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  • Dry Conditions expected to persist for the Missouri River Basin

    The 2021 calendar year runoff summation for the Missouri River basin above Sioux City, Iowa was 15.2 million acre-feet, 59% of average. The ongoing drought shows no relief in sight and the U.S. Army Corps of Engineers is predicting runoff into the mainstem reservoir system will remain below normal. This was the 10th lowest annual runoff for the Missouri River Basin in 123 years of record-keeping.

  • Gavins Point Dam releases reduced to winter release rate

    The U.S. Army Corps of Engineers began reducing the Gavins Point releases to the winter release rate on Nov. 23, marking the end of flow support for the 2021 Missouri River navigation season. “Releases from Gavins Point Dam are being reduced to the winter release of 12,000 cubic feet per second,” said John Remus, Chief of the Missouri River Basin Water Management Division. “Releases from Gavins Point are currently 13,000 cfs and we will slowly reduce releases to 12,000 by December 8. We will closely monitor river conditions, and releases will be adjusted this winter as needed to lessen the impacts of river ice formation on stages in the lower river.”

  • Development of a Sand Boil Testing Laboratory and Preliminary Results

    Purpose: To document the purpose, use, and preliminary results of a full-scale sand boil generator developed at the Geotechnical and Structures Laboratory.

  • Engineering With Nature: The Role of Mangroves in Coastal Protection

    Purpose: The purpose of this Engineering With Nature technical note (EWN TN) is to review previous studies of mangroves as a nature-based adaptation alternative for coastal protection and flood hazard mitigation.

  • Army Corps, Yakima conduct flood response training

    COVID-19 may have put a damper on how training and meetings are conducted, but Seattle District flood team managers learn to adapt, overcome and even improve on this year’s spring flood exercises.

  • Gavins Point Dam releases to be reduced in late November

    “We will continue to make releases from Gavins Point Dam to provide flow support at an intermediate service level, 1,500 cubic feet per second (cfs) less than full service, through the end of the navigation flow support season,” said John Remus, chief of the USACE, Missouri River Water Management Division.

  • Engineering With Nature®: Supporting Mission Resilience and Infrastructure Value at Department of Defense Installations

    Abstract: This book illustrates some of the current challenges and hazards experienced by military installations, and the content highlights activities at seven military installations to achieve increased resilience through natural infrastructure.

  • Dry conditions persist in Upper Missouri River Basin; Public meetings set for Oct. 25-29

    September precipitation was once again below average in the Missouri River Basin. September runoff in the Missouri River Basin above Sioux City, Iowa (upper Basin) was 0.8 million acre-feet, 67% of the long-term average. Soil conditions in the upper Basin continue to be very dry. According to the Drought Mitigation Center, approximately 88% of the Missouri River basin is currently experiencing some form of abnormally dry conditions or drought, which is a 6% increase from the end of August.

  • Backward Erosion Testing: Magnolia Levee

    Abstract: Using a confined flume device, an experimental study investigated the critical horizontal gradient of soils obtained from a site identified as potentially vulnerable to backward erosion piping (BEP). Tests were conducted on glacial outwash material obtained from a sand and gravel quarry in the vicinity of Magnolia Levee in the community of Magnolia, OH. The two bulk samples collected from the quarry had similar grain-size distributions, grain roundness, and depositional environments as the foundation materials beneath the levee. Samples were prepared at various densities and subjected to gradual increases of flow in a wooden flume with an acrylic top until BEP was observed. The critical average horizontal gradient ranged from 0.21 to 0.30 for a bulk sample with a coefficient of uniformity of 1.6, while tests conducted on a bulk sample with a coefficient of uniformity of 2.5 yielded critical average horizontal gradients of 0.31 to 0.36. The critical average gradients measured during these tests compared favorably to values in the literature after applying adjustments according to Schmertmann’s method.

  • Backward Erosion Progression Rates from Small-Scale Flume Tests

    Abstract: Backward erosion piping (BEP) is an internal erosion mechanism by which erosion channels progress upstream, typically through cohesionless or highly erodible foundation materials of dams and levees. As one of the primary causes of embankment failures, usually during high pool events, the probability of BEP-induced failure is commonly evaluated by the U.S. Army Corps of Engineers for existing dams and levees. In current practice, BEP failure probability is quantitatively assessed assuming steady state conditions with qualitative adjustments for temporal aspects of the process. In cases with short-term hydraulic loads, the progression rate of the erosion pipe may control the failure probability such that more quantitative treatment of the temporal development of erosion is necessary to arrive at meaningful probabilities of failure. This report builds upon the current state of the practice by investigating BEP progression rates through a series of laboratory experiments. BEP progression rates were measured for nine uniform sands in a series of 55 small-scale flume tests. Results indicate that the pipe progression rates are proportional to the seepage velocity and can be predicted using equations recently proposed in the literature.