5 Nov 2021

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.

13 Oct 2021

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.

12 Oct 2021

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.

29 Sep 2021

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.

28 Sep 2021

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.

7 Sep 2021

Sabine Pass to Galveston Bay, TX Pre-Construction, Engineering and Design (PED): Coastal Storm Surge and Wave Hazard Assessment: Report 1 – Background and Approach

Abstract: The US Army Corps of Engineers, Galveston District, is executing the Sabine Pass to Galveston Bay Coastal Storm Risk Management (CSRM) project for Brazoria, Jefferson, and Orange Counties regions. The project is currently in the Pre-construction, Engineering, and Design phase. This report documents coastal storm water level and wave hazards for the Port Arthur CSRM structures. Coastal storm water level (SWL) and wave loading and overtopping are quantified using high-fidelity hydrodynamic modeling and stochastic simulations. The CSTORM coupled water level and wave modeling system simulated 195 synthetic tropical storms on three relative sea level change scenarios for with- and without-project meshes. Annual exceedance probability (AEP) mean values were reported for the range of 0.2 to 0.001 for peak SWL and wave height (Hm0) along with associated confidence limits. Wave period and mean wave direction associated with Hm0 were also computed. A response-based stochastic simulation approach is applied to compute AEP runup and overtopping for levees and overtopping, nappe geometry, and combined hydrostatic and hydrodynamic fluid pressures for floodwalls. CSRM structure crest design elevations are defined based on overtopping rates corresponding to incipient damage. Survivability and resilience are evaluated. A system-wide hazard level assessment was conducted to establish final recommended system-wide CSRM structure elevations.

3 Sep 2021

Winter Gavins Point releases will be at minimum rates

Updated: Fort Peck release reductions was incorrectly reported as Sept 6 and has been corrected to Sept. 16. Drought conditions, particularly in the Missouri River Basin above Sioux City, Iowa (upper Basin), are persisting. Per the Master Manual and the Sept. 1 System storage check, winter releases from Gavins Point Dam will be 12,000 cubic feet per second, as part of the overall water conservation measures. “Reservoir inflows in August were much lower than average. We expect below-average inflows into the System through the rest of 2021,” said John Remus, chief of the U.S. Army Corps of Engineers’ Missouri River Basin Water Management Division.

30 Aug 2021

Army Corps to draw down reservoirs at Francis E. Walter Dam and Blue Marsh Lake in advance of Hurricane Ida

The U.S. Army Corps Engineers Philadelphia District has announced it will draw down the reservoirs at Blue Marsh Lake and Francis E. Walter Dam in preparation for significant forecasted rainfall associated with Hurricane Ida. Blue Marsh Lake is located on the Tulpehocken Creek, a tributary of the Schuylkill River, about four miles northwest of Reading, Pa. Francis E. Walter Dam is located at the confluence of the Lehigh River and Bear Creek in Luzerne and Carbon Counties, Pa.

24 Aug 2021

Expert Elicitation Workshop for Planning Wetland and Reef Natural and Nature-Based Features (NNBF) Futures

Abstract: This special report discusses the outcomes of a September 2019 workshop intended to identify barriers to the consideration and implementation of natural and nature-based features (NNBF) in US Army Corps of Engineers (USACE) civil works projects. A total of 23 participants representing seven USACE districts, the US Army Engineer Research and Development Center (ERDC), and the University of California–Santa Cruz met at USACE’s South Atlantic Division Headquarters in Atlanta, Georgia, to discuss how to facilitate the implementation of NNBF into USACE project planning for wetlands and reefs using six categories: (1) site characterization, (2) engineering and design analysis, (3) life-cycle analysis, (4) economic analysis, (5) construction analysis, (6) and operation and maintenance (and monitoring). The workshop identified seven future directions in wetland and reef NNBF research and development: • Synthesize existing literature and analysis of existing projects to better define failure modes. • Determine trigger points that lead to loss of feature function. • Identify performance factors with respect to coastal storm risk management (CSRM) performance as well as ecological performance. • Focus additional research into cobenefits of NNBF. • Quantify the economic life-cycle costs of a project. • Improve technology transfer with regards to NNBF research and topics.

13 Aug 2021

Geotechnical Inspection and Technical Review of Santa Margarita River Marine Corps Air Station Levee, U.S. Marine Corps, Camp Pendleton, CA, 19-20 November 2019

Abstract: This report describes activities performed, results obtained, and conclusions made from an independent technical review of past levee inspections and the proposed remediation plan for the Santa Margarita Levee that surrounds the U.S. Marine Corps Air Station (MCAS) Camp Pendleton. In support of the technical review, ERDC personnel performed a supplemental levee inspection on 19 and 20 November 2019 with MCAS personnel. Previous levee inspections had rated the levee system as Unacceptable due to unwanted vegetation encroaching on the levee right-of-way, which prevents full inspection during flooding. Concerns were raised by the U.S. Fish and Wildlife (USFW) about environmental impacts of the proposed remediation measures and the necessity of such actions. USFW personnel requested an engineering review from an independent party, and ERDC was tasked with performing the independent technical review. The following special report describes the tasks performed and results obtained from the independent technical review.