This work was performed to assist the U.S. Army Corps of Engineers, Omaha and Kansas City Districts, in quantifying sediment bed load and suspended load at several sites on the Missouri River for the purpose of defining sediment-discharge rating curves and for possible parameterization of bed-load transport equations. Seven sites were selected, and all sites were surveyed three times, separated by at least 4 weeks (or 20% flow difference) between surveys. Multi-beam, acoustic Doppler current profiler, suspended sediment, and bed material samples were collected for each site visit. As requested by the Districts, all units are in English units. In addition to quantifying all the intended data types listed above, bed-load transport values were computed for all sites and all trips using the Integrated Section Surface Difference Over Time version 2 (ISSDOTv2) method and compared with the Meyer-Peter Mueller and Einstein bed-load transport functions.The study provides a complete sediment picture (bed load, suspended bedmaterial load, and wash load) over a 630-mile reach of a large sand bed river, with seven sites representing increasingly larger flows along the river length. The data set will be very useful for additional studies. DISCLAIMER:The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents.

This Coastal and Hydraulics Engineering Technical Note (CHETN) provides an overview of the current state-of-the-practice screening criteria for reservoir sediment management actions, as well as a listing of historical reservoir flushing events and programs. This document also outlines the next steps in the Reservoir Flushing Research and Development Work Unit.

The workshop included 3 days of training on reservoir sedimentation impacts and sediment management strategies with a specific focus on regulators, planners, and managers. INTRODUCTION: Most sediment detention dams in the United States were designed to trap and store sediment over a predetermined sediment design life of 50 to 100 years. Over half of the USACE dams have now passed their 50-year life, and the need for sediment management is becoming more evident. The old strategy to trap and store sediment while starving downstream channels is not sustainable and will lead to both a dramatic increase in operations and maintenance costs and an eventual complete loss of reservoir benefits. Reservoir sediment management is a necessity to sustain the level of benefits initially provided by these reservoirs. Regulators, planners, and managers need to be prepared to make informed decisions about reservoir sediment management activities. On 15-17 August 2017, the RSM Program facilitated a training workshop at the USACE Risk Management Center in Lakewood, CO, on reservoir sediment management, with a specific focus on topics of interest to regulators, planners, and managers. Thirty-six people attended, with robust participation by 14 USACE districts and research laboratories. Other participants included the U.S. Bureau of Reclamation (USBR), Denver Water, the Kansas Water Office, Electric Power Research Institute (a hydropower industry group), Brigham Young University, and reservoir sedimentation experts Dr. George Annandale and Dr. Rollin Hotchkiss.

The US Army Corps of Engineers (USACE) maintains and operates 419 reservoirs nationwide for diverse purposes. This infrastructure is essential to the nation’s continued economic progress and provides numerous benefits. Sedimentation in reservoirs causes the loss of storage capacity, leading to interference with operations, reduction of project benefits, and eventual rendering of project operation technically infeasible or uneconomical. All reservoirs trap sediment, and sustainable long-term operation can be achieved only if sedimentation is managed. With many of the USACE reservoirs now reaching 50 years of age, sedimentation is starting to encroach on the beneficial pools. Under the paradigm of sustainable use, it is important to identify and implement strategies to sustain reservoir operation in the long term, beyond the period contemplated in the original project design life. This report outlines the major types of sediment management strategies available for reservoirs. Because the rate of new reservoir construction by USACE is very low, this report focuses on remedial strategies at existing reservoirs and presents a general methodology for the preliminary analysis of such sites. This report examines four example USACE reservoirs with known sedimentation issues to highlight the types of problems encountered and the development of strategies that can lead to sustainable use.

Regional Sediment Management Technical Note (RSM-TN) discusses the impacts of wildfires on USACE Flood Risk Management (FRM) and provides information to evaluate post-fire impacts to USACE missions. The effort was conducted in partnership with the USACE Albuquerque District and was funded through the National RSM and the Flood and Coastal Storm Damage Reduction Research, Development, and Technology Program(s) to understand the impacts of the Las Conchas wildfire on USACE FRM by highlighting the post-fire impacts to the Middle Rio Grande River and Cochiti Reservoir in north-central New Mexico and by presenting approaches to quantify impacts to the USACE mission. BACKGROUND: The 2011 Las Conchas Wildfire burned more than 600 square kilometers (km²) of forested land in the Jemez Mountains (Figure 1), in north central New Mexico. Burn severity was greatest in the mountainous headwaters of some 15 streams that drain directly to the Rio Grande and into the USACE Cochiti Lake (see Figure 1). Since the wildfire, the affected basins have shed sediment at rates far above their historic quantities (Tillery et al. 2012). Based on previous similar events (Cannon et al. 2008), recovery of these watersheds is decades away, creating an ongoing sediment management challenge at Cochiti Lake.