulted in slightly below-average July runoff in the upper Basin. The 2020 calendar year upper basin runoff forecast, updated on August 3, is 30.9 million acre-feet (MAF), 120% of average. Average annual runoff for the upper basin is 25.8 MAF.