12 May 2021

Wintertime Snow and Precipitation Conditions in the Willow Creek Watershed above Ririe Dam, Idaho

ABSTRACT:  The Ririe Dam and Reservoir project is located on Willow Creek near Idaho Falls, Idaho, and is important for flood risk reduction and water supply. The current operating criteria is based on fully storing a large winter runoff event. These winter runoff events are generally from large storm events, termed atmospheric rivers, which produce substantial precipitation. In addition to the precipitation, enhanced runoff is produced due to frozen soil and snowmelt. However, the need for additional water supply by local stakeholders has prompted the U.S. Army Corps of Engineers to seek to better understand the current level of flood risk reduction provided by Ririe Dam and Reservoir.  Flood risk analysis using hydrologic modeling software requires quantification of the probability for all of the hydrometeorologic inputs. Our study develops the precipitation, SWE, and frozen ground probabilities that are required for the hydrologic modeling necessary to quantify the current winter flood risk.

12 May 2021

Lock Operation Improvements

Abstract: The U.S. Army Corps of Engineers (USACE) owns or operates 236 locks at 191 sites (HQUSACE 2016). Although the locks at these sites generally perform reliably, more than half of these structures have surpassed their 50-year economic design life and as such, there are increasing concerns about their continued safe, reliable operation. This work was undertaken to review lock operating equipment, maintenance practices, records pertaining to accidents and equipment failures, and lighting systems; to identify alternative improvements to equipment and equipment maintenance practices; and to analyze and compare those alternatives to determine and recommend optimal solutions. This report documents some lessons learned, primarily to share information that others might find useful. Note that the recommendations in this report should not be viewed as policy, although some might be considered by those creating policy.

30 Apr 2021

Sustainment Management System, Water Control Structures: Inventory and Inspection Template

Abstract: Department of Defense (DoD) military services own and maintain a portfolio of dams, dikes, and levees including over 800 assets with a total replacement value of over $2 Billion. The Inspector General has previously found that the DoD requires an inspection policy for dams, to prevent failures. The Office of the Secretary of Defense (OSD) directed the U.S. Army Engineer Research and Development Center, Construction Engineering Laboratory (ERDC-CERL), to create an inspection method and integrate that method with the Enterprise Sustainment Management System, with aims to provide OSD a consistent description of all DoD real property and facilitate calculation of the Facility Condition Index (FCI) for each asset. This report builds upon ERDC-CERL TR-18-9 to propose a method for both inventory and inspection rating for DoD dams, levees, and dikes. A new real property classification system for DoD water control structures is proposed. To better fulfil the OSD requirement for consistent condition and FCI reporting, it is proposed that DoD reevaluate the replacement values and sustainment cost factors for its water retaining structures. A draft guide for linear segmentation for levees is proposed. Future work will allow CERL to develop an Initial Operating Capability for a module within the Enterprise Sustainment Management System to support the OSD requirement.

1 Oct 2020

Laboratory Evaluation of Aquablok™ Erosion Resistance: Implications for Geotechnical Applications

Abstract: AquaBlok™ (AB) is a commercial product traditionally used as an alternative material for contaminated sediment capping applications. Previous studies of AB capping performance have reported enhanced stabilization through increased erosion resistance. Subsequently, AB has been considered for use as an alternative levee repair material due to its cohesive properties. Through a series of laboratory experiments, this study investigated the erosion behavior of new AquaBlok formulations (10%, 20%, and 30% clay by weight) under increased shear stresses previously unachievable in the previous tests. The new AquaBlok formulations were tested in non-compacted and compacted states to simulate the physical properties in capping and levee repair applications. In the non-compacted state, excess hydration of the clay matrix extended approximately 5 cm below the bed surface, which greatly reduced erosion resistance and was independent of clay percentage. Below this horizon, critical shear stress increased, and erosion rates decreased, with clay percentage, respectively. However, this does not consider a continuous change in hydration state when exposed to free water. In the compacted state, erosion rates were greatly arrested, with measureable erosion only possible under the maximum applied shear stress (24 Pa). The results are discussed in the context of capping and levee applications.